AMD AMD-K6-2E/400AMZ

Preliminary Information
®
AMD-K6 -2E
TM
Embedded Processor
Data Sheet
Publication # 22529
Issue Date: Jan 2000
Rev: B
Amendment/0
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
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iv
Preliminary Information
22529B/0—January 2000
AMD-K6™-2E Processor Data Sheet
Contents
Revision History.......................................................................... xv
About this Data Sheet...............................................................xvii
Overview ................................................................................. xvii
1
AMD-K6™-2E Processor .............................................................. 1
1.1
1.2
1.3
2
Internal Architecture .................................................................. 7
2.1
2.2
2.3
2.4
2.5
2.6
3
AMD-K6™-2E Processor Microarchitecture Overview ........... 7
Cache, Instruction Prefetch, and Predecode Bits.................. 12
Instruction Fetch and Decode ................................................. 13
Centralized Scheduler .............................................................. 17
Execution Units......................................................................... 18
Branch-Prediction Logic........................................................... 20
Software Environment ............................................................... 23
3.1
3.2
3.3
3.4
3.5
3.6
3.7
4
5
AMD-K6™-2E Embedded Processor Features ......................... 2
Process Technology..................................................................... 4
Super7™ Platform Initiative ..................................................... 4
Registers .................................................................................... 23
Model-Specific Registers (MSR) ............................................. 40
Memory Management Registers.............................................. 47
Paging......................................................................................... 49
Descriptors and Gates .............................................................. 52
Exceptions and Interrupts ....................................................... 55
Instructions Supported by the AMD-K6™-2E Processor ...... 56
Logic Symbol Diagram ............................................................... 83
Signal Descriptions .................................................................... 85
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
5.9
5.10
5.11
5.12
5.13
5.14
5.15
5.16
5.17
5.18
5.19
5.20
Contents
Signal Terminology................................................................... 85
A20M# (Address Bit 20 Mask) ................................................. 86
A[31:3] (Address Bus)............................................................... 87
ADS# (Address Strobe) ............................................................ 88
ADSC# (Address Strobe Copy) ................................................ 88
AHOLD (Address Hold) ........................................................... 89
AP (Address Parity).................................................................. 90
APCHK# (Address Parity Check)............................................ 91
BE[7:0]# (Byte Enables) ........................................................... 92
BF[2:0] (Bus Frequency) .......................................................... 93
BOFF# (Backoff) ....................................................................... 94
BRDY# (Burst Ready)............................................................... 95
BRDYC# (Burst Ready Copy) .................................................. 96
BREQ (Bus Request)................................................................. 96
CACHE# (Cacheable Access) .................................................. 97
CLK (Clock) ............................................................................... 97
D/C# (Data/Code) ...................................................................... 98
D[63:0] (Data Bus)..................................................................... 99
DP[7:0] (Data Parity).............................................................. 100
EADS# (External Address Strobe)........................................ 101
v
Preliminary Information
AMD-K6™-2E Processor Data Sheet
5.21
5.22
5.23
5.24
5.25
5.26
5.27
5.28
5.29
5.30
5.31
5.32
5.33
5.34
5.35
5.36
5.37
5.38
5.39
5.40
5.41
5.42
5.43
5.44
5.45
5.46
5.47
5.48
5.49
5.50
5.51
5.52
5.53
5.54
5.55
5.56
6
Timing Diagrams.....................................................................
Bus States.................................................................................
Memory Reads and Writes.....................................................
I/O Read and Write .................................................................
Inquire and Bus Arbitration Cycles ......................................
Special Bus Cycles ..................................................................
133
135
138
146
148
170
Power-On Configuration and Initialization ........................... 179
7.1
7.2
7.3
vi
EWBE# (External Write Buffer Empty) ............................... 102
FERR# (Floating-Point Error) ............................................... 103
FLUSH# (Cache Flush) .......................................................... 104
HIT# (Inquire Cycle Hit)........................................................ 105
HITM# (Inquire Cycle Hit To Modified Line)...................... 105
HLDA (Hold Acknowledge) ................................................... 106
HOLD (Bus Hold Request)..................................................... 107
IGNNE# (Ignore Numeric Exception)................................... 108
INIT (Initialization) ................................................................ 109
INTR (Maskable Interrupt).................................................... 110
INV (Invalidation Request) ................................................... 110
KEN# (Cache Enable)............................................................. 111
LOCK# (Bus Lock) .................................................................. 112
M/IO# (Memory or I/O) ........................................................... 113
NA# (Next Address)................................................................ 114
NMI (Non-Maskable Interrupt) ............................................. 114
PCD (Page Cache Disable)..................................................... 115
PCHK# (Parity Check) ........................................................... 116
PWT (Page Writethrough) ..................................................... 117
RESET (Reset) ........................................................................ 118
RSVD (Reserved).................................................................... 119
SCYC (Split Cycle).................................................................. 120
SMI# (System Management Interrupt)................................. 121
SMIACT# (System Management Interrupt Active)............. 122
STPCLK# (Stop Clock) ........................................................... 123
TCK (Test Clock)..................................................................... 124
TDI (Test Data Input) ............................................................. 124
TDO (Test Data Output)......................................................... 124
TMS (Test Mode Select) ......................................................... 125
TRST# (Test Reset)................................................................. 125
VCC2DET (VCC2 Detect) ...................................................... 126
VCC2H/L# (VCC2 High/Low)................................................. 127
W/R# (Write/Read) ................................................................. 128
WB/WT# (Writeback or Writethrough)................................. 129
Pin Tables by Type ................................................................. 130
Bus Cycle Definitions ............................................................. 132
Bus Cycles ................................................................................. 133
6.1
6.2
6.3
6.4
6.5
6.6
7
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Signals Sampled During the Falling Transition of RESET .. 179
RESET Requirements ............................................................ 180
State of Processor After RESET............................................ 180
Contents
Preliminary Information
22529B/0—January 2000
7.4
8
Floating-Point Execution Unit............................................... 213
Multimedia and 3DNow!™ Execution Units ........................ 215
Floating-Point and MMX™/3DNow!™
Instruction Compatibility....................................................... 216
SMM Operating Mode and Default Register Values...........
SMM State-Save Area.............................................................
SMM Revision Identifier........................................................
SMM Base Address .................................................................
Halt Restart Slot .....................................................................
I/O Trap Doubleword ..............................................................
I/O Trap Restart Slot ..............................................................
Exceptions, Interrupts, and Debug in SMM.........................
217
219
221
222
222
223
224
226
Built-In Self-Test (BIST) .........................................................
Three-State Test Mode ...........................................................
Boundary-Scan Test Access Port (TAP)................................
L1 Cache Inhibit......................................................................
Debug .......................................................................................
227
228
229
239
240
Clock Control ............................................................................ 247
13.1
13.2
13.3
13.4
13.5
14
205
207
209
211
Test and Debug ......................................................................... 227
12.1
12.2
12.3
12.4
12.5
13
EWBE# Control .......................................................................
Memory Type Range Registers .............................................
Memory-Range Restrictions ..................................................
Examples..................................................................................
System Management Mode (SMM) ........................................ 217
11.1
11.2
11.3
11.4
11.5
11.6
11.7
11.8
12
186
187
187
190
191
192
192
197
198
199
204
204
Floating-Point and Multimedia Execution Units .................. 213
10.1
10.2
10.3
11
MESI States in the Data Cache .............................................
Predecode Bits.........................................................................
Cache Operation .....................................................................
Cache Disabling and Flushing ...............................................
Cache-Line Fills ......................................................................
Cache-Line Replacements......................................................
Write Allocate .........................................................................
Prefetching ..............................................................................
Cache States ............................................................................
Cache Coherency ....................................................................
Writethrough and Writeback Coherency States..................
A20M# Masking of Cache Accesses ......................................
Write Merge Buffer ................................................................. 205
9.1
9.2
9.3
9.4
10
State of Processor After INIT ................................................ 183
Cache Organization .................................................................. 185
8.1
8.2
8.3
8.4
8.5
8.6
8.7
8.8
8.9
8.10
8.11
8.12
9
AMD-K6™-2E Processor Data Sheet
Clock Control States ...............................................................
Halt State.................................................................................
Stop Grant State......................................................................
Stop Grant Inquire State........................................................
Stop Clock State......................................................................
247
249
250
251
252
Electrical Data .......................................................................... 253
14.1
Contents
Operating Ranges ................................................................... 254
vii
Preliminary Information
AMD-K6™-2E Processor Data Sheet
14.2
14.3
14.4
14.5
14.6
14.7
15
Absolute Ratings.....................................................................
DC Characteristics ..................................................................
Power Dissipation ...................................................................
Power Derating Based on Lower CPU Frequencies ............
Power and Grounding.............................................................
I/O Buffer Characteristics ......................................................
22529B/0—January 2000
255
256
258
260
262
264
Signal Switching Characteristics ............................................ 267
15.1
15.2
CLK Switching Characteristics.............................................. 267
Clock Switching Characteristics
for 100-MHz Bus Operation.................................................... 268
15.3 Clock Switching Characteristics
for 66-MHz Bus Operation...................................................... 268
15.4 Valid Delay, Float, Setup, and Hold Timings ...................... 269
15.5 Output Delay Timings for 100-MHz Bus Operation............. 270
15.6 Input Setup and Hold Timings
for 100-MHz Bus Operation.................................................... 272
15.7 Output Delay Timings for 66-MHz Bus Operation............... 274
15.8 Input Setup and Hold Timings
for 66-MHz Bus Operation...................................................... 276
15.9 RESET and Test Signal Timing ............................................. 278
15.10 Timing Diagrams..................................................................... 281
16
Thermal Design ........................................................................ 285
16.1
16.2
16.3
16.4
17
viii
Pin Designations by Functional Grouping ........................... 301
Package Specifications ............................................................ 303
18.1
19
285
288
289
295
Pin Designation Diagrams ....................................................... 299
17.1
18
Package Thermal Specifications ...........................................
Measuring Case Temperature ...............................................
Sample Heatsink Measured Data..........................................
Layout and Airflow Considerations ......................................
321-Pin Staggered CPGA Package Specification................. 303
Ordering Information .............................................................. 305
Index........................................................................................... 307
Contents
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
List of Figures
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.
Figure 9.
Figure 10.
Figure 11.
Figure 12.
Figure 13.
Figure 14.
Figure 15.
Figure 16.
Figure 17.
Figure 18.
Figure 19.
Figure 20.
Figure 21.
Figure 22.
Figure 23.
Figure 24.
Figure 25.
Figure 26.
Figure 27.
Figure 28.
Figure 29.
Figure 30.
Figure 31.
Figure 32.
Figure 33.
Figure 34.
Figure 35.
Figure 36.
Figure 37.
Figure 38.
Figure 39.
Figure 40.
Figure 41.
Figure 42.
Figure 43.
List of Figures
AMD-K6™-2E Processor Block Diagram.........................9
Cache Sector Organization .............................................12
The Instruction Buffer ....................................................14
AMD-K6™-2E Processor Decode Logic .........................15
AMD-K6™-2E Processor Scheduler...............................18
Register X and Y Functional Units ...............................20
EAX Register with 16-Bit and 8-Bit
Name Components ..........................................................24
Integer Data Registers....................................................25
Segment Register ............................................................26
Segment Usage ................................................................27
Floating-Point Register...................................................28
FPU Status Word Register .............................................28
FPU Control Word Register ...........................................29
FPU Tag Word Register..................................................29
Packed Decimal Data Register ......................................30
Precision Real Data Registers .......................................30
MMX™/3DNow!™ Registers ..........................................31
MMX™ Data Types .........................................................32
3DNow!™ Data Types .....................................................33
EFLAGS Register ............................................................34
Control Register 4 (CR4) ................................................35
Control Register 3 (CR3) ................................................35
Control Register 2 (CR2) ................................................35
Control Register 1 (CR1) ................................................36
Control Register 0 (CR0) ................................................36
Debug Register DR7 .......................................................37
Debug Register DR6 .......................................................38
Debug Registers DR5 and DR4......................................38
Debug Registers DR3, DR2, DR1, and DR0..................39
Machine-Check Address Register (MCAR) ..................41
Machine-Check Type Register (MCTR) ........................41
Test Register 12 (TR12)..................................................42
Time Stamp Counter (TSC) ............................................42
Extended Feature Enable Register (EFER).................43
SYSCALL/SYSRET Target Address
Register (STAR) ..............................................................44
Write Handling Control Register (WHCR)...................44
UC/WC Cacheability Control Register (UWCCR) .......45
Processor State Observability Register (PSOR) ..........45
Page Flush/Invalidate Register (PFIR).........................46
Memory Management Registers ....................................47
Task State Segment (TSS) ..............................................48
4-Kbyte Paging Mechanism ............................................49
4-Mbyte Paging Mechanism ...........................................50
ix
Preliminary Information
AMD-K6™-2E Processor Data Sheet
Figure 44.
Figure 45.
Figure 46.
Figure 47.
Figure 48.
Figure 49.
Figure 50.
Figure 51.
Figure 52.
Figure 53.
Figure 54.
Figure 55.
Figure 56.
Figure 57.
Figure 58.
Figure 59.
Figure 60.
Figure 61.
Figure 62.
Figure 63.
Figure 64.
Figure 65.
Figure 66.
Figure 67.
Figure 68.
Figure 69.
Figure 70.
Figure 71.
Figure 72.
Figure 73.
Figure 74.
Figure 75.
Figure 76.
Figure 77.
Figure 78.
Figure 79.
Figure 80.
Figure 81.
Figure 82.
Figure 83.
Figure 84.
x
22529B/0—January 2000
Page Directory Entry 4-Kbyte Page Table (PDE) ........51
Page Directory Entry 4-Mbyte Page Table (PDE) .......51
Page Table Entry (PTE)..................................................52
Application Segment Descriptor ...................................53
System Segment Descriptor ...........................................54
Gate Descriptor ...............................................................55
Waveform Definitions...................................................134
Bus State Machine Diagram .........................................135
Non-Pipelined Single-Transfer Memory
Read/Write and Write Delayed by EWBE# ................139
Misaligned Single-Transfer Memory
Read and Write..............................................................141
Burst Reads and Pipelined Burst Reads .....................143
Burst Writeback due to Cache-Line Replacement.....145
Basic I/O Read and Write .............................................146
Misaligned I/O Transfer................................................147
Basic HOLD/HLDA Operation .....................................149
HOLD-Initiated Inquire Hit to Shared
or Exclusive Line...........................................................151
HOLD-Initiated Inquire Hit to Modified Line............153
AHOLD-Initiated Inquire Miss ....................................155
AHOLD-Initiated Inquire Hit to Shared
or Exclusive Line...........................................................157
AHOLD-Initiated Inquire Hit to Modified Line.........159
AHOLD Restriction.......................................................161
BOFF# Timing................................................................163
Basic Locked Operation................................................165
Locked Operation with BOFF# Intervention..............167
Interrupt Acknowledge Operation ..............................169
Basic Special Bus Cycle (Halt Cycle) ..........................171
Shutdown Cycle .............................................................172
Stop Grant and Stop Clock Modes, Part 1 ..................174
Stop Grant and Stop Clock Modes, Part 2 ..................175
INIT-Initiated Transition from Protected Mode
to Real Mode..................................................................177
Cache Organization .......................................................185
Cache Sector Organization ...........................................186
Write Handling Control Register (WHCR).................194
Write Allocate Logic Mechanisms and Conditions ....195
Page Flush/Invalidate Register (PFIR).......................200
UC/WC Cacheability Control Register (UWCCR) .....208
External Logic for Supporting Floating-Point
Exceptions......................................................................215
SMM Memory.................................................................218
TAP State Diagram .......................................................237
Debug Register DR7 .....................................................241
Debug Register DR6 .....................................................242
List of Figures
Preliminary Information
22529B/0—January 2000
Figure 85.
Figure 86.
Figure 87.
Figure 88.
Figure 89.
Figure 90.
Figure 91.
Figure 92.
Figure 93.
Figure 94.
Figure 95.
Figure 96.
Figure 97.
Figure 98.
Figure 99.
Figure 100.
Figure 101.
Figure 102.
Figure 103.
Figure 104.
Figure 105.
Figure 106.
Figure 107.
Figure 108.
Figure 109.
Figure 110.
Figure 111.
Figure 112.
Figure 113.
Figure 114.
Figure 115.
List of Figures
AMD-K6™-2E Processor Data Sheet
Debug Registers DR5 and DR4....................................242
Debug Registers DR3, DR2, DR1, and DR0................243
Clock Control State Transitions...................................248
Suggested Component Placement ...............................263
CLK Waveform ..............................................................269
Key to Timing Diagrams ...............................................281
Output Valid Delay Timing ..........................................281
Maximum Float Delay Timing .....................................282
Input Setup and Hold Timing ......................................282
Reset and Configuration Timing .................................283
TCK Timing....................................................................284
TRST# Timing................................................................284
Test Signal Timing ........................................................284
Thermal Model ..............................................................286
Power Consumption v. Thermal Resistance ...............287
Processor Heat Dissipation Path .................................288
Measuring Case Temperature......................................289
Heatsink A (15 mm height) ..........................................290
Heatsink B (20 mm height)...........................................290
Heatsink C (30 mm height) ..........................................290
Measured Thermal Resistance v. Airflow
(Socketed 321-Pin CPGA Package) .............................291
Measured Maximum Ambient Temperature
(Socketed 321-Pin CPGA Package) .............................292
Measured Thermal Resistance v. Airflow
(Soldered 321-Pin CPGA Package)..............................293
Measured Maximum Ambient Temperature
(Soldered, 321-Pin CPGA Package).............................294
Voltage Regulator Placement ......................................295
Airflow for a Heatsink with Fan ..................................296
Airflow Path in a Dual-Fan System .............................296
Airflow Path in an ATX Form-Factor System ............297
AMD-K6™-2E Processor Connection Diagram
(Top-Side View CPGA) .................................................299
AMD-K6™-2E Processor Connection Diagram
(Bottom-Side View CPGA)............................................300
321-Pin Staggered CPGA Package Specification .......303
xi
Preliminary Information
AMD-K6™-2E Processor Data Sheet
xii
22529B/0—January 2000
List of Figures
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
List of Tables
Table 1.
Table 2.
Table 3.
Table 4.
Table 5.
Table 6.
Table 7.
Table 8.
Table 9.
Table 10.
Table 11.
Table 12.
Table 13.
Table 14.
Table 15.
Table 16.
Table 17.
Table 18.
Table 19.
Table 20.
Table 21.
Table 22.
Table 23.
Table 24.
Table 25.
Table 26.
Table 27.
Table 28.
Table 29.
Table 30.
Table 31.
Table 32.
Table 33.
Table 34.
Table 35.
Table 36.
Table 37.
Table 38.
Table 39.
Table 40.
Table 41.
List of Tables
Execution Latency and Throughput of Execution Units .19
General-Purpose Registers .................................................24
General-Purpose Register Doubleword, Word,
and Byte Names....................................................................25
Segment Registers ...............................................................26
AMD-K6™-2E Processor Model 8/[F:8]
Model-Specific Registers.....................................................40
Extended Feature Enable Register (EFER)Definition ...43
SYSCALL/SYSRET Target Address Register
(STAR) Definition ................................................................44
Memory Management Registers.........................................47
Application Segment Types ................................................53
System Segment and Gate Types .......................................54
Summary of Exceptions and Interrupts.............................55
Integer Instructions .............................................................57
Floating-Point Instructions .................................................74
MMX™ Instructions.............................................................78
3DNow!™ Instructions.........................................................81
Processor-to-Bus Clock Ratios ............................................93
Output Pin Float Conditions .............................................127
Input Pin Types ..................................................................130
Output Pin Float Conditions .............................................131
Input/Output Pin Float Conditions ..................................131
Test Pins..............................................................................131
Bus Cycle Definition ..........................................................132
Special Cycles.....................................................................132
Bus-Cycle Order During Misaligned Memory Transfers . 140
A[4:3] Address-Generation Sequence During Bursts .....142
Bus-Cycle Order During Misaligned I/O Transfers .........147
Interrupt Acknowledge Operation Definition ................168
Encodings for Special Bus Cycles.....................................170
Output Signal State After RESET....................................180
Register State After RESET .............................................181
PWT Signal Generation .....................................................188
PCD Signal Generation .....................................................189
CACHE# Signal Generation..............................................189
Data Cache States for Read and Write Accesses............198
Cache States for Inquire Cycles, Snoops, Flushes,
and Invalidation .................................................................202
Snoop Action ......................................................................203
EWBEC Settings.................................................................207
WC/UC Memory Type ........................................................209
Valid Masks and Range Sizes ...........................................210
Initial State of Registers in System Management Mode . 219
SMM State-Save Area Map ...............................................219
xiii
Preliminary Information
AMD-K6™-2E Processor Data Sheet
Table 42.
Table 43.
Table 44.
Table 45.
Table 46.
Table 47.
Table 48.
Table 49.
Table 50.
Table 51.
Table 52.
Table 53.
Table 54.
Table 55.
Table 56.
Table 57.
Table 58.
Table 59.
Table 60.
Table 61.
Table 62.
Table 63.
Table 64.
Table 65.
Table 66.
Table 67.
Table 68.
Table 69.
Table 70.
Table 71.
Table 72.
Table 73.
xiv
22529B/0—January 2000
SMM Revision Identifier ...................................................222
I/O Trap Doubleword Configuration ................................224
I/O Trap Restart Slot .........................................................225
Boundary Scan Bit Definitions .........................................233
Device Identification Register .........................................234
Supported Test Access Port (TAP) Instructions .............235
DR7 LEN and RW Definitions ..........................................245
Operating Ranges ..............................................................254
Absolute Ratings................................................................255
DC Characteristics .............................................................256
Typical and Maximum Power Dissipation
for OPN Suffix AMZ (Low-Power Devices) .....................258
Typical and Maximum Power Dissipation
for OPN Suffix AFR (Standard-Power Devices) .............259
Power Derating Specification for Standard-Power
Devices (AMD-K6-2E/233AFR and 266AFR) ..................260
Power Derating Specification for Low-Power
Devices (AMD-K6-2E/233AMZ and 266AMZ) .................261
CLK Switching Characteristics
for 100-MHz Bus Operation ...............................................268
CLK Switching Characteristics
for 66-MHz Bus Operation .................................................268
Output Delay Timings for 100-MHz Bus Operation ........270
Input Setup and Hold Timings
for 100-MHz Bus Operation ...............................................272
Output Delay Timings for 66-MHz Bus Operation ..........274
Input Setup and Hold Timings for 66-MHz Bus Operation 276
RESET and Configuration Signals
for 100-MHz Bus Operation..............................................278
RESET and Configuration Signals
for 66-MHz Bus Operation .................................................279
TCK Waveform and TRST# Timing at 25 MHz ...............280
Test Signal Timing at 25 MHz...........................................280
Package Thermal Specification
for OPN Suffix AMZ (Low-Power Devices) .....................285
Package Thermal Specification
for OPN Suffix AFR (Standard-Power Devices) .............285
Passive Heatsink Samples.................................................289
Socketed CPGA Package: Measured Thermal
Resistance (°C/W) qJC and qCA .........................................291
Socketed CPGA Package: Measured Maximum
Ambient Temperature (°C) ...............................................292
Soldered CPGA Package: Measured Thermal
Resistance (°C/W) qJC and qCA .........................................293
Soldered CPGA Package: Measured Maximum
Ambient Temperature (°C) ...............................................294
Valid Ordering Part Number Combinations ...................306
List of Tables
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AMD-K6™-2E Processor Data Sheet
Revision History
Date
Rev Description
June 1999
A
Initial published release.
Jan 2000
B
Replaced Figure 4, “AMD-K6™-2E Processor Decode Logic,” on page 15 with updated figure.
Jan 2000
B
Replaced Table 45 on page 233 with revised boundary scan bit definitions.
B
Changed the Vcc2 maximum specification from 2.6 V to 2.4 V in Table 50, “Absolute Ratings,” on
page 255 for all OPNs with the exception of the 233AFR, 233AMZ, 266AFR, 266AMZ, and 300 AFR,
provided that the processor is not marked with a “7” following the date code.
B
For the 300AMZ, 333AMZ, and 350AMZ ordering part numbers, added DC characteristics to
Table 51 on page 256, added power dissipation specifications to Table 52 on page 258, added
package thermal specifications to Table 66 on page 285, and added ordering information
beginning on page 305.
Jan 2000
B
For the 333AFR, 350AFR, and 400AFR ordering part numbers, added DC characteristics to Table 51
on page 256, added power dissipation specifications to Table 53 on page 259, added package
thermal specifications to Table 67 on page 285, and added ordering information beginning on
page 305.
Jan 2000
B
Added power derating specifications beginning on page 260.
Jan 2000
B
Added sample measured heat sink data beginning on page 289.
Jan 2000
Jan 2000
Revision History
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AMD-K6™-2E Processor Data Sheet
About this Data Sheet
The AMD-K6™-2E Processor Data Sheet is the complete specification of the
AMD-K6-2E embedded processor.
Overview
This data sheet is organized into the following sections:
Chapter 1, “AMD-K6™-2E Processor” on page 1, provides a list of the AMD-K6-2E
processor’s distinguishing characteristics, a description of the key features, and a
discussion about the Super7™ platform initiative.
Chapter 2, “Internal Architecture” on page 7, describes the functional elements of the
advanced design techniques, known as the RISC86® microarchitecture, implemented
by the AMD-K6-2E processor.
Chapter 3, “Software Environment” on page 23, provides a general overview of the
AMD-K6-2E processor’s x86 software environment and briefly describes the data
types, registers, operating modes, interrupts, and instructions supported by the
AMD-K6-2E processor’s architecture and design implementation.
Chapter 4, “Logic Symbol Diagram” on page 83, contains the AMD-K6-2E processor
logic symbol diagram.
Chapter 5, “Signal Descriptions” on page 85, lists the signals and their descriptions
alphabetically and by function.
Chapter 6, “Bus Cycles” on page 133, describes and illustrates the timing and
relationship of bus signals during various types of bus cycles.
Chapter 7, “Power-On Configuration and Initialization” on page 179, describes how
the system logic resets the AMD-K6-2E processor using the RESET signal.
Chapter 8, “Cache Organization” on page 185, describes the basic architecture and
resources of the AMD-K6-2E processor’s internal caches.
Chapter 9, “Write Merge Buffer” on page 205, describes the 8-byte write merge buffer
and how merging multiple write cycles into a single write cycle ultimately increases
overall system performance.
Chapter 10, “Floating-Point and Multimedia Execution Units” on page 213, describes
the AMD-K6-2E processor’s IEEE 754-compatible and 854-compatible floating point
About this Data Sheet
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execution unit, the multimedia and 3DNow!™ technology execution units, and the
floating-point and MMX/3DNow! technology instruction compatibility.
Chapter 11, “System Management Mode (SMM)” on page 217, describes SMM, the
state-save area, entry into and exit from SMM, exceptions and interrupts in SMM,
memory allocation and addressing in SMM, and the SMI# and SMIACT# signals.
Chapter 12, “Test and Debug” on page 227, describes the various test and debug modes
that enable the functional and manufacturing testing of systems and boards that use
the AMD-K6-2E processor and that allow designers to debug the instruction execution
of software components.
Chapter 13, “Clock Control” on page 247, describes the five modes of clock control
supported by the AMD-K6-2E processor.
Chapter 14, “Electrical Data” on page 253, includes operating ranges, absolute
ratings, DC characteristics, power dissipation data, power and grounding information,
decoupling recommendations, and I/O buffer characteristics.
Chapter 15, “Signal Switching Characteristics” on page 267, provides tables listing
valid delay, float, setup, and hold timing specifications for the AMD-K6-2E processor
signals.
Chapter 16, “Thermal Design” on page 285, lists the package thermal specifications,
discusses how to measure case temperature, and provides sample heat sink
measurement data, along with layout and airflow considerations.
Chapter 17, “Pin Designation Diagrams” on page 299, lists the AMD-K6-2E processor’s
pin designations by functional grouping.
Chapter 18, “Package Specifications” on page 303, provides a table and diagram
containing the 321-pin CPGA package specifications.
Chapter 19, “Ordering Information” on page 305, provides the ordering part number
(OPN) and valid OPN combinations.
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1
AMD-K6™-2E Processor
The following are key features of the AMD-K6™-2E processor:
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■
■
■
■
■
■
■
■
■
■
■
Advanced 6-Issue RISC86® Superscalar Microarchitecture
• Ten parallel specialized execution units
• Multiple sophisticated x86-to-RISC86 instruction decoders
• Advanced two-level branch prediction
• Speculative execution
• Out-of-order execution
• Register renaming and data forwarding
• Up to six RISC86 instructions per clock
Large on-chip split 64-Kbyte level-one (L1) cache
• 32-Kbyte instruction cache with additional 20 Kbytes of predecode cache
• 32-Kbyte writeback dual-ported data cache
• Two-way set associative
• MESI protocol support
3DNow!™ technology
• Additional instructions to improve 3D graphics and multimedia performance
• Separate multiplier and ALU for superscalar instruction execution
321-pin ceramic pin grid array (CPGA) package
Socket 7 platform compatible, 66-MHz frontside bus
Super7™ platform compatible, 100-MHz frontside bus supported on the 300-MHz,
350-MHz, and 400-MHz versions of the AMD-K6-2E processor
High-performance industry-standard MMX™ instructions
• Dual integer ALU for superscalar execution
High-performance IEEE 754-compatible and 854-compatible floating-point unit
Industry-standard system management mode (SMM)
IEEE 1149.1 boundary scan
x86 binary software compatibility
Low-power 0.25-micron process technology
• Split-plane power with support for full 3.3 V I/O
• Available with a low-power 1.9-V core voltage and extended temperature rating
or with a standard-power 2.2-V core voltage and standard temperature rating
Chapter 1
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1.1
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AMD-K6™-2E Embedded Processor Features
The AMD-K6-2E processor with 3DNow!™ technology is a functionally compatible
embedded version of the sixth generation, Microsoft® Windows® compatible
AMD-K6-2 processor. The AMD-K6-2E embedded processor delivers the same high
performance and incorporates the same leading-edge features, including the
innovative and efficient RISC86® microarchitecture, a large 64-Kbyte level-one cache
(32-Kbyte dual-ported data cache, 32-Kbyte instruction cache with predecode data),
and a powerful IEEE 754-compatible and 854-compatible floating-point execution
unit.
The AMD-K6-2E embedded processor also supports the new features incorporated
into the AMD-K6-2 processor. These features include superscalar MMX™ instruction
execution support, support for the Super7™ 100-MHz frontside bus, and AMD’s
innovative 3DNow!™ technology for high-performance multimedia and 3D graphics
operation based on high-performance single instruction multiple data (SIMD)
execution resources.
The AMD-K6-2E embedded processor includes several key features that are very
beneficial to the embedded market. The AMD-K6-2E processor offers leading-edge
performance for embedded systems requiring compatibility with the extensive
installed base of x86 software. The AMD-K6-2E processor’s Socket 7 and Super7
platform-compatible, 321-pin ceramic pin grid array (CPGA) package allows the
product designer to reduce time-to-market by leveraging today’s cost-effective
industry-standard infrastructure to deliver a superior-performing embedded solution.
The AMD-K6-2E embedded processor is available in two versions.
■
■
The low-power version has a 1.9-V core voltage and extended temperature rating.
The standard-power version has a 2.2-V core voltage and is the embedded
equivalent of the industry-standard desktop version of the AMD-K6-2 processor.
System Management Mode and Power Management Features
The AMD-K6-2E processor includes the complete industry-standard system
management mode (SMM), which is critical to system resource and power
management. (See “System Management Mode (SMM)” on page 217 for more
detailed information about this feature.)
The AMD-K6-2E processor also features the industry-standard Stop-Clock (STPCLK#)
control circuitry and the Halt instruction, both required for implementing the ACPI
power management specification. (“Clock Control” on page 247 provides more
information on these power management features.)
2
AMD-K6™-2E Processor
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Microarchitecture
Th e A M D -K 6 -2 E p ro c e s s o r ’s R I S C 8 6 m i c ro a rch i t e c t u re i s a d e c o u p l e d
decode/execution superscalar design that implements state-of-the-art design
techniques to achieve leading-edge performance.
Advanced design techniques implemented in the AMD-K6-2E processor include
multiple x86 instruction decode, single-clock internal RISC operations, ten execution
units that support superscalar operation, out-of-order execution, data forwarding,
speculative execution, and register renaming.
In addition, the processor supports advanced branch prediction logic by
implementing an 8192-entry branch history table, a branch target cache, and a return
address stack, which combine to deliver better than a 95% prediction rate. These
design techniques enable the AMD-K6-2E to issue, execute, and retire multiple x86
instructions per clock, resulting in excellent scalable performance. The
microarchitecture of the AMD-K6-2E processor is more completely described in
“Internal Architecture” on page 7.
3DNow!™ Technology
AMD’s 3DNow! technology is an instruction-set extension to x86, which includes 21
new instructions to accelerate 3D graphics and other single-precision floating-point
compute intensive operations.
Improvements include fast frame rates on high-resolution graphics applications,
superior modeling of real-world environments and physics, life-like images, graphics,
and audio.
AMD has already shipped millions of processors with 3DNow! technology for desktop
and notebook PCs, revolutionizing the 3D experience with up to four times the peak
floating-point performance of previous sixth generation solutions. AMD is now
bringing this advanced capability to embedded systems.
AMD has taken a leadership role in developing these new instructions that enable
exciting new levels of performance and realism. 3DNow! technology was defined and
implemented in collaboration with Microsoft, application developers, and graphics
vendors, and has received an enthusiastic reception. It is compatible with today’s
existing x86 software, is supported by industry-standard APIs, and requires no
operating system support, thereby enabling a broad class of applications to benefit
from 3DNow! technology.
Industry-Standard x86 Architecture
The AMD-K6-2E processor is x86 binary code compatible. AMD’s extensive
experience through six generations of x86 processors has been carefully integrated
into the processor to enable compatibility with Windows®-based operating systems,
including Windows 95, Windows 98, Windows CE, Windows NT®, and Windows NTE.
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The AMD-K6-2E processor is also compatible with DOS, OS/2, UNIX, and other
leading operating systems, including real-time operating systems (RTOS) commonly
used in embedded applications such as pSOS, QNX, RTXC, and VxWorks.
The AMD-K6-2E processor is compatible with more than 60,000 software
applications, including the latest software optimized for 3DNow! and MMX
technologies. AMD has shipped more than 120 million x86 microprocessors, including
more than 60 million Windows-compatible processors.
The AMD-K6-2E processor is among a long line of Microsoft Windows compatible
processors from AMD. The combination of state-of-the-art features, leading-edge
performance, high-performance multimedia engine, x86 compatibility, and low-cost
infrastructure enable decreased development costs and improved time-to-market,
making the AMD-K6-2E processor the superior choice for embedded systems.
1.2
Process Technology
The AMD-K6-2E processor is implemented using an advanced CMOS 0.25-micron
process technology that utilizes a split core and I/O voltage supply, which allows the
core of the processor to operate at a low voltage while the I/O portion operates at the
industry-standard 3.3 V.
This technology enables high performance while reducing power consumption by
operating the core at a low voltage and limiting power requirements to the acceptable
levels for today’s embedded systems.
1.3
Super7™ Platform Initiative
All AMD-K6-2E processors remain pin compatible with existing Socket 7 solutions;
however, for maximum system performance, the 300-MHz, 350-MHz, and 400-MHz
versions of the processor work optimally in Super7 designs that incorporate advanced
features such as support for the 100-MHz frontside bus and AGP graphics.
AMD and its industry partners are investing in the future of Socket 7 with the new
Super7 platform initiative. The goal of the initiative is to maintain the competitive
vitality of the Socket 7 infrastructure through a series of enhancements, including
the development of an industry-standard 100-MHz processor bus protocol. In addition
to the 100-MHz processor bus protocol, the Super7 initiative includes the
introduction of chipsets that support the AGP specification and support for a
backside L2 cache and frontside L3 cache.
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Super7™ Platform Enhancements
■
100-MHz processor bus—The AMD-K6-2E processor supports a 100-MHz, 800
Mbyte/second frontside bus to provide a high-speed interface to Super7
platform-based chipsets. The 100-MHz interface to the frontside Level 2 (L2)
cache and main system memory speeds up access to the frontside cache and main
memory by 50 percent over the 66-MHz Socket 7 interface, resulting in a
significant increase of 10% in overall system performance.
■
■
Accelerated graphics port support —AGP improves the performance of video
graphics systems that have small amounts of video memory on the graphics card.
The industry-standard AGP specification enables a 133-MHz graphics interface
and will scale to even higher levels of performance.
Support for backside L2 and frontside L3 cache—The Super7 platform has the
‘headroom’ to support higher-performance AMD-K6 processors with clock speeds
scaling to 500 MHz and beyond. The Super7 platform also supports the
AMD-K6-III processor, which features a full-speed, internal backside 256-Kbyte L2
cache designed to deliver new levels of system performance to desktop and
notebook PC systems. The AMD-K6-III processor also supports an optional
100-MHz frontside L3 cache for even higher-performance system configurations.
Super7™ Platform Advantages
The Super7 platform has the following advantages:
■
■
■
■
■
■
Delivers performance and features competitive with alternate platforms at the
same clock speed, and at a significantly lower cost
Takes advantage of existing system designs for superior value
Enables OEMs and resellers to take advantage of mature, high-volume
infrastructure supported by multiple BIOS, chipset, graphics, and motherboard
suppliers
Reduces inventory and design costs with one motherboard for a wide range of
products
Builds on a huge installed base of more than 100 million motherboards
Provides an easy upgrade path for future embedded applications, as well as a
bridge to legacy applications
By taking advantage of the low-cost, mature Socket 7 infrastructure, the Super7
platform will continue to provide superior value and leading-edge performance for
embedded systems.
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2
Internal Architecture
The AMD-K6-2E processor implements advanced design
techniques known as the RISC86 microarchitecture. The
RISC86 microarchitecture is a decoupled decode/execution
design approach that yields superior sixth-generation
performance for x86-based software. This chapter describes the
techniques used and the functional elements of the RISC86
microarchitecture.
2.1
AMD-K6™-2E Processor Microarchitecture Overview
When discussing processor design, it is important to understand
t h e t e r m s a r ch i t e c t u re , m i c r o a r ch i t e c t u re , a nd d e s i g n
implementation.
■
■
■
Chapter 2
Architecture refers to the instruction set and features of a
processor that are visible to software programs running on
the processor. The architecture determines which software
the processor can run. The architecture of the AMD-K6-2E
processor is the industry-standard x86 instruction set.
Microarchitecture refers to the design techniques used in the
processor to reach the target cost, performance, and
functionality goals. The AMD-K6-2E processor is based on a
sophisticated RISC core known as the Enhanced RISC86
microarchitecture. The Enhanced RISC86 microarchitecture
is an advanced, second-order decoupled decode/execution
design approach that enables industry-leading performance
for x86-based software.
Design implementation refers to the actual logic and circuit
designs from which the processor is created according to the
microarchitecture specifications.
Internal Architecture
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Enhanced RISC86®
Microarchitecture
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Th e E n h anced RISC86 mi croarchi tecture d efi ne s t h e
characteristics of the AMD-K6-2E processor. The innovative
RISC86 microarchitecture approach implements the x86
instruction set by internally translating x86 instructions into
RISC86 operations. These RISC86 operations were specially
designed to include direct support for the x86 instruction set
while observing the RISC performance principles of fixed
length encoding, regularized instruction fields, and a large
register set.
Th e Enh a n c e d R I S C8 6 m ic ro arch i t e c t u re u s e d i n t h e
A M D -K 6 -2 E p ro ce s s o r e nabl e s h ig he r p ro ce s s o r c o re
performance and promotes straightforward extensibility in
future designs. Instead of directly executing complex x86
instruct ions, which have lengths of 1 to 15 bytes, the
AMD-K6-2E processor executes the simpler and easier
fixed-length RISC86 opcodes, while maintaining the instruction
coding efficiencies found in x86 programs.
The AMD-K6-2E processor contains parallel decoders, a
centralized RISC86 operation scheduler, and ten execution
units that support superscalar operation—multiple decode,
execution, and retirement—of x86 instructions. These elements
are packed into an aggressive and highly efficient six-stage
pipeline.
AMD-K6™-2E
Processor Block
Diagram
As shown in Figure 1 on page 9, the high-performance,
out-of-order execution engine of the AMD-K6-2E processor is
mated to a split level-one 64-Kbyte writeback cache with 32
Kbytes of instruction cache and 32 Kbytes of data cache. The
instruction cache feeds the decoders and, in turn, the decoders
feed the scheduler. The Instruction Control Unit (ICU) issues
and retires RISC86 operations contained in the scheduler. The
system bus interface is an industry-standard 64-bit Super7 and
Socket 7 demultiplexed bus.
The AMD-K6-2E processor combines the latest in processor
microarchitecture to provide the highest x86 performance for
today’s computational systems. The AMD-K6-2E offers true
sixth-generation performance and x86 binary software
compatibility.
8
Internal Architecture
Chapter 2
Preliminary Information
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32-KByte Level-One Instruction Cache
Predecode
Logic
64-Entry ITLB
20-KByte Predecode Cache
16-Byte Fetch
Level-One Cache
Controller
Branch Logic
(8192-Entry BHT)
(16-Entry BTC)
(16-Entry RAS)
Multiple Instruction Decoders
x86 to RISC86
100 MHz
Super7
Bus
Interface
Œ
Four RISC86
Decode
Out-of-Order
Execution Engine
Scheduler
Buffer
Six RISC86
Operation Issue
Load
Unit
Store
Unit
Instruction
Control Unit
(24 RISC86)
®
Register X Functional Units
Integer/
Multimedia/3DNow!
É
Register Y Functional Units
Integer/
Multimedia /3DNow!
FPU
Branch
Unit
Store
Queue
32-KByte Level-One Dual-Port Data Cache
128-Entry DTLB
Figure 1. AMD-K6™-2E Processor Block Diagram
Decoders
Decoding of the x86 instructions begins when the on-chip
instruction cache is filled. Predecode logic determines the
length of an x86 instruction on a byte-by-byte basis. This
p re d e c o d e i n fo r m a t i o n i s s t o re d , a l o n g w i t h t h e x 8 6
instructions, in the instruction cache, to be used later by the
decoders. The decoders translate on-the-fly, with no additional
latency, up to two x86 instructions per clock into RISC86
operations.
Note: In this chapter, “clock” refers to a processor clock.
The AMD-K6-2E processor categorizes x86 instructions into
three types of decodes—short, long, and vector. The decoders
process either two short, one long, or one vector decode at a
time.
Chapter 2
Internal Architecture
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The three types of decodes have the following characteristics:
■
■
■
Short decodes—x86 instructions that are less than or equal
to seven bytes long
Long decodes—x86 instructions less than or equal to 11
bytes long
Vector decodes—complex x86 instructions
Short and long decodes are processed completely within the
decoders. Vector decodes are started by the decoders and then
completed by fetched sequences from an on-chip ROM. After
decoding, the RISC86 operations are delivered to the scheduler
for dispatching to the execution units.
Scheduler/Instruction
Control Unit
The centralized scheduler or buffer is managed by the ICU. The
ICU buffers and manages up to 24 RISC86 operations at a time.
This equals from 6 to 12 x86 instructions. This buffer size (24) is
perfectly matched to the processor’s six-stage RISC86 pipeline,
four RISC86-operations decode rate, and ten parallel execution
units.
The scheduler accepts as many as four RISC86 operations at a
time from the decoders and retires up to four RISC86
o p e ra t i o n s p e r c l o ck cy c l e . T h e I C U i s c a p a b l e o f
simultaneously issuing up to six RISC86 operations at a time to
the execution units. This consists of the following types of
operations:
■
■
■
■
■
■
Registers
When managing the RISC86 operations, the ICU uses 69
p hy s i c a l re g i s t e rs c o n t a i n e d w i t h i n t h e R I S C 8 6
microarchitecture.
■
10
Memory load operation
Memory store operation
Complex integer, MMX, or 3DNOW! register operation
Simple integer register operation
Floating-point register operation
Branch condition evaluation
Forty-eight of the physical registers are located in a general
register file.
• Twenty-four of these are rename registers.
• The other twenty-four are committed or architectural
registers, consisting of 16 scratch registers and 8 registers
Internal Architecture
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■
Branch Logic
that correspond to the x86 general-purpose registers—
EAX, EBX, ECX, EDX, EBP, ESP, ESI, and EDI.
An analogous set of 21 registers is available specifically for
MMX and 3DNow! operations.
• Twelve of these are MMX/3DNow! rename registers.
• Nine are MMX/3DNow! committed or architectural
registers, consisting of one scratch register and eight
registers that correspond to the MMX registers (mm0–
mm7). For more detailed information, see the 3DNow!™
Technology Manual, order #21928.
T h e A M D -K 6 -2 E p r o c e s s o r i s d e s i g n e d w i t h h i g h ly
sophisticated dynamic branch logic consisting of the following:
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■
Branch history/Prediction table
Branch target cache
Return address stack
The AMD-K6-2E processor implements a two-level branch
prediction scheme based on an 8192-entry branch history table.
The branch history table stores prediction information that is
used for predicting conditional branches. Because the branch
history table does not store predicted target addresses, special
address ALUs calculate target addresses on-the-fly during
instruction decode.
Th e b ra n ch t a rg e t c a ch e a u g m e n t s p re d i c t e d b ra n ch
performance by avoiding a one clock cache-fetch penalty. This
specialized target cache does this by supplying the first 16 bytes
of target instructions to the decoders when branches are
predicted. The return address stack is a unique device
specifically designed for optimizing CALL and RETURN pairs.
In summary, the AMD-K6-2E processor uses dynamic branch
logic to minimize delays due to the branch instructions that are
common in x86 software.
3DNow!™ Technology
Chapter 2
AMD has taken a lead role in improving the multimedia and 3D
capabilities of the x86 processor family with the introduction of
3DNow! technology, which uses a packed, single-precision,
floating-point data format and Single Instruction Multiple Data
(SIMD) operations also found in the MMX technology model.
Internal Architecture
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AMD-K6™-2E Processor Data Sheet
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Cache, Instruction Prefetch, and Predecode Bits
The writeback level-one cache on the AMD-K6-2E processor is
organized as a separate 32-Kbyte instruction cache and a
32-Kbyte data cache with two-way set associativity. The cache
line size is 32 bytes and lines are prefetched from main memory
using an efficient pipelined burst transaction.
As the instruction cache is filled, each instruction byte is
analyzed for instruction boundaries using predecoding logic.
Predecoding annotates each instruction byte with information
(5 bits per byte) that later enables the decoders to efficiently
decode multiple instructions simultaneously.
Cache
Tag Address
The processor cache design takes advantage of a sectored
organization (see Figure 2). Each sector consists of 64 bytes
configured as two 32-byte cache lines. The two cache lines of a
sector share a common tag but have separate pairs of MESI
(Modified, Exclusive, Shared, Invalid) bits that track the state
of each cache line.
Cache Line 0 Byte 31 Predecode Bits Byte 30 Predecode Bits ........ ........ Byte 0 Predecode Bits MESI Bits
Cache Line 1 Byte 31 Predecode Bits Byte 30 Predecode Bits ........ ........ Byte 0 Predecode Bits MESI Bits
Figure 2. Cache Sector Organization
Two forms of cache misses and associated cache fills can take
place—a tag-miss cache fill and a tag-hit cache fill.
■
■
Prefetching
12
Tag-miss cache fill—The miss is due to a tag mismatch, in
which case the required cache line is filled from external
memory, and the cache line within the sector that was not
required is marked as invalid.
Tag-hit cache fill—The address matches the tag, but the
requested cache line is marked as invalid. The required
cache line is filled from external memory, and the cache line
within the sector that is not required remains in the same
cache state.
The AMD-K6-2E processor conditionally performs cache
prefetching which results in the filling of the required cache
line first, and a prefetch of the second cache line making up the
other half of the sector. From the perspective of the external
bus, the two cache-line fills typically appear as two 32-byte
Internal Architecture
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
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burst read cycles occurring back-to-back or, if allowed, as
pipelined cycles.
The 3DNow! technology includes a new instruction named
PREFETCH that allows a cache line to be prefetched into the
data cache. The PREFETCH instruction format is defined in
Table 15, “3DNow!™ Instructions,” on page 81. For more
detailed information, see the 3DNow!™ Technology Manual,
order #21928.
Predecode Bits
2.3
Decoding x86 instructions is particularly difficult because the
instructions are variable in length (1 to 15 bytes). Predecode
logic supplies the five predecode bits associated with each
instruction byte. The predecode bits indicate the number of
bytes to the start of the next x86 instruction. The predecode
bits are stored in an extended instruction cache alongside each
x86 instruction byte, as shown in Figure 2 on page 12. The
predecode bits are passed with the instruction bytes to the
decoders where they assist with parallel x86 instruction
decoding.
Instruction Fetch and Decode
Instruction Fetch
The processor can fetch up to 16 bytes per clock out of the
instruction cache or branch target cache. The fetched
information is placed into a 16-byte instruction buffer that
feeds directly into the decoders (see Figure 3 on page 14).
Fetching can occur along a single execution stream with up to
seven outstanding branches taken.
The instruction fetch logic is capable of retrieving any 16
contiguous bytes of information within a 32-byte boundary.
There is no additional penalty when the 16 bytes of instructions
lie across a cache line boundary. The instruction bytes are
loaded into the instruction buffer as they are consumed by the
decoders.
Although instructions can be consumed with byte granularity,
the instruction buffer is managed on a memory-aligned word
(two bytes) organization. Therefore, instructions are loaded and
replaced with word granularity. When a control transfer
occurs — such as a JMP instruction — the entire instruction
buffer is flushed and reloaded with a new set of 16 instruction
bytes.
Chapter 2
Internal Architecture
13
Preliminary Information
AMD-K6™-2E Processor Data Sheet
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16 Bytes
32-Kbyte Level-One
Instruction Cache
Branch-Target Cache
16 x 16 Bytes
16 Bytes
2:1
Branch Target
Address Adders
Return Address Stack
16 x 16 Bytes
Fetch Unit
16 Instruction Bytes
plus
16 Sets of Predecode Bits
Instruction Buffer
Figure 3. The Instruction Buffer
Instruction Decode
The AMD-K6-2E processor decode logic is designed to decode
multiple x86 instructions per clock (see Figure 4 on page 15).
The decode logic accepts x86 instruction bytes and their
predecode bits from the instruction buffer, locates the actual
instruction boundaries, and generates RISC86 operations from
these x86 instructions.
RISC86 operations are fixed-format internal instructions. Most
RISC86 operations execute in a single clock. RISC86 operations
are combined to perform every function of the x86 instruction
set. Some x86 instructions are decoded into as few as zero
RISC86 opcodes, for instance a NOP, or one RISC86 operation,
a register-to-register add. More complex x86 instructions are
decoded into several RISC86 operations.
14
Internal Architecture
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AMD-K6™-2E Processor Data Sheet
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Instruction Buffer
Short Decoder #1
Short Decoder #2
Long Decoder
On-Chip ROM
Vector Decoder
RISC86® Sequencer
Vector Address
4 RISC86 Operations
Figure 4. AMD-K6™-2E Processor Decode Logic
The AMD-K6-2E processor uses a combination of decoders to
convert x86 instructions into RISC86 operations. The hardware
consists of three sets of decoders—two parallel short decoders,
one long decoder, and one vector decoder.
Parallel Short Decoders. The two parallel short decoders translate
the most commonly-used x86 instructions ( moves, shifts,
branches, ALU, FPU) and the extensions to the x86 instruction
set (MMX and 3DNow! technology) into zero, one, or two
RISC86 operations each. The short decoders only operate on
x86 instructions that are up to seven bytes long. In addition, the
decoders are designed to decode up to two x86 instructions per
clock.
Chapter 2
Internal Architecture
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Preliminary Information
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Long Decoder. The commonly-used x86 instructions that are
greater than seven bytes but not more than 11 bytes long, and
the x86 instructions that are slightly less common and are up to
seven bytes long are handled by the long decoder. The long
decoder only performs one decode per clock and generates up
to four RISC86 operations.
Vector Decoder. All other translations (complex instructions,
serializing conditions, interrupts and exceptions, etc.) are
handled by a combination of the vector decoder and RISC86
operation sequences fetched from an on-chip ROM. For
complex operations, the vector decoder logic provides the first
set of RISC86 operations and a vector (initial ROM address) to a
sequence of further RISC86 operations. The same types of
RISC86 operations are fetched from the ROM as those that are
generated by the hardware decoders.
Note: Although all three sets of decoders are simultaneously fed a
copy of the instruction buffer contents, only one of the three
types of decoders is used during any one decode clock.
Grouped Operations. The decoders or the RISC86 sequencer
always generate a group of four RISC86 operations. For decodes
that cannot fill the entire group with four RISC86 operations,
RISC86 NOP operations are placed in the empty locations of
the grouping. For example, a long-decoded x86 instruction that
converts to only three RISC86 operations is padded with a
single RISC86 NOP operation and then passed to the scheduler.
Up to six groups, or 24 RISC86 operations, can be placed in the
scheduler at a time.
Floating Point Instructions. All of the common, and a few of the
uncommon, floating-point instructions (also known as ESC
instructions) are hardware decoded as short decodes. This
decode generates a RISC86 floating-point operation and,
optionally, an associated floating-point load or store operation.
Floating-point or ESC instruction decode is only allowed in the
first short decoder, but non-ESC instructions, excluding MMX
instructions, can be decoded simultaneously by the second
short decoder along with an ESC instruction decode in the first
short decoder.
MMX and 3DNow!™ Instructions. A l l o f t h e M M X a n d 3 D N ow !
instructions, with the exception of the EMMS, FEMMS, and
PREFETCH instructions, are hardware decoded as short
16
Internal Architecture
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
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decodes. The MMX instruction decode generates a RISC86
MMX operation and, optionally, an associated MMX load or
store operation. A 3DNow! instruction decode generates a
RISC86 3DNow! operation and, optionally, an associated load or
store operation. MMX and 3DNow! instructions can be decoded
in either or both of the short decoders.
2.4
Centralized Scheduler
The scheduler is the heart of the AMD-K6-2E processor (see
Figure 5 on page 18). The scheduler contains the logic necessary
to manage out-of-order execution, data forwarding, register
renaming, simultaneous issue and retirement of multiple
RISC86 operations, and speculative execution.
The scheduler’s buffer can hold up to 24 RISC86 operations.
This equates to a maximum of 12 x86 instructions. When
possible, the scheduler can simultaneously issue a RISC86
operation to any available execution unit (store, load, branch,
integer, integer/multimedia, or floating-point). In total, the
scheduler can issue up to six and retire up to four RISC86
operations per clock.
The main advantage of the scheduler and its operation buffer is
the ability to examine an x86 instruction window equal to 12
x86 instructions at one time. This advantage is due to the fact
that the scheduler operates on the RISC86 operations in
parallel and allows the AMD-K6-2E processor to perform
dynamic on-the-fly instruction code scheduling for optimized
execution. Although the scheduler can issue RISC86 operations
for out-of-order execution, it always retires x86 instructions in
order.
Chapter 2
Internal Architecture
17
Preliminary Information
AMD-K6™-2E Processor Data Sheet
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From Decode Logic
RISC86 #0
RISC86 #1
RISC86 #2
Centralized RISC86®
Operation Scheduler
RISC86 #3
RISC86 Issue Buses
RISC86 Operation Buffer
Figure 5. AMD-K6™-2E Processor Scheduler
2.5
Execution Units
The AMD-K6-2E processor contains ten parallel execution
units—store, load, integer X ALU, integer Y ALU, MMX ALU
(X), MMX ALU (Y), MMX/3DNow! multiplier, 3DNow! ALU,
floating-point, and branch condition. Each unit is independent
and capable of handling the RISC86 operations. Table 1 on
page 19 details the execution units, functions performed within
these units, operation latency, and operation throughput.
The store and load execution units are two-stage pipelined
designs.
■
■
18
The store unit performs data writes and register calculation
for LEA/PUSH. Data memory and register writes from stores
are available after one clock. Store operations are held in a
store queue prior to execution. From there, they execute in
order.
The load unit performs data memory reads. Data is available
from the load unit after two clocks.
Internal Architecture
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
The I nte ger X executio n unit can operat e on a ll AL U
operations, multiplies, divides (signed and unsigned), shifts,
and rotates.
The Integer Y execution unit can operate on the basic word and
doubleword ALU operations — ADD, AND, CMP, OR, SUB,
XOR, zero-extend, and sign-extend operands.
Table 1. Execution Latency and Throughput of Execution Units
Functional Unit
Latency
Throughput
LEA/PUSH, Address (Pipelined)
1
1
Memory Store (Pipelined)
1
1
Memory Loads (Pipelined)
2
1
Integer ALU
1
1
2–3
2–3
Integer Shift
1
1
Multimedia
(processes
MMX instructions)
MMX ALU
1
1
MMX Shifts, Packs, Unpack
1
1
MMX Multiply
2
1
Integer Y
Basic ALU (16-bit and 32-bit operands)
1
1
Branch
Resolves Branch Conditions
1
1
FPU
FADD, FSUB, FMUL
2
2
3DNow! ALU
2
1
3DNow! Multiply
2
1
3DNow! Convert
2
1
Store
Load
Integer X
3DNow!
Function
Integer Multiply
The functional units that execut e MMX and 3DNow!
instructions share pipeline control with the Integer X and
Integer Y units.
Register X and Y
Pipelines
Chapter 2
The register X and Y functional units are attached to the issue
bus for the register X execution pipeline or the issue bus for the
register Y execution pipeline or both. Each register pipeline
has dedicated resources that consist of an integer execution
unit and an MMX ALU execution unit, therefore allowing
superscalar operation on integer and MMX instructions. In
addition, both the X and Y issue buses are connected to the
3DNow! ALU, the MMX/3DNow! multiplier, and MMX shifter,
which allows the appropriate RISC86 operation to be issued
through either bus. Figure 6 on page 20 shows the details of the
X and Y register pipelines.
Internal Architecture
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
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Scheduler
Buffer
(24 RISC86® Operations)
Issue Bus
for the
Register X
Execution
Pipeline
Integer X
ALU
MMXÉ
ALU
Issue Bus
for the
Register Y
Execution
Pipeline
MMX
Shifter
MMX/
3DNow!É
Multiplier
3DNow!
ALU
MMX
ALU
Integer Y
ALU
Figure 6. Register X and Y Functional Units
The branch condition unit is separate from the branch
prediction logic in that it resolves conditional branches such as
JCC and LOOP after the branch condition has been evaluated.
2.6
Branch-Prediction Logic
Sophisticated branch logic that can minimize or hide the impact
of changes in program flow is designed into the AMD-K6-2E
processor. Branches in x86 code fit into two categories:
20
■
Unconditional branches always change program flow (that is,
the branches are always taken)
■
Conditional branches may or may not divert program flow
(that is, the branches are taken or not-taken). When a
conditional branch is not taken, the processor simply
continues decoding and executing the next instructions in
memory.
Internal Architecture
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Typical applications have up to 10% of unconditional branches
and another 10% to 20% conditional branches. The AMD-K6-2E
processor branch logic has been designed to handle this type of
program behavior and its negative effects on instruction
execution, such as stalls due to delayed instruction fetching and
the draining of the processor pipeline. The branch logic
contains an 8192-entry branch history table, a 16-entry by
16-byte branch target cache, a 16-entry return address stack,
and a branch execution unit.
Branch History Table
The AMD-K6-2E processor handles unconditional branches
without any penalty by redirecting instruction fetching to the
target address of the unconditional branch. However,
c o n d i t i o n a l b ra n che s re q u i re t h e u se o f t h e dy n a m i c
branch-prediction mechanism built into the AMD-K6-2E
processor.
A two-level adaptive history algorithm is implemented in an
8192-entry branch history table. This table stores executed
branch information, predicts individual branches, and predicts
the behavior of groups of branches.
To accommodate the large branch history table, the AMD-K6-2E
processor does not store predicted target addresses. Instead,
the branch target addresses are calculated on-the-fly using
ALUs during the decode stage. The adders calculate all
possible target addresses before the instructions are fully
decoded, and the processor chooses which addresses are valid.
Branch Target Cache
To avoid a one clock cache-fetch penalty when a branch is
predicted taken, a built-in branch target cache supplies the first
16 bytes of instructions directly to the instruction buffer
(assuming the target address hits this cache). (See Figure 3 on
page 14.)
The branch target cache is organized as 16 entries of 16 bytes.
In total, the branch prediction logic achieves branch prediction
rates greater than 95%.
Return Address Stack
Chapter 2
The return address stack is a special device designed to
optimize CALL and RET pairs. Software is typically compiled
with subroutines that are frequently called from various places
in a program. This is usually done to save space.
Internal Architecture
21
Preliminary Information
AMD-K6™-2E Processor Data Sheet
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Entry into the subroutine occurs with the execution of a CALL
instruction. At that time, the processor pushes the address of
the next instruction in memory following the CALL instruction
onto the stack (allocated space in memory). When the processor
encounters a RET instruction (within or at the end of the
subroutine), the branch logic pops the address from the stack
and begins fetching from that location. To avoid the latency of
main memory accesses during CALL and RET operations, the
return address stack caches the pushed addresses.
Branch Execution
Unit
The branch execution unit enables efficient speculative
execution. This unit gives the processor the ability to execute
instructions beyond conditional branches before knowing
whether the branch prediction was correct.
The AMD-K6-2E processor does not permanently update the
x86 registers or memory locations until all speculatively
executed conditional branch instructions are resolved. When a
prediction is incorrect, the processor backs out to the point of
the mispredicted branch instruction and restores all registers.
The AMD-K6-2E processor can support up to seven outstanding
branches.
22
Internal Architecture
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
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3
Software Environment
This chapter provides a general overview of the AMD-K6-2E
processor’s x86 software environment and briefly describes the
data types, registers, operating modes, interrupts, and
instructions supported by the AMD-K6-2E architecture and
design implementation.
The s tepping of the Model 8 versi on of the proces sor
determines the implementation and format of ten ModelSpecific Registers (MSRs).
The AMD-K6-2E processor supports Model 8 steppings [F:8] in
any of eight possible model/steppings—Models 8/8, 8/9, 8/A, 8/B,
8/C, 8/D, 8/E, or 8/F.
Note that the name AMD-K6-2E processor by itself refers to all
steppings of the Model 8/[F:8] version.
3.1
Registers
The AMD-K6-2E processor contains all the registers defined by
the x86 architecture, including general-purpose, segment,
floating-point, MMX/3DNow!, EFLAGS, control, task, debug,
test, and descriptor/memory-management registers.
In addition to information about these registers, this chapter
provides information on the AMD-K6-2E processor MSRs.
Note: Areas of the register designated as Reserved should not be
modified by software.
Chapter 3
Software Environment
23
Preliminary Information
AMD-K6™-2E Processor Data Sheet
General-Purpose
Registers
22529B/0—January 2000
The eight 32-bit x86 general-purpose registers are used to hold
integer data or memory pointers used by instructions. Table 2
contains a list of the general-purpose registers and the
functions for which they are used.
Table 2. General-Purpose Registers
Register Function
EAX
Commonly used as an accumulator
EBX
Commonly used as a pointer
ECX
Commonly used for counting in loop operations
EDX
Commonly used to hold I/O information and to pass parameters
EDI
Commonly used as a destination pointer by the ES segment
ESI
Commonly used as a source pointer by the DS segment
ESP
Used to point to the stack segment
EBP
Used to point to data within the stack segment
To support byte and word operations, EAX, EBX, ECX, and
EDX can also be used as 8-bit and 16-bit registers. The shorter
registers are overlaid on the longer ones. For example, the
name of the 16-bit version of EAX is AX (low 16 bits of EAX)
and the 8-bit names for AX are AH (high order bits) and AL (low
order bits). The same naming convention applies to EBX, ECX,
and EDX.
EDI, ESI, ESP, and EBP can be used as smaller 16-bit registers
called DI, SI, SP, and BP respectively, but these registers do not
have 8-bit versions. Figure 7 shows the EAX register with its
name components, and Table 3 on page 25 lists the doubleword
(32-bit) general-purpose registers and their corresponding word
(16-bit) and byte (8-bit) versions.
31
16 15
8
7
0
EAX
AX
AH
AL
Figure 7. EAX Register with 16-Bit and 8-Bit Name Components
24
Software Environment
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
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Table 3. General-Purpose Register Doubleword, Word, and Byte Names
Integer Data Types
32-Bit Name
(Doubleword)
16-Bit Name
(Word)
8-Bit Name
8-Bit Name
(High-order Bits) (Low-order Bits)
EAX
AX
AH
AL
EBX
BX
BH
BL
ECX
CX
CH
CL
EDX
DX
DH
DL
EDI
DI
–
–
ESI
SI
–
–
ESP
SP
–
–
EBP
BP
–
–
Four types of data are used in general-purpose registers—byte,
word, doubleword, and quadword integers. Figure 8 shows the
format of the integer data registers.
Byte Integer
7
0
Precision —
8 Bits
Word Integer
15
0
Precision — 16 Bits
Doubleword Integer
31
0
Precision — 32 Bits
Quadword Integer
63
0
Precision — 64 Bits
Figure 8. Integer Data Registers
Chapter 3
Software Environment
25
Preliminary Information
AMD-K6™-2E Processor Data Sheet
Segment Registers
22529B/0—January 2000
The six 16-bit segment registers are used as pointers to areas
(segments) of memory. Table 4 lists the segment registers and
their functions. Figure 9 shows the format for all six segment
registers.
Table 4. Segment Registers
Segment
Segment Register Function
Register
CS
Code segment, where instructions are located
DS
Data segment, where data is located
ES
Data segment, where data is located
FS
Data segment, where data is located
GS
Data segment, where data is located
SS
Stack segment
15
0
Figure 9. Segment Register
Segment Usage
The operating system determines the type of memory model
that is implemented. The segment register usage is determined
by the operating system’s memory model. In a real mode
memory model, the segment register points to the base address
in memory.
In a protected mode memory model, the segment register is
called a selector and it selects a segment descriptor in a
descriptor table. This descriptor contains a pointer to the base
of the segment, the limit of the segment, and various protection
attributes. For more information on descriptor formats, see
“Descriptors and Gates” on page 52. Figure 10 on page 27 shows
segment usage for real mode and protected mode memory
models.
26
Software Environment
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
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Physical Memory
Segment Base
Segment Register
Real Mode Memory Model
Descriptor Table
Physical Memory
Base
Limit
Base
Base
Limit
Segment Base
Segment Selector
Protected Mode Memory Model
Figure 10. Segment Usage
Instruction Pointer
The instruction pointer (EIP or IP) is used in conjunction with
the code segment register (CS). The instruction pointer is
either a 32-bit register (EIP) or a 16-bit register (IP) that keeps
track of where the next instruction resides within memory. This
register cannot be directly manipulated, but can be altered by
modifying return pointers when a JMP or CALL instruction is
used.
Floating-Point
Registers
The floating-point execution unit in the AMD-K6-2E processor
is designed to perform mathematical operations on non-integer
numbers. This floating-point unit conforms to the IEEE 754 and
854 standards and uses several registers to meet these
standards — eight numeric floating-point registers, a status
word register, a control word register, and a tag word register.
Chapter 3
Software Environment
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
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The eight floating-point registers are physically 80 bits wide
and labeled FPR0–FPR7. Figure 11 shows the format of these
floating-point registers. See “Floating-Point Register Data
Types” on page 30 for information on allowable floating-point
data types.
79 78
64 63
Sign
0
Exponent
Significand
Figure 11. Floating-Point Register
The 16-bit FPU status word register contains information about
the state of the floating-point unit. Figure 12 shows the format
of the FPU status word register.
15 14 13 12 11 10 9 8
B
Symbol
B
C3
TOSP
C2
C1
C0
ES
SF
PE
UE
OE
ZE
DE
IE
C
3
TOSP
C
2
C C
1 0
7
6
5
4
3
2
1
0
E
S
S
F
P U O Z
E E E E
D
E
I
E
Description
Bits
FPU Busy
15
Condition Code
14
Top of Stack Pointer
13–11
Condition Code
10
Condition Code
9
Condition Code
8
Error Summary Status
7
Stack Fault
6
Exception Flags
Precision Error
5
Underflow Error
4
Overflow Error
3
Zero Divide Error
2
Denormalized Operation Error 1
Invalid Operation Error
0
TOSP Information
000 = FPR0
111 = FPR7
Figure 12. FPU Status Word Register
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Software Environment
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
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The FPU control word register allows a programmer to manage
the FPU processing options. Figure 13 shows the format of the
FPU control word register.
15 14 13 12 11 10 9 8
Y
R
C
7
P
C
6
5
4
3
2
1
0
P U O Z D I
M M M M M M
Reserved
Symbol
Y
RC
PC
PM
UM
OM
ZM
DM
IM
Description
Infinity Bit (80287 compatibility)
Rounding Control
Precision Control
Exception Masks
Precision
Underflow
Overflow
Zero Divide
Denormalized Operation
Invalid Operation
Bits
12
11–10
9–8
5
4
3
2
1
0
Rounding Control Information
00b = Round to the nearest or even number
01b = Round down toward negative infinity
10b = Round up toward positive infinity
11b = Truncate toward zero
Precision Control Information
00b = 24 bits Single Precision Real
01b = Reserved
10b = 53 bits Double Precision Real
11b = 64 bits Extended Precision Real
Figure 13. FPU Control Word Register
The FPU tag word register contains information about the
registers in the register stack. Figure 14 shows the format of the
FPU tag word register.
15
14 13
TAG
(FPR7)
12 11
TAG
(FPR6)
10 9
TAG
(FPR5)
87
TAG
(FPR4)
65
TAG
(FPR3)
43
TAG
(FPR2)
2 1
TAG
(FPR1)
0
TAG
(FPR0)
Tag Values
00 = Valid
01 = Zero
10 = Special
11 = Empty
Figure 14. FPU Tag Word Register
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
Floating-Point
Register Data Types
79 78
S
22529B/0—January 2000
Floating-point registers use four different types of data —
packed decimal, single-precision real, double-precision real,
and extended-precision real. Figures 15 and 16 show the
formats for these registers.
72 71
0
Ignore
or
Zero
Precision — 18 Digits, 72 Bits Used, 4-Bits/Digit
Description
Bits
Ignored on Load, Zeros on Store 78-72
Sign Bit
79
Figure 15. Packed Decimal Data Register
31 30
Single-Precision Real
S
23 22
0
Biased
Exponent
Significand
S = Sign Bit
Double-Precision Real
52 51
63 62
S
0
Biased
Exponent
Significand
S = Sign Bit
Extended-Precision Real
79 78
S
64 63 62
Biased
Exponent
S = Sign Bit
0
I
Significand
I = Integer Bit
Figure 16. Precision Real Data Registers
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Software Environment
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Preliminary Information
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AMD-K6™-2E Processor Data Sheet
MMX™/3DNow!™
Registers
T h e A M D -K 6 -2 E p r o c e s s o r i m p l e m e n t s e i g h t 6 4 -b i t
MMX/3DNow! registers for use by multimedia software. These
registers are mapped on the floating-point register stack. The
MMX and 3DNow! instructions refer to these registers as mm0
to mm7. Figure 17 shows the format of these registers. For more
information, see the AMD-K6® Processor Multimedia
Technology Manual, order #20726 and the 3DNow! Technology
Manual, order #21928.
63
0
mm0
mm1
mm2
mm3
mm4
mm5
mm6
mm7
Figure 17. MMX™/3DNow!™ Registers
Chapter 3
Software Environment
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
MMX™ Data Types
22529B/0—January 2000
For the MMX instructions, the MMX registers use three types of
data — packed 8-byte integer, packed quadword integer, and
packed dual doubleword integer. Figure 18 shows the format of
the MMX data types.
Packed Bytes Integer
56 55
63
Byte 7
48
47
Byte 6
40
39
Byte 5
32
31
Byte 4
24
23
Byte 3
16
15
Byte 2
8
7
Byte 1
0
Byte 0
Packed Words Integer
63
48 47
Word 3
32
31
Word 2
16
0
15
Word 1
Word 0
Packed Doubleword Integer
63
32
0
31
Doubleword 1
Doubleword 0
Figure 18. MMX™ Data Types
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AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
3DNow!™ Data Types
For 3DNow! instructions, the MMX/3DNow! registers use
packed single-precision real data. Figure 19 shows the format of
the 3DNow! data type.
Packed Single Precision Floating Point
63 62
S
55 54
32 31 30
Biased
Exponent
Significand
S
0
23 22
Biased
Exponent
S = Sign Bit
Significand
S = Sign Bit
Figure 19. 3DNow!™ Data Types
Chapter 3
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33
Preliminary Information
AMD-K6™-2E Processor Data Sheet
EFLAGS Register
22529B/0—January 2000
The EFLAGS register provides for three different types of
flags — system, control, and status. The system flags provide
operating system controls, the control flag provides directional
information for string operations, and the status flags provide
information resulting from logical and arithmetic operations.
Figure 20 shows the format of the EFLAGS register.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
V
I I
D P
V
I
F
A V R
C M F
N
T
I
O
P
L
O D
F F
I
F
8
7
6
T
F
S
F
Z
F
5
4
A
F
3
2
P
F
1
0
C
F
Reserved
Symbol
ID
VIP
VIF
AC
VM
RF
NT
IOPL
OF
DF
IF
TF
SF
ZF
AF
PF
CF
Description
Bits
ID Flag
21
Virtual Interrupt Pending
20
Virtual Interrupt Flag
19
Alignment Check
18
Virtual-8086 Mode
17
Resume Flag
16
Nested Task
14
I/O Privilege Level
13–12
Overflow Flag
11
Direction Flag
10
Interrupt Flag
9
Trap Flag
8
Sign Flag
7
Zero Flag
6
Auxiliary Flag
4
Parity Flag
2
Carry Flag
0
Figure 20. EFLAGS Register
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Software Environment
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AMD-K6™-2E Processor Data Sheet
Control Registers
The five control registers contain system control bits and
pointers. Figures 21 through 25 show the formats of the control
registers.
31
7
6
5
M
C
E
4
3
2
1
0
P
S
E
T
D S
E D
P V
V M
I E
4
3
1
Reserved
Symbol
MCE
PSE
DE
TSD
PVI
VME
Description
Machine Check Enable
Page Size Extensions
Debugging Extensions
Time Stamp Disable
Protected Virtual Interrupts
Virtual-8086 Mode Extensions
Bit
6
4
3
2
1
0
Figure 21. Control Register 4 (CR4)
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
Page Directory Base
8
7
6
5
2
0
P P
C W
D T
Reserved
Symbol
PCD
PWT
Description
Page Cache Disable
Page Writethrough
Bit
4
3
Figure 22. Control Register 3 (CR3)
31
0
Page Fault Linear Address
Figure 23. Control Register 2 (CR2)
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
31
0
Reserved
Figure 24. Control Register 1 (CR1)
Symbol
PG
CD
NW
Description
Paging
Cache Disable
Not Writethrough
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
P C N
G D W
A
M
W
P
Bit
31
30
29
8
7
6
5
4
3
2
1
0
N
E
E T E M P
T S M P E
Reserved
Symbol
AM
WP
NE
ET
TS
EM
MP
PE
Description
Alignment Mask
Write Protect
Numeric Error
Extension Type
Task Switched
Emulation
Monitor Co-processor
Protection Enabled
Bit
18
16
5
4
3
2
1
0
Figure 25. Control Register 0 (CR0)
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Software Environment
Chapter 3
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Debug Registers
Figures 26 through 29 show the 32-bit debug registers
supported by the processor. These registers are further
described in “Debug” on page 240.
Symbol
LEN 3
R/W 3
LEN 2
R/W 2
LEN 1
R/W 1
LEN 0
R/W 0
Description
Length of Breakpoint #3
Type of Transaction(s) to Trap
Length of Breakpoint #2
Type of Transaction(s) to Trap
Length of Breakpoint #1
Type of Transaction(s) to Trap
Length of Breakpoint #0
Type of Transaction(s) to Trap
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
LEN
3
R/W
3
LEN
2
R/W
2
LEN
1
R/W
1
LEN
0
R/W
0
G
D
G
E
8
7
Bits
31–30
29–28
27–26
25–24
23–22
21–20
19–18
17–16
6
5
4
3
L G L
E 3 3
L
2
L G
2 1
2
1
0
L G
1 0
L
0
Reserved
Symbol
GD
GE
LE
G3
L3
G2
L2
G1
L1
G0
L0
Description
General Detect Enabled
Global Exact Breakpoint Enabled
Local Exact Breakpoint Enabled
Global Exact Breakpoint # 3 Enabled
Local Exact Breakpoint # 3 Enabled
Global Exact Breakpoint # 2 Enabled
Local Exact Breakpoint # 2 Enabled
Global Exact Breakpoint # 1 Enabled
Local Exact Breakpoint # 1 Enabled
Global Exact Breakpoint # 0 Enabled
Local Exact Breakpoint # 0 Enabled
Bit
13
9
8
7
6
5
4
3
2
1
0
Figure 26. Debug Register DR7
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
8
7
6
5
4
B B B
T S D
3
2
1
0
B
3
B
2
B
1
B
0
Reserved
Symbol
BT
BS
BD
B3
B2
B1
B0
Description
Breakpoint Task Switch
Breakpoint Single Step
Breakpoint Debug Access Detected
Breakpoint #3 Condition Detected
Breakpoint #2 Condition Detected
Breakpoint #1 Condition Detected
Breakpoint #0 Condition Detected
Bit
15
14
13
3
2
1
0
Figure 27. Debug Register DR6
DR5
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
8
7
6
5
4
3
2
1
0
8
7
6
5
4
3
2
1
0
Reserved
DR4
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
Reserved
Figure 28. Debug Registers DR5 and DR4
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Software Environment
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AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
DR3
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
8
7
6
5
4
3
2
1
0
8
7
6
5
4
3
2
1
0
8
7
5
4
3
2
1
0
8
7
5
4
3
2
1
0
Breakpoint 3 32-bit Linear Address
DR2
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
Breakpoint 2 32-bit Linear Address
DR1
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
6
Breakpoint 1 32-bit Linear Address
DR0
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
6
Breakpoint 0 32-bit Linear Address
Figure 29. Debug Registers DR3, DR2, DR1, and DR0
Chapter 3
Software Environment
39
Preliminary Information
AMD-K6™-2E Processor Data Sheet
3.2
22529B/0—January 2000
Model-Specific Registers (MSR)
The AMD-K6-2E processor is based on and functionally
identical to the AMD-K6-2 processor Model 8/[F:8], which
provides ten model-specific registers (MSRs).
■
■
The value in the ECX register selects the MSR to be
addressed by the RDMSR and WRMSR instructions.
The values in EAX and EDX are used as inputs and outputs
by the RDMSR and WRMSR instructions.
Table 5 lists the MSRs and the corresponding value of the ECX
register. Figures 30 through 39 show the MSR formats.
Table 5. AMD-K6™-2E Processor Model 8/[F:8] Model-Specific Registers
Model-Specific Register
Value of ECX
Machine-Check Address Register (MCAR)
00h
Machine-Check Type Register (MCTR)
01h
Test Register 12 (TR12)
0Eh
Time Stamp Counter (TSC)
10h
Extended Feature Enable Register (EFER)
C000_0080h
SYSCALL/SYSRET Target Address Register (STAR)
C000_0081h
Write Handling Control Register (WHCR)
C000_0082h
UC/WC Cacheability Control Register (UWCCR)
C000_0085h
Processor State Observability Register (PSOR)
C000_0087h
Page Flush/Invalidate Register (PFIR)
C000_0088h
For more information about the MSRs, see the AMD-K6®
Processor BIOS Design Application Note, order #21329.
For mo re info rma tio n abo ut the RD MSR and WRMSR
instructions, see the AMD K86™ Family BIOS and Software Tools
Development Guide, order #21062.
40
Software Environment
Chapter 3
Preliminary Information
22529B/0—January 2000
AMD-K6™-2E Processor Data Sheet
MCAR and MCTR
The AMD-K6-2E processor does not support the generation of a
machine-check exception. However, the processor does provide
a 64-bit machine-check address register (MCAR), a 64-bit
machine-check type register (MCTR), and a machine check
enable (MCE) bit in CR4.
Because the processor does not support machine check
exceptions, the contents of the MCAR and MCTR registers are
only affected by the WRMSR instruction and by RESET being
sampled asserted (where all bits in each register are reset to 0).
The formats for the machine-check address register and the
machine-check type register are shown in Figure 30 and Figure
31, respectively.
63
0
MCAR
Figure 30. Machine-Check Address Register (MCAR)
63
5
4
0
MCTR
Reserved
Figure 31. Machine-Check Type Register (MCTR)
Chapter 3
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41
Preliminary Information
AMD-K6™-2E Processor Data Sheet
Test Register 12
(TR12)
22529B/0—January 2000
Test register 12 provides a method for disabling the L1 caches.
Figure 32 shows the format of the TR12 register.
63
4 3
2
1
0
C
I
Reserved
Symbol Description
CI
Cache Inhibit Bit
Bit
3
Figure 32. Test Register 12 (TR12)
Time Stamp Counter
With each processor clock cycle, the processor increments the
64-bit time stamp counter (TSC) MSR. Figure 33 shows the
format of the TSC register.
63
0
TSC
Figure 33. Time Stamp Counter (TSC)
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Software Environment
Chapter 3
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AMD-K6™-2E Processor Data Sheet
Extended Feature
Enable Register
(EFER)
The extended feature enable register (EFER) contains the
contro l bits that enable the extended features of the
AMD-K6-2E processor. Figure 34 shows the format of the EFER
register, and Table 6 defines the function of each bit in the
EFER register.
63
4
3
2 1
0
D S
EWBEC P C
E E
Reserved
Symbol
EWBEC
DPE
SCE
Description
EWBE# Control
Data Prefetch Enable
System Call Extension
Bit
3-2
1
0
Figure 34. Extended Feature Enable Register (EFER)
Table 6. Extended Feature Enable Register (EFER)Definition
Bit
63–4
3-2
Description
Reserved
R/W Function
R
Writing a 1 to any reserved bit causes a general protection fault to occur. All
reserved bits are always read as 0.
EWBE# Control
(EWBEC)
R/W
This 2-bit field controls the behavior of the processor with respect to the ordering of
write cycles and the EWBE# signal. EFER[3] and EFER[2] are Global EWBE# Disable
(GEWBED) and Speculative EWBE# Disable (SEWBED), respectively.
1
Data Prefetch Enable
(DPE)
R/W
DPE must be set to 1 to enable data prefetching (this is the default setting following
reset). If enabled, cache misses initiated by a memory read within a 32-byte cache
line are conditionally followed by cache-line fetches of the other line in the 64-byte
sector.
0
System Call Extension
(SCE)
R/W
SCE must be set to 1 to enable the usage of the SYSCALL and SYSRET instructions.
For more information about the EWBEC bits, see “EWBE#
Control” on page 205.
Chapter 3
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43
Preliminary Information
AMD-K6™-2E Processor Data Sheet
SYSCALL/SYSRET
Target Address
Register (STAR)
63
22529B/0—January 2000
The SYSCALL/SYSRET target address register (STAR)
contains the target EIP address used by the SYSCALL
instruction and the 16-bit code and stack segment selector
bases used by the SYSCALL and SYSRET instructions. Figure
35 shows the format of the STAR register, and Table 7 defines
the function of each bit of the STAR register. For more
information, see the SYSCALL and SYSRET Instruction
Specification Application Note, order #21086.
32 31
48 47
SYSRET CS Selector and SS
Selector Base
0
SYSCALL CS Selector and SS
Selector Base
Target EIP Address
Figure 35. SYSCALL/SYSRET Target Address Register (STAR)
Table 7. SYSCALL/SYSRET Target Address Register (STAR) Definition
Bit
Write Handling
Control Register
(WHCR)
Description
R/W
63–48
SYSRET CS and SS Selector Base
R/W
47–32
SYSCALL CS and SS Selector Base
R/W
31–0
Target EIP Address
R/W
The write handling control register (WHCR) is an MSR that
contains two fields—the write allocate enable limit (WAELIM)
field, and the write allocate enable 15-to-16-Mbyte (WAE15M)
bit. Figure 36 shows the format of the WHCR register. See
“Write Allocate” on page 192 for more information.
63
32 31
22 21
WAELIM
17 16 15
0
W
A
E
1
5
M
Reserved
Symbol
WAELIM
WAE15M
Description
Bits
Write Allocate Enable Limit
31-22
Write Allocate Enable 15-to-16-Mbyte 16
Note: Hardware RESET initializes this MSR to all zeros.
Figure 36. Write Handling Control Register (WHCR)
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AMD-K6™-2E Processor Data Sheet
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UC/WC Cacheability
Control Register
(UWCCR)
The AMD-K6-2E processor provides two variable-range Memory
Type Range Registers (MTRRs)—MTRR0 and MTRR1—that
each specify a range of memory. Each range can be defined as
uncacheable (UC) or write-combining (WC) memory. Figure 37
shows the format of the UWCCR register. For more detailed
information about the MTRR0, MTRR1, and UWCCR registers,
see “Memory Type Range Registers” on page 207.
.
Symbol
UC1
WC1
Description
Uncacheable Memory Type
Write-Combining Memory Type
49
63
Physical Base Address 1
Bits
32
33
48
Symbol
UC0
WC0
Description
Uncacheable Memory Type
Write-Combining Memory Type
34 33 32 31
W U
Physical Address Mask 1 C C
1 1
17 16
Physical Base Address 0
MTRR1
Bits
0
1
2
1
0
W
Physical Address Mask 0 C
0
U
C
0
MTRR0
Figure 37. UC/WC Cacheability Control Register (UWCCR)
Processor State
Observability
Register (PSOR)
The AMD-K6-2E processor provides the processor state
observability register (PSOR) (see Figure 38).
63
9
8
N
O
L
2
4 3 2
7
STEP
0
BF
Reserved
Symbol
NOL2
STEP
BF
Description
No L2 Functionality
Processor Stepping
Bus Frequency Divisor
Bit
8
7-4
2-0
Figure 38. Processor State Observability Register (PSOR)
Chapter 3
Software Environment
45
Preliminary Information
AMD-K6™-2E Processor Data Sheet
Page Flush/Invalidate
Register (PFIR)
22529B/0—January 2000
The AMD-K6-2E processor contains the Page Flush/Invalidate
Register (PFIR) (see Figure 39) that allows cache invalidation
and optional flushing of a specific 4-Kbyte page from the linear
address space. Using this register can result in a much lower
cycle count for flushing particular pages versus flushing the
entire cache. When the PFIR is written to (using the WRMSR
instruction), the invalidation and, optionally, the flushing
begins.
32 31
63
12 11
LINPAGE
9 8 7
P
F
1 0
F
/
I
Reserved
Symbol
LINPAGE
PF
F/I
Description
20-bit Linear Page Address
Page Fault Occurred
Flush/Invalidate Command
Bit
31-12
8
0
Figure 39. Page Flush/Invalidate Register (PFIR)
46
Software Environment
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AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
3.3
Memory Management Registers
The AMD-K6-2E processor controls segmented memory
management with the registers listed in Table 8. Figure 40
shows the formats of the memory management registers.
Table 8. Memory Management Registers
Register Name
Function
Global Descriptor Table Register
Contains a pointer to the base of the global descriptor table
Interrupt Descriptor Table Register
Contains a pointer to the base of the interrupt descriptor table
Local Descriptor Table Register
Contains a pointer to the local descriptor table of the current task
Task Register
Contains a pointer to the task state segment of the current task
Global and Interrupt Descriptor Table Registers
16 15
47
32-Bit Linear Base Address
Local Descriptor Table Register and Task Register
0
16-Bit Limit
15
0
Selector
63
0
32 31
32-Bit Linear Base Address
32-Bit Limit
15
0
Attributes
Figure 40. Memory Management Registers
Chapter 3
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
Task State Segment
22529B/0—January 2000
Figure 41 shows the format of the task state segment (TSS).
31
0
TSS Limit
from TR
I/O Permission Bitmap (IOPB)
(up to 8 Kbytes)
Interrupt Redirection Bitmap (IRB)
(eight 32-bit locations)
Operating System
Data Structure
Base Address of IOPB
0000h
0000h
LDT Selector
0000h
GS
0000h
0000h
FS
0000h
DS
SS
0000h
CS
0000h
ES
T
64h
EDI
ESI
EBP
ESP
EBX
EDX
ECX
EAX
EFLAGS
EIP
CR3
SS2
0000h
ESP2
0000h
SS1
ESP1
0000h
SS0
ESP0
0000h
Link (Prior TSS Selector)
0
Figure 41. Task State Segment (TSS)
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AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
3.4
Paging
The AMD-K6-2E processor can physically address up to four
Gbytes of memory. This memory can be segmented into pages.
The size of these pages is determined by the operating system
design and the values set up in the page directory entries (PDE)
and page table entries (PTE).
The processor can access both 4-Kbyte pages and 4-Mbyte
pages, and the page sizes can be intermixed within a page
directory. When the page size extension (PSE) bit in CR4 is set,
the processor translates linear addresses using either the
4-Kbyte translation lookaside buffer (TLB) or the 4-Mbyte TLB,
depending on the state of the page size (PS) bit in the page
directory entry. Figures 42 and 43 show how 4-Kbyte and
4-Mbyte page translations work.
Page
Directory
4-Kbyte
Page
Frame
Page
Table
PTE
Physical
Address
PDE
CR3
31
22 21
Page Directory
Offset
12 11
Page Table
Offset
0
Page
Offset
Linear Address
Figure 42. 4-Kbyte Paging Mechanism
Chapter 3
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49
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
4-Mbyte
Page
Frame
Page
Directory
Physical
Address
PDE
CR3
31
22 21
0
Page Directory
Offset
Page
Offset
Linear Address
Figure 43. 4-Mbyte Paging Mechanism
Figures 44 through 46 show the formats of the PDE and PTE.
These entries contain information regarding the location of
pages and their status.
50
Software Environment
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AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
31
12 11 10 9 8
A
V
L
Page Table Base Address
Symbol
AVL
PS
A
PCD
PWT
U/S
W/R
P
Description
Available to Software
Reserved
Page Size
Reserved
Accessed
Page Cache Disable
Page Writethrough
User/Supervisor
Write/Read
Present (valid)
7
6
0
5
4
3
2
1
0
A
P P U W
C W / / P
D T S R
5
4
A
P P U W
C W / / P
D T S R
Bits
11–9
8
7
6
5
4
3
2
1
0
Figure 44. Page Directory Entry 4-Kbyte Page Table (PDE)
31
12 11 10 9 8
22 21
Physical Page Base Address
Symbol
AVL
PS
A
PCD
PWT
U/S
W/R
P
Description
Available to Software
Reserved
Page Size
Reserved
Accessed
Page Cache Disable
Page Writethrough
User/Supervisor
Write/Read
Present (valid)
Reserved
A
V
L
7
1
6
3
2
1
0
Bits
11–9
8
7
6
5
4
3
2
1
0
Figure 45. Page Directory Entry 4-Mbyte Page Table (PDE)
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
31
12 11 10 9 8
A
V
L
Physical Page Base Address
Symbol
AVL
D
A
PCD
PWT
U/S
W/R
P
Description
Available to Software
Reserved
Dirty
Accessed
Page Cache Disable
Page Writethrough
User/Supervisor
Write/Read
Present (valid)
7
6
5
D A
4
3
2
1
0
P P U W
C W / / P
D T S R
Bits
11–9
8–7
6
5
4
3
2
1
0
Figure 46. Page Table Entry (PTE)
3.5
Descriptors and Gates
There are various types of structures and registers in the x86
architecture that define, protect, and isolate code segments,
data segments, task state segments, and gates. These structures
are called descriptors.
■
■
■
52
The application segment descriptor is used to point to either a
data or code segment. Figure 47 on page 53 shows the
application segment descriptor format. Table 9 contains
information describing the memory segment type to which
the descriptor points.
The system segment descriptor is used to point to a task state
segment, a call gate, or a local descriptor table. Figure 48 on
page 54 shows the system segment descriptor format. Table
10 contains information describing the type of segment or
gate to which the descriptor points.
The AMD-K6-2E processor uses gates to transfer control
between executable segments with different privilege
levels. Figure 49 on page 55 shows the format of the gate
descriptor types. Table 10 contains information describing
the type of segment or gate to which the descriptor points.
Software Environment
Chapter 3
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Symbol
G
D
AVL
P
DPL
DT
Type
Reserved
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
Base Address 31–24
G D
A
V
L
Segment
Limit
P
DPL
1
Base Address 15–0
8
7
Description
Granularity
32-Bit/16-Bit
Available to Software
Present/Valid Bit
Descriptor Privilege Level
Descriptor Type
See Table 9
6
Type
5
4
3
2
1
Bits
23
22
20
15
14-13
12
11-8
0
Base Address 23–16
Segment Limit 15–0
Figure 47. Application Segment Descriptor
Table 9. Application Segment Types
Type Data/Code Description
0
Read-Only
1
Read-Only—Accessed
2
Read/Write
3
4
Read/Write—Accessed
Read-Only—Expand-down
5
Read-Only—Expand-down, Accessed
6
Read/Write—Expand-down
7
Read/Write—Expand-down, Accessed
8
Execute-Only
9
Execute-Only—Accessed
A
Execute/Read
B
C
Chapter 3
Data
Code
Execute/Read—Accessed
Execute-Only—Conforming
D
Execute-Only—Conforming, Accessed
E
Execute/Read-Only—Conforming
F
Execute/Read-Only—Conforming, Accessed
Software Environment
53
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Symbol
G
X
AVL
P
DPL
DT
Type
Reserved
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
Base Address 31–24
A
V
L
G X
Segment
Limit
P
DPL
0
Base Address 15–0
8
7
Description
Granularity
Not Needed
Availability to Software
Present/Valid Bit
Descriptor Privilege Level
Descriptor Type
See Table 10
6
Type
5
4
3
2
1
Bits
23
22
20
15
14-13
12
11-8
0
Base Address 23–16
Segment Limit 15–0
Figure 48. System Segment Descriptor
Table 10. System Segment and Gate Types
Type Description
54
0
Reserved
1
Available 16-bit TSS
2
LDT
3
Busy 16-bit TSS
4
16-bit Call Gate
5
Task Gate
6
16-bit Interrupt Gate
7
16-bit Trap Gate
8
Reserved
9
Available 32-bit TSS
A
Reserved
B
Busy 32-bit TSS
C
32-bit Call Gate
D
Reserved
E
32-bit Interrupt Gate
F
32-bit Trap Gate
Software Environment
Chapter 3
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Symbol
P
DPL
DT
Type
Reserved
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
Offset 31–16
P
DPL
0
Segment Selector
8
7
6
5
Description
Present/Valid Bit
Descriptor Privilege Level
Descriptor Type
See Table 10
4
3
2
1
Bits
15
14-13
12
11-8
0
Type
Offset 15–0
Figure 49. Gate Descriptor
3.6
Exceptions and Interrupts
Table 11 summarizes the exceptions and interrupts.
Table 11. Summary of Exceptions and Interrupts
Interrupt
Interrupt Type
Number
Cause
0
Divide by Zero Error
DIV, IDIV
1
Debug
Debug trap or fault
2
Non-Maskable Interrupt
NMI signal sampled asserted
3
Breakpoint
Int 3
4
Overflow
INTO
5
Bounds Check
BOUND
6
Invalid Opcode
Invalid instruction
7
Device Not Available
ESC and WAIT
8
Double Fault
Fault occurs while handling a fault
9
Reserved - Interrupt 13
—
10
Invalid TSS
Task switch to an invalid segment
11
Segment Not Present
Instruction loads a segment and present bit is 0 (invalid segment)
12
Stack Segment
Stack operation causes limit violation or present bit is 0
13
General Protection
Segment related or miscellaneous invalid actions
14
Page Fault
Page protection violation or a reference to missing page
16
Floating-Point Error
Arithmetic error generated by floating-point instruction
17
Alignment Check
Data reference to an unaligned operand. (The AC flag and the AM bit of CR0 are set to 1.)
0–255
Software Interrupt
INT n
Chapter 3
Software Environment
55
Preliminary Information
AMD-K6™-2E Processor Data Sheet
3.7
22529B/0—January 2000
Instructions Supported by the AMD-K6™-2E Processor
This section documents all of the x86 instructions supported by
the AMD-K6™-2E processor. Tables 12 through 15 define the
integer, floating-point, MMX, and 3DNow! instructions for the
AMD-K6-2E processor, respectively.
Each table shows the instruction mnemonic, opcode, modR/M
by t e , d e c o d e t y p e, a n d R I S C 8 6 o p e ra t i o n ( s ) fo r e a ch
instruction.
Instruction
Mnemonic and
Operand Types
The first column in each table indicates the instruction
mnemonic and operand types, with the following notations:
■
■
■
■
■
■
■
■
■
■
■
■
■
■
■
■
■
■
■
■
56
disp16/32—16-bit or 32-bit displacement value
disp32/48—doubleword or 48-bit displacement value
disp8—8-bit displacement value
eXX—register width depending on the operand size
imm16/32—16-bit or 32-bit immediate value
imm8—8-bit immediate value
mem16/32—word or doubleword integer value in memory
mem32/48—doubleword or 48-bit integer value in memory
mem32real—32-bit floating-point value in memory
mem48—48-bit integer value in memory
mem64—64-bit value in memory
mem64real—64-bit floating-point value in memory
mem8—byte integer value in memory
mem80real—80-bit floating-point value in memory
mmreg—MMX/3DNow! register
mmreg1—MMX/3DNow! register defined by bits 5, 4, and 3
of the modR/M byte
mmreg2—MMX/3DNow! register defined by bits 2, 1, and 0
of the modR/M byte
mreg16/32—word or doubleword integer register, or word or
doubleword integer value in memory defined by the
modR/M byte
mreg8—byte integer register or byte integer value in
memory defined by the modR/M byte
reg8—byte integer register defined by instruction byte(s) or
bits 5, 4, and 3 of the modR/M byte
Software Environment
Chapter 3
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
■
reg16/32—word or doubleword integer register defined by
instruction byte(s) or bits 5, 4, and 3 of the modR/M byte
Opcode Bytes
The second and third columns list all applicable opcode bytes.
ModR/M Byte
The fourth column lists the modR/M byte when used by the
instruction. The modR/M byte defines the instruction as a
register or memory form. If modR/M bits 7 and 6 are documented
as mm (memory form), mm can only be 10b, 01b or 00b.
Decode Type
The fifth column lists the type of instruction decode — short,
long, and vector. The AMD-K6-2E processor decode logic can
process two short, one long, or one vector decode per clock.
RISC86 Operation
The sixth column lists the type of RISC86 operation(s) required
for the instruction. The operation types and corresponding
execution units are as follows:
■
■
■
■
■
■
■
■
alu—either of the integer execution units
alux—integer X execution unit only
branch—branch condition unit
float—floating-point execution unit
limm—load immediate, instruction control unit
load, fload, mload—load unit
meu—Multimedia execution units for MMX and 3DNow!
instructions
store, fstore, mstore—store unit
Table 12. Integer Instructions
Instruction Mnemonic
First
Byte
AAA
37h
AAD
D5h
0Ah
vector
AAM
D4h
0Ah
vector
AAS
3Fh
ADC mreg8, reg8
10h
11-xxx-xxx
vector
ADC mem8, reg8
10h
mm-xxx-xxx
vector
ADC mreg16/32, reg16/32
11h
11-xxx-xxx
vector
ADC mem16/32, reg16/32
11h
mm-xxx-xxx
vector
ADC reg8, mreg8
12h
11-xxx-xxx
vector
ADC reg8, mem8
12h
mm-xxx-xxx
vector
Chapter 3
Second
Byte
ModR/M
Byte
Decode RISC86
Type Operations
vector
vector
Software Environment
57
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 12. Integer Instructions (continued)
Instruction Mnemonic
First
Byte
ADC reg16/32, mreg16/32
13h
11-xxx-xxx
vector
ADC reg16/32, mem16/32
13h
mm-xxx-xxx
vector
ADC AL, imm8
14h
vector
ADC EAX, imm16/32
15h
vector
ADC mreg8, imm8
80h
11-010-xxx
vector
ADC mem8, imm8
80h
mm-010-xxx
vector
ADC mreg16/32, imm16/32
81h
11-010-xxx
vector
ADC mem16/32, imm16/32
81h
mm-010-xxx
vector
ADC mreg16/32, imm8 (signed ext.)
83h
11-010-xxx
vector
ADC mem16/32, imm8 (signed ext.)
83h
mm-010-xxx
vector
ADD mreg8, reg8
00h
11-xxx-xxx
short
alux
ADD mem8, reg8
00h
mm-xxx-xxx
long
load, alux, store
ADD mreg16/32, reg16/32
01h
11-xxx-xxx
short
alu
ADD mem16/32, reg16/32
01h
mm-xxx-xxx
long
load, alu, store
ADD reg8, mreg8
02h
11-xxx-xxx
short
alux
ADD reg8, mem8
02h
mm-xxx-xxx
short
load, alux
ADD reg16/32, mreg16/32
03h
11-xxx-xxx
short
alu
ADD reg16/32, mem16/32
03h
mm-xxx-xxx
short
load, alu
ADD AL, imm8
04h
short
alux
ADD EAX, imm16/32
05h
short
alu
ADD mreg8, imm8
80h
11-000-xxx
short
alux
ADD mem8, imm8
80h
mm-000-xxx
long
load, alux, store
ADD mreg16/32, imm16/32
81h
11-000-xxx
short
alu
ADD mem16/32, imm16/32
81h
mm-000-xxx
long
load, alu, store
ADD mreg16/32, imm8 (signed ext.)
83h
11-000-xxx
short
alux
ADD mem16/32, imm8 (signed ext.)
83h
mm-000-xxx
long
load, alux, store
AND mreg8, reg8
20h
11-xxx-xxx
short
alux
AND mem8, reg8
20h
mm-xxx-xxx
long
load, alux, store
AND mreg16/32, reg16/32
21h
11-xxx-xxx
short
alu
AND mem16/32, reg16/32
21h
mm-xxx-xxx
long
load, alu, store
AND reg8, mreg8
22h
11-xxx-xxx
short
alux
AND reg8, mem8
22h
mm-xxx-xxx
short
load, alux
AND reg16/32, mreg16/32
23h
11-xxx-xxx
short
alu
AND reg16/32, mem16/32
23h
mm-xxx-xxx
short
load, alu
AND AL, imm8
24h
short
alux
58
Second
Byte
ModR/M
Byte
Software Environment
Decode RISC86
Type Operations
Chapter 3
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 12. Integer Instructions (continued)
Instruction Mnemonic
First
Byte
AND EAX, imm16/32
25h
AND mreg8, imm8
80h
AND mem8, imm8
Second
Byte
ModR/M
Byte
Decode RISC86
Type Operations
short
alu
11-100-xxx
short
alux
80h
mm-100-xxx
long
load, alux, store
AND mreg16/32, imm16/32
81h
11-100-xxx
short
alu
AND mem16/32, imm16/32
81h
mm-100-xxx
long
load, alu, store
AND mreg16/32, imm8 (signed ext.)
83h
11-100-xxx
short
alux
AND mem16/32, imm8 (signed ext.)
83h
mm-100-xxx
long
load, alux, store
ARPL mreg16, reg16
63h
11-xxx-xxx
vector
ARPL mem16, reg16
63h
mm-xxx-xxx
vector
BOUND
62h
BSF reg16/32, mreg16/32
0Fh
BCh
11-xxx-xxx
vector
BSF reg16/32, mem16/32
0Fh
BCh
mm-xxx-xxx
vector
BSR reg16/32, mreg16/32
0Fh
BDh
11-xxx-xxx
vector
BSR reg16/32, mem16/32
0Fh
BDh
mm-xxx-xxx
vector
BSWAP EAX
0Fh
C8h
long
alu
BSWAP ECX
0Fh
C9h
long
alu
BSWAP EDX
0Fh
CAh
long
alu
BSWAP EBX
0Fh
CBh
long
alu
BSWAP ESP
0Fh
CCh
long
alu
BSWAP EBP
0Fh
CDh
long
alu
BSWAP ESI
0Fh
CEh
long
alu
BSWAP EDI
0Fh
CFh
long
alu
BT mreg16/32, reg16/32
0Fh
A3h
11-xxx-xxx
vector
BT mem16/32, reg16/32
0Fh
A3h
mm-xxx-xxx
vector
BT mreg16/32, imm8
0Fh
BAh
11-100-xxx
vector
BT mem16/32, imm8
0Fh
BAh
mm-100-xxx
vector
BTC mreg16/32, reg16/32
0Fh
BBh
11-xxx-xxx
vector
BTC mem16/32, reg16/32
0Fh
BBh
mm-xxx-xxx
vector
BTC mreg16/32, imm8
0Fh
BAh
11-111-xxx
vector
BTC mem16/32, imm8
0Fh
BAh
mm-111-xxx
vector
BTR mreg16/32, reg16/32
0Fh
B3h
11-xxx-xxx
vector
BTR mem16/32, reg16/32
0Fh
B3h
mm-xxx-xxx
vector
BTR mreg16/32, imm8
0Fh
BAh
11-110-xxx
vector
BTR mem16/32, imm8
0Fh
BAh
mm-110-xxx
vector
BTS mreg16/32, reg16/32
0Fh
ABh
11-xxx-xxx
vector
Chapter 3
vector
Software Environment
59
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 12. Integer Instructions (continued)
Instruction Mnemonic
First
Byte
Second
Byte
ModR/M
Byte
BTS mem16/32, reg16/32
0Fh
ABh
mm-xxx-xxx
vector
BTS mreg16/32, imm8
0Fh
BAh
11-101-xxx
vector
BTS mem16/32, imm8
0Fh
BAh
mm-101-xxx
vector
CALL full pointer
9Ah
vector
CALL near imm16/32
E8h
short
CALL mem16:16/32
FFh
11-011-xxx
vector
CALL near mreg32 (indirect)
FFh
11-010-xxx
vector
CALL near mem32 (indirect)
FFh
mm-010-xxx
vector
CBW/CWDE EAX
98h
vector
CLC
F8h
vector
CLD
FCh
vector
CLI
FAh
vector
CLTS
0Fh
CMC
F5h
CMP mreg8, reg8
38h
11-xxx-xxx
short
alux
CMP mem8, reg8
38h
mm-xxx-xxx
short
load, alux
CMP mreg16/32, reg16/32
39h
11-xxx-xxx
short
alu
CMP mem16/32, reg16/32
39h
mm-xxx-xxx
short
load, alu
CMP reg8, mreg8
3Ah
11-xxx-xxx
short
alux
CMP reg8, mem8
3Ah
mm-xxx-xxx
short
load, alux
CMP reg16/32, mreg16/32
3Bh
11-xxx-xxx
short
alu
CMP reg16/32, mem16/32
3Bh
mm-xxx-xxx
short
load, alu
CMP AL, imm8
3Ch
short
alux
CMP EAX, imm16/32
3Dh
short
alu
CMP mreg8, imm8
80h
11-111-xxx
short
alux
CMP mem8, imm8
80h
mm-111-xxx
short
load, alux
CMP mreg16/32, imm16/32
81h
11-111-xxx
short
alu
CMP mem16/32, imm16/32
81h
mm-111-xxx
short
load, alu
CMP mreg16/32, imm8 (signed ext.)
83h
11-111-xxx
long
load, alu
CMP mem16/32, imm8 (signed ext.)
83h
mm-111-xxx
long
load, alu
CMPSB mem8, mem8
A6h
vector
CMPSW mem16, mem32
A7h
vector
CMPSD mem32, mem32
A7h
vector
CMPXCHG mreg8, reg8
0Fh
B0h
11-xxx-xxx
vector
CMPXCHG mem8, reg8
0Fh
B0h
mm-xxx-xxx
vector
60
06h
Decode RISC86
Type Operations
store
vector
vector
Software Environment
Chapter 3
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 12. Integer Instructions (continued)
First
Byte
Second
Byte
ModR/M
Byte
CMPXCHG mreg16/32, reg16/32
0Fh
B1h
11-xxx-xxx
vector
CMPXCHG mem16/32, reg16/32
0Fh
B1h
mm-xxx-xxx
vector
CMPXCHG8B EDX:EAX
0Fh
C7h
11-xxx-xxx
vector
CMPXCHG8B mem64
0Fh
C7h
mm-xxx-xxx
vector
CPUID
0Fh
A2h
CWD/CDQ EDX, EAX
99h
vector
DAA
27h
vector
DAS
2Fh
vector
DEC EAX
48h
short
alu
DEC ECX
49h
short
alu
DEC EDX
4Ah
short
alu
DEC EBX
4Bh
short
alu
DEC ESP
4Ch
short
alu
DEC EBP
4Dh
short
alu
DEC ESI
4Eh
short
alu
DEC EDI
4Fh
short
alu
DEC mreg8
FEh
11-001-xxx
vector
DEC mem8
FEh
mm-001-xxx
long
DEC mreg16/32
FFh
11-001-xxx
vector
DEC mem16/32
FFh
mm-001-xxx
long
DIV AL, mreg8
F6h
11-110-xxx
vector
DIV AL, mem8
F6h
mm-110-xxx
vector
DIV EAX, mreg16/32
F7h
11-110-xxx
vector
DIV EAX, mem16/32
F7h
mm-110-xxx
vector
IDIV mreg8
F6h
11-111-xxx
vector
IDIV mem8
F6h
mm-111-xxx
vector
IDIV EAX, mreg16/32
F7h
11-111-xxx
vector
IDIV EAX, mem16/32
F7h
mm-111-xxx
vector
IMUL reg16/32, imm16/32
69h
11-xxx-xxx
vector
IMUL reg16/32, mreg16/32, imm16/32
69h
11-xxx-xxx
vector
IMUL reg16/32, mem16/32, imm16/32
69h
mm-xxx-xxx
vector
IMUL reg16/32, imm8 (sign extended)
6Bh
11-xxx-xxx
vector
IMUL reg16/32, mreg16/32, imm8 (signed)
6Bh
11-xxx-xxx
vector
IMUL reg16/32, mem16/32, imm8 (signed)
6Bh
mm-xxx-xxx
vector
IMUL AX, AL, mreg8
F6h
11-101-xxx
vector
Instruction Mnemonic
Chapter 3
Decode RISC86
Type Operations
vector
Software Environment
load, alux, store
load, alu, store
61
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 12. Integer Instructions (continued)
Instruction Mnemonic
First
Byte
IMUL AX, AL, mem8
F6h
mm-101-xxx
vector
IMUL EDX:EAX, EAX, mreg16/32
F7h
11-101-xxx
vector
IMUL EDX:EAX, EAX, mem16/32
F7h
mm-101-xxx
vector
IMUL reg16/32, mreg16/32
0Fh
AFh
11-xxx-xxx
vector
IMUL reg16/32, mem16/32
0Fh
AFh
mm-xxx-xxx
vector
IN AL, imm8
E4h
vector
IN AX, imm8
E5h
vector
IN EAX, imm8
E5h
vector
IN AL, DX
ECh
vector
IN AX, DX
EDh
vector
IN EAX, DX
EDh
vector
INC EAX
40h
short
alu
INC ECX
41h
short
alu
INC EDX
42h
short
alu
INC EBX
43h
short
alu
INC ESP
44h
short
alu
INC EBP
45h
short
alu
INC ESI
46h
short
alu
INC EDI
47h
short
alu
INC mreg8
FEh
11-000-xxx
vector
INC mem8
FEh
mm-000-xxx
long
INC mreg16/32
FFh
11-000-xxx
vector
INC mem16/32
FFh
mm-000-xxx
long
INVD
0Fh
08h
INVLPG
0Fh
01h
JO short disp8
70h
short
branch
JB/JNAE short disp8
71h
short
branch
JNO short disp8
71h
short
branch
JNB/JAE short disp8
73h
short
branch
JZ/JE short disp8
74h
short
branch
JNZ/JNE short disp8
75h
short
branch
JBE/JNA short disp8
76h
short
branch
JNBE/JA short disp8
77h
short
branch
JS short disp8
78h
short
branch
JNS short disp8
79h
short
branch
62
Second
Byte
ModR/M
Byte
Decode RISC86
Type Operations
load, alux, store
load, alu, store
vector
mm-111-xxx
Software Environment
vector
Chapter 3
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 12. Integer Instructions (continued)
Instruction Mnemonic
First
Byte
JP/JPE short disp8
7Ah
short
branch
JNP/JPO short disp8
7Bh
short
branch
JL/JNGE short disp8
7Ch
short
branch
JNL/JGE short disp8
7Dh
short
branch
JLE/JNG short disp8
7Eh
short
branch
JNLE/JG short disp8
7Fh
short
branch
JCXZ/JEC short disp8
E3h
vector
JO near disp16/32
0Fh
80h
short
branch
JNO near disp16/32
0Fh
81h
short
branch
JB/JNAE near disp16/32
0Fh
82h
short
branch
JNB/JAE near disp16/32
0Fh
83h
short
branch
JZ/JE near disp16/32
0Fh
84h
short
branch
JNZ/JNE near disp16/32
0Fh
85h
short
branch
JBE/JNA near disp16/32
0Fh
86h
short
branch
JNBE/JA near disp16/32
0Fh
87h
short
branch
JS near disp16/32
0Fh
88h
short
branch
JNS near disp16/32
0Fh
89h
short
branch
JP/JPE near disp16/32
0Fh
8Ah
short
branch
JNP/JPO near disp16/32
0Fh
8Bh
short
branch
JL/JNGE near disp16/32
0Fh
8Ch
short
branch
JNL/JGE near disp16/32
0Fh
8Dh
short
branch
JLE/JNG near disp16/32
0Fh
8Eh
short
branch
JNLE/JG near disp16/32
0Fh
8Fh
short
branch
JMP near disp16/32 (direct)
E9h
short
branch
JMP far disp32/48 (direct)
EAh
vector
JMP disp8 (short)
EBh
short
JMP far mreg32 (indirect)
EFh
11-101-xxx
vector
JMP far mem32 (indirect)
EFh
mm-101-xxx
vector
JMP near mreg16/32 (indirect)
FFh
11-100-xxx
vector
JMP near mem16/32 (indirect)
FFh
mm-100-xxx
vector
LAHF
9Fh
LAR reg16/32, mreg16/32
0Fh
02h
11-xxx-xxx
vector
LAR reg16/32, mem16/32
0Fh
02h
mm-xxx-xxx
vector
LDS reg16/32, mem32/48
C5h
mm-xxx-xxx
vector
LEA reg16/32, mem16/32
8Dh
mm-xxx-xxx
short
Chapter 3
Second
Byte
ModR/M
Byte
Decode RISC86
Type Operations
branch
vector
Software Environment
load, alu
63
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 12. Integer Instructions (continued)
Instruction Mnemonic
First
Byte
LEAVE
C9h
LES reg16/32, mem32/48
C4h
LFS reg16/32, mem32/48
0Fh
B4h
LGDT mem48
0Fh
01h
LGS reg16/32, mem32/48
0Fh
B5h
LIDT mem48
0Fh
01h
mm-011-xxx
vector
LLDT mreg16
0Fh
00h
11-010-xxx
vector
LLDT mem16
0Fh
00h
mm-010-xxx
vector
LMSW mreg16
0Fh
01h
11-100-xxx
vector
LMSW mem16
0Fh
01h
mm-100-xxx
vector
LODSB AL, mem8
ACh
long
load, alu
LODSW AX, mem16
ADh
long
load, alu
LODSD EAX, mem32
ADh
long
load, alu
LOOP disp8
E2h
short
alu, branch
LOOPE/LOOPZ disp8
E1h
vector
LOOPNE/LOOPNZ disp8
E0h
vector
LSL reg16/32, mreg16/32
0Fh
03h
11-xxx-xxx
vector
LSL reg16/32, mem16/32
0Fh
03h
mm-xxx-xxx
vector
LSS reg16/32, mem32/48
0Fh
B2h
mm-xxx-xxx
vector
LTR mreg16
0Fh
00h
11-011-xxx
vector
LTR mem16
0Fh
00h
mm-011-xxx
vector
MOV mreg8, reg8
88h
11-xxx-xxx
short
alux
MOV mem8, reg8
88h
mm-xxx-xxx
short
store
MOV mreg16/32, reg16/32
89h
11-xxx-xxx
short
alu
MOV mem16/32, reg16/32
89h
mm-xxx-xxx
short
store
MOV reg8, mreg8
8Ah
11-xxx-xxx
short
alux
MOV reg8, mem8
8Ah
mm-xxx-xxx
short
load
MOV reg16/32, mreg16/32
8Bh
11-xxx-xxx
short
alu
MOV reg16/32, mem16/32
8Bh
mm-xxx-xxx
short
load
MOV mreg16, segment reg
8Ch
11-xxx-xxx
long
load
MOV mem16, segment reg
8Ch
mm-xxx-xxx
vector
MOV segment reg, mreg16
8Eh
11-xxx-xxx
vector
MOV segment reg, mem16
8Eh
mm-xxx-xxx
vector
MOV AL, mem8
A0h
short
load
MOV EAX, mem16/32
A1h
short
load
64
Second
Byte
ModR/M
Byte
Decode RISC86
Type Operations
long
mm-xxx-xxx
load, alu, alu
vector
vector
mm-010-xxx
vector
vector
Software Environment
Chapter 3
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 12. Integer Instructions (continued)
Instruction Mnemonic
First
Byte
MOV mem8, AL
A2h
short
store
MOV mem16/32, EAX
A3h
short
store
MOV AL, imm8
B0h
short
limm
MOV CL, imm8
B1h
short
limm
MOV DL, imm8
B2h
short
limm
MOV BL, imm8
B3h
short
limm
MOV AH, imm8
B4h
short
limm
MOV CH, imm8
B5h
short
limm
MOV DH, imm8
B6h
short
limm
MOV BH, imm8
B7h
short
limm
MOV EAX, imm16/32
B8h
short
limm
MOV ECX, imm16/32
B9h
short
limm
MOV EDX, imm16/32
BAh
short
limm
MOV EBX, imm16/32
BBh
short
limm
MOV ESP, imm16/32
BCh
short
limm
MOV EBP, imm16/32
BDh
short
limm
MOV ESI, imm16/32
BEh
short
limm
MOV EDI, imm16/32
BFh
short
limm
MOV mreg8, imm8
C6h
11-000-xxx
short
limm
MOV mem8, imm8
C6h
mm-000-xxx
long
store
MOV mreg16/32, imm16/32
C7h
11-000-xxx
short
limm
MOV mem16/32, imm16/32
C7h
mm-000-xxx
long
store
MOVSB mem8,mem8
A4h
long
load, store, alux, alux
MOVSD mem16, mem16
A5h
long
load, store, alu, alu
MOVSW mem32, mem32
A5h
long
load, store, alu, alu
MOVSX reg16/32, mreg8
0Fh
BEh
11-xxx-xxx
short
alu
MOVSX reg16/32, mem8
0Fh
BEh
mm-xxx-xxx
short
load, alu
MOVSX reg32, mreg16
0Fh
BFh
11-xxx-xxx
short
alu
MOVSX reg32, mem16
0Fh
BFh
mm-xxx-xxx
short
load, alu
MOVZX reg16/32, mreg8
0Fh
B6h
11-xxx-xxx
short
alu
MOVZX reg16/32, mem8
0Fh
B6h
mm-xxx-xxx
short
load, alu
MOVZX reg32, mreg16
0Fh
B7h
11-xxx-xxx
short
alu
MOVZX reg32, mem16
0Fh
B7h
mm-xxx-xxx
short
load, alu
MUL AL, mreg8
F6h
11-100-xxx
vector
MUL AL, mem8
F6h
mm-100-xxx
vector
Chapter 3
Second
Byte
ModR/M
Byte
Software Environment
Decode RISC86
Type Operations
65
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 12. Integer Instructions (continued)
Instruction Mnemonic
First
Byte
Second
Byte
ModR/M
Byte
Decode RISC86
Type Operations
MUL EAX, mreg16/32
F7h
11-100-xxx
vector
MUL EAX, mem16/32
F7h
mm-100-xxx
vector
NEG mreg8
F6h
11-011-xxx
short
NEG mem8
F6h
mm-011-xxx
vector
NEG mreg16/32
F7h
11-011-xxx
short
NEG mem16/32
F7h
mm-011-xxx
vector
NOP (XCHG EAX, EAX)
90h
NOT mreg8
F6h
NOT mem8
alux
alu
short
limm
11-010-xxx
short
alux
F6h
mm-010-xxx
vector
NOT mreg16/32
F7h
11-010-xxx
short
NOT mem16/32
F7h
mm-010-xxx
vector
OR mreg8, reg8
08h
11-xxx-xxx
short
alux
OR mem8, reg8
08h
mm-xxx-xxx
long
load, alux, store
OR mreg16/32, reg16/32
09h
11-xxx-xxx
short
alu
OR mem16/32, reg16/32
09h
mm-xxx-xxx
long
load, alu, store
OR reg8, mreg8
0Ah
11-xxx-xxx
short
alux
OR reg8, mem8
0Ah
mm-xxx-xxx
short
load, alux
OR reg16/32, mreg16/32
0Bh
11-xxx-xxx
short
alu
OR reg16/32, mem16/32
0Bh
mm-xxx-xxx
short
load, alu
OR AL, imm8
0Ch
short
alux
OR EAX, imm16/32
0Dh
short
alu
OR mreg8, imm8
80h
11-001-xxx
short
alux
OR mem8, imm8
80h
mm-001-xxx
long
load, alux, store
OR mreg16/32, imm16/32
81h
11-001-xxx
short
alu
OR mem16/32, imm16/32
81h
mm-001-xxx
long
load, alu, store
OR mreg16/32, imm8 (signed ext.)
83h
11-001-xxx
short
alux
OR mem16/32, imm8 (signed ext.)
83h
mm-001-xxx
long
load, alux, store
OUT imm8, AL
E6h
vector
OUT imm8, AX
E7h
vector
OUT imm8, EAX
E7h
vector
OUT DX, AL
EEh
vector
OUT DX, AX
EFh
vector
OUT DX, EAX
EFh
vector
POP ES
07h
vector
POP SS
17h
vector
66
Software Environment
alu
Chapter 3
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 12. Integer Instructions (continued)
Instruction Mnemonic
First
Byte
Second
Byte
ModR/M
Byte
Decode RISC86
Type Operations
POP DS
1Fh
POP FS
0Fh
A1h
vector
POP GS
0Fh
A9h
vector
POP EAX
58h
short
load, alu
POP ECX
59h
short
load, alu
POP EDX
5Ah
short
load, alu
POP EBX
5Bh
short
load, alu
POP ESP
5Ch
short
load, alu
POP EBP
5Dh
short
load, alu
POP ESI
5Eh
short
load, alu
POP EDI
5Fh
short
load, alu
POP mreg 16/32
8Fh
11-000-xxx
short
load, alu
POP mem 16/32
8Fh
mm-000-xxx
long
load, store, alu
POPA/POPAD
61h
vector
POPF/POPFD
9Dh
vector
PUSH ES
06h
long
PUSH CS
0Eh
vector
PUSH FS
0Fh
A0h
vector
PUSH GS
0Fh
A8h
vector
PUSH SS
16h
vector
PUSH DS
1Eh
long
load, store
PUSH EAX
50h
short
store
PUSH ECX
51h
short
store
PUSH EDX
52h
short
store
PUSH EBX
53h
short
store
PUSH ESP
54h
short
store
PUSH EBP
55h
short
store
PUSH ESI
56h
short
store
PUSH EDI
57h
short
store
PUSH imm8
6Ah
long
store
PUSH imm16/32
68h
long
store
PUSH mreg16/32
FFh
11-110-xxx
vector
PUSH mem16/32
FFh
mm-110-xxx
long
PUSHA/PUSHAD
60h
vector
PUSHF/PUSHFD
9Ch
vector
Chapter 3
vector
Software Environment
load, store
load, store
67
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 12. Integer Instructions (continued)
Instruction Mnemonic
First
Byte
RCL mreg8, imm8
C0h
11-010-xxx
vector
RCL mem8, imm8
C0h
mm-010-xxx
vector
RCL mreg16/32, imm8
C1h
11-010-xxx
vector
RCL mem16/32, imm8
C1h
mm-010-xxx
vector
RCL mreg8, 1
D0h
11-010-xxx
vector
RCL mem8, 1
D0h
mm-010-xxx
vector
RCL mreg16/32, 1
D1h
11-010-xxx
vector
RCL mem16/32, 1
D1h
mm-010-xxx
vector
RCL mreg8, CL
D2h
11-010-xxx
vector
RCL mem8, CL
D2h
mm-010-xxx
vector
RCL mreg16/32, CL
D3h
11-010-xxx
vector
RCL mem16/32, CL
D3h
mm-010-xxx
vector
RCR mreg8, imm8
C0h
11-011-xxx
vector
RCR mem8, imm8
C0h
mm-011-xxx
vector
RCR mreg16/32, imm8
C1h
11-011-xxx
vector
RCR mem16/32, imm8
C1h
mm-011-xxx
vector
RCR mreg8, 1
D0h
11-011-xxx
vector
RCR mem8, 1
D0h
mm-011-xxx
vector
RCR mreg16/32, 1
D1h
11-011-xxx
vector
RCR mem16/32, 1
D1h
mm-011-xxx
vector
RCR mreg8, CL
D2h
11-011-xxx
vector
RCR mem8, CL
D2h
mm-011-xxx
vector
RCR mreg16/32, CL
D3h
11-011-xxx
vector
RCR mem16/32, CL
D3h
mm-011-xxx
vector
RET near imm16
C2h
vector
RET near
C3h
vector
RET far imm16
CAh
vector
RET far
CBh
vector
ROL mreg8, imm8
C0h
11-000-xxx
vector
ROL mem8, imm8
C0h
mm-000-xxx
vector
ROL mreg16/32, imm8
C1h
11-000-xxx
vector
ROL mem16/32, imm8
C1h
mm-000-xxx
vector
ROL mreg8, 1
D0h
11-000-xxx
vector
ROL mem8, 1
D0h
mm-000-xxx
vector
ROL mreg16/32, 1
D1h
11-000-xxx
vector
68
Second
Byte
ModR/M
Byte
Software Environment
Decode RISC86
Type Operations
Chapter 3
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 12. Integer Instructions (continued)
Instruction Mnemonic
First
Byte
ROL mem16/32, 1
D1h
mm-000-xxx
vector
ROL mreg8, CL
D2h
11-000-xxx
vector
ROL mem8, CL
D2h
mm-000-xxx
vector
ROL mreg16/32, CL
D3h
11-000-xxx
vector
ROL mem16/32, CL
D3h
mm-000-xxx
vector
ROR mreg8, imm8
C0h
11-001-xxx
vector
ROR mem8, imm8
C0h
mm-001-xxx
vector
ROR mreg16/32, imm8
C1h
11-001-xxx
vector
ROR mem16/32, imm8
C1h
mm-001-xxx
vector
ROR mreg8, 1
D0h
11-001-xxx
vector
ROR mem8, 1
D0h
mm-001-xxx
vector
ROR mreg16/32, 1
D1h
11-001-xxx
vector
ROR mem16/32, 1
D1h
mm-001-xxx
vector
ROR mreg8, CL
D2h
11-001-xxx
vector
ROR mem8, CL
D2h
mm-001-xxx
vector
ROR mreg16/32, CL
D3h
11-001-xxx
vector
ROR mem16/32, CL
D3h
mm-001-xxx
vector
SAHF
9Eh
SAR mreg8, imm8
C0h
11-111-xxx
short
SAR mem8, imm8
C0h
mm-111-xxx
vector
SAR mreg16/32, imm8
C1h
11-111-xxx
short
SAR mem16/32, imm8
C1h
mm-111-xxx
vector
SAR mreg8, 1
D0h
11-111-xxx
short
SAR mem8, 1
D0h
mm-111-xxx
vector
SAR mreg16/32, 1
D1h
11-111-xxx
short
SAR mem16/32, 1
D1h
mm-111-xxx
vector
SAR mreg8, CL
D2h
11-111-xxx
short
SAR mem8, CL
D2h
mm-111-xxx
vector
SAR mreg16/32, CL
D3h
11-111-xxx
short
SAR mem16/32, CL
D3h
mm-111-xxx
vector
SBB mreg8, reg8
18h
11-xxx-xxx
vector
SBB mem8, reg8
18h
mm-xxx-xxx
vector
SBB mreg16/32, reg16/32
19h
11-xxx-xxx
vector
SBB mem16/32, reg16/32
19h
mm-xxx-xxx
vector
SBB reg8, mreg8
1Ah
11-xxx-xxx
vector
Chapter 3
Second
Byte
ModR/M
Byte
Decode RISC86
Type Operations
vector
Software Environment
alux
alu
alux
alu
alux
alu
69
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 12. Integer Instructions (continued)
Instruction Mnemonic
First
Byte
SBB reg8, mem8
1Ah
mm-xxx-xxx
vector
SBB reg16/32, mreg16/32
1Bh
11-xxx-xxx
vector
SBB reg16/32, mem16/32
1Bh
mm-xxx-xxx
vector
SBB AL, imm8
1Ch
vector
SBB EAX, imm16/32
1Dh
vector
SBB mreg8, imm8
80h
11-011-xxx
vector
SBB mem8, imm8
80h
mm-011-xxx
vector
SBB mreg16/32, imm16/32
81h
11-011-xxx
vector
SBB mem16/32, imm16/32
81h
mm-011-xxx
vector
SBB mreg16/32, imm8 (signed ext.)
83h
11-011-xxx
vector
SBB mem16/32, imm8 (signed ext.)
83h
mm-011-xxx
vector
SCASB AL, mem8
AEh
vector
SCASW AX, mem16
AFh
vector
SCASD EAX, mem32
AFh
vector
SETO mreg8
0Fh
90h
11-xxx-xxx
vector
SETO mem8
0Fh
90h
mm-xxx-xxx
vector
SETNO mreg8
0Fh
91h
11-xxx-xxx
vector
SETNO mem8
0Fh
91h
mm-xxx-xxx
vector
SETB/SETNAE mreg8
0Fh
92h
11-xxx-xxx
vector
SETB/SETNAE mem8
0Fh
92h
mm-xxx-xxx
vector
SETNB/SETAE mreg8
0Fh
93h
11-xxx-xxx
vector
SETNB/SETAE mem8
0Fh
93h
mm-xxx-xxx
vector
SETZ/SETE mreg8
0Fh
94h
11-xxx-xxx
vector
SETZ/SETE mem8
0Fh
94h
mm-xxx-xxx
vector
SETNZ/SETNE mreg8
0Fh
95h
11-xxx-xxx
vector
SETNZ/SETNE mem8
0Fh
95h
mm-xxx-xxx
vector
SETBE/SETNA mreg8
0Fh
96h
11-xxx-xxx
vector
SETBE/SETNA mem8
0Fh
96h
mm-xxx-xxx
vector
SETNBE/SETA mreg8
0Fh
97h
11-xxx-xxx
vector
SETNBE/SETA mem8
0Fh
97h
mm-xxx-xxx
vector
SETS mreg8
0Fh
98h
11-xxx-xxx
vector
SETS mem8
0Fh
98h
mm-xxx-xxx
vector
SETNS mreg8
0Fh
99h
11-xxx-xxx
vector
SETNS mem8
0Fh
99h
mm-xxx-xxx
vector
SETP/SETPE mreg8
0Fh
9Ah
11-xxx-xxx
vector
70
Second
Byte
ModR/M
Byte
Software Environment
Decode RISC86
Type Operations
Chapter 3
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 12. Integer Instructions (continued)
First
Byte
Second
Byte
ModR/M
Byte
SETP/SETPE mem8
0Fh
9Ah
mm-xxx-xxx
vector
SETNP/SETPO mreg8
0Fh
9Bh
11-xxx-xxx
vector
SETNP/SETPO mem8
0Fh
9Bh
mm-xxx-xxx
vector
SETL/SETNGE mreg8
0Fh
9Ch
11-xxx-xxx
vector
SETL/SETNGE mem8
0Fh
9Ch
mm-xxx-xxx
vector
SETNL/SETGE mreg8
0Fh
9Dh
11-xxx-xxx
vector
SETNL/SETGE mem8
0Fh
9Dh
mm-xxx-xxx
vector
SETLE/SETNG mreg8
0Fh
9Eh
11-xxx-xxx
vector
SETLE/SETNG mem8
0Fh
9Eh
mm-xxx-xxx
vector
SETNLE/SETG mreg8
0Fh
9Fh
11-xxx-xxx
vector
SETNLE/SETG mem8
0Fh
9Fh
mm-xxx-xxx
vector
SGDT mem48
0Fh
01h
mm-000-xxx
vector
SIDT mem48
0Fh
01h
mm-001-xxx
vector
SHL/SAL mreg8, imm8
C0h
11-100-xxx
short
SHL/SAL mem8, imm8
C0h
mm-100-xxx
vector
SHL/SAL mreg16/32, imm8
C1h
11-100-xxx
short
SHL/SAL mem16/32, imm8
C1h
mm-100-xxx
vector
SHL/SAL mreg8, 1
D0h
11-100-xxx
short
SHL/SAL mem8, 1
D0h
mm-100-xxx
vector
SHL/SAL mreg16/32, 1
D1h
11-100-xxx
short
SHL/SAL mem16/32, 1
D1h
mm-100-xxx
vector
SHL/SAL mreg8, CL
D2h
11-100-xxx
short
SHL/SAL mem8, CL
D2h
mm-100-xxx
vector
SHL/SAL mreg16/32, CL
D3h
11-100-xxx
short
SHL/SAL mem16/32, CL
D3h
mm-100-xxx
vector
SHR mreg8, imm8
C0h
11-101-xxx
short
SHR mem8, imm8
C0h
mm-101-xxx
vector
SHR mreg16/32, imm8
C1h
11-101-xxx
short
SHR mem16/32, imm8
C1h
mm-101-xxx
vector
SHR mreg8, 1
D0h
11-101-xxx
short
SHR mem8, 1
D0h
mm-101-xxx
vector
SHR mreg16/32, 1
D1h
11-101-xxx
short
SHR mem16/32, 1
D1h
mm-101-xxx
vector
SHR mreg8, CL
D2h
11-101-xxx
short
SHR mem8, CL
D2h
mm-101-xxx
vector
Instruction Mnemonic
Chapter 3
Software Environment
Decode RISC86
Type Operations
alux
alu
alux
alu
alux
alu
alux
alu
alux
alu
alux
71
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 12. Integer Instructions (continued)
Instruction Mnemonic
First
Byte
SHR mreg16/32, CL
D3h
11-101-xxx
short
SHR mem16/32, CL
D3h
mm-101-xxx
vector
SHLD mreg16/32, reg16/32, imm8
0Fh
A4h
11-xxx-xxx
vector
SHLD mem16/32, reg16/32, imm8
0Fh
A4h
mm-xxx-xxx
vector
SHLD mreg16/32, reg16/32, CL
0Fh
A5h
11-xxx-xxx
vector
SHLD mem16/32, reg16/32, CL
0Fh
A5h
mm-xxx-xxx
vector
SHRD mreg16/32, reg16/32, imm8
0Fh
ACh
11-xxx-xxx
vector
SHRD mem16/32, reg16/32, imm8
0Fh
ACh
mm-xxx-xxx
vector
SHRD mreg16/32, reg16/32, CL
0Fh
ADh
11-xxx-xxx
vector
SHRD mem16/32, reg16/32, CL
0Fh
ADh
mm-xxx-xxx
vector
SLDT mreg16
0Fh
00h
11-000-xxx
vector
SLDT mem16
0Fh
00h
mm-000-xxx
vector
SMSW mreg16
0Fh
01h
11-100-xxx
vector
SMSW mem16
0Fh
01h
mm-100-xxx
vector
STC
F9h
vector
STD
FDh
vector
STI
FBh
vector
STOSB mem8, AL
AAh
long
store, alux
STOSW mem16, AX
ABh
long
store, alux
STOSD mem32, EAX
ABh
long
store, alux
STR mreg16
0Fh
00h
11-001-xxx
vector
STR mem16
0Fh
00h
mm-001-xxx
vector
SUB mreg8, reg8
28h
11-xxx-xxx
short
alux
SUB mem8, reg8
28h
mm-xxx-xxx
long
load, alux, store
SUB mreg16/32, reg16/32
29h
11-xxx-xxx
short
alu
SUB mem16/32, reg16/32
29h
mm-xxx-xxx
long
load, alu, store
SUB reg8, mreg8
2Ah
11-xxx-xxx
short
alux
SUB reg8, mem8
2Ah
mm-xxx-xxx
short
load, alux
SUB reg16/32, mreg16/32
2Bh
11-xxx-xxx
short
alu
SUB reg16/32, mem16/32
2Bh
mm-xxx-xxx
short
load, alu
SUB AL, imm8
2Ch
short
alux
SUB EAX, imm16/32
2Dh
short
alu
SUB mreg8, imm8
80h
11-101-xxx
short
alux
SUB mem8, imm8
80h
mm-101-xxx
long
load, alux, store
SUB mreg16/32, imm16/32
81h
11-101-xxx
short
alu
72
Second
Byte
ModR/M
Byte
Software Environment
Decode RISC86
Type Operations
alu
Chapter 3
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 12. Integer Instructions (continued)
Instruction Mnemonic
First
Byte
SUB mem16/32, imm16/32
81h
mm-101-xxx
long
load, alu, store
SUB mreg16/32, imm8 (signed ext.)
83h
11-101-xxx
short
alux
SUB mem16/32, imm8 (signed ext.)
83h
mm-101-xxx
long
load, alux, store
SYSCALL
0Fh
05h
vector
SYSRET
0Fh
07h
vector
TEST mreg8, reg8
84h
11-xxx-xxx
short
TEST mem8, reg8
84h
mm-xxx-xxx
vector
TEST mreg16/32, reg16/32
85h
11-xxx-xxx
short
TEST mem16/32, reg16/32
85h
mm-xxx-xxx
vector
TEST AL, imm8
A8h
long
alux
TEST EAX, imm16/32
A9h
long
alu
TEST mreg8, imm8
F6h
11-000-xxx
long
alux
TEST mem8, imm8
F6h
mm-000-xxx
long
load, alux
TEST mreg16/32, imm16/32
F7h
11-000-xxx
long
alu
TEST mem16/32, imm16/32
F7h
mm-000-xxx
long
load, alu
VERR mreg16
0Fh
00h
11-100-xxx
vector
VERR mem16
0Fh
00h
mm-100-xxx
vector
VERW mreg16
0Fh
00h
11-101-xxx
vector
VERW mem16
0Fh
00h
mm-101-xxx
vector
WAIT
9Bh
WBINVD
0Fh
09h
XADD mreg8, reg8
0Fh
C0h
11-100-xxx
vector
XADD mem8, reg8
0Fh
C0h
mm-100-xxx
vector
XADD mreg16/32, reg16/32
0Fh
C1h
11-101-xxx
vector
XADD mem16/32, reg16/32
0Fh
C1h
mm-101-xxx
vector
XCHG reg8, mreg8
86h
11-xxx-xxx
vector
XCHG reg8, mem8
86h
mm-xxx-xxx
vector
XCHG reg16/32, mreg16/32
87h
11-xxx-xxx
vector
XCHG reg16/32, mem16/32
87h
mm-xxx-xxx
vector
XCHG EAX, EAX
90h
short
limm
XCHG EAX, ECX
91h
long
alu, alu, alu
XCHG EAX, EDX
92h
long
alu, alu, alu
XCHG EAX, EBX
93h
long
alu, alu, alu
XCHG EAX, ESP
94h
long
alu, alu, alu
XCHG EAX, EBP
95h
long
alu, alu, alu
Chapter 3
Second
Byte
ModR/M
Byte
Decode RISC86
Type Operations
alux
alu
vector
vector
Software Environment
73
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 12. Integer Instructions (continued)
Instruction Mnemonic
First
Byte
Second
Byte
ModR/M
Byte
Decode RISC86
Type Operations
XCHG EAX, ESI
96h
long
alu, alu, alu
XCHG EAX, EDI
97h
long
alu, alu, alu
XLAT
D7h
vector
XOR mreg8, reg8
30h
11-xxx-xxx
short
alux
XOR mem8, reg8
30h
mm-xxx-xxx
long
load, alux, store
XOR mreg16/32, reg16/32
31h
11-xxx-xxx
short
alu
XOR mem16/32, reg16/32
31h
mm-xxx-xxx
long
load, alu, store
XOR reg8, mreg8
32h
11-xxx-xxx
short
alux
XOR reg8, mem8
32h
mm-xxx-xxx
short
load, alux
XOR reg16/32, mreg16/32
33h
11-xxx-xxx
short
alu
XOR reg16/32, mem16/32
33h
mm-xxx-xxx
short
load, alu
XOR AL, imm8
34h
short
alux
XOR EAX, imm16/32
35h
short
alu
XOR mreg8, imm8
80h
11-110-xxx
short
alux
XOR mem8, imm8
80h
mm-110-xxx
long
load, alux, store
XOR mreg16/32, imm16/32
81h
11-110-xxx
short
alu
XOR mem16/32, imm16/32
81h
mm-110-xxx
long
load, alu, store
XOR mreg16/32, imm8 (signed ext.)
83h
11-110-xxx
short
alux
XOR mem16/32, imm8 (signed ext.)
83h
mm-110-xxx
long
load, alux, store
Table 13. Floating-Point Instructions
Instruction Mnemonic
First
Byte
Second
Byte
F2XM1
D9h
F0h
short
float
FABS
D9h
F1h
short
float
FADD ST(0), ST(i)1
D8h
11-000-xxx
short
float
FADD ST(0), mem32real
D8h
mm-000-xxx
short
fload, float
FADD ST(i), ST(0)1
DCh
11-000-xxx
short
float
DCh
mm-000-xxx
short
fload, float
DEh
11-000-xxx
short
float
FBLD
DFh
mm-100-xxx
vector
FBSTP
DFh
mm-110-xxx
vector
FCHS
D9h
E0h
short
FCLEX
DBh
E2h
vector
FADD ST(0), mem64real
FADDP ST(i), ST(0)
74
1
ModR/M
Byte
Software Environment
Decode RISC86
Type
Operations
float
Chapter 3
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 13. Floating-Point Instructions (continued)
Instruction Mnemonic
First
Byte
FCOM ST(0), ST(i)1
D8h
11-010-xxx
short
float
FCOM ST(0), mem32real
D8h
mm-010-xxx
short
fload, float
FCOM ST(0), mem64real
DCh
mm-010-xxx
short
fload, float
FCOMP ST(0), ST(i)1
D8h
11-011-xxx
short
float
FCOMP ST(0), mem32real
D8h
mm-011-xxx
short
fload, float
FCOMP ST(0), mem64real
DCh
mm-011-xxx
short
fload, float
FCOMPP
DEh
D9h
11-011-001
short
float
FCOS
D9h
FFh
short
float
D9h
F6h
short
float
FDECSTP
1
Second
Byte
ModR/M
Byte
Decode RISC86
Type
Operations
D8h
11-110-xxx
short
float
FDIV ST(0), ST(i) (double precision)1
D8h
11-110-xxx
short
float
FDIV ST(0), ST(i) (extended precision)1
D8h
11-110-xxx
short
float
FDIV ST(i), ST(0) (single precision)1
DCh
11-111-xxx
short
float
FDIV ST(i), ST(0) (double precision)1
DCh
11-111-xxx
short
float
FDIV ST(i), ST(0) (extended precision)1
DCh
11-111-xxx
short
float
FDIV ST(0), mem32real
D8h
mm-110-xxx
short
fload, float
FDIV ST(0), mem64real
FDIV ST(0), ST(i) (single precision)
DCh
mm-110-xxx
short
fload, float
1
FDIVP ST(0), ST(i)
DEh
11-111-xxx
short
float
FDIVR ST(0), ST(i)1
D8h
11-110-xxx
short
float
FDIVR ST(i), ST(0)1
DCh
11-111-xxx
short
float
FDIVR ST(0), mem32real
D8h
mm-111-xxx
short
fload, float
FDIVR ST(0), mem64real
DCh
mm-111-xxx
short
fload, float
DEh
11-110-xxx
short
float
FFREE ST(i)1
DDh
11-000-xxx
short
float
FIADD ST(0), mem32int
DAh
mm-000-xxx
short
fload, float
FIADD ST(0), mem16int
DEh
mm-000-xxx
short
fload, float
FICOM ST(0), mem32int
DAh
mm-010-xxx
short
fload, float
FICOM ST(0), mem16int
DEh
mm-010-xxx
short
fload, float
FICOMP ST(0), mem32int
DAh
mm-011-xxx
short
fload, float
FICOMP ST(0), mem16int
DEh
mm-011-xxx
short
fload, float
FIDIV ST(0), mem32int
DAh
mm-110-xxx
short
fload, float
FIDIV ST(0), mem16int
DEh
mm-110-xxx
short
fload, float
FIDIVR ST(0), mem32int
DAh
mm-111-xxx
short
fload, float
FDIVRP ST(i), ST(0)
Chapter 3
1
Software Environment
75
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 13. Floating-Point Instructions (continued)
Instruction Mnemonic
First
Byte
FIDIVR ST(0), mem16int
DEh
mm-111-xxx
short
fload, float
FILD mem16int
DFh
mm-000-xxx
short
fload, float
FILD mem32int
DBh
mm-000-xxx
short
fload, float
FILD mem64int
DFh
mm-101-xxx
short
fload, float
FIMUL ST(0), mem32int
DAh
mm-001-xxx
short
fload, float
FIMUL ST(0), mem16int
DEh
mm-001-xxx
short
fload, float
FINCSTP
D9h
F7h
short
FINIT
DBh
E3h
vector
FIST mem16int
DFh
mm-010-xxx
short
fload, float
FIST mem32int
DBh
mm-010-xxx
short
fload, float
FISTP mem16int
DFh
mm-011-xxx
short
fload, float
FISTP mem32int
DBh
mm-011-xxx
short
fload, float
FISTP mem64int
DFh
mm-111-xxx
short
fload, float
FISUB ST(0), mem32int
DAh
mm-100-xxx
short
fload, float
FISUB ST(0), mem16int
DEh
mm-100-xxx
short
fload, float
FISUBR ST(0), mem32int
DAh
mm-101-xxx
short
fload, float
FISUBR ST(0), mem16int
DEh
mm-101-xxx
short
fload, float
FLD ST(i)1
D9h
11-000-xxx
short
fload, float
FLD mem32real
D9h
mm-000-xxx
short
fload, float
FLD mem64real
DDh
mm-000-xxx
short
fload, float
FLD mem80real
DBh
mm-101-xxx
vector
FLD1
D9h
FLDCW
D9h
mm-101-xxx
vector
FLDENV
D9h
mm-100-xxx
short
fload, float
FLDL2E
D9h
EAh
short
float
FLDL2T
D9h
E9h
short
float
FLDLG2
D9h
ECh
short
float
FLDLN2
D9h
EDh
short
float
FLDPI
D9h
EBh
short
float
FLDZ
D9h
EEh
short
float
FMUL ST(0), ST(i)1
D8h
11-001-xxx
short
float
FMUL ST(i), ST(0)1
DCh
11-001-xxx
short
float
FMUL ST(0), mem32real
D8h
mm-001-xxx
short
fload, float
FMUL ST(0), mem64real
DCh
mm-001-xxx
short
fload, float
FMULP ST(0), ST(i)1
DEh
11-001-xxx
short
float
76
Second
Byte
ModR/M
Byte
E8h
Decode RISC86
Type
Operations
short
Software Environment
fload, float
Chapter 3
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 13. Floating-Point Instructions (continued)
Instruction Mnemonic
First
Byte
Second
Byte
ModR/M
Byte
FNOP
D9h
D0h
short
float
FPATAN
D9h
F3h
short
float
FPREM
D9h
F8h
short
float
FPREM1
D9h
F5h
short
float
FPTAN
D9h
F2h
vector
FRNDINT
D9h
FCh
short
FRSTOR
DDh
mm-100-xxx
vector
FSAVE
DDh
mm-110-xxx
vector
FSCALE
D9h
FDh
short
float
FSIN
D9h
FEh
short
float
FSINCOS
D9h
FBh
vector
FSQRT (single precision)
D9h
FAh
short
float
FSQRT (double precision)
D9h
FAh
short
float
FSQRT (extended precision)
D9h
FAh
short
float
FST mem32real
D9h
mm-010-xxx
short
fstore
FST mem64real
DDh
mm-010-xxx
short
fstore
FST ST(i)1
DDh
11-010-xxx
short
fstore
FSTCW
D9h
mm-111-xxx
vector
FSTENV
D9h
mm-110-xxx
vector
FSTP mem32real
D9h
mm-011-xxx
short
fstore
FSTP mem64real
DDh
mm-011-xxx
short
fstore
FSTP mem80real
D9h
mm-111-xxx
vector
FSTP ST(i)1
DDh
11-011-xxx
short
FSTSW AX
DFh
FSTSW mem16
DDh
mm-111-xxx
vector
FSUB ST(0), mem32real
D8h
mm-100-xxx
short
fload, float
FSUB ST(0), mem64real
E0h
Decode RISC86
Type
Operations
float
float
vector
DCh
mm-100-xxx
short
fload, float
1
D8h
11-100-xxx
short
float
FSUB ST(i), ST(0)1
DCh
11-101-xxx
short
float
FSUBP ST(0), ST(i)1
DEh
11-101-xxx
short
float
FSUBR ST(0), mem32real
D8h
mm-101-xxx
short
fload, float
FSUBR ST(0), mem64real
FSUB ST(0), ST(i)
DCh
mm-101-xxx
short
fload, float
1
FSUBR ST(0), ST(i)
D8h
11-100-xxx
short
float
FSUBR ST(i), ST(0)1
DCh
11-101-xxx
short
float
Chapter 3
Software Environment
77
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 13. Floating-Point Instructions (continued)
Instruction Mnemonic
First
Byte
Second
Byte
ModR/M
Byte
FSUBRP ST(i), ST(0)1
DEh
FTST
D9h
FUCOM
DDh
FUCOMP
DDh
FUCOMPP
DAh
FXAM
D9h
FXCH
D9h
FXTRACT
D9h
F4h
vector
FYL2X
D9h
F1h
short
float
FYL2XP1
D9h
F9h
short
float
FWAIT
9Bh
11-100-xxx
Decode RISC86
Type
Operations
short
float
short
float
11-100-xxx
short
float
11-101-xxx
short
float
E9h
short
float
E5h
short
float
short
float
E4h
11-001-xxx
vector
Notes:
1. The last three bits of the modR/M byte select the stack entry ST(i).
Table 14. MMX™ Instructions
Prefix
Byte(s)
First
Byte
EMMS
0Fh
77h
MOVD mmreg, mreg321
0Fh
6Eh
11-xxx-xxx
short
meu
MOVD mmreg, mem32
0Fh
6Eh
mm-xxx-xxx
short
mload
MOVD mreg32, mmreg1
0Fh
7Eh
11-xxx-xxx
short
mstore, load
MOVD mem32, mmreg
0Fh
7Eh
mm-xxx-xxx
short
mstore
MOVQ mmreg1, mmreg2
0Fh
6Fh
11-xxx-xxx
short
meu
MOVQ mmreg, mem64
0Fh
6Fh
mm-xxx-xxx
short
mload
MOVQ mmreg2, mmreg1
0Fh
7Fh
11-xxx-xxx
short
meu
MOVQ mem64, mmreg
0Fh
7Fh
mm-xxx-xxx
short
mstore
PACKSSDW mmreg1, mmreg2
0Fh
6Bh
11-xxx-xxx
short
meu
PACKSSDW mmreg, mem64
0Fh
6Bh
mm-xxx-xxx
short
mload, meu
PACKSSWB mmreg1, mmreg2
0Fh
63h
11-xxx-xxx
short
meu
PACKSSWB mmreg, mem64
0Fh
63h
mm-xxx-xxx
short
mload, meu
PACKUSWB mmreg1, mmreg2
0Fh
67h
11-xxx-xxx
short
meu
PACKUSWB mmreg, mem64
0Fh
67h
mm-xxx-xxx
short
mload, meu
PADDB mmreg1, mmreg2
0Fh
FCh
11-xxx-xxx
short
meu
PADDB mmreg, mem64
0Fh
FCh
mm-xxx-xxx
short
mload, meu
Instruction Mnemonic
78
ModR/M
Byte
Decode RISC86
Type
Operations
vector
Software Environment
Chapter 3
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 14. MMX™ Instructions (continued)
Instruction Mnemonic
Prefix
Byte(s)
First
Byte
ModR/M
Byte
PADDD mmreg1, mmreg2
0Fh
FEh
11-xxx-xxx
short
meu
PADDD mmreg, mem64
0Fh
FEh
mm-xxx-xxx
short
mload, meu
PADDSB mmreg1, mmreg2
0Fh
ECh
11-xxx-xxx
short
meu
PADDSB mmreg, mem64
0Fh
ECh
mm-xxx-xxx
short
mload, meu
PADDSW mmreg1, mmreg2
0Fh
EDh
11-xxx-xxx
short
meu
PADDSW mmreg, mem64
0Fh
EDh
mm-xxx-xxx
short
mload, meu
PADDUSB mmreg1, mmreg2
0Fh
DCh
11-xxx-xxx
short
meu
PADDUSB mmreg, mem64
0Fh
DCh
mm-xxx-xxx
short
mload, meu
PADDUSW mmreg1, mmreg2
0Fh
DDh
11-xxx-xxx
short
meu
PADDUSW mmreg, mem64
0Fh
DDh
mm-xxx-xxx
short
mload, meu
PADDW mmreg1, mmreg2
0Fh
FDh
11-xxx-xxx
short
meu
PADDW mmreg, mem64
0Fh
FDh
mm-xxx-xxx
short
mload, meu
PAND mmreg1, mmreg2
0Fh
DBh
11-xxx-xxx
short
meu
PAND mmreg, mem64
0Fh
DBh
mm-xxx-xxx
short
mload, meu
PANDN mmreg1, mmreg2
0Fh
DFh
11-xxx-xxx
short
meu
PANDN mmreg, mem64
0Fh
DFh
mm-xxx-xxx
short
mload, meu
PCMPEQB mmreg1, mmreg2
0Fh
74h
11-xxx-xxx
short
meu
PCMPEQB mmreg, mem64
0Fh
74h
mm-xxx-xxx
short
mload, meu
PCMPEQD mmreg1, mmreg2
0Fh
76h
11-xxx-xxx
short
meu
PCMPEQD mmreg, mem64
0Fh
76h
mm-xxx-xxx
short
mload, meu
PCMPEQW mmreg1, mmreg2
0Fh
75h
11-xxx-xxx
short
meu
PCMPEQW mmreg, mem64
0Fh
75h
mm-xxx-xxx
short
mload, meu
PCMPGTB mmreg1, mmreg2
0Fh
64h
11-xxx-xxx
short
meu
PCMPGTB mmreg, mem64
0Fh
64h
mm-xxx-xxx
short
mload, meu
PCMPGTD mmreg1, mmreg2
0Fh
66h
11-xxx-xxx
short
meu
PCMPGTD mmreg, mem64
0Fh
66h
mm-xxx-xxx
short
mload, meu
PCMPGTW mmreg1, mmreg2
0Fh
65h
11-xxx-xxx
short
meu
PCMPGTW mmreg, mem64
0Fh
65h
mm-xxx-xxx
short
mload, meu
PMADDWD mmreg1, mmreg2
0Fh
F5h
11-xxx-xxx
short
meu
PMADDWD mmreg, mem64
0Fh
F5h
mm-xxx-xxx
short
mload, meu
PMULHW mmreg1, mmreg2
0Fh
E5h
11-xxx-xxx
short
meu
PMULHW mmreg, mem64
0Fh
E5h
mm-xxx-xxx
short
mload, meu
PMULLW mmreg1, mmreg2
0Fh
D5h
11-xxx-xxx
short
meu
PMULLW mmreg, mem64
0Fh
D5h
mm-xxx-xxx
short
mload, meu
POR mmreg1, mmreg2
0Fh
EBh
11-xxx-xxx
short
meu
Chapter 3
Software Environment
Decode RISC86
Type
Operations
79
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 14. MMX™ Instructions (continued)
Prefix
Byte(s)
First
Byte
ModR/M
Byte
POR mmreg, mem64
0Fh
EBh
mm-xxx-xxx
short
mload, meu
PSLLD mmreg1, mmreg2
0Fh
F2h
11-xxx-xxx
short
meu
PSLLD mmreg, mem64
0Fh
F2h
mm-xxx-xxx
short
mload, meu
PSLLD mmreg, imm8
0Fh
72h
11-110-xxx
short
meu
PSLLQ mmreg1, mmreg2
0Fh
F3h
11-xxx-xxx
short
meu
PSLLQ mmreg, mem64
0Fh
F3h
mm-xxx-xxx
short
mload, meu
PSLLQ mmreg, imm8
0Fh
73h
11-110-xxx
short
meu
PSLLW mmreg1, mmreg2
0Fh
F1h
11-xxx-xxx
short
meu
PSLLW mmreg, mem64
0Fh
F1h
mm-xxx-xxx
short
mload, meu
PSLLW mmreg, imm8
0Fh
71h
11-110-xxx
short
meu
PSRAD mmreg1, mmreg2
0Fh
E2h
11-xxx-xxx
short
meu
PSRAD mmreg, mem64
0Fh
E2h
mm-xxx-xxx
short
mload, meu
PSRAD mmreg, imm8
0Fh
72h
11-100-xxx
short
meu
PSRAW mmreg1, mmreg2
0Fh
E1h
11-xxx-xxx
short
meu
PSRAW mmreg, mem64
0Fh
E1h
mm-xxx-xxx
short
mload, meu
PSRAW mmreg, imm8
0Fh
71h
11-100-xxx
short
meu
PSRLD mmreg1, mmreg2
0Fh
D2h
11-xxx-xxx
short
meu
PSRLD mmreg, mem64
0Fh
D2h
mm-xxx-xxx
short
mload, meu
PSRLD mmreg, imm8
0Fh
72h
11-010-xxx
short
meu
PSRLQ mmreg1, mmreg2
0Fh
D3h
11-xxx-xxx
short
meu
PSRLQ mmreg, mem64
0Fh
D3h
mm-xxx-xxx
short
mload, meu
PSRLQ mmreg, imm8
0Fh
73h
11-010-xxx
short
meu
PSRLW mmreg1, mmreg2
0Fh
D1h
11-xxx-xxx
short
meu
PSRLW mmreg, mem64
0Fh
D1h
mm-xxx-xxx
short
mload, meu
PSRLW mmreg, imm8
0Fh
71h
11-010-xxx
short
meu
PSUBB mmreg1, mmreg2
0Fh
F8h
11-xxx-xxx
short
meu
PSUBB mmreg, mem64
0Fh
F8h
mm-xxx-xxx
short
mload, meu
PSUBD mmreg1, mmreg2
0Fh
FAh
11-xxx-xxx
short
meu
PSUBD mmreg, mem64
0Fh
FAh
mm-xxx-xxx
short
mload, meu
PSUBSB mmreg1, mmreg2
0Fh
E8h
11-xxx-xxx
short
meu
PSUBSB mmreg, mem64
0Fh
E8h
mm-xxx-xxx
short
mload, meu
PSUBSW mmreg1, mmreg2
0Fh
E9h
11-xxx-xxx
short
meu
PSUBSW mmreg, mem64
0Fh
E9h
mm-xxx-xxx
short
mload, meu
PSUBUSB mmreg1, mmreg2
0Fh
D8h
11-xxx-xxx
short
meu
PSUBUSB mmreg, mem64
0Fh
D8h
mm-xxx-xxx
short
mload, meu
Instruction Mnemonic
80
Software Environment
Decode RISC86
Type
Operations
Chapter 3
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 14. MMX™ Instructions (continued)
Prefix
Byte(s)
First
Byte
ModR/M
Byte
PSUBUSW mmreg1, mmreg2
0Fh
D9h
11-xxx-xxx
short
meu
PSUBUSW mmreg, mem64
0Fh
D9h
mm-xxx-xxx
short
mload, meu
PSUBW mmreg1, mmreg2
0Fh
F9h
11-xxx-xxx
short
meu
PSUBW mmreg, mem64
0Fh
F9h
mm-xxx-xxx
short
mload, meu
PUNPCKHBW mmreg1, mmreg2
0Fh
68h
11-xxx-xxx
short
meu
PUNPCKHBW mmreg, mem64
0Fh
68h
mm-xxx-xxx
short
mload, meu
PUNPCKHDQ mmreg1, mmreg2
0Fh
6Ah
11-xxx-xxx
short
meu
PUNPCKHDQ mmreg, mem64
0Fh
6Ah
mm-xxx-xxx
short
mload, meu
PUNPCKHWD mmreg1, mmreg2
0Fh
69h
11-xxx-xxx
short
meu
PUNPCKHWD mmreg, mem64
0Fh
69h
mm-xxx-xxx
short
mload, meu
PUNPCKLBW mmreg1, mmreg2
0Fh
60h
11-xxx-xxx
short
meu
PUNPCKLBW mmreg, mem64
0Fh
60h
mm-xxx-xxx
short
mload, meu
PUNPCKLDQ mmreg1, mmreg2
0Fh
62h
11-xxx-xxx
short
meu
PUNPCKLDQ mmreg, mem64
0Fh
62h
mm-xxx-xxx
short
mload, meu
PUNPCKLWD mmreg1, mmreg2
0Fh
61h
11-xxx-xxx
short
meu
PUNPCKLWD mmreg, mem64
0Fh
61h
mm-xxx-xxx
short
mload, meu
PXOR mmreg1, mmreg2
0Fh
EFh
11-xxx-xxx
short
meu
PXOR mmreg, mem64
0Fh
EFh
mm-xxx-xxx
short
mload, meu
Prefix
Byte(s)
Opcode
Byte
ModR/M
Byte
0Fh
0Eh
PAVGUSB mmreg1, mmreg2
0Fh, 0Fh
BFh
11-xxx-xxx
short
meu
PAVGUSB mmreg, mem64
0Fh, 0Fh
BFh
mm-xxx-xxx
short
mload, meu
PF2ID mmreg1, mmreg2
0Fh, 0Fh
1Dh
11-xxx-xxx
short
meu
PF2ID mmreg, mem64
0Fh, 0Fh
1Dh
mm-xxx-xxx
short
mload, meu
PFACC mmreg1, mmreg2
0Fh, 0Fh
AEh
11-xxx-xxx
short
meu
PFACC mmreg, mem64
0Fh, 0Fh
AEh
mm-xxx-xxx
short
mload, meu
PFADD mmreg1, mmreg2
0Fh, 0Fh
9Eh
11-xxx-xxx
short
meu
PFADD mmreg, mem64
0Fh, 0Fh
9Eh
mm-xxx-xxx
short
mload, meu
PFCMPEQ mmreg1, mmreg2
0Fh, 0Fh
B0h
11-xxx-xxx
short
meu
PFCMPEQ mmreg, mem64
0Fh, 0Fh
B0h
mm-xxx-xxx
short
mload, meu
Instruction Mnemonic
Decode RISC86
Type
Operations
Notes:
1. Bits 2, 1, and 0 of the modR/M byte select the integer register.
Table 15. 3DNow!™ Instructions
Instruction Mnemonic
FEMMS
Chapter 3
Decode RISC86
Type Operations
vector
Software Environment
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 15. 3DNow!™ Instructions (continued)
Instruction Mnemonic
Prefix
Byte(s)
Opcode
Byte
ModR/M
Byte
Decode RISC86
Type Operations
PFCMPGE mmreg1, mmreg2
0Fh, 0Fh
90h
11-xxx-xxx
short
meu
PFCMPGE mmreg, mem64
0Fh, 0Fh
90h
mm-xxx-xxx
short
mload, meu
PFCMPGT mmreg1, mmreg2
0Fh, 0Fh
A0h
11-xxx-xxx
short
meu
PFCMPGT mmreg, mem64
0Fh, 0Fh
A0h
mm-xxx-xxx
short
mload, meu
PFMAX mmreg1, mmreg2
0Fh, 0Fh
A4h
11-xxx-xxx
short
meu
PFMAX mmreg, mem64
0Fh, 0Fh
A4h
mm-xxx-xxx
short
mload, meu
PFMIN mmreg1, mmreg2
0Fh, 0Fh
94h
11-xxx-xxx
short
meu
PFMIN mmreg, mem64
0Fh, 0Fh
94h
mm-xxx-xxx
short
mload, meu
PFMUL mmreg1, mmreg2
0Fh, 0Fh
B4h
11-xxx-xxx
short
meu
PFMUL mmreg, mem64
0Fh, 0Fh
B4h
mm-xxx-xxx
short
mload, meu
PFRCP mmreg1, mmreg2
0Fh, 0Fh
96h
11-xxx-xxx
short
meu
PFRCP mmreg, mem64
0Fh, 0Fh
96h
mm-xxx-xxx
short
mload, meu
PFRCPIT1 mmreg1, mmreg2
0Fh, 0Fh
A6h
11-xxx-xxx
short
meu
PFRCPIT1 mmreg, mem64
0Fh, 0Fh
A6h
mm-xxx-xxx
short
mload, meu
PFRCPIT2 mmreg1, mmreg2
0Fh, 0Fh
B6h
11-xxx-xxx
short
meu
PFRCPIT2 mmreg, mem64
0Fh, 0Fh
B6h
mm-xxx-xxx
short
mload, meu
PFRSQIT1 mmreg1, mmreg2
0Fh, 0Fh
A7h
11-xxx-xxx
short
meu
PFRSQIT1 mmreg, mem64
0Fh, 0Fh
A7h
mm-xxx-xxx
short
mload, meu
PFRSQRT mmreg1, mmreg2
0Fh, 0Fh
97h
11-xxx-xxx
short
meu
PFRSQRT mmreg, mem64
0Fh, 0Fh
97h
mm-xxx-xxx
short
mload, meu
PFSUB mmreg1, mmreg2
0Fh, 0Fh
9Ah
11-xxx-xxx
short
meu
PFSUB mmreg, mem64
0Fh, 0Fh
9Ah
mm-xxx-xxx
short
mload, meu
PFSUBR mmreg1, mmreg2
0Fh, 0Fh
AAh
11-xxx-xxx
short
meu
PFSUBR mmreg, mem64
0Fh, 0Fh
AAh
mm-xxx-xxx
short
mload, meu
PI2FD mmreg1, mmreg2
0Fh, 0Fh
0Dh
11-xxx-xxx
short
meu
PI2FD mmreg, mem64
0Fh, 0Fh
0Dh
mm-xxx-xxx
short
mload, meu
PMULHRW mmreg1, mmreg2
0Fh, 0Fh
B7h
11-xxx-xxx
short
meu
PMULHRW mmreg1, mem64
0Fh, 0Fh
B7h
mm-xxx-xxx
short
mload, meu
PREFETCH mem81
0Fh
0Dh
mm-000-xxx
vector
load
PREFETCHW mem81,2
0Fh
0Dh
mm-001-xxx
vector
load
Notes:
1. For PREFETCH and PREFETCHW, the mem8 value refers to a byte address within the 32-byte line that will be prefetched.
2. PREFETCHW will be implemented in a future K86 processor. On the AMD-K6-2E processor, this instruction performs in the same
manner as the PREFETCH instruction.
82
Software Environment
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
4
Logic Symbol Diagram
Clock
CLK
Bus
Arbitration
Address
and
Address
Parity
Cycle
Definition
and
Control
Cache
Control
Voltage Detection
BF[2:0]
AHOLD
BOFF#
BREQ
HLDA
HOLD
A20M#
A[31:3]
AP
ADS#
ADSC#
APCHK#
BE[7:0]#
AMD-K6™-2E
D/C#
EWBE#
LOCK#
M/IO#
NA#
SCYC
W/R#
Processor
CACHE#
KEN#
PCD
PWT
WB/WT#
TCK
Notes:
VCC2DET VCC2H/L#
TDI
TDO
BRDY#
BRDYC#
D[63:0]
DP[7:0]
PCHK#
Data
and
Data
Parity
EADS#
HIT#
HITM#
INV
Inquire
Cycles
FERR#
IGNNE#
Floating-Point
Error Handling
FLUSH#
INIT
INTR
NMI
RESET
SMI#
SMIACT#
STPCLK#
External
Interrupts,
SMM, Reset and
Initialization
TMS TRST#
JTAG Test
The signals are grouped by function. The arrows show the direction of the signal, either into or out of the processor. Signals with doubleheaded arrows are bidirectional. Signals with pound signs (#) are active Low.
Chapter 4
Logic Symbol Diagram
83
Preliminary Information
AMD-K6™-2E Processor Data Sheet
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22529B/0—January 2000
Logic Symbol Diagram
Chapter 4
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
5
Signal Descriptions
This chapter includes a detailed description of each signal
supported on the AMD-K6-2E processor. This chapter also
provides tables listing the signals grouped by type, beginning
on page 130.
The logic symbol diagram on page 83 shows the signals grouped
by function.
Connection diagrams and pins listed by high-level function are
included in Chapter 17, “Pin Designation Diagrams” on page
299.
5.1
Signal Terminology
The following terminology is used in this chapter:
■
■
■
■
■
Chapter 5
Driven—The processor actively pulls the signal up to the
High-voltage state or pulls the signal down to the
Low-voltage state.
Floated—The the signal is not being driven by the processor
(high-impedance state), which allows another device to
drive this signal.
Asserted—For all active-High signals, the term asserted
means the signal is in the High-voltage state. For all
active-Low signals, the term asserted means the signal is in
the Low-voltage state.
Negated—For all active-High signals, the term negated
means the signal is in the Low-voltage state. For all
active-Low signals, the term negated means the signal is in
the High-voltage state.
Sampled—The processor has measured the state of a signal
at predefined points in time and will take the appropriate
action based on the state of the signal. If a signal is not
sampled by the processor, its assertion or negation has no
effect on the operation of the processor.
Signal Descriptions
85
Preliminary Information
AMD-K6™-2E Processor Data Sheet
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A20M# (Address Bit 20 Mask)
Pin Attribute
Input
Pin Location
AK-08
Summary
A20M# is used to simulate the behavior of the 8086 when
running in real mode. The assertion of A20M # causes the
processor to force bit 20 of the physical address to 0 prior to
accessing the cache or driving out a memory bus cycle. The
clearing of address bit 20 maps addresses that wrap above
1 Mbyte to addresses below 1 Mbyte.
Sampled
The processor samples A20M # as a level-sensitive input on
every clock edge. The system logic can drive the signal either
s y n ch ro n o u s ly o r a s y n ch ro n o u s ly. I f i t i s a s s e r t e d
asynchronously, it must be asserted for a minimum pulse width
of two clocks.
The following list explains the effects of the processor sampling
A20M# asserted under various conditions:
■
■
■
■
■
86
Inquire cycles and writeback cycles are not affected by the
state of A20M#.
The assertion of A20M# in system management mode
(SMM) is ignored.
When A20M# is sampled asserted in protected mode, it
causes unpredictable processor operation. A20M# is only
defined in real mode.
To ensure that A20M# is recognized before the first ADS#
occurs following the negation of RESET, A20M# must be
sampled asserted on the same clock edge that RESET is
sampled negated or on one of the two subsequent clock
edges.
To ensure A20M# is recognized before the execution of an
instruction, a serializing instruction must be executed
between the instruction that asserts A20M# and the
targeted instruction.
Signal Descriptions
Chapter 5
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
5.3
A[31:3] (Address Bus)
Pin Attribute
A[31:5] Bidirectional, A[4:3] Output
Pin Location
See “Pin Designations by Functional Grouping” on page 301.
Summary
A[31:3] contain the physical address for the current bus cycle.
The processor drives addresses on A[31:3] during memory and
I/O cycles, and cycle definition information during special bus
cycles. The processor samples addresses on A[31:5] during
inquire cycles.
Driven, Sampled, and
Floated
As Outputs: A[31:3] are driven valid off the same clock edge as
ADS # and remain in the same state until the clock edge on
which NA# or the last expected BRDY# of the cycle is sampled
asserted. A[31:3] are driven during memory cycles, I/O cycles,
special bus cycles, and interrupt acknowledge cycles. The
processor continues to drive the address bus while the bus is
idle.
As Inputs: The processor samples A[31:5] during inquire cycles
on the clock edge on which EADS# is sampled asserted. Even
though A4 and A3 are not used during the inquire cycle, they
must be driven to a valid state and must meet the same timings
as A[31:5].
A[31:3] are floated off the clock edge that AHOLD or BOFF# is
sampled asserted and off the clock edge that the processor
asserts HLDA in recognition of HOLD.
The processor resumes driving A[31:3] off the clock edge on
which the processor samples AHOLD or BOFF# negated and off
the clock edge on which the processor negates HLDA.
Chapter 5
Signal Descriptions
87
Preliminary Information
AMD-K6™-2E Processor Data Sheet
5.4
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ADS# (Address Strobe)
Pin Attribute
Output
Pin Location
AJ-05
Summary
The assertion of ADS # indicates the beginning of a new bus
cycle. The address bus and all cycle definition signals
corresponding to this bus cycle are driven valid off the same
clock edge as ADS#.
Driven and Floated
ADS # is asserted for one clock at the beginning of each bus
cycle. For non-pipelined cycles, ADS# can be asserted as early
as the clock edge after the clock edge on which the last
expected BRDY# of the cycle is sampled asserted, resulting in a
single idle state between cycles. For pipelined cycles if the
processor is prepared to start a new cycle, ADS# can be asserted
as early as one clock edge after NA# is sampled asserted.
If AHOLD is sampled asserted, ADS# is only driven in order to
perform a writeback cycle due to an inquire cycle that hits a
modified cache line.
The processor floats ADS # off the clock edge that BOFF # is
sampled asserted and off the clock edge that the processor
asserts HLDA in recognition of HOLD.
5.5
ADSC# (Address Strobe Copy)
Pin Attribute
Output
Pin Location
AM-02
Summary
ADSC # has the identical function and timing as ADS#. In the
event ADS# becomes too heavily loaded due to a large fanout in
a system, ADSC # can be used to split the load across two
outputs, which can improve system timing.
88
Signal Descriptions
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
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5.6
AHOLD (Address Hold)
Pin Attribute
Input
Pin Location
V-04
Summary
AHOLD can be asserted by the system to initiate one or more
inquire cycles. To allow the system to drive the address bus
during an inquire cycle, the processor floats A[31:3] and AP off
the clock edge on which AHOLD is sampled asserted. The data
bus and all other control and status signals remain under the
control of the processor and are not floated. This allows a bus
cycle that is in progress when AHOLD is sampled asserted to
continue to completion. The processor resumes driving the
address bus off the clock edge on which AHOLD is sampled
negated.
If AHOLD is sampled asserted, ADS# is only asserted in order
to perform a writeback cycle due to an inquire cycle that hits a
modified cache line.
Sampled
Chapter 5
The processor samples AHOLD on every clock edge. AHOLD is
recognized while INIT and RESET are sampled asserted.
Signal Descriptions
89
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AMD-K6™-2E Processor Data Sheet
5.7
22529B/0—January 2000
AP (Address Parity)
Pin Attribute
Bidirectional
Pin Location
AK-02
Summary
AP contains the even parity bit for cache line addresses driven
and sampled on A[31:5]. Even parity means that the total
number of 1 bits on AP and A[31:5] is even. (A4 and A3 are not
used for the generation or checking of address parity because
these bits are not required to address a cache line.) AP is driven
by the processor during processor-initiated cycles and is
sampled by the processor during inquire cycles. If AP does not
reflect even parity during an inquire cycle, the processor
asserts APCHK # to indicate an address bus parity check. The
processor does not take an internal exception as the result of
detecting an address bus parity check, and system logic must
respond appropriately to the assertion of this signal.
Driven, Sampled, and
Floated
As an Output: The processor drives AP valid off the clock edge
on which ADS# is asserted until the clock edge on which NA# or
the last expected BRDY# of the cycle is sampled asserted. AP is
driven during memory cycles, I/O cycles, special bus cycles, and
interrupt acknowledge cycles. The processor continues to drive
AP while the bus is idle.
As an Input: The processor samples AP during inquire cycles on
the clock edge on which EADS# is sampled asserted.
The processor floats AP off the clock edge that AHOLD or
BOFF # is sampled asserted and off the clock edge that the
processor asserts HLDA in recognition of HOLD.
The processor resumes driving AP off the clock edge on which
the processor samples AHOLD or BOFF # negated and off the
clock edge on which the processor negates HLDA.
90
Signal Descriptions
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
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5.8
APCHK# (Address Parity Check)
Pin Attribute
Output
Pin Location
AE-05
Summary
If the processor detects an address parity error during an
inquire cycle, APCHK# is asserted for one clock. The processor
does not take an internal exception as the result of detecting an
address bus parity check, and system logic must respond
appropriately to the assertion of this signal.
The processor is designed so that APCHK # does not glitch,
enabling the signal to be used as a clocking source for system
logic.
Driven
APCHK# is driven valid off the clock edge after the clock edge
on which the processor samples EADS# asserted. It is negated
off the next clock edge.
APCHK# is always driven except in the three-state test mode.
Chapter 5
Signal Descriptions
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AMD-K6™-2E Processor Data Sheet
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BE[7:0]# (Byte Enables)
Pin Attribute
Output
Pin Location
See “Pin Designations by Functional Grouping” on page 301.
Summary
BE[7:0]# are used by the processor to indicate the valid data
bytes during a write cycle and the requested data bytes during
a read cycle. The byte enables can be used to derive address bits
A[2:0], which are not physically part of the processor’s address
bus. The processor checks and generates valid data parity for
the data bytes that are valid as defined by the byte enables. The
eight byte enables correspond to the eight bytes of the data bus
as follows:
■
■
■
■
BE7#: D[63:56]
BE6#: D[55:48]
BE5#: D[47:40]
BE4#: D[39:32]
■
■
■
■
BE3#: D[31:24]
BE2#: D[23:16]
BE1#: D[15:8]
BE0#: D[7:0]
The processor expects data to be driven by the system logic on
all eight bytes of the data bus during a burst cache-line read
cycle, independent of the byte enables that are asserted.
The byte enables are also used to distinguish between special
bus cycles as defined in Table 23 on page 132.
Driven and Floated
BE[7:0]# are driven off the same clock edge as ADS # and
remain in the same state until the clock edge on which NA# or
the last expected BRDY # of the cycle is sampled asserted.
BE[7:0]# are driven during memory cycles, I/O cycles, special
bus cycles, and interrupt acknowledge cycles.
The processor floats BE[7:0]# off the clock edge that BOFF# is
sampled asserted and off the clock edge that the processor
asserts HLDA in recognition of HOLD. Unlike the address bus,
BE[7:0]# are not floated in response to AHOLD.
92
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AMD-K6™-2E Processor Data Sheet
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5.10
BF[2:0] (Bus Frequency)
Pin Attributes
Inputs, Internal Pullups
Pin Location
See “Pin Designations by Functional Grouping” on page 301.
Summary
BF[2:0] determine the internal operating frequency of the
processor. The frequency of the CLK input signal is multiplied
internally by a ratio determined by the state of these signals as
defined in Table 16. BF[2:0] have weak internal pullups and
default to the 3.5 multiplier if left unconnected.
Table 16. Processor-to-Bus Clock Ratios
Sampled
Chapter 5
State of BF[2:0] Inputs
Processor-Clock to Bus-Clock Ratio
100b
2.5x
101b
3.0x
111b
3.5x
010b
4.0x
000b
4.5x
001b
5.0x
011b
5.5x
110b
6.0x
BF[2:0] are sampled during the falling transition of RESET.
They must meet a minimum setup time of 1.0 ms and a
minimum hold time of two clocks relative to the negation of
RESET.
Signal Descriptions
93
Preliminary Information
AMD-K6™-2E Processor Data Sheet
5.11
22529B/0—January 2000
BOFF# (Backoff)
Pin Attribute
Input
Pin Location
Z-04
Summary
If BOFF # is sampled asserted, the processor unconditionally
aborts any cycles in progress and transitions to a bus hold state
by floating the following signals: A[31:3], ADS #, ADSC #, AP,
BE[7:0]#, CACHE #, D[63:0], D/C #, DP[7:0], LOCK #, M/IO #,
PCD, PWT, SCYC, and W/R#. These signals remain floated until
BOFF# is sampled negated. This allows an alternate bus master
or the system to control the bus.
When BOFF# is sampled negated, any processor cycle that was
aborted due to the assertion of BOFF # is restarted from the
beginning of the cycle, regardless of the number of transfers
that were completed. If BOFF# is sampled asserted on the same
clock edge as BRDY# of a bus cycle of any length, then BOFF#
takes precedence over the BRDY #. In this case, the cycle is
aborted and restarted after BOFF# is sampled negated.
Sampled
BOFF# is sampled on every clock edge. The processor floats its
bus signals off the clock edge on which BOFF # is sampled
asserted. These signals remain floated until the clock edge on
which BOFF# is sampled negated.
BOFF # is recognized while INIT and RESET are sampled
asserted.
94
Signal Descriptions
Chapter 5
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5.12
BRDY# (Burst Ready)
Pin Attribute
Input, Internal Pullup
Pin Location
X-04
Summary
BRDY# is asserted to the processor by system logic to indicate
either that the data bus is being driven with valid data during a
read cycle or that the data bus has been latched during a write
cycle. If necessary, the system logic can insert bus cycle wait
states by negating BRDY# until it is ready to continue the data
transfer. BRDY # is also used to indicate the completion of
special bus cycles.
Sampled
BRDY# is sampled every clock edge within a bus cycle starting
with the clock edge after the clock edge that negates ADS #.
BRDY# is ignored while the bus is idle. The processor samples
the following inputs on the clock edge on which BRDY # is
sampled asserted: D[63:0], DP[7:0], and KEN # during read
cycles, EWBE # during write cycles (if not masked off), and
WB/WT # during read and write cycles. If NA # is sampled
asserted prior to BRDY#, then KEN# and WB/WT# are sampled
on the clock edge on which NA# is sampled asserted.
The number of times the processor expects to sample BRDY #
asserted depends on the type of bus cycle, as follows:
■
■
One time for a single-transfer cycle, a special bus cycle, or
each of two cycles in an interrupt acknowledge sequence
Four times for a burst cycle (once for each data transfer)
BRDY # can be held asserted for four consecutive clocks
throughout the four transfers of the burst, or it can be negated
to insert wait states.
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BRDYC# (Burst Ready Copy)
Pin Attribute
Input, Internal Pullup
Pin Location
Y-03
Summary
BRDYC # has the identical function as BRDY #. In the event
BRDY # becomes too heavily loaded due to a large fanout or
loading in a system, BRDYC # can be used to reduce this
loading, which improves timing.
Sampled
BRDYC# is sampled every clock edge within a bus cycle starting
with the clock edge after the clock edge that negates ADS#.
5.14
BREQ (Bus Request)
Pin Attribute
Output
Pin Location
AJ-01
Summary
BREQ is asserted by the processor to request the bus in order to
complete an internally pending bus cycle. The system logic can
use BREQ to arbitrate among the bus participants. If the
processor does not own the bus, BREQ is asserted until the
processor gains access to the bus in order to begin the pending
cycle or until the processor no longer needs to run the pending
cycle. If the processor currently owns the bus, BREQ is asserted
with ADS#. The processor asserts BREQ for each assertion of
ADS# but does not necessarily assert ADS# for each assertion of
BREQ.
Driven
BREQ is asserted off the same clock edge on which ADS # is
asserted. BREQ can also be asserted off any clock edge,
independent of the assertion of ADS#. BREQ can be negated
one clock edge after it is asserted.
The processor always drives BREQ except in the three-state test
mode.
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5.15
CACHE# (Cacheable Access)
Pin Attribute
Output
Pin Location
U-03
Summary
For reads, CACHE# is asserted to indicate the cacheability of
the current bus cycle. In addition, if the processor samples
KEN # assert ed, which indicates t he driven address is
cacheable, the cycle is a 32-byte burst read cycle. For write
cycles, CACHE# is asserted to indicate the current bus cycle is a
modified cache-line writeback. KEN # is ignored during
writebacks. If CACHE# is not asserted, or if KEN # is sampled
negated during a read cycle, the cycle is not cacheable and
defaults to a single-transfer cycle.
Driven and Floated
CACHE# is driven off the same clock edge as ADS# and remains
in the same state until the clock edge on which NA# or the last
expected BRDY# of the cycle is sampled asserted.
CACHE # is floated off the clock edge that BOFF # is sampled
asserted and off the clock edge that the processor asserts HLDA
in recognition of HOLD.
5.16
CLK (Clock)
Pin Attribute
Input
Pin Location
AK-18
Summary
The CLK signal is the bus clock for the processor and is the
reference for all signal timings under normal operation (except
for TDI, TDO, TMS, and TRST#). BF[2:0] determine the internal
frequency multiplier applied to CLK to obtain the processor’s
core operating frequency. See “BF[2:0] (Bus Frequency)” on
page 93 for a list of the processor-to-bus clock ratios.
Sampled
The CLK signal must be stable a minimum of 1.0 ms prior to the
negation of RESET to ensure the proper operation of the
processor. See “CLK Switching Characteristics” on page 267 for
details regarding the CLK specifications.
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D/C# (Data/Code)
Pin Attribute
Output
Pin Location
AK-04
Summary
The processor drives D/C # during a memory bus cycle to
indicate whether it is addressing data or executable code. D/C#
is also used to define other bus cycles, including interrupt
acknowledge and special cycles. See Table 23 on page 132 for
more details.
Driven and Floated
D/C# is driven off the same clock edge as ADS# and remains in
the same state until the clock edge on which NA # or the last
expected BRDY # of the cycle is sampled asserted. D/C # is
driven during memory cycles, I/O cycles, special bus cycles, and
interrupt acknowledge cycles.
D/C # is floated off the clock edge that BOFF # is sampled
asserted and off the clock edge that the processor asserts HLDA
in recognition of HOLD.
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5.18
D[63:0] (Data Bus)
Pin Attribute
Bidirectional
Pin Location
See “Pin Designations by Functional Grouping” on page 301.
Summary
D[63:0] represent the processor’s 64-bit data bus. Each of the
eight bytes of data that comprise this bus is qualified as valid
by its corresponding byte enable. See “BE[7:0]# (Byte
Enables)” on page 92.
Driven, Sampled, and
Floated
As Outputs: For single-transfer write cycles, the processor drives
D[63:0] with valid data one clock edge after the clock edge on
which ADS# is asserted and D[63:0] remain in the same state
until the clock edge on which BRDY# is sampled asserted. If the
cycle is a writeback—in which case four, 8-byte transfers
occur—D[63:0] are driven one clock edge after the clock edge
on which ADS# is asserted and are subsequently changed off
the clock edge on which each BRDY# assertion of the burst
cycle is sampled.
If the assertion of ADS# represents a pipelined write cycle that
follows a read cycle, the processor does not drive D[63:0] until it
is certain that contention on the data bus will not occur. In this
case, D[63:0] are driven the clock edge after the last expected
BRDY# of the previous cycle is sampled asserted.
As Inputs: During read cycles, the processor samples D[63:0] on
the clock edge on which BRDY# is sampled asserted.
The processor always floats D[63:0] except when they are being
driven during a write cycle as described above. In addition,
D[63:0] are floated off the clock edge that BOFF # is sampled
asserted and off the clock edge that the processor asserts
HLDA in recognition of HOLD.
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DP[7:0] (Data Parity)
Pin Attribute
Bidirectional
Pin Location
See “Pin Designations by Functional Grouping” on page 301.
Summary
DP[7:0] are even parity bits for each valid byte of data — as
defined by BE[7:0]#—driven and sampled on the D[63:0] data
bus. Even parity means that the total number of odd (1) bits
within each byte of data and its respective data parity bit is an
even number. DP[7:0] are driven by the processor during write
cycles and sampled by the processor during read cycles.
If the processor detects bad parity on any valid byte of data
during a read cycle, PCHK# is asserted for one clock beginning
the clock edge after BRDY# is sampled asserted. The processor
does not take an internal exception as the result of detecting a
data parity check, and system logic must respond appropriately
to the assertion of this signal.
The eight data parity bits correspond to the eight bytes of the
data bus as follows:
■
DP7: D[63:56]
■
DP3: D[31:24]
■
DP6: D[55:48]
■
DP2: D[23:16]
■
DP5: D[47:40]
■
DP1: D[15:8]
■
DP4: D[39:32]
■
DP0: D[7:0]
For systems that do not support data parity, DP[7:0] should be
connected to VCC3 through pullup resistors.
Driven, Sampled, and
Floated
As Outputs: For single-transfer write cycles, the processor drives
DP[7:0] with valid parity one clock edge after the clock edge on
which ADS# is asserted and DP[7:0] remain in the same state
until the clock edge on which BRDY# is sampled asserted. If the
cycle is a writeback, DP[7:0] are driven one clock edge after the
clock edge on which ADS# is asserted and are subsequently
changed off the clock edge on which each BRDY# assertion of
the burst cycle is sampled.
As Inputs: During read cycles, the processor samples DP[7:0] on
the clock edge on which BRDY# is sampled asserted.
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The processor always floats DP[7:0] except when they are being
driven during a write cycle as described above. In addition,
DP[7:0] are floated off the clock edge that BOFF # is sampled
asserted and off the clock edge that the processor asserts HLDA
in recognition of HOLD.
5.20
EADS# (External Address Strobe)
Pin Attribute
Input
Pin Location
AM-04
Summary
System logic asserts EADS # during a cache inquire cycle to
indicate that the address bus contains a valid address. EADS#
can only be driven after the system logic has taken control of
the address bus by asserting AHOLD or BOFF# or by receiving
HLDA. The processor responds to the sampling of EADS# and
the address bus by driving HIT#, which indicates if the inquired
cache line exists in the processor’s cache, and HITM#, which
indicates if it is in the modified state.
Sampled
If AHOLD or BOFF# is asserted by the system logic in order to
execute a cache inquire cycle, the processor begins sampling
EADS # two clock edges after AHOLD or BOFF # is sampled
asserted. If the system logic asserts HOLD in order to execute a
cache inquire cycle, the processor begins sampling EADS# two
clock edges after the clock edge HLDA is asserted by the
processor.
EADS# is ignored during the following conditions:
■
■
■
■
Chapter 5
One clock edge after the clock edge on which EADS# is
sampled asserted
Two clock edges after the clock edge on which ADS# is
asserted
When the processor is driving the address bus
When the processor asserts HITM#
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EWBE# (External Write Buffer Empty)
Pin Attribute
Input
Pin Location
W-03
Summary
The system logic can negate EWBE# to the processor to indicate
that its external write buffers are full and that additional data
cannot be stored at this time. This causes the processor to delay
the following activities until EWBE# is sampled asserted:
■
■
■
■
The commitment of write hit cycles to cache lines in the
modified state or exclusive state in the processor’s cache
The decode and execution of an instruction that follows a
currently-executing serializing instruction
The assertion or negation of SMIACT#
The entering of the Halt state and the Stop Grant state
Negating EWBE# does not prevent the completion of any type
of cycle that is currently in progress.
Sampled
The processor samples EWBE# on each clock edge that BRDY#
is sampled asserted during all memory write cycles (except
writeback cycles), I/O write cycles, and special bus cycles.
If EWBE# is sampled negated, it is sampled on every clock edge
until it is asserted, and then it is ignored until BRDY # is
sampled asserted in the next write cycle or special cycle.
If EFER[3] is 1, then EWBE# is ignored by the processor. For
more information on the EFER settings and EWBE#, see
“EWBE# Control” on page 205.
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5.22
FERR# (Floating-Point Error)
Pin Attribute
Output
Pin Location
Q-05
Summary
The assertion of FERR # indicates the occurrence of an
unmasked floating-point exception resulting from the
execution of a floating-point instruction. This signal is provided
to allow the system logic to handle this exception in a manner
consistent with IBM-compatible PC/AT systems. See “Handling
Floating-Point Exceptions” on page 213 for a system logic
implementation that supports floating-point exceptions.
The state of the numeric error (NE) bit in CR0 does not affect
the FERR# signal.
The processor is designed so that FERR # does not glitch,
enabling the signal to be used as a clocking source for system
logic.
Driven
The processor asserts FERR # on the instruction boundary of
the next floating-point instruction, MMX instruction, 3DNow!
instruction, or WAIT instruction that occurs following the
f l o a t i ng -po i nt i ns t r u c t i o n t h a t c a u s e d t h e u n m a s ke d
floating-point exception—that is, FERR# is not asserted at the
time the exception occurs. The IGNNE# signal does not affect
the assertion of FERR#.
FERR# is negated during the following conditions:
■
■
■
Following the successful execution of the floating-point
instructions FCLEX, FINIT, FSAVE, and FSTENV
Under certain circumstances, following the successful
execution of the floating-point instructions FLDCW,
FLDENV, and FRSTOR, which load the floating-point status
word or the floating-point control word
Following the falling transition of RESET
FERR# is always driven except in the three-state test mode.
See “IGNNE# (Ignore Numeric Exception)” on page 108 for
more details on floating-point exceptions.
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FLUSH# (Cache Flush)
Pin Attribute
Input
Pin Location
AN-07
Summary
In response to sampling FLUSH# asserted, the processor writes
back any data cache lines that are in the modified state,
invalidates all lines in the instruction and data caches, and then
executes a flush acknowledge special cycle. See Table 23 on
page 132 for the bus definition of special cycles.
In addition, FLUSH # is sampled when RESET is negated to
determine if the processor enters the three-state test mode. If
FLUSH # is 0 during the falling transition of RESET, the
proc esso r e nt ers t he t hree- sta te te st mode ins tea d of
performing the normal RESET functions.
Sampled
FLUSH # is sampled and latched as a falling edge-sensitive
signal. During normal operation (not RESET), FLUSH # is
sampled on every clock edge but is not recognized until the next
instruction boundary. If FLUSH# is asserted synchronously, it
can be asserted for a minimum of one clock. If FLUSH # is
asserted asynchronously, it must have been negated for a
minimum of two clocks, followed by an assertion of a minimum
of two clocks.
FLUSH# is also sampled during the falling transition of RESET.
If RESET and FLUSH# are driven synchronously, FLUSH# is
sampled on the clock edge prior to the clock edge on which
RESET is sampled negated. If RESET is driven asynchronously,
the minimum setup and hold time for FLUSH#, relative to the
negation of RESET, is two clocks.
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5.24
HIT# (Inquire Cycle Hit)
Pin Attribute
Output
Pin Location
AK-06
Summary
The processor asserts HIT# during an inquire cycle to indicate
that the cache line is valid within the processor’s instruction or
data cache (also known as a cache hit). The cache line can be in
the modified, exclusive, or shared state.
Driven
HIT # is always driven—except in the three-state test mode —
and only changes state the clock edge after the clock edge on
which EADS# is sampled asserted. It is driven in the same state
until the next inquire cycle.
5.25
HITM# (Inquire Cycle Hit To Modified Line)
Pin Attribute
Output
Pin Location
AL-05
Summary
The processor asserts HITM # during an inquire cycle to
indicate that the cache line exists in the processor’s data cache
in the modified state. The processor performs a writeback cycle
as a result of this cache hit. If an inquire cycle hits a cache line
that is currently being written back, the processor asserts
HITM # but does not execute another writeback cycle. The
system logic must not expect the processor to assert ADS# each
time HITM# is asserted.
Driven
HITM# is always driven—except in the three-state test mode—
and, in particular, is driven to represent the result of an inquire
cycle the clock edge after the clock edge on which EADS # is
sampled asserted. If HITM # is negated in response to the
inquire address, it remains negated until the next inquire cycle.
If HITM # is asserted in response to the inquire address, it
remains asserted throughout the writeback cycle and is negated
one clock edge after the last BRDY # of the writeback is
sampled asserted.
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HLDA (Hold Acknowledge)
Pin Attribute
Output
Pin Location
AJ-03
Summary
When HOLD is sampled asserted, the processor completes the
current bus cycles, floats the processor bus, and asserts HLDA
in an acknowledgment that these events have been completed.
The processor does not assert HLDA until the completion of a
locked sequence of cycles. While HLDA is asserted, another bus
master can drive cycles on the bus, including inquire cycles to
the processor. The following signals are floated when HLDA is
asserted: A[31:3], ADS #, ADSC #, AP, BE[7:0]#, CACHE #,
D[63:0], D/C #, DP[7:0], LOCK #, M/IO #, PCD, PWT, SCYC, and
W/R#.
The processor is designed so that HLDA does not glitch.
Driven
HLDA is always driven except in the three-state test mode. If a
processor cycle is in progress while HOLD is sampled asserted,
HLDA is asserted one clock edge after the last BRDY # of the
cycle is sampled asserted. If the bus is idle, HLDA is asserted
one clock edge after HOLD is sampled asserted. HLDA is
negated one clock edge after the clock edge on which HOLD is
sampled negated.
The assertion of HLDA is independent of the sampled state of
BOFF#.
The processor floats the bus every clock in which HLDA is
asserted.
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5.27
HOLD (Bus Hold Request)
Pin Attribute
Input
Pin Location
AB-04
Summary
The system logic can assert HOLD to gain control of the
processor’s bus. When HOLD is sampled asserted, the processor
completes the current bus cycles, floats the processor bus, and
asserts HLDA in an acknowledgment that these events have
been completed.
Sampled
The processor samples HOLD on every clock edge. If a
processor cycle is in progress while HOLD is sampled asserted,
HLDA is asserted one clock edge after the last BRDY # of the
cycle is sampled asserted. If the bus is idle, HLDA is asserted
one clock edge after HOLD is sampled asserted. HOLD is
recognized while INIT and RESET are sampled asserted.
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IGNNE# (Ignore Numeric Exception)
Pin Attribute
Input
Pin Location
AA-35
Summary
IGNNE#, in conjunction with the numeric error (NE) bit in CR0,
is used by the system logic to control the effect of an unmasked
floating-point exception on a previous floating-point instruction
during the execution of a floating-point instruction, MMX
instruction, 3DNow! instruction, or the WAIT instruction—
hereafter referred to as the target instruction.
If an unmasked floating-point exception is pending and the
target instruction is considered error-sensitive, then the
relationship between NE and IGNNE# is as follows:
■
■
If NE = 0, then:
• If IGNNE# is sampled asserted, the processor ignores the
floating-point exception and continues with the
execution of the target instruction.
• If IGNNE# is sampled negated, the processor waits until
it samples IGNNE#, INTR, SMI#, NMI, or INIT asserted.
If IGNNE# is sampled asserted while waiting, the
processor ignores the floating-point exception and
continues with the execution of the target instruction.
If INTR, SMI#, NMI, or INIT is sampled asserted while
waiting,
the
processor
handles
its
assertion
appropriately.
If NE = 1, the processor invokes the INT 10h exception
handler.
If an unmasked floating-point exception is pending and the
target instruction is considered error-insensitive, then the
processor ignores the floating-point exception and continues
with the execution of the target instruction.
FERR # is not affected by the state of the NE bit or IGNNE #.
FERR # is always asserted at the instruction boundary of the
target instruction that follows the floating-point instruction
that caused the unmasked floating-point exception.
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This signal is provided to allow the system logic to handle
exceptions in a manner consistent with IBM-compatible PC/AT
systems.
Sampled
5.29
The processor samples IGNNE # as a level-sensitive input on
every clock edge. The system logic can drive the signal either
s y n ch ro n o u s ly o r a s y n ch ro n o u s ly. I f i t i s a s s e r t e d
asynchronously, it must be asserted for a minimum pulse width
of two clocks.
INIT (Initialization)
Pin Attribute
Input
Pin Location
AA-33
Summary
The assertion of INIT causes the processor to empty its
pipelines, to initialize most of its internal state, and to branch
to address FFFF_FFF0h—the same instruction execution
starting point used after RESET. Unlike RESET, the processor
preserves the contents of its caches, the floating-point state, the
MMX state, model-specific registers, the CD and NW bits of the
CR0 register, and other specific internal resources.
INIT can be used as an accelerator for 80286 code that requires
a reset to exit from protected mode back to real mode.
Sampled
INIT is sampled and latched as a rising edge-sensitive signal.
INIT is sampled on every clock edge but is not recognized until
the next instruction boundary. During an I/O write cycle, it must
be sampled asserted a minimum of three clock edges before
BRDY # is sampled asserted if it is to be recognized on the
boundary between the I/O write instruction and the following
instruction.
If INIT is asserted synchronously, it can be asserted for a
minimum of one clock. If it is asserted asynchronously, it must
have been negated for a minimum of two clocks, followed by an
assertion of a minimum of two clocks.
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INTR (Maskable Interrupt)
Pin Attribute
Input
Pin Location
AD-34
Summary
INTR is the system’s maskable interrupt input to the processor.
When the processor samples and recognizes INTR asserted, the
processor executes a pair of interrupt acknowledge bus cycles
and then jumps to the interrupt service routine specified by the
interrupt number that was returned during the interrupt
acknowledge sequence. The processor only recognizes INTR if
the interrupt flag (IF) in the EFLAGS register equals 1.
Sampled
The processor samples INTR as a level-sensitive input on every
clock edge, but the interrupt request is not recognized until the
next instruction boundary. The system logic can drive INTR
either synchronously or asynchronously. If it is asserted
asynchronously, it must be asserted for a minimum pulse width
of two clocks. In order to be recognized, INTR must remain
asserted until an interrupt acknowledge sequence is complete.
5.31
INV (Invalidation Request)
Pin Attribute
Input
Pin Location
U-05
Summary
During an inquire cycle, the state of INV determines whether
an addressed cache line that is found in the processor’s
instruction or data cache transitions to the invalid state or the
shared state.
If INV is sampled asserted during an inquire cycle, the
processor transitions the cache line (if found) to the invalid
state, regardless of its previous state. If INV is sampled negated
during an inquire cycle, the processor transitions the cache line
(if found) to the shared state. In either case, if the cache line is
found in the modified state, the processor writes it back to
memory before changing its state.
Sampled
110
INV is sampled on the clock edge on which EADS# is sampled
asserted.
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5.32
KEN# (Cache Enable)
Pin Attribute
Input
Pin Location
W-05
Summary
If KEN # is sampled asserted, it indicates that the address
presented by the processor is cacheable. If KEN # is sampled
asserted and the processor intends to perform a cache-line fill
(signified by the assertion of CACHE#), the processor executes
a 32-byte burst read cycle and expects to sample BRDY #
asserted a total of four times. If KEN # is sampled negated
during a read cycle, a single-transfer cycle is executed and the
processor does not cache the data. For write cycles, CACHE# is
asserted to indicate the current bus cycle is a modified
cache-line writeback. KEN# is ignored during writebacks.
If PCD is asserted during a bus cycle, the processor does not
cache any data read during that cycle, regardless of the state of
KEN#. See “PCD (Page Cache Disable)” on page 115 for more
details.
If the processor has sampled the state of KEN# during a cycle,
and that cycle is aborted due to the sampling of BOFF #
asserted, the system logic must ensure that KEN# is sampled in
the same state when the processor restarts the aborted cycle.
Sampled
Chapter 5
KEN# is sampled on the clock edge on which the first BRDY# or
NA # of a read cycle is sampled asserted. If the read cycle is a
burst, KEN # is ignored during the last three assertions of
BRDY #. KEN # is sampled during read cycles only when
CACHE# is asserted.
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LOCK# (Bus Lock)
Pin Attribute
Output
Pin Location
AH-04
Summary
The processor asserts LOCK# during a sequence of bus cycles to
ensure that the cycles are completed without allowing other bus
masters to intervene. Locked operations consist of two to five
bus cycles. LOCK# is asserted during the following operations:
■
■
■
■
■
An interrupt acknowledge sequence
Descriptor Table accesses
Page Directory and Page Table accesses
XCHG instruction
An instruction with an allowable LOCK prefix
In order to ensure that locked operations appear on the bus and
are visible to the entire system, any data operands addressed
during a locked cycle that reside in the processor’s cache are
flushed and invalidated from the cache prior to the locked
operation. If the cache line is in the modified state, it is written
back and invalidated prior to the locked operation. Likewise,
any data read during a locked operation is not cached.
The processor is designed so that LOCK# does not glitch.
Driven and Floated
During a locked cycle, LOCK# is asserted off the same clock
edge on which ADS# is asserted and remains asserted until the
last BRDY# of the last bus cycle is sampled asserted. The
processor negates LOCK# for at least one clock between
consecutive sequences of locked operations to allow the system
logic to arbitrate for the bus.
LOCK# is floated off the clock edge on which BOFF# is sampled
asserted and off the clock edge on which the processor asserts
HLDA in response to HOLD. When LOCK# is floated due to
BOFF# sampled asserted, the system logic is responsible for
p re s e rv i ng t h e l o ck c o n di t i o n w h i l e L O C K # i s i n t he
high-impedance state.
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5.34
M/IO# (Memory or I/O)
Pin Attribute
Output
Pin Location
T-04
Summary
The processor drives M/IO# during a bus cycle to indicate
whether it is addressing the memory or I/O space. If M/IO# = 1,
the processor is addressing memory or a memory-mapped I/O
port as the result of an instruction fetch or an instruction that
loads or stores data. If M/IO# = 0, the processor is addressing an
I/O port during the execution of an I/O instruction. In addition,
M/IO# is used to define other bus cycles, including interrupt
acknowledge and special cycles. See Table 23 on page 132 for
more details.
Driven and Floated
M/IO# is driven off the same clock edge as ADS# and remains in
the same state until the clock edge on which NA# or the last
expected BRDY# of the cycle is sampled asserted. M/IO# is
driven during memory cycles, I/O cycles, special bus cycles, and
interrupt acknowledge cycles.
M/IO# is floated off the clock edge on which BOFF# is sampled
asserted and off the clock edge on which the processor asserts
HLDA in response to HOLD.
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NA# (Next Address)
Pin Attribute
Input
Pin Location
Y-05
Summary
System logic asserts NA# to indicate to the processor that it is
ready to accept another bus cycle pipelined into the previous
bus cycle. ADS#, along with address and status signals, can be
asserted as early as one clock edge after NA# is sampled
asserted if the processor is prepared to start a new cycle.
Because the processor allows a maximum of two cycles to be in
progress at a time, the assertion of NA# is sampled while two
cycles are in progress, but ADS# is not asserted until the
completion of the first cycle.
Sampled
NA# is sampled every clock edge during bus cycles, starting one
clock edge after the clock edge that negates ADS#, until the last
expected BRDY# of the last executed cycle is sampled asserted
(with the exception of the clock edge after the clock edge that
negates the ADS# for a second pending cycle). Because the
processor latches NA# when sampled, the system logic only
needs to assert NA# for one clock.
5.36
NMI (Non-Maskable Interrupt)
Pin Attribute
Input
Pin Location
AC-33
Summary
When NMI is sampled asserted, the processor jumps to the
interrupt service routine defined by interrupt number 02h.
Unlike the INTR signal, software cannot mask the effect of NMI
if it is sampled asserted by the processor. However, NMI is
temporarily masked upon entering system management mode
(SMM). In addition, an interrupt acknowledge cycle is not
executed because the interrupt number is predefined.
If NMI is sampled asserted while the processor is executing the
interrupt service routine for a previous NMI, the subsequent
NMI remains pending until the completion of the execution of
the IRET instruction at the end of the interrupt service routine.
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Sampled
5.37
NMI is sampled and latched as a rising edge-sensitive signal.
During normal operation, NMI is sampled on every clock edge
but is not recognized until the next instruction boundary. If it is
asserted synchronously, it can be asserted for a minimum of one
clock. If it is asserted asynchronously, it must have been
negated for a minimum of two clocks, followed by an assertion
of a minimum of two clocks.
PCD (Page Cache Disable)
Pin Attribute
Output
Pin Location
AG-05
Summary
The processor drives PCD to indicate the operating system’s
specification of cacheability for the page being addressed.
System logic can use PCD to control external caching. If PCD is
asserted, the addressed page is not cached. If PCD is negated,
the cacheability of the addressed page depends upon the state
of CACHE# and KEN#.
The state of PCD depends upon the processor’s operating mode
and the state of certain bits in its control registers and TLB as
follows:
■
■
Chapter 5
In real mode, or in protected and virtual-8086 modes while
paging is disabled (PG bit in CR0 is 0):
PCD output = CD bit in CR0
In protected and virtual-8086 modes while caching is
enabled (CD bit in CR0 is 0) and paging is enabled (PG bit in
CR0 is 1):
• For accesses to I/O space, page directory entries, and
other non-paged accesses:
PCD output = PCD bit in CR3
• For accesses to 4-Kbyte page table entries or 4-Mbyte
pages:
PCD output = PCD bit in page directory entry
• For accesses to 4-Kbyte pages:
PCD output = PCD bit in page table entry
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PCD is driven off the same clock edge as ADS# and remains in
the same state until the clock edge on which NA# or the last
expected BRDY# of the cycle is sampled asserted.
PCD is floated off the clock edge that BOFF# is sampled
asserted and off the clock edge that the processor asserts HLDA
in response to HOLD.
5.38
PCHK# (Parity Check)
Pin Attribute
Output
Pin Location
AF-04
Summary
The processor asserts PCHK# during read cycles if it detects an
even parity error on one or more valid bytes of D[63:0] during a
read cycle. (Even parity means that the total number of odd (1)
bits within each byte of data and its respective data parity bit is
even.) The processor checks data parity for the data bytes that
are valid, as defined by BE[7:0]#, the byte enables.
PCHK# is always driven but is only asserted for memory and I/O
re a d b u s cy c l es a n d t he se c o n d cy c l e of a n i n t e r ru p t
acknowledge sequence. PCHK# is not driven during any type of
write cycles or special bus cycles. The processor does not take
an internal exception as the result of detecting a data parity
error, and system logic must respond appropriately to the
assertion of this signal.
The processor is designed so that PCHK# does not glitch,
enabling the signal to be used as a clocking source for system
logic.
Driven
116
PCHK# is always driven except in the three-state test mode. For
each BRDY# returned to the processor during a read cycle with
a parity error detected on the data bus, PCHK# is asserted for
one clock, one clock edge after BRDY# is sampled asserted.
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5.39
PWT (Page Writethrough)
Pin Attribute
Output
Pin Location
AL-03
Summary
The processor drives PWT to indicate the operating system’s
specification of the writeback state or writethrough state for
the page being addressed. PWT, together with WB/WT#,
specifies the data cache-line state during cacheable read misses
and write hits to shared cache lines. See “WB/WT# (Writeback
or Writethrough)” on page 129 for more details.
The state of PWT depends upon the processor’s operating mode
and the state of certain bits in its control registers and TLB as
follows:
■
■
In real mode, or in protected and virtual-8086 modes while
paging is disabled (PG bit in CR0 is 0):
PWT output = 0 (writeback state)
In protected and virtual-8086 modes while paging is enabled
(PG bit in CR0 is 1):
• For accesses to I/O space, page directory entries, and
other non-paged accesses:
PWT output = PWT bit in CR3
•
•
Driven and Floated
For accesses to 4-Kbyte page table entries or 4-Mbyte
pages:
PWT output = PWT bit in page directory entry
For accesses to 4-Kbyte pages:
PWT output = PWT bit in page table entry
PWT is driven off the same clock edge as ADS# and remains in
the same state until the clock edge on which NA# or the last
expected BRDY# of the cycle is sampled asserted.
PWT is floated off the clock edge on which BOFF# is sampled
asserted and off the clock edge on which the processor asserts
HLDA in response to HOLD.
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RESET (Reset)
Pin Attribute
Input
Pin Location
AK-20
Summary
When the processor samples RESET asserted, it immediately
flushes and initializes all internal resources and its internal
state including its pipelines and caches, the floating-point
state, the MMX state, the 3DNow! state, and all registers, and
then the processor jumps to address FFFF_FFF0h to start
instruction execution.
The FLUSH# signal is sampled during the falling transition of
RESET to invoke the three-state test mode.
Sampled
RESET is sampled as a level-sensitive input on every clock
edge. System logic can drive the signal either synchronously or
asynchronously.
During the initial power-on reset of the processor, RESET must
remain asserted for a minimum of 1.0 ms after CLK and VCC
reach specification before it is negated.
During a warm reset, while CLK and V CC are within their
specification, RESET must remain asserted for a minimum of
15 clocks prior to its negation.
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5.41
RSVD (Reserved)
Pin Attribute
Not Applicable
Pin Location
See “Pin Designations by Functional Grouping” on page 301.
Summary
Reserved signals are a special class of pins that can be treated
in one of the following ways:
■
■
■
As no-connect (NC) pins, in which case these pins are left
unconnected
As pins connected to the system logic as defined by the
industry-standard Pentium® interface (Socket 7)
Any combination of NC and Socket 7 pins
In any case, if the RSVD pins are treated accordingly, the
normal operation of the AMD-K6-2E processor is not adversely
affected in any manner.
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SCYC (Split Cycle)
Pin Attribute
Output
Pin Location
AL-17
Summary
The processor asserts SCYC during misaligned, locked transfers
on the D[63:0] data bus. The processor generates additional bus
cycles to complete the transfer of misaligned data.
For purposes of bus cycles, the term aligned means:
■
■
■
Driven and Floated
Any 1-byte transfers
2-byte and 4-byte transfers that lie within 4-byte address
boundaries
8-byte transfers that lie within 8-byte address boundaries
SCYC is asserted off the same clock edge as ADS#, and negated
off the clock edge on which NA# or the last expected BRDY# of
the entire locked sequence is sampled asserted. SCYC is only
valid during locked memory cycles.
SCYC is floated off the clock edge on which BOFF# is sampled
asserted and off the clock edge on which the processor asserts
HLDA in response to HOLD.
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5.43
SMI# (System Management Interrupt)
Pin Attribute
Input, Internal Pullup
Pin Location
AB-34
Summary
The assertion of SMI# causes the processor to enter system
management mode (SMM). Upon recognizing SMI#, the
processor performs the following actions, in the order shown:
1. Flushes its instruction pipelines
2. Completes all pending and in-progress bus cycles
3. Acknowledges the interrupt by asserting SMIACT# after
sampling EWBE# asserted (if EWBE# is masked off, then
SMIACT# is not affected by EWBE#)
4. Saves the internal processor state in SMM memory
5. Disables interrupts by clearing the interrupt flag (IF) in
EFLAGS and disables NMI interrupts
6. Jumps to the entry point of the SMM service routine at the
SMM base physical address which defaults to 0003_8000h in
SMM memory
See “System Management Mode (SMM)” on page 217 for more
details regarding SMM.
Sampled
SMI# is sampled and latched as a falling edge-sensitive signal.
SMI# is sampled on every clock edge but is not recognized until
the next instruction boundary. If SMI# is to be recognized on
the instruction boundary associated with a BRDY#, it must be
sampled asserted a minimum of three clock edges before the
BRDY# is sampled asserted. If it is asserted synchronously, it
can be asserted for a minimum of one clock. If it is asserted
asynchronously, it must have been negated for a minimum of
two clocks followed by an assertion of a minimum of two clocks.
A second assertion of SMI# while in SMM is latched but is not
recognized until the SMM service routine is exited.
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SMIACT# (System Management Interrupt Active)
Pin Attribute
Output
Pin Location
AG-03
Summary
The processor acknowledges the assertion of SMI# with the
assertion of SMIACT# to indicate that the processor has
entered system management mode (SMM). The system logic
can use SMIACT# to enable SMM memory. See “SMI# (System
Management Interrupt)” on page 121 for more details.
See “System Management Mode (SMM)” on page 217 for more
details regarding SMM.
Driven
The processor asserts SMIACT# after the last BRDY# of the last
pending bus cycle is sampled asserted (including all pending
write cycles) and after EWBE# is sampled asserted (if EWBE#
is masked off, then SMIACT# is not affected by EWBE#).
SMIACT# remains asserted until after the last BRDY# of the
last pending bus cycle associated with exiting SMM is sampled
asserted.
SMIACT# remains asserted during any flush, internal snoop, or
writeback cycle due to an inquire cycle.
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STPCLK# (Stop Clock)
Pin Attribute
Input, Internal Pullup
Pin Location
V-34
Summary
The assertion of STPCLK# causes the processor to enter the
Stop Grant state, during which the processor’s internal clock is
stopped. From the Stop Grant state, the processor can
subsequently transition to the Stop Clock state, in which the
bus clock CLK is stopped. Upon recognizing STPCLK#, the
processor performs the following actions, in the order shown:
1. Flushes its instruction pipelines
2. Completes all pending and in-progress bus cycles
3. Acknowledges the STPCLK# assertion by executing a Stop
Grant special bus cycle (see Table 23 on page 132)
4. Stops its internal clock after BRDY# of the Stop Grant
special bus cycle is sampled asserted and after EWBE# is
sampled asserted (if EWBE# is masked off, then entry into
the Stop Grant state is not affected by EWBE#)
5. Enters the Stop Clock state if the system logic stops the bus
clock CLK (optional)
See “Clock Control States” on page 247 for more details
regarding clock control.
Sampled
STPCLK# is sampled as a level-sensitive input on every clock
edge but is not recognized until the next instruction boundary.
System logic can drive the signal either synchronously or
asynchronously. If it is asserted asynchronously, it must be
asserted for a minimum pulse width of two clocks.
STPCLK# must remain asserted until recognized, which is
indicated by the completion of the Stop Grant special cycle.
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TCK (Test Clock)
Pin Attribute
Input, Internal Pullup
Pin Location
M-34
Summary
TCK is the clock for boundary-scan testing using the Test
Access Port (TAP). See “Boundary-Scan Test Access Port
(TAP)” on page 229 for details regarding the operation of the
TAP controller.
Sampled
The processor always samples TCK, except while TRST# is
asserted.
5.47
TDI (Test Data Input)
Pin Attribute
Input, Internal Pullup
Pin Location
N-35
Summary
T D I i s t h e s e r i a l t e s t d a t a a n d i n s t r u c t i o n i n p u t fo r
boundary-scan testing using the Test Access Port (TAP). See
“Boundary-Scan Test Access Port (TAP)” on page 229 for details
regarding the operation of the TAP controller.
Sampled
The processor samples TDI on every rising TCK edge, but only
while in the Shift-IR and Shift-DR states.
5.48
TDO (Test Data Output)
Pin Attribute
Output
Pin Location
N-33
Summary
TDO is the serial test data and instruction out put for
boundary-scan testing using the Test Access Port (TAP). See
“Boundary-Scan Test Access Port (TAP)” on page 229 for details
regarding the operation of the TAP controller.
Driven and Floated
The processor drives TDO on every falling TCK edge, but only
while in the Shift-IR and Shift-DR states. TDO is floated at all
other times.
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5.49
TMS (Test Mode Select)
Pin Attribute
Input, Internal Pullup
Pin Location
P-34
Summary
TMS specifies the test function and sequence of state changes
for boundary-scan testing using the Test Access Port (TAP). See
“Boundary-Scan Test Access Port (TAP)” on page 229 for details
regarding the operation of the TAP controller.
Sampled
The processor samples TMS on every rising TCK edge. If TMS is
sampled High for five or more consecutive clocks, the TAP
controller enters its Test-Logic-Reset state, regardless of the
controller state. This action is the same as that achieved by
asserting TRST#.
5.50
TRST# (Test Reset)
Pin Attribute
Input, Internal Pullup
Pin Location
Q-33
Summary
The assertion of TRST# initializes the Test Access Port (TAP) by
resetting its state machine to the Test-Logic-Reset state. See
“Boundary-Scan Test Access Port (TAP)” on page 229 for details
regarding the operation of the TAP controller.
Sampled
TRST# is a completely asynchronous input that does not
require a minimum setup and hold time relative to TCK. See
Ta b l e 6 4 o n p a g e 2 8 0 f o r t h e m i n i m u m p u l s e w i d t h
requirement.
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VCC2DET (VCC2 Detect)
Pin Attribute
Output
Pin Location
AL-01
Summary
VCC2DET is internally tied to VSS (logic level 0) to indicate to
the system logic that it must supply the specified dual-voltage
requirements to the VCC2 and VCC3 pins. The VCC2 pins supply
voltage to the processor core, independent of the voltage
supplied to the I/O buffers on the V CC3 pins. Upon sampling
VCC2DET Low, system logic should sample VCC2H/L# to
identify core voltage requirements.
Driven
VCC2DET always equals 0 and is never floated—even during
the three-state test mode.
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5.52
VCC2H/L# (VCC2 High/Low)
Pin Attribute
Output
Pin Location
AN-05
Summary
VCC2H/L# is internally tied to VSS (logic level 0) to indicate to
the system logic that it must supply the specified processor core
voltage to the VCC2 pins. The VCC2 pins supply voltage to the
processor core, independent of the voltage supplied to the I/O
buffers on the VCC3 pins.
Upon sampling VCC2DET Low to identify dual-voltage
processor requirements, system logic should sample VCC2H/L#
to identify the core voltage requirements for 2.9 V and 3.2 V
products (High) or 2.4 V, 2.2 V, and 1.9 V products (Low).
Driven
VCC2H/L# always equals 0 and is never floated for 2.4 V, 2.2 V,
and 1.9 V products—even during the three-state test mode. To
ensure proper operation for 2.9 V and 3.2 V products, system
logic that samples VCC2H/L# should design a weak pullup
resistor for this signal.
The output pin float conditions for VCC2DET and VCC2H/L#
are listed in Table 17.
Table 17. Output Pin Float Conditions
Name
Floated At:
VCC2DET1
Always Driven
VCC2H/L#
Always Driven
Notes:
1. All outputs except VCC2DET, VCC2H/L#, and TDO float during the three-state test mode.
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W/R# (Write/Read)
Pin Attribute
Output
Pin Location
AM-06
Summary
The processor drives W/R# to indicate whether it is performing
a write or a read cycle on the bus. In addition, W/R# is used to
define other bus cycles, including interrupt acknowledge and
special cycles. See Table 23 on page 132 for more details.
Driven and Floated
W/R# is driven off the same clock edge as ADS# and remains in
the same state until the clock edge on which NA# or the last
expected BRDY# of the cycle is sampled asserted. W/R# is
driven during memory cycles, I/O cycles, special bus cycles, and
interrupt acknowledge cycles.
W/R# is floated off the clock edge on which BOFF# is sampled
asserted and off the clock edge on which the processor asserts
HLDA in response to HOLD.
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5.54
WB/WT# (Writeback or Writethrough)
Pin Attribute
Input
Pin Location
AA-05
Summary
WB/WT#, together with PWT, specifies the data cache-line state
during cacheable read misses and write hits to shared cache
lines.
■
■
Sampled
Chapter 5
If WB/WT# = 0 or PWT = 1 during a cacheable read miss or
write hit to a shared cache line, the accessed line is cached
in the shared state. This is referred to as the writethrough
state, because all write cycles to this cache line are driven
externally on the bus.
If WB/WT# = 1 and PWT = 0 during a cacheable read miss or
a write hit to a shared cache line, the accessed line is cached
in the exclusive state. Subsequent write hits to the same line
cause its state to transition from exclusive to modified. This
is referred to as the writeback state, because the data cache
can contain modified cache lines that are subject to be
written back—referred to as a writeback cycle—as the result
of an inquire cycle, an internal snoop, a flush operation, or
the WBINVD instruction.
WB/WT# is sampled on the clock edge on which the first BRDY#
or NA# of a bus cycle is sampled asserted. If the cycle is a burst
read, WB/WT# is ignored during the last three assertions of
BRDY #. WB /WT# is sampled during mem ory re ad and
non-writeback write cycles and is ignored during all other types
of cycles.
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Pin Tables by Type
Table 18. Input Pin Types
Name
Type
Name
Type
A20M#1
Asynchronous
IGNNE#1
Asynchronous
AHOLD
Synchronous
INIT2
Asynchronous
BF[2:0]3
Synchronous
INTR1
Asynchronous
BOFF#
Synchronous
INV
Synchronous
BRDY#
Synchronous
KEN#
Synchronous
BRDYC#
Synchronous
NA#
Synchronous
CLK
Clock
NMI2
Asynchronous
EADS#
Synchronous
RESET4,5
Asynchronous
EWBE#6
Synchronous
SMI#2
Asynchronous
FLUSH#2,7
Asynchronous
STPCLK#1
Asynchronous
HOLD
Synchronous
WB/WT#
Synchronous
Notes:
1. These level-sensitive signals can be asserted synchronously or asynchronously. To be sampled on a specific clock edge, setup
and hold times must be met. If asserted asynchronously, they must be asserted for a minimum pulse width of two clocks.
2. These edge-sensitive signals can be asserted synchronously or asynchronously. To be sampled on a specific clock edge, setup
and hold times must be met. If asserted asynchronously, they must have been negated at least two clocks prior to assertion and
must remain asserted at least two clocks.
3. BF[2:0] are sampled during the falling transition of RESET. They must meet a minimum setup time of 1.0 ms and a minimum
hold time of two clocks relative to the negation of RESET.
4. During the initial power-on reset of the processor, RESET must remain asserted for a minimum of 1.0 ms after CLK and VCC
reach specification before it is negated.
5. During a warm reset, while CLK and VCC are within their specification, RESET must remain asserted for a minimum of 15 clocks
prior to its negation.
6. When EFER[3] is 1, EWBE# is ignored by the processor.
7. FLUSH# is also sampled during the falling transition of RESET and can be asserted synchronously or asynchronously. To be
sampled on a specific clock edge, setup and hold times must be met relative to the clock edge before the clock edge on which
RESET is sampled negated. If asserted asynchronously, FLUSH# must meet a minimum setup and hold time of two clocks
relative to the negation of RESET.
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Table 19. Output Pin Float Conditions
Name
Floated At:1
Name
Floated At:1
A[4:3]2,3
HLDA, AHOLD, BOFF#
HLDA
Always Driven
ADS#2
HLDA, BOFF#
LOCK#2
HLDA, BOFF#
ADSC#2
HLDA, BOFF#
M/IO#2
HLDA, BOFF#
APCHK#
Always Driven
PCD2
HLDA, BOFF#
BE[7:0]#2
HLDA, BOFF#
PCHK#
Always Driven
BREQ
Always Driven
PWT2
HLDA, BOFF#
CACHE#2
HLDA, BOFF#
SCYC2
HLDA, BOFF#
D/C#2
HLDA, BOFF#
SMIACT#
Always Driven
FERR#
Always Driven
VCC2DET
Always Driven
HIT#
Always Driven
VCC2H/L#
Always Driven
HITM#
Always Driven
W/R#2
HLDA, BOFF#
Notes:
1. All outputs except VCC2DET, VCC2H/L#, and TDO float during three-state test mode.
2. Floated off the clock edge that BOFF# is sampled asserted and off the clock edge that HLDA is asserted.
3. Floated off the clock edge that AHOLD is sampled asserted.
Table 20. Input/Output Pin Float Conditions
Name
Floated At:1
A[31:5]2,3
HLDA, AHOLD, BOFF#
AP2,3
HLDA, AHOLD, BOFF#
D[63:0]2
HLDA, BOFF#
DP[7:0]2
HLDA, BOFF#
Notes:
1. All outputs except VCC2DET and TDO float during three-state test mode.
2. Floated off the clock edge that BOFF# is sampled asserted and off the clock edge that
HLDA is asserted.
3. Floated off the clock edge that AHOLD is sampled asserted.
Table 21. Test Pins
Name
Type
Comment
TCK
Clock
TDI
Input
Sampled on the rising edge of TCK
TDO
Output
Driven on the falling edge of TCK
TMS
Input
Sampled on the rising edge of TCK
TRST#
Input
Asynchronous (Independent of TCK)
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Bus Cycle Definitions
Table 22. Bus Cycle Definition
Generated
by System Logic
Generated by CPU
Bus Cycle Initiated
M/IO#
D/C#
W/R#
CACHE#
KEN#
Code Read, Instruction Cache Line Fill
1
0
0
0
0
Code Read, Noncacheable
1
0
0
1
x
Code Read, Noncacheable
1
0
0
x
1
Encoding for Special Cycle
0
0
1
1
x
Interrupt Acknowledge
0
0
0
1
x
I/O Read
0
1
0
1
x
I/O Write
0
1
1
1
x
Memory Read, Data Cache Line Fill
1
1
0
0
0
Memory Read, Noncacheable
1
1
0
1
x
Memory Read, Noncacheable
1
1
0
x
1
Memory Write, Data Cache Writeback
1
1
1
0
x
Memory Write, Noncacheable
1
1
1
1
x
Notes:
x means “don’t care”.
Special Cycle
A4
BE7#
BE6#
BE5#
BE4#
BE3#
BE2#
BE1#
BE0#
M/IO#
D/C#
W/R#
CACHE#
KEN#
Table 23. Special Cycles
Stop Grant
1
1
1
1
1
1
0
1
1
0
0
1
1
x
Flush Acknowledge
(FLUSH# sampled asserted)
0
1
1
1
0
1
1
1
1
0
0
1
1
x
Writeback (WBINVD
instruction)
0
1
1
1
1
0
1
1
1
0
0
1
1
x
Halt
0
1
1
1
1
1
0
1
1
0
0
1
1
x
Flush (INVD, WBINVD
instruction)
0
1
1
1
1
1
1
0
1
0
0
1
1
x
Shutdown
0
1
1
1
1
1
1
1
0
0
0
1
1
x
Notes:
x means “don’t care”.
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6
Bus Cycles
The following sections describe and illustrate the timing and
relationship of bus signals during various types of bus cycles. A
representative set of bus cycles is illustrated.
6.1
Timing Diagrams
The timing diagrams illustrate the signals on the external local
bus as a function of time, as measured by the bus clock (CLK).
Bus Clock (CLK)
Throughout this chapter, the term clock refers to a single
bus-clock cycle. A clock extends from one rising CLK edge to
the next rising CLK edge. The processor samples and drives
most signals relative to the rising edge of CLK. The exceptions
to this rule include the following:
■
■
■
Waveform
Definitions
BF[2:0]—Sampled on the falling edge of RESET
FLUSH#—Sampled on the falling edge of RESET, also
sampled on the rising edge of CLK
All inputs and outputs are sampled relative to TCK in
boundary-scan test mode. Inputs are sampled on the rising
edge of TCK, outputs are driven off of the falling edge of
TCK.
For each signal in the timing diagrams, the High level
represents 1, the Low level represents 0, and the Middle level
represents the floating (high-impedance) state.
When both the High and Low levels are shown, the meaning
depends on the signal:
■
■
A single signal indicates ‘don’t care’.
In the case of bus activity, if both High and Low levels are
shown, it indicates that the processor, alternate master, or
system logic is driving a value, but this value may or may not
be valid. (For example, the value on the address bus is valid
only during the assertion of ADS#, but addresses are also
driven on the bus at other times.)
Figure 50 defines the different waveform representations.
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Active High Signals
For all active High signals, the term asserted means the signal is
in the High-voltage state and the term negated means the signal
is in the Low-voltage state.
Active Low Signals
For all active Low signals, the term asserted means the signal is
in the Low-voltage state and the term negated means the signal
is in the High-voltage state.
Description
Waveform
Don’t care or bus is driven
Signal or bus is changing from Low to High
Signal or bus is changing from High to Low
Bus is changing
Bus is changing from valid to invalid
Signal or bus is floating
Denotes multiple clock periods
Figure 50. Waveform Definitions
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6.2
Bus States
Bus State
Branch Condition
Addr
No
Pending
Request?
Yes
Address
Data
Idle
Data
Idle
Yes
Last BRDY#
Asserted?
No
NA# Sampled
Asserted?
Data-NA#
Yes
No
Yes
Data-NA#
Requested
Last BRDY#
Asserted?
No
Yes
No
Pending
Request?
Pipe-A
NA# Sampled
Asserted?
No
Yes
Pipeline
Address
Pipe-D
No
Pipeline
Data
Last BRDY#
Asserted?
Yes
Trans
Yes
NA# Sampled
Asserted?
Transition
Yes
Bus Transition?
No
No
Note: The processor transitions to the IDLE state on the clock edge on which BOFF# or RESET is sampled asserted.
Figure 51. Bus State Machine Diagram
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Idle
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The processor does not drive the system bus in the Idle state
and remains in this state until a new bus cycle is requested. The
processor enters this state off the clock edge on which the last
BRDY# of a cycle is sampled asserted during the following
conditions:
■
■
The processor is in the Data state
The processor is in the Data-NA# Requested state and no
internal pending cycle is requested
In addition, the processor is forced into this state when the
system logic asserts RESET or BOFF#. The transition to this
state occurs on the clock edge on which RESET or BOFF# is
sampled asserted.
Address
In this state, the processor drives ADS# to indicate the
beginning of a new bus cycle by validating the address and
control signals. The processor remains in this state for one clock
and unconditionally enters the Data state on the next clock
edge.
Data
In the Data state, the processor drives the data bus during a
write cycle or expects data to be returned during a read cycle.
The processor remains in this state until either NA# or the last
BRDY# is sampled asserted. If the last BRDY# is sampled
asserted or both the last BRDY# and NA# are sampled asserted
on the same clock edge, the processor enters the Idle state. If
NA# is sampled asserted first, the processor enters the
Data-NA# Requested state.
Data-NA# Requested
If the processor samples NA# asserted while in the Data state
and the current bus cycle is not completed (the last BRDY# is
not sampled asserted), it enters the Data-NA# Requested state.
The processor remains in this state until either the last BRDY#
is sampled asserted or an internal pending cycle is requested. If
the last BRDY# is sampled asserted before the processor drives
a new bus cycle, the processor enters the Idle state (no internal
pending cycle is requested) or the Address state (processor has
a internal pending cycle).
Pipeline Address
In this state, the processor drives ADS# to indicate the
beginning of a new bus cycle by validating the address and
control signals. In this state, the processor is still waiting for the
current bus cycle to be completed (until the last BRDY# is
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sampled asserted). If the last BRDY# is not sampled asserted,
the processor enters the Pipeline Data state.
If the processor samples the last BRDY# asserted in this state, it
determines if a bus transition is required between the current
bus cycle and the pipelined bus cycle. A bus transition is
required when the data bus direction changes between bus
cycles, such as a memory write cycle followed by a memory read
cycle. If a bus transition is required, the processor enters the
Transition state for one clock to prevent data bus contention. If
a bus transition is not required, the processor enters the Data
state.
The processor does not transition to the Data-NA# Requested
state from the Pipeline Address state because the processor
does not begin sampling NA# until it has exited the Pipeline
Address state.
Pipeline Data
Two bus cycles are executing concurrently in this state. The
processor cannot issue any additional bus cycles until the
current bus cycle is completed. The processor drives the data
bus during write cycles or expects data to be returned during
read cycles for the current bus cycle until the last BRDY# of the
current bus cycle is sampled asserted.
If the processor samples the last BRDY# asserted in this state, it
determines if a bus transition is required between the current
bus cycle and the pipelined bus cycle. If the bus transition is
required, the processor enters the Transition state for one clock
to prevent data bus contention. If a bus transition is not
required, the processor enters the Data state (NA# was not
sampled asserted) or the Data-NA# Requested state (NA# was
sampled asserted).
Transition
Chapter 6
The processor enters the Transition state for one clock during
data bus transitions and enters the Data state on the next clock
edge if NA# is not sampled asserted. The sole purpose of this
state is to avoid bus contention caused by bus transitions during
pipeline operation.
Bus Cycles
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Memory Reads and Writes
The AMD-K6-2E processor performs single or burst memory bus
cycles.
■
■
■
Single-Transfer
Memory Read and
Write
The single-transfer memory bus cycle transfers 1, 2, 4, or 8
bytes and requires a minimum of two clocks.
Misaligned instructions or operands result in a split cycle,
which requires multiple transactions on the bus.
A burst cycle consists of four back-to-back 8-byte (64-bit)
transfers on the data bus.
Figure 52 on page 139 shows a single-transfer read from memory,
followed by two single-transfer writes to memory. For the
memory read cycle, the processor asserts ADS# for one clock to
validate the bus cycle and also drives A[31:3], BE[7:0]#, D/C#,
W/R#, and M/IO# to the bus. The processor then waits for the
system logic to return the data on D[63:0] (with DP[7:0] for
parity checking) and assert BRDY#. The processor samples
BRDY# on every clock edge starting with the clock edge after
the clock edge that negates ADS#. See “BRDY# (Burst Ready)”
on page 95.
During the read cycle, the processor drives PCD, PWT, and
CACHE# to indicate its caching and cache-coherency intent for
the access. The system logic returns KEN# and WB/WT# to
either confirm or change this intent. If the processor asserts
PCD and negates CACHE#, the accesses are noncacheable, even
though the system logic asserts KEN# during the BRDY# to
indicate its support for cacheability. The processor (which
drives CACHE#) and the system logic (which drives KEN#) must
agree in order for an access to be cacheable.
The processor can drive another cycle (in this example, a write
cycle) by asserting ADS# off the next clock edge after BRDY# is
sampled asserted. Therefore, an idle clock is guaranteed
between any two bus cycles. The processor drives D[63:0] with
valid data one clock edge after the clock edge on which ADS# is
asserted. To minimize processor idle times, the system logic
stores the address and data in write buffers, returns BRDY#, and
performs the store to memory later. If the processor samples
EWBE# negated during a write cycle, it suspends certain
activities until EWBE# is sampled asserted. See “EWBE#
(External Write Buffer Empty)” on page 102. In Figure 52, the
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second write cycle occurs during the execution of a serializing
instruction. The processor delays the following cycle until
EWBE# is sampled asserted.
Read Cycle
ADDR DATA
IDLE
Write Cycle (Next Cycle Delayed by EWBE#)
Write Cycle
ADDR DATA DATA
IDLE
ADDR DATA DATA
IDLE
IDLE
IDLE
IDLE
IDLE
ADDR
CLK
A[31:3]
BE[7:0]#
ADS#
M/IO#
D/C#
W/R#
BREQ
D[63:0]
DP[7:0]
CACHE#
EWBE#
KEN#
BRDY#
WB/WT#
Figure 52. Non-Pipelined Single-Transfer Memory Read/Write and Write Delayed by EWBE#
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Misaligned
Single-Transfer
Memory Read and
Write
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Figure 53 on page 141 shows a misaligned (split) memory read
followed by a misaligned memory write. Any cycle that is not
aligned as defined in “SCYC (Split Cycle)” on page 120 is
considered misaligned. When the processor encounters a
misaligned access, it determines the appropriate pair of bus
cycles — each with its own ADS# and BRDY# — required to
complete the access.
The AMD-K6-2E processor performs misaligned memory reads
and memory writes using least-significant bytes (LSBs) first
followed by most-significant bytes (MSBs). Table 24 shows the
order. In the first memory read cycle in Figure 53, the processor
reads the least-significant bytes. Immediately after the
processor samples BRDY# asserted, it drives the second bus
cycle to read the most-significant bytes to complete the
misaligned transfer.
Table 24. Bus-Cycle Order During Misaligned Memory Transfers
Type of Access
First Cycle
Second Cycle
Memory Read
LSBs
MSBs
Memory Write
LSBs
MSBs
Similarly, the misaligned memory write cycle in Figure 53
transfers the LSBs to the memory bus first. In the next cycle,
after the processor samples BRDY# asserted, the MSBs are
written to the memory bus.
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Memory Read (Misaligned)
Memory Write (Misaligned)
ADDR DATA DATA IDLE ADDR DATA DATA IDLE ADDR DATA DATA DATA IDLE ADDR DATA DATA DATA IDLE
CLK
A[31:3]
BE[7:0]#
ADS#
M/IO#
D/C#
W/R#
D[63:0]
LSB
MSB
LSB
MSB
BRDY#
Figure 53. Misaligned Single-Transfer Memory Read and Write
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Burst Reads and
Pipelined Burst Reads
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Figure 54 on page 143 shows normal burst read cycles and a
pipelined burst read cycle. The AMD-K6-2E processor drives
CACHE# and ADS# together to specify that the current bus
cycle is a burst cycle. If the processor samples KEN# asserted
with the first BRDY#, it performs burst transfers. During the
burst transfers, the system logic must ignore BE[7:0]# and must
return all eight bytes beginning at the starting address the
processor asserts on A[31:3]. Depending on the starting
address, the system logic must determine the successive
quadword addresses (A[4:3]) for each transfer in a burst, as
shown in Table 25. The processor expects the second, third, and
fourth quadwords to occur in the sequences shown in Table 25.
Table 25. A[4:3] Address-Generation Sequence During Bursts
A[4:3] Addresses of Subsequent
Quadwords1 Generated by System Logic
Address Driven By
Processor on A[4:3]
Quadword 1
Quadword 2
Quadword 3
Quadword 4
00b
01b
10b
11b
01b
00b
11b
10b
10b
11b
00b
01b
11b
10b
01b
00b
Notes:
1. quadword = 8 bytes
In Figure 54, the processor drives CACHE# throughout all burst
read cycles. In the first burst read cycle, the processor drives
ADS# and CACHE#, then samples BRDY# on every clock edge
starting with the clock edge after the clock edge that negates
ADS#. The processor samples KEN# asserted on the clock edge
on which the first BRDY# is sampled asserted, executes a
32-byte burst read cycle, and expects a total of four BRDY#
signals. An ideal no-wait state access is shown in Figure 54,
whereas most system logic solutions add wait states between
the transfers.
The second burst read cycle illustrates a similar sequence, but
the processor samples NA# asserted on the same clock edge
that the first BRDY# is sampled asserted. NA# assertion
indicates the system logic is requesting the processor to output
the next address early (also known as a pipeline transfer
request). Without waiting for the current cycle to complete, the
processor drives ADS# and related signals for the next burst
cycle. Pipelining can reduce processor cycle-to-cycle idle times.
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Burst Read
Burst Read
Pipelined Burst Read
DATA PIPE
ADDR DATA DATA DATA DATA IDLE ADDR DATA DATA
DATA DATA DATA DATA IDLE
-NA -ADDR
CLK
A[31:3]
ADDR1
ADDR2
ADDR3
BE[7:0]#
ADS#
M/IO#
D/C#
W/R#
NA#
D[63:0]
DATA1
DATA2
DATA3
CACHE#
KEN#
BRDY#
Figure 54. Burst Reads and Pipelined Burst Reads
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Burst Writeback
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Figure 55 on page 145 shows a burst read followed by a
writeback transaction. The AMD-K6-2E processor initiates
writebacks under the following conditions:
■
■
■
■
Replacement—If a cache-line fill is initiated for a cache line
currently filled with valid entries, the processor selects a
line for replacement based on a least-recently-used (LRU)
algorithm
for
the
instruction
cache,
and
a
least-recently-allocated (LRA) algorithm for the data cache.
Before a replacement is made to an L1 data cache line that is
in the Modified state, the modified line is scheduled to be
written back to memory.
Internal Snoop—The processor snoops its instruction cache
during read or write misses to its data cache, and it snoops
its data cache during read misses to its instruction cache.
This snooping is performed to determine whether the same
address is stored in both caches, a situation that implies the
occurrence of self-modifying code. If a snoop hits a data
cache line in the Modified state, the line is written back to
memory before being invalidated.
WBINVD Instruction—When the processor executes a
WBINVD instruction, it writes back all modified lines in the
data cache and then invalidates all lines in both caches.
Cache Flush—When the processor samples FLUSH#
asserted, it executes a flush acknowledge special cycle and
writes back all modified lines in the data cache and then
invalidates all lines in both caches.
The processor drives writeback cycles during inquire or cache
flush cycles. The writeback shown in Figure 55 is caused by a
cache-line replacement. The processor completes the burst read
cycle that fills the cache line. Immediately following the burst
read cycle is the burst writeback cycle that represents the
modified line to be written back to memory. D[63:0] are driven
one clock edge after the clock edge on which ADS# is asserted
and are subsequently changed off the clock edge on which each
of the four BRDY# signals of the burst cycle are sampled
asserted.
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Burst Writeback from L1 Cache
Burst Read
ADDR
DATA
DATA
DATA
DATA
IDLE
ADDR
DATA
DATA
DATA
DATA
IDLE
CLK
A[31:3]
BE[7:0]#
ADS#
CACHE#
M/IO#
D/C#
W/R#
D[63:0]
KEN#
BRDY#
WB/WT#
Figure 55. Burst Writeback due to Cache-Line Replacement
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I/O Read and Write
Basic I/O Read and
Write
The processor accesses I/O when it executes an I/O instruction
(for example, IN or OUT). Figure 56 shows an I/O read followed
by an I/O write. The processor drives M/IO# Low and D/C# High
during I/O cycles. In this example, the first cycle shows a single
wait state I/O read cycle. It follows the same sequence as a
single-transfer memory read cycle. The processor drives ADS#
to initiate the bus cycle, then it samples BRDY# on every clock
edge starting with the clock edge after the clock edge that
negates ADS#. The system logic must return BRDY# to
complete the cycle. When the processor samples BRDY#
asserted, it can assert ADS# for the next cycle off the next clock
edge. (In this example, an I/O write cycle.)
The I/O write cycle is similar to a memory write cycle, but the
processor drives M/IO# low during an I/O write cycle. The
processor asserts ADS# to initiate the bus cycle. The processor
drives D[63:0] with valid data one clock edge after the clock
edge on which ADS# is asserted. The system logic must assert
BRDY# when the data is properly stored to the I/O destination.
The processor samples BRDY# on every clock edge starting with
the clock edge after the clock edge that negates ADS#. In this
example, two wait states are inserted while the processor waits
for BRDY# to be asserted.
I/O Write Cycle
I/O Read Cycle
ADDR
DATA
DATA
IDLE
ADDR
DATA
DATA
DATA
IDLE
CLK
A[31:3]
BE[7:0]#
ADS#
M/IO#
D/C#
W/R#
D[63:0]
BRDY#
Figure 56. Basic I/O Read and Write
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Misaligned I/O Read
and Write
Table 26 shows the misaligned I/O read and write cycle order
executed by the AMD-K6-2E processor. In Figure 57, the
least-significant bytes (LSBs) are transferred first. Immediately
after the processor samples BRDY# asserted, it drives the
second bus cycle to transfer the most-significant bytes (MSBs)
to complete the misaligned bus cycle.
Table 26. Bus-Cycle Order During Misaligned I/O Transfers
Type of Access
First Cycle
Second Cycle
I/O Read
LSBs
MSBs
I/O Write
LSBs
MSBs
Misaligned I/O Write
Misaligned I/O Read
ADDR DATA DATA IDLE ADDR DATA DATA IDLE ADDR DATA DATA DATA IDLE ADDR DATA DATA DATA IDLE
CLK
A[31:3]
BE[7:0]#
ADS#
M/IO#
D/C#
W/R#
SCYC
D[63:0]
LSB
MSB
LSB
MSB
BRDY#
Figure 57. Misaligned I/O Transfer
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Inquire and Bus Arbitration Cycles
The AMD-K6-2E processor provides built-in level-one data and
instruction caches. Each cache is 32 Kbytes and two-way
set-associative. The system logic or other bus master devices
can initiate an inquire cycle to maintain cache/memory
coherency. In response to the inquire cycle, the processor
compares the inquire address with its cache tag addresses in
both caches, and, if necessary, updates the MESI state of the
cache line and performs writebacks to memory.
An inquire cycle can be initiated by asserting AHOLD, BOFF#,
or HOLD. AHOLD is exclusively used to support inquire cycles.
During AHOLD-initiated inquire cycles, the processor only
floats the address bus. BOFF# provides the fastest access to the
bus because it aborts any processor cycle that is in-progress,
whereas AHOLD and HOLD both permit an in-progress bus
cycle to complete. During HOLD-initiated and BOFF#-initiated
inquire cycles, the processor floats all of its bus-driving signals.
Hold and Hold
Acknowledge Cycle
The system logic or another bus device can assert HOLD to
initiate an inquire cycle or to gain full control of the bus. When
the A MD -K 6-2E p rocess or sam p l es H OL D as sert ed, i t
completes any in-progress bus cycle and asserts HLDA to
acknowledge release of the bus. The processor floats the
following signals off the same clock edge on which HLDA is
asserted:
■
■
■
■
■
■
■
A[31:3]
ADS#
AP#
BE[7:0]#
CACHE#
D[63:0]
D/C#
■
■
■
■
■
■
■
DP[7:0]
LOCK#
M/IO#
PCD
PWT
SCYC
W/R#
Figure 58 shows a basic HOLD/HLDA operation. In this
example, the processor samples HOLD asserted during the
memory read cycle. It continues the current memory read cycle
until BRDY# is sampled asserted. The processor drives HLDA
and floats its outputs one clock edge after the last BRDY# of the
cycle is sampled asserted. The system logic can assert HOLD for
as long as it needs to utilize the bus. The processor samples
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HOLD on every clock edge but does not assert HLDA until any
in-progress cycle or sequence of locked cycles is completed.
When the processor samples HOLD negated during a hold
acknowledge cycle, it negates HLDA off the next clock edge.
The processor regains control of the bus and can assert ADS#
off the same clock edge on which HLDA is negated.
CLK
A[31:3]
BE[7:0]#
ADS#
M/IO#
D/C#
W/R#
D[63:0]
HOLD
HLDA
BRDY#
Figure 58. Basic HOLD/HLDA Operation
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HOLD-Initiated
Inquire Hit to Shared
or Exclusive Line
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Figure 59 on page 151 shows a HOLD-initiated inquire cycle. In
this example, the processor samples HOLD asserted during the
burst memory read cycle. The processor completes the current
cycle (until the last expected BRDY# is sampled asserted),
asserts HLDA, and floats its outputs as described on “Hold and
Hold Acknowledge Cycle” on page 148.
The system logic drives an inquire cycle within the hold
acknowledge cycle. It asserts EADS#, which validates the
inquire address on A[31:5]. If EADS# is sampled asserted
before HOLD is sampled negated, the processor recognizes it as
a valid inquire cycle.
In Figure 59, the processor asserts HIT# and negates HITM# on
the clock edge after the clock edge on which EADS# is sampled
asserted, indicating the current inquire cycle hit a shared or
exclusive cache line. (Shared and exclusive cache lines have not
been modified and do not need to be written back.) During an
inquire cycle, the processor samples INV to determine whether
the addressed cache line found in the processor’s instruction or
data cache transitions to the Invalid state or the Shared state.
In this example, the processor samples INV asserted with
EADS#, which invalidates the cache line.
The system logic can negate HOLD off the same clock edge on
which EADS# is sampled asserted. The processor continues
driving HIT# in the same state until the next inquire cycle.
HITM# is not asserted unless HIT# is asserted.
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Burst Memory Read
Inquire
CLK
A[31:3]
BE[7:0]#
ADS#
M/IO#
D/C#
W/R#
HIT#
HITM#
D[63:0]
KEN#
BRDY#
HOLD
HLDA
EADS#
INV
Figure 59. HOLD-Initiated Inquire Hit to Shared or Exclusive Line
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HOLD-Initiated
Inquire Hit to
Modified Line
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Figure 60 on page 153 shows the same sequence as Figure 59,
but in Figure 60, the inquire cycle hits a modified line and the
processor asserts both HIT# and HITM#. In this example, the
processor performs a writeback cycle immediately after the
inquire cycle. It updates the modified cache line to the external
memory (normally, external cache or DRAM). The processor
uses the address (A[31:5]) that was latched during the inquire
cycle to perform the writeback cycle. The processor asserts
HITM# throughout the writeback cycle and negates HITM# one
clock edge after the last expected BRDY# of the writeback is
sampled asserted.
When the processor samples EADS# during the inquire cycle, it
also samples INV to determine the cache line MESI state after
the inquire cycle. If INV is sampled asserted during an inquire
cycle, the processor transitions the line (if found) to the Invalid
stat e, regardless of its previous sta te. The cache line
invalidation operation is not visible on the bus. If INV is
sampled negated during an inquire cycle, the processor
transitions the line (if found) to the Shared state. In Figure 60
the processor samples INV asserted during the inquire cycle.
In a HOLD-initiated inquire cycle, the system logic can negate
HOLD off the same clock edge on which EADS# is sampled
asserted. The processor drives HIT# and HITM# on the clock
edge after the clock edge on which EADS# is sampled asserted.
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Burst Memory Read
Inquire
Writeback Cycle
CLK
A[31:3]
BE[7:0]#
ADS#
M/IO#
D/C#
W/R#
HIT#
HITM#
D[63:0]
KEN#
BRDY#
HOLD
HLDA
EADS#
INV
Figure 60. HOLD-Initiated Inquire Hit to Modified Line
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AMD-K6™-2E Processor Data Sheet
AHOLD-Initiated
Inquire Miss
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AHOLD can be asserted by the system to initiate one or more
inquire cycles. To allow the system to drive the address bus
during an inquire cycle, the processor floats A[31:3] and AP off
the clock edge on which AHOLD is sampled asserted. The data
bus and all other control and status signals remain under the
control of the processor and are not floated. This functionality
allows a bus cycle in progress when AHOLD is sampled asserted
to continue to completion. The processor resumes driving the
address bus off the clock edge on which AHOLD is sampled
negated.
In Figure 61 on page 155, the processor samples AHOLD
asserted during the memory burst read cycle, and it floats the
address bus off the same clock edge on which it samples AHOLD
asserted. While the processor still controls the bus, it completes
the current cycle until the last expected BRDY# is sampled
asserted. The system logic drives EADS# with an inquire
address on A[31:5] during an inquire cycle. The processor
samples EADS# asserted and compares the inquire address to
its tag address in both the instruction and data caches. In Figure
61, the inquire address misses the tag address in the processor
(both HIT# and HITM# are negated). Therefore, the processor
proceeds to the next cycle when it samples AHOLD negated.
(The processor can drive a new cycle by asserting ADS# off the
same clock edge that it samples AHOLD negated.)
For an AHOLD-initiated inquire cycle to be recognized, the
processor must sample AHOLD asserted for at least two
consecutive clocks before it samples EADS# asserted. If the
processor detects an address parity error during an inquire
cycle, APCHK# is asserted for one clock. The system logic must
respond appropriately to the assertion of this signal.
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Inquire
Read
CLK
A[31:3]
BE[7:0]#
AP
APCHK#
ADS#
HIT#
HITM#
D[63:0]
KEN#
BRDY#
AHOLD
EADS#
INV
Figure 61. AHOLD-Initiated Inquire Miss
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Preliminary Information
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AHOLD-Initiated
Inquire Hit to Shared
or Exclusive Line
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In Figure 62, the processor asserts HIT# and negates HITM# off
the clock edge after the clock edge on which EADS# is sampled
asserted, indicating the current inquire cycle hits either a
shared or exclusive line. (HIT# is driven in the same state until
the next inquire cycle.) The processor samples INV asserted
during the inquire cycle and transitions the line to the Invalid
state regardless of its previous state.
During an AHOLD-initiated inquire cycle, the processor
samples AHOLD on every clock edge until it is negated. In
Figure 62, the processor asserts ADS# off the same clock on
which AHOLD is sampled negated. If the inquire cycle hits a
modified line, the processor performs a writeback cycle before
it drives a new bus cycle. The next section describes the
AHOLD-initiated inquire cycle that hits a modified line.
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Inquire
Burst Memory Read
CLK
A[31:3]
BE[7:0]#
ADS#
M/IO#
D/C#
W/R#
HIT#
HITM#
D[63:0]
KEN#
BRDY#
AHOLD
EADS#
INV
Figure 62. AHOLD-Initiated Inquire Hit to Shared or Exclusive Line
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
AHOLD-Initiated
Inquire Hit to
Modified Line
22529B/0—January 2000
Figure 63 on page 159 shows an AHOLD-initiated inquire cycle
that hits a modified line. During the inquire cycle in this
example, the processor asserts both HIT# and HITM# on the
clock edge after the clock edge that it samples EADS# asserted.
This condition indicates that the cache line exists in the
processor’s data cache in the Modified state.
If the inquire cycle hits a modified line, the processor performs
a writeback cycle immediately after the inquire cycle to update
the modified cache line to shared memory (normally external
cache or DRAM). In Figure 63, the system logic holds AHOLD
asserted throughout the inquire cycle and the processor
writeback cycle. In this case, the processor is not driving the
address bus during the writeback cycle because AHOLD is
sampled asserted. The system logic writes the data to memory
by using its latched copy of the inquire cycle address. If the
processor samples AHOLD negated before it performs the
writeback cycle, it drives the writeback cycle by using the
address (A[31:5]) that it latched during the inquire cycle.
If INV is sampled asserted during an inquire cycle, the
processor transitions the line (if found) to the Invalid state,
regardless of its previous state (the cache invalidation
operation is not visible on the bus). If INV is sampled negated
during an inquire cycle, the processor transitions the line (if
found) to the Shared state. In either case, if the line is found in
the Modified state, the processor writes it back to memory
before changing its state. Figure 63 shows that the processor
samples INV asserted during the inquire cycle and invalidates
the cache line after the inquire cycle.
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Burst Memory Read
Inquire
Writeback
CLK
A[31:3]
BE[7:0]#
ADS#
M/IO#
D/C#
W/R#
HIT#
HITM#
D[63:0]
KEN#
BRDY#
AHOLD
EADS#
INV
Figure 63. AHOLD-Initiated Inquire Hit to Modified Line
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
AHOLD Restriction
When the system logic drives an AHOLD-initiated inquire
cycle, it must assert AHOLD for at least two clocks before it
asserts EADS#. This requirement guarantees the processor
recognizes and responds to the inquire cycle properly. The
processor’s 32 address bus drivers turn on almost immediately
after AHOLD is sampled negated. If the processor switches the
data bus (D[63:0] and DP[7:0]) during a write cycle off the same
clock edge that switches the address bus (A[31:3] and AP), the
processor switches 102 drivers simultaneously, which can lead
to ground-bounce spikes. Therefore, before negating AHOLD,
the following restrictions must be observed by the system logic:
■
■
■
160
22529B/0—January 2000
When the system logic negates AHOLD during a write cycle,
it must ensure that AHOLD is not sampled negated on the
clock edge on which BRDY# is sampled asserted (See Figure
64 on page 161).
When the system logic negates AHOLD during a writeback
cycle, it must ensure that AHOLD is not sampled negated on
the clock edge on which ADS# is negated (See Figure 64).
When a write cycle is pipelined into a read cycle, AHOLD
must not be sampled negated on the clock edge after the
clock edge on which the last BRDY# of the read cycle is
sampled asserted. This avoids the processor simultaneously
driving the data bus (for the pending write cycle) and the
address bus off this same clock edge.
Bus Cycles
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
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CLK
ADS#
W/R#
HITM#
EADS#
D[63:0]
BRDY#
Legal AHOLD negation during write cycle
AHOLD
Illegal AHOLD negation during write cycle
The system must ensure that AHOLD is not sampled negated on the clock edge that ADS# is negated .
The system must ensure that AHOLD is not sampled negated on the clock edge on which BRDY# is sampled asserted.
Figure 64. AHOLD Restriction
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Bus Backoff (BOFF#)
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BOFF# provides the fastest response among bus-hold inputs.
Either the system logic or another bus master can assert BOFF#
to gain control of the bus immediately. BOFF# is also used to
resolve potential deadlock problems that arise as a result of
inquire cycles. The processor samples BOFF# on every clock
e d g e . I f B O F F # i s s a m p l e d a s s e r t e d , t h e p ro c e s s o r
unconditionally aborts any cycles in progress and transitions to
a Bus Hold state. (See “BOFF# (Backoff)” on page 94.) Figure
65 on page 163 shows a read cycle that is aborted when the
processor samples BOFF# asserted even though BRDY# is
sampled asserted on the same clock edge. The read cycle is
restarted after BOFF# is sampled negated (KEN# must be in
the same state during the restarted cycle as its state during the
aborted cycle).
During a BOFF#-initiated inquire cycle that hits a shared or
exclusive line, the processor samples BOFF# negated and
restarts any bus cycle that was aborted when BOFF# was
asserted. If a BOFF#-initiated inquire cycle hits a modified line,
the processor performs a writeback cycle before it restarts the
aborted cycle.
If the processor samples BOFF# asserted on the same clock
edge that it asserts ADS#, ADS# is floated but the system logic
may erroneously interpret ADS# as asserted. In this case, the
system logic must properly interpret the state of ADS# when
BOFF# is negated.
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Read
Backoff Cycle
Restart Read Cycle
CLK
A[31:3]
BE[7:0]#
ADS#
M/IO#
D/C#
W/R#
BOFF#
D[63:0]
BRDY#
Figure 65. BOFF# Timing
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AMD-K6™-2E Processor Data Sheet
Locked Cycles
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The processor asserts LOCK# during a sequence of bus cycles to
ensure the cycles are completed without allowing other bus
masters to intervene. Locked operations can consist of two to
five cycles. LOCK# is asserted during the following operations:
■
■
■
■
■
An interrupt acknowledge sequence
Descriptor Table accesses
Page Directory and Page Table accesses
XCHG instruction
An instruction with an allowable LOCK prefix
In order to ensure that locked operations appear on the bus and
are visible to the entire system, any data operands addressed
during a locked cycle that reside in the processor’s cache are
flushed and invalidated from the cache prior to the locked
operation. If the cache line is in the Modified state, it is written
back and invalidated prior to the locked operation. Likewise,
any data read during a locked operation is not cached. The
processor negates LOCK# for at least one clock between
consecutive sequences of locked operations to allow the system
logic to arbitrate for the bus.
The processor asserts SCYC during misaligned locked transfers
on the D[63:0] data bus. The processor generates additional bus
cycles to complete the transfer of misaligned data.
Basic Locked
Operation
164
Figure 66 on page 165 shows a pair of read-write bus cycles. It
represents a typical read-modify-write locked operation. The
processor asserts LOCK# off the same clock edge that it asserts
ADS# of the first bus cycle in the locked operation and holds it
asserted until the last expected BRDY# of the last bus cycle in
the locked operation is sampled asserted. (The processor
negates LOCK# off of the same clock edge.)
Bus Cycles
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
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Locked Write Cycle
Locked Read Cycle
ADDR DATA DATA DATA IDLE IDLE ADDR DATA DATA DATA IDLE IDLE ADDR
CLK
A[31:3]
BE[7:0]#
ADS#
LOCK#
M/IO#
D/C#
W/R#
SCYC
D[63:0]
BRDY#
Figure 66. Basic Locked Operation
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Locked Operation
with BOFF#
Intervention
22529B/0—January 2000
Figure 67 on page 167 shows BOFF# asserted within a locked
read-write pair of bus cycles. In this example, the processor
asserts LOCK# with ADS# to drive a locked memory read cycle
followed by a locked memory write cycle. During the locked
memory write cycle in this example, the processor samples
BOFF# asserted. The processor immediately aborts the locked
memory write cycle and floats all its bus-driving signals,
including LOCK#. The system logic or another bus master can
initiate an inquire cycle or drive a new bus cycle one clock edge
after the clock edge on which BOFF# is sampled asserted. If the
system logic drives a BOFF#-initiated inquire cycle and hits a
modified line, the processor performs a writeback cycle before
it restarts the locked cycle (the processor asserts LOCK# during
the writeback cycle).
In Figure 67, the processor immediately restarts the aborted
locked write cycle by driving the bus off the clock edge on
which BOFF# is sampled negated. The system logic must ensure
the processor results for interrupted and uninterrupted locked
cycles are consistent. That is, the system logic must guarantee
the memory accessed by the processor is not modified during
the time another bus master controls the bus.
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Locked Read Cycle
Aborted Write Cycle
Restart Write Cycle
CLK
A[31:3]
BE[7:0]#
ADS#
LOCK#
M/IO#
D/C#
W/R#
BOFF#
D[63:0]
BRDY#
Figure 67. Locked Operation with BOFF# Intervention
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Interrupt
Acknowledge
22529B/0—January 2000
In response to recognizing the system’s maskable interrupt
(INTR), the processor drives an interrupt acknowledge cycle at
t h e n e x t i n s t r u c t i o n b o u n d a ry. D u r i n g a n i n t e r r u p t
acknowledge cycle, the processor drives a locked pair of read
cycles as shown in Figure 68 on page 169. The first read cycle is
not functional, and the second read cycle returns the interrupt
number on D[7:0] (00h–FFh). Table 27 shows the state of the
signals during an interrupt acknowledge cycle.
Table 27. Interrupt Acknowledge Operation Definition
Processor
Outputs
First Bus Cycle
Second Bus Cycle
D/C#
Low
Low
M/IO#
Low
Low
W/R#
Low
Low
BE[7:0]#
EFh
FEh (low byte enabled)
A[31:3]
0000_0000h
0000_0000h
D[63:0]
(ignored)
Interrupt number expected from interrupt controller
on D[7:0]
The system logic can drive INTR either synchronously or
asynchronously. If it is asserted asynchronously, it must be
asserted for a minimum pulse width of two clocks. To ensure it
is recognized, INTR must remain asserted until an interrupt
acknowledge sequence is complete.
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Interrupt Acknowledge Cycles
CLK
A[31:3]
BE[7:0]#
ADS#
M/IO#
D/C#
W/R#
LOCK#
INTR
D[63:0]
Interrupt Number
KEN#
BRDY#
Figure 68. Interrupt Acknowledge Operation
Chapter 6
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
6.6
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Special Bus Cycles
The AMD-K6-2E processor drives special bus cycles that
include the following:
■
■
■
■
■
■
Stop grant
Flush acknowledge
Cache writeback invalidation
Halt
Cache invalidation
Shutdown
During all special cycles, D/C# = 0, M/IO# = 0, and W/R# = 1.
BE[7:0]# and A[31:3] are driven to differentiate among the
special cycles, as shown in Table 28. (See also Table 23 on
page 132.)
Note that the system logic must return BRDY# in response to all
processor special cycles.
Table 28. Encodings for Special Bus Cycles
BE[7:0]#
A[4:3]1
FBh
Special Bus Cycle
Cause
10b
Stop Grant
STPCLK# sampled asserted
EFh
00b
Flush Acknowledge
FLUSH# sampled asserted
F7h
00b
Writeback
WBINVD instruction
FBh
00b
Halt
HLT instruction
FDh
00b
Flush
INVD,WBINVD instruction
FEh
00b
Shutdown
Triple fault
Notes:
1. A[31:5] = 0
Basic Special Bus
Cycle
Figure 69 on page 171 shows a basic special bus cycle.
The processor drives D/C# = 0, M/IO# = 0, and W/R# = 1 off the
same clock edge that it asserts ADS#.
In this example, BE[7:0]# = FBh and A[31:3] = 0000_0000h,
which indicates that the special cycle is a halt special cycle (See
Table 28). A halt special cycle is generated after the processor
executes the HLT instruction.
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If the processor samples FLUSH# asserted, it writes back any
data cache lines that are in the Modified state and invalidates
all lines in the instruction and data cache. The processor then
drives a flush acknowledge special cycle.
If the processor executes a WBINVD instruction, it drives a
writeback special cycle after the processor completes
invalidating and writing back the cache lines.
Halt Cycle
CLK
A[31:3]
BE[7:0]#
A[4:3] = 00b
FBh
ADS#
M/IO#
D/C#
W/R#
BRDY#
Figure 69. Basic Special Bus Cycle (Halt Cycle)
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Shutdown Cycle
22529B/0—January 2000
In Figure 70, a shutdown (triple fault) occurs in the first half of
the waveform, and a shutdown special cycle follows in the
second half. The processor enters shutdown when an interrupt
or exception occurs during the handling of a double fault (INT
8), which amounts to a triple fault. When the processor
encounters a triple fault, it stops its activity on the bus and
generates the shutdown special bus cycle (BE[7:0]# = FEh).
The system logic must assert NMI, INIT, RESET, or SMI# to get
the processor out of the Shutdown state.
Shutdown Occurs
(Triple Fault)
Shutdown Special Cycle
CLK
A[4:3] = 00b
A[31:3]
FEh
BE[7:0]#
ADS#
LOCK#
M/IO#
D/C#
W/R#
D[63:0]
KEN#
BRDY#
Figure 70. Shutdown Cycle
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Stop Grant and Stop
Clock States
Figure 71 on page 174 and Figure 72 on page 175 show the
processor transition from normal execution to the Stop Grant
state, then to the Stop Clock state, back to the Stop Grant state,
and finally back to normal execution. The series of transitions
begins when the processor samples STPCLK# asserted. On
recognizing a STPCLK# interrupt at the next instruction
retirement boundary, the processor performs the following
actions, in the order shown:
1. Its instruction pipelines are flushed.
2. All pending and in-progress bus cycles are completed.
3. The STPCLK# assertion is acknowledged by executing a
Stop Grant special bus cycle.
4. Its internal clock is stopped after BRDY# of the Stop Grant
special bus cycle is sampled asserted and after EWBE# is
sampled asserted (if EWBE# is masked off, then entry into
the Stop Grant state is not affected by EWBE#).
5. The Stop Clock state is entered if the system logic stops the
bus clock CLK (optional).
STPCLK# is sampled as a level-sensitive input on every clock
edge but is not recognized until the next instruction boundary.
The system logic drives the signal either synchronously or
asynchronously. If it is asserted asynchronously, it must be
asserted for a minimum pulse width of two clocks. STPCLK#
must remain asserted until recognized, which is indicated by
the completion of the Stop Grant special cycle.
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STPCLK# Sampled Asserted
Stop Grant Special Cycle
Stop Clock
CLK
A[4:3] = 10b
A[31:3]
FBh
BE[7:0]#
ADS#
M/IO#
D/C#
W/R#
CACHE#
STPCLK#
D[63:0]
KEN#
BRDY#
Figure 71. Stop Grant and Stop Clock Modes, Part 1
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AMD-K6™-2E Processor Data Sheet
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Stop Clock
STPCLK# Sampled Negated Normal
Stop Grant State
(Re-entered after PLL stabilization)
CLK
A[31:3]
BE[7:0]#
ADS#
M/IO#
D/C#
W/R#
CACHE#
STPCLK#
D[63:0]
KEN#
BRDY#
Figure 72. Stop Grant and Stop Clock Modes, Part 2
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INIT-Initiated
Transition from
Protected Mode to
Real Mode
22529B/0—January 2000
INIT is typically asserted in response to a BIOS interrupt that
writes to an I/O port. This interrupt is often in response to a
Ctrl-Alt-Del keyboard input. The BIOS writes to a port (similar
to port 64h in the keyboard controller) that asserts INIT. INIT is
also used to support 80286 software that must return to real
mode after accessing extended memory in protected mode.
The assertion of INIT causes the processor to empty its
pipelines, initialize most of its internal state, and branch to
address FFFF_FFF0h—the same instruction execution starting
point used after RESET. Unlike RESET, the processor
preserves the contents of its caches, the Floating-Point state,
the MMX state, Model-Specific Registers (MSRs), the CD and
NW bits of the CR0 register, the time stamp counter, and other
specific internal resources.
Figure 73 on page 177 shows an example in which the operating
system writes to an I/O port, causing the system logic to assert
INIT. The sampling of INIT asserted starts an extended
microcode sequence that terminates with a code fetch from
FFFF_FFF0h, the reset location. INIT is sampled on every clock
edge but is not recognized until the next instruction boundary.
During an I/O write cycle, it must be sampled asserted a
minimum of three clock edges before BRDY# is sampled
asserted if it is to be recognized on the boundary between the
I/O write instruction and the following instruction. If INIT is
asserted synchronously, it can be asserted for a minimum of one
clock. If it is asserted asynchronously, it must have been
negated for a minimum of two clocks, followed by an assertion
of a minimum of two clocks.
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INIT Sampled Asserted
CLK
Code Fetch
FFFF_FFF0h
A[31:3]
BE[7:0]#
ADS#
M/IO#
D/C#
W/R#
D[63:0]
KEN#
BRDY#
INIT
Figure 73. INIT-Initiated Transition from Protected Mode to Real Mode
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AMD-K6™-2E Processor Data Sheet
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Bus Cycles
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AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
7
Power-On Configuration and Initialization
On power-on, the system logic must reset the AMD-K6-2E
processor by asserting the RESET signal. When the processor
samples RESET asserted, it immediately flushes and initializes
all internal resources and its internal state, including its
pipelines and caches, the floating-point state, the MMX and
3DNow! states, and all registers. Then, the processor jumps to
address FFFF_FFF0h to start instruction execution.
7.1
FLUSH#
Signals Sampled During the Falling Transition of RESET
FLUSH# is sampled on the falling transition of RESET to
determine if the processor begins normal instruction execution
or enters three-state test mode.
■
■
BF[2:0]
Chapter 7
If FLUSH# is High during the falling transition of RESET,
the processor unconditionally runs its Built-In Self Test
(BIST), performs the normal reset functions, then jumps to
address FFFF_FFF0h to start instruction execution. (See
“Built-In Self-Test (BIST)” on page 227 for more details.)
If FLUSH# is Low during the falling transition of RESET,
the processor enters three-state test mode. (See
“Three-State Test Mode” on page 228 and “FLUSH# (Cache
Flush)” on page 104 for more details.)
The in t er n a l op erat i n g f re q u e n cy o f t h e p roce s so r is
determined by the state of the bus frequency signals BF[2:0]
when they are sampled during the falling transition of RESET.
The frequency of the CLK input signal is multiplied internally
by a ratio defined by BF[2:0]. (See “BF[2:0] (Bus Frequency)”
on page 93 for the processor-clock to bus-clock ratios.)
Power-On Configuration and Initialization
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7.2
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RESET Requirements
During the initial power-on reset of the processor, RESET must
remain asserted for a minimum of 1.0 ms after CLK and VCC
reach specification. (See “CLK Switching Characteristics” on
page 267 for clock specifications. See “Electrical Data” on page
253 for VCC specifications.)
D u r i n g a wa r m re s e t w h i l e C L K a n d V C C a re w i t h i n
specification, RESET must remain asserted for a minimum of
15 clocks prior to its negation.
7.3
State of Processor After RESET
Output Signals
Table 29 show s the state of all processor outputs and
bidirectional signals immediately after RESET is sampled
asserted.
Table 29. Output Signal State After RESET
Signal
State
Signal
State
Floating
LOCK#
High
ADS#, ADSC#
High
M/IO#
Low
APCHK#
High
PCD
Low
BE[7:0]#
Floating
PCHK#
High
A[31:3], AP
BREQ
Low
PWT
Low
CACHE#
High
SCYC
Low
D/C#
Low
SMIACT#
High
D[63:0], DP[7:0]
Registers
180
Floating
TDO
Floating
FERR#
High
VCC2DET
Low
HIT#
High
VCC2H/L#
Low
HITM#
High
W/R#
Low
HLDA
Low
–
–
Table 30 on page 181 shows the state of all architecture
registers and Model-Specific Registers (MSRs) after the
processor has completed its initialization due to the recognition
of the assertion of RESET.
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Table 30. Register State After RESET
Register
State (hex)
GDTR
base:0000_0000h limit:0FFFFh
IDTR
base:0000_0000h limit:0FFFFh
TR
0000h
LDTR
0000h
EIP
FFFF_FFF0h
EFLAGS
0000_0002h
EAX1
0000_0000h
EBX
0000_0000h
ECX
EDX
0000_0000h
2
0000_058Xh
ESI
0000_0000h
EDI
0000_0000h
EBP
0000_0000h
ESP
0000_0000h
CS
F000h
SS
0000h
DS
0000h
ES
0000h
FS
0000h
GS
0000h
3
FPU Stack R7–R0
0000_0000_0000_0000_0000h
FPU Control Word3
FPU Status Word
3
FPU Tag Word3
Chapter 7
0040h
0000h
5555h
FPU Instruction Pointer3
0000_0000_0000h
FPU Data Pointer3
0000_0000_0000h
FPU Opcode Register3
000_0000_0000b
CR04
6000_0010h
CR2
0000_0000h
CR3
0000_0000h
CR4
0000_0000h
DR7
0000_0400h
DR6
FFFF_0FF0h
DR3
0000_0000h
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Table 30. Register State After RESET (continued)
Register
State (hex)
DR2
0000_0000h
DR1
0000_0000h
DR0
0000_0000h
MCAR3
0000_0000_0000_0000h
MCTR3
0000_0000_0000_0000h
TR123
0000_0000_0000_0000h
TSC3
0000_0000_0000_0000h
EFER
3
0000_0000_0000_0002h (Model 8/[F:8])
STAR3
0000_0000_0000_0000h
WHCR3
0000_0000_0000_0000h
UWCCR3
0000_0000_0000_0000h
PSOR3,5
0000_0000_0000_01SBh
PFIR3
0000_0000_0000_0000h
Notes:
1. The contents of EAX indicate if BIST was successful. If EAX = 0000_0000h, BIST was successful.
If EAX is non-zero, BIST failed.
2. EDX contains the AMD-K6-2E processor signature, where X indicates the processor Stepping
ID.
3. The contents of these registers are preserved following the recognition of INIT.
4. The CD and NW bits of CR0 are preserved following the recognition of INIT.
5. “S” represents the Stepping. “B” represents PSOR[3:0], where PSOR[3] equals 0, and
PSOR[2:0] is equal to the value of the BF[2:0] signals sampled during the falling transition of
RESET.
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7.4
State of Processor After INIT
The recognition of the assertion of INIT causes the processor to
empty its pipelines, to initialize most of its internal state, and to
branch to address FFFF_FFF0h—the same instruction
execution starting point used after RESET.
Unlike RESET, the processor preserves the contents of its
caches, the floating-point state, the MMX and 3DNow! states,
MSRs, and the CD and NW bits of the CR0 register.
The edge-sensitive interrupts FLUSH# and SMI# are sampled
and preserved during the INIT process and are handled
accordingly after the initialization is complete. However, the
processor resets any pending NMI interrupt upon sampling
INIT asserted.
INIT can be used as an accelerator for 80286 code that requires
a reset to exit from protected mode back to real mode.
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8
Cache Organization
The following sections describe the basic architecture and
resources of the AMD-K6-2E processor internal caches.
The performance of the AMD-K6-2E processor is enhanced by a
writeback level-one (L1) cache. The cache is organized as a
separate 32-Kbyte instruction cache and a 32-Kbyte data cache,
each with two-way set associativity (See Figure 74). The cache
line size is 32 bytes, and lines are prefetched from external
memory using an efficient, pipelined burst transaction.
As the instruction cache is filled, each instruction byte is
analyzed for instruction boundaries using predecode logic.
Predecoding annotates each instruction byte with information
that later enables the decoders to efficiently decode multiple
instructions simultaneously. Translation lookaside buffers
(TLB) are also used to translate linear addresses to physical
addresses. The instruction cache is associated with a 64-entry
TLB, while the data cache is associated with a 128-entry TLB.
32-Kbyte Instruction Cache
Tag
RAM
Way 0
State Tag
Bit RAM
Way 1
State
Bit
64-Entry TLB
System Bus
Interface Unit
Processor
Core
Predecode Instruction Cache
128-Entry TLB
Tag
RAM
Way 0
MESI Tag
Bits RAM
Way 1
MESI
Bits
32-Kbyte Data Cache
Figure 74. Cache Organization
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The processor cache design takes advantage of a sectored
organization (See Figure 75). Each sector consists of 64 bytes
configured as two 32-byte cache lines. The two cache lines of a
sector share a common tag but have separate MESI (modified,
exclusive, shared, invalid) bits that track the state of each cache
line.
Instruction Cache Line
Tag
Address
Cache Line 0
Byte 31
Predecode Bits
Byte 30
Predecode Bits
........
........
Byte 0
Predecode Bits
1 MESI Bit
Cache Line 1
Byte 31
Predecode Bits
Byte 30
Predecode Bits
........
........
Byte 0
Predecode Bits
1 MESI Bit
Data Cache Line
Tag
Address
Cache Line 0
Byte 31
Byte 30
........
........
Byte 0
2 MESI Bits
Cache Line 1
Byte 31
Byte 30
........
........
Byte 0
2 MESI Bits
Notes:
Instruction-cache lines have only two coherency states (valid or invalid) rather than the four MESI coherency states of data-cache lines.
Only two states are needed for the instruction cache because these lines are read-only.
Figure 75. Cache Sector Organization
8.1
MESI States in the Data Cache
The state of each line in the caches is tracked by the MESI bits.
The coherency of these states or MESI bits is maintained by
internal processor snoops and external inquiries by the system
logic. The following four states are defined for the data cache:
■
■
■
■
186
Modified—This line has been modified and is different from
main memory.
Exclusive—This line is not modified and is the same as
external memory. If this line is written to, it becomes
Modified.
Shared—If a cache line is in the Shared state it means that
the same line can exist in more than one cache system.
Invalid—The information in this line is not valid.
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8.2
Predecode Bits
Decoding x86 instructions is particularly difficult because the
instructions vary in length, ranging from 1 to 15 bytes long.
Predecode logic supplies the predecode bits associated with
each instruction byte.
Predecode bits indicate the number of bytes to the start of the
next x86 instruction. The predecode bits are passed with the
instruction bytes to the decoders, where they assist with
parallel x86 instruction decoding. The predecode bits use
memory separate from the 32-Kbyte instruction cache. The
predecode bits are stored in an extended instruction cache
alongside each x86 instruction byte as shown in Figure 75 on
page 186.
8.3
Cache Operation
The operating modes for the caches are configured by software
using the Not Writethrough (NW) and Cache Disable (CD) bits
of control register 0 (CR0 bits 29 and 30 respectively). These
bits are used in all operating modes.
When the CD and NW bits are both 0, the cache is fully
enabled. This is the standard operating mode for the cache.
If a read miss occurs when the processor reads from the
cache, a line fill (32-byte burst read) on the system bus
occurs in order to fetch the cache line. Write hits to the
cache are updated, while write misses and writes to shared
lines cause external memory updates. Refer to Table 34,
“Data Cache States for Read and Write Accesses,” on
page 198 for a summary of cache read and write cycles and
the effect of these operations on the cache MESI state.
Note: A write allocate operation can modify the behavior of write
misses to the cache. See “Write Allocate” on page 192.
■
■
■
Chapter 8
When the CD bit is 0 and the NW bit is 1, an invalid mode of
operation exists that causes a general protection fault to
occur.
When the CD bit is 1 (disabled) and the NW bit is 0, the
cache fill mechanism is disabled but the contents of the
cache are still valid. The processor reads from the cache, and
if a read miss occurs, no line fills take place. Write hits to the
cache are updated, while write misses and writes to shared
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lines cause external memory updates. If PWT is driven Low
and WB/WT# is sampled High, a write hit to a shared line
changes the cache-line state to Exclusive.
■
When the CD and NW bits are both 1, the cache is fully
disabled. Even though the cache is disabled, the contents
are not necessarily invalid. The processor reads from the
cache and, if a read miss occurs, no line fills take place. If a
write hit occurs, the cache is updated but an external
memory update does not occur. If a cache line is in the
Exclusive state during a write hit, the cache-line state is
changed to Modified. Cache lines in the Shared state remain
in the Shared state after a write hit. Write misses access
external memory directly.
The operating system can control the cacheability of a page.
The paging mechanism is controlled by CR3, the Page Directory
Entry (PDE), and the Page Table Entry (PTE). Within CR3,
PDE, and PTE are Page Cache Disable (PCD) and Page
Writethrough (PWT) bits. The values of the PCD and PWT bits
used in Table 31 and Table 32 are taken from either the PTE or
PDE. For more information see the descriptions of PCD and
PWT on page 115 and page 117, respectively.
Tables 31 through 33 describe the logic that determines the
cacheability of a cycle and how that cacheability is affected by
the PCD bits, the PWT bits, the PG and CD bits of CR0,
writeback cycles, the Cache Inhibit (CI) bit of Test Register 12
(TR12), and unlocked memory reads.
Table 31 describes how the PWT signal is driven based on the
values of the PWT bits and the PG bit of CR0.
Table 31. PWT Signal Generation
PWT Bit1
PG Bit of CR0
PWT Signal
1
1
High
0
1
Low
1
0
Low
0
0
Low
Notes:
1.
188
PWT is taken from PTE or PDE.
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Table 32 describes how the PCD signal is driven based on the
values of the CD bit of CR0, the PCD bits, and the PG bit of
CR0.
Table 32. PCD Signal Generation
CD Bit of CR0
PCD Bit1
PG Bit of CR0
PCD Signal
1
Don’t care
Don’t care
High
0
1
1
High
0
0
1
Low
0
1
0
Low
0
0
0
Low
Notes:
1. PCD is taken from PTE or PDE.
Table 33 describes how the CACHE# signal is driven based on
the cycle type, the CI bit of TR12, the PCD signal, and the
UWCCR model-specific register.
Table 33. CACHE# Signal Generation
Cycle Type
CI Bit of TR12
PCD Signal
Access Within
WC/UC Range1
CACHE#
Writebacks
Don’t care
Don’t care
Don’t care
Low
0
0
0
Low
Locked Reads
Don’t care
Don’t care
Don’t care
High
Single Writes
Don’t care
Don’t care
Don’t care
High
Any Cycle Except Writebacks
1
Don’t care
Don’t care
High
Any Cycle Except Writebacks
Don’t care
1
Don’t care
High
Any Cycle Except Writebacks
Don’t care
Don’t care
1
High
Unlocked Reads
Notes:
1. WC and UC refer to Write-Combining and Uncacheable Memory Ranges as defined in the UWCCR.
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Cache-Related Signals
Complete descriptions of the signals that control cacheability
and cache coherency are given on the following pages:
■
■
■
■
■
■
■
■
■
■
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CACHE#—page 97
EADS#—page 101
FLUSH#—page 104
HIT#—page 105
HITM#—page 105
INV—page 110
KEN#—page 111
PCD—page 115
PWT—page 117
WB/WT#—page 129
Cache Disabling and Flushing
To completely disable all cache accesses, the CD bit must be set
to 1 and the cache must be completely flushed. There are three
different methods for flushing the cache. The first method
relies on the system logic, and the other two rely on software.
■
■
■
190
For the system logic to flush the cache, the processor must
sample FLUSH# asserted. In this method, the processor
writes back any data cache lines that are in the Modified
state, invalidates all lines in the instruction and data caches,
and then executes a flush acknowledge special cycle (See
Table 23 on page 132).
The second method relies on software to execute the
WBINVD instruction which causes all modified lines to first
be written back to memory, then marks all cache lines as
invalid. Alternatively, if writing modified lines back to
memory is not necessary, the INVD instruction can be used
to invalidate all cache lines.
The third method is to make use of the Page Flush/Invalidate
Register (PFIR), which allows cache invalidation and
optional flushing of a specific 4-Kbyte page from the linear
address space (see “Page Flush/Invalidate Register (PFIR)”
on page 200). Unlike the previous two methods of flushing
the cache, this particular method requires the software to be
aware of which specific pages must be flushed and
invalidated.
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8.5
Cache-Line Fills
The processor performs a cache-line fill for any area of system
memory defined as cacheable. If an area of system memory is
not explicitly defined as uncacheable by the software or system
logic, or implicitly treated as uncacheable by the processor,
then the memory access is assumed to be cacheable.
Software can prevent caching of certain pages by setting the
PCD bit in the page directory entry (PDE) or page table entry
(PTE). Additionally, software can define regions of memory as
uncacheable or write combinable by programming the MTRRs
in the UC/WC cacheability control register (UWCCR) (see
“Memory Type Range Registers” on page 207). Writecombinable memory is defined as uncacheable.
The system logic also has control of the cacheability of bus
cycles. If system logic determines the address is not cacheable,
system logic negates the KEN# signal when asserting the first
BRDY# or NA# of a cycle.
The processor does not cache certain memory accesses, such as
locked operations. In addition, the processor does not cache
PDE or PTE memory reads in the L1 cache (referred to as page
table walks).
When the processor needs to read memory, the processor drives
a read cycle onto the bus. If the cycle is cacheable, the
processor asserts CACHE#. If the cycle is not cacheable, a
non-burst, single-transfer read takes place. The processor waits
for the system logic to return the data and assert a single
BRDY# (See Figure 52 on page 139). If the cycle is cacheable,
the processor executes a 32-byte burst read cycle. The processor
expects a total of four BRDY# signals for a burst read cycle to
take place (See Figure 54 on page 143).
Cache-line fills initiate 32-byte burst read cycles from memory
on the system bus for the instruction cache and the data cache.
If a data-cache line being filled replaces a modified line, the
modified contents of the line are copied to a 32-byte writeback
(copyback) buffer in the bus interface unit while the new line is
being read.
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Cache-Line Replacements
As programs execute and task switches occur, some cache lines
eventually require replacement.
Instruction cache lines are replaced using a Least Recently
Used (LRU) algorithm. If line replacement is required, lines are
replaced when read cache misses occur.
The data cache uses a slightly different approach to line
replacement. If a miss occurs, and a replacement is required,
lines are replaced by using a Least Recently Allocated (LRA)
algorithm.
Two forms of cache misses and associated cache fills can take
place—a tag-miss cache fill and a tag-hit cache fill.
■
■
8.7
In the case of a tag-miss cache fill, the miss is due to a tag
mismatch, in which case the required cache line is filled
from external memory, and the cache line within the sector
that was not required is marked as invalid.
In the case of a tag-hit cache fill, the address matches the
tag, but the requested cache line is marked as invalid. The
required cache line is filled from external memory, and the
cache line within the sector that is not required remains in
the same cache state.
Write Allocate
Write allocate, if enabled, occurs when the processor has a
pending memory write cycle to a cacheable line and the line
does not currently reside in the data cache. In this case, the
processor performs a 32-byte burst read cycle to fetch the
data-cache line addressed by the pending write cycle. The data
associated with the pending write cycle is merged with the
recently-allocated data-cache line and stored in the processor’s
data cache. The final MESI state of the cache line depends on
the state of the WB/WT# and PWT signals during the burst read
cycle and the subsequent data cache write hit (See Table 34 on
page 198 to determine the cache-line states and the access
types following a cache read miss and cache write hit).
If a data-cache line fetch from memory is attempted because
the write allocate misses the data cache, and KEN# is sampled
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negated, the processor does not perform an allocation. In this
case, the pending write cycle is executed as a single write cycle
on the system bus.
During write allocates, a 32-byte burst read cycle is executed in
place of a non-burst write cycle. While the burst read cycle
generally takes longer to execute than the write cycle,
performance gains are realized on subsequent write cycle hits
to the write-allocated cache line. Due to the nature of software,
memory accesses tend to occur in proximity of each other
(principle of locality). The likelihood of additional write hits to
the write-allocated cache line is high.
The following is a description of three mechanisms by which the
AMD-K6-2E processor performs write allocations. A write
al lo c at e is p e r fo rm e d wh en a ny o n e o r m o re of t h e se
mechanisms indicates that a pending write is to a cacheable
area of memory.
Write to a Cacheable
Page
Every time the processor performs a cache line fill, the address
of the page in which the cache line resides is saved in the
Cacheability Control Register (CCR). The page address of
subsequent write cycles is compared with the page address
stored in the CCR. If the two addresses are equal, then the
processor performs a write allocate because the page has
already been determined to be cacheable.
When the processor performs a cache line fill from a different
page than the address saved in the CCR, the CCR is updated
with the new page address.
Write to a Sector
If the address of a pending write cycle matches the tag address
of a valid cache sector, but the addressed cache line within the
sector is marked invalid (a sector hit but a cache line miss),
then the processor performs a write allocate. The pending write
cycle is determined to be cacheable because the sector hit
indicates the presence of at least one valid cache line in the
sector. The two cache lines within a sector are guaranteed by
design to be within the same page.
Write Allocate Limit
The AMD-K6-2E processor uses two mechanisms that are
programmable within the Write Handling Control register
(WHCR) to enable write allocations for write cycles that
address a definable or special 1-Mbyte memory area.
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Write Handling Control Register (WHCR) . Th e W H C R re g i s t e r
contains two fields —the Write Allocate Enable Limit
(WAELIM) field, and the Write Allocate Enable 15-to-16-Mbyte
(WAE15M) bit (see Figure 76).
63
32 31
22 21
WAELIM
17 16 15
0
W
A
E
1
5
M
Reserved
Symbol
WAELIM
WAE15M
Description
Bits
Write Allocate Enable Limit
31-22
Write Allocate Enable 15-to-16-Mbyte 16
Note: Hardware RESET initializes this MSR to all zeros.
Figure 76. Write Handling Control Register (WHCR)
Write Allocate Enable Limit Field. The WAELIM field is 10 bits wide.
This field, multiplied by 4 Mbytes, defines an upper memory
limit. Any pending write cycle that addresses memory below
this limit causes the processor to perform a write allocate
(assuming the address is not within a range where write
allocates are disallowed). Write allocate is disabled for memory
accesses at and above this limit unless the processor determines
a pending write cycle is cacheable by means of one of the other
write allocate mechanisms—“Write to a Cacheable Page” and
“Write to a Sector.” The maximum value of this limit is ((210 –1)
· 4 Mbytes) = 4092 Mbytes. When all the bits in this field are 0,
all memory is above this limit and the write allocate mechanism
is disabled (even if all bits in the WAELIM field are 0, write
allocates can still occur due to the “Write to a Cacheable Page”
and “Write to a Sector” mechanisms).
Write Allocate Enable 15-to-16-Mbyte Bit. The Write Allocate Enable
1 5-t o -1 6 -M by t e ( WA E1 5 M) b it i s u se d t o e n able w r it e
allocations for the memory write cycles that address the 1
Mbyte of memory between 15 Mbytes and 16 Mbytes. This bit
must be set to 1 to allow write allocate in this memory area. This
bit is provided to account for a small number of uncommon
memory-mapped I/O adapters that use this particular memory
address space. If the system contains one of these peripherals,
the bit should be written to 0 (even if the WAE15M bit is 0,
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write allocates can still occur between 15 Mbytes and 16
Mbytes due to the “Write to a Cacheable Page” and “Write to a
Sector” mechanisms). The WAE15M bit is ignored if the value
in the WAELIM field is less than 16 Mbytes.
By definition, a write allocate is never performed in the
memory area between 640 Kbytes and 1 Mbyte unless the
processor determines a pending write cycle is cacheable by
means of one of the other write allocate mechanisms—“Write
to a Cacheable Page” and “Write to a Sector”. It is not
considered safe to perform write allocations between 640
Kbytes and 1 Mbyte (000A_0000h to 000F_FFFFh) because it is
considered a noncacheable region of memory.
If a memory region is defined as w rite- combinable or
uncacheable by a MTRR, write allocates are not performed in
that region.
Write Allocate Logic
Mechanisms and
Conditions
Figure 77 shows the logic flow for all the mechanisms involved
with write allocate for memory bus cycles. The left side of the
diagram (the text) describes the conditions that need to be true
for the value of that line to be a 1. Items 1–4 of the diagram are
related to general cache operation and items 5–10 are related to
the write allocate mechanisms.
Fo r m o re i n f o r m a t i o n a b o u t w r i t e a l l o c a t e , s e e t h e
Implementation of Write Allocate in the K86™ Processors
Application Note, order #21326.
Perform
Write Allocate
1) CD Bit of CR0
2) PCD Signal
3) CI Bit of TR12
4) UC or WC
5) Write to Cacheable Page (CCR)
6) Write to a Sector
7) Less Than Limit (WAELIM)
8) Between 640 Kbytes and 1 Mbyte
9) Between 15–16 Mbytes
10) Write Allocate Enable 15–16 Mbyte (WAE15M)
Figure 77. Write Allocate Logic Mechanisms and Conditions
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The following list corresponds to the items in Figure 77 on page
195:
1. CD Bit of CR0—When the Cache Disable (CD) bit within
control register 0 (CR0) is 1, the cache fill mechanism for
both reads and writes is disabled, and write allocate does
not occur.
2. PCD Signal—When the PCD (page cache disable) signal is
driven High, caching for that page is disabled even if KEN#
is sampled asserted, and write allocate does not occur.
3. CI Bit of TR12—When the cache inhibit bit of test register 12
is 1, L1 cache fills are disabled, and write allocate does not
occur.
4. UC or WC—If a pending write cycle addresses a region of
memory defined as write combinable or uncacheable by an
MTRR, write allocates are not performed in that region.
5. Write to a Cacheable Page (CCR)—A write allocate is
performed if the processor knows that a page is cacheable.
The CCR is used to store the page address of the last cache
fill for a read miss. See “Write to a Cacheable Page” on page
193 for a detailed description of this condition.
6. Write to a Sector—A write allocate is performed if the
address of a pending write cycle matches the tag address of a
valid cache sector, but the addressed cache line within the
sector is invalid. See “Write to a Sector” on page 193 for a
detailed description of this condition.
7. Less Than Limit (WAELIM)—The write allocate limit
mechanism determines if the memory area being addressed
is less than the limit set in the WAELIM field of WHCR. If
the address is less than the limit, write allocate for that
memory address is performed as long as conditions 8
through 10 do not prevent write allocate (even if conditions
8 and 10 attempt to prevent write allocate, condition 5 or 6
allows write allocates to occur).
8. Between 640 Kbytes and 1 Mbyte —Write allocate is not
performed in the memory area between 640 Kbytes and 1
Mbyte. It is not considered safe to perform write allocations
between 640 Kbytes and 1 Mbyte (000A_0000h to
000F_FFFFh) because this area of memory is considered a
noncacheable region of memory (even if condition 8
attempts to prevent write allocate, condition 5 or 6 allows
write allocate to occur).
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9. Between 15–16 Mbytes—If the address of a pending write
cycle is in the 1 Mbyte of memory between 15 Mbytes and 16
Mbytes, and the WAE15M bit is 1, write allocate for this
cycle is enabled.
10. Write Allocate Enable 15–16 Mbytes (WAE15M)—This
condition is associated with the Write Allocate Limit
mechanism and affects write allocate only if the limit
specified by the WAELIM field is greater than or equal to
16 Mbytes. If the memory address is between 15 Mbytes and
16 Mbytes, and the WAE15M bit in the WHCR is 0, write
allocate for this cycle is disabled (even if condition 10
attempts to prevent write allocate, condition 5 or 6 allows
write allocate to occur).
8.8
Prefetching
Hardware
Prefetching
The AMD-K6-2E processor conditionally performs cache
prefetching which results in the filling of the required cache
line first, and a prefetch of the second cache line making up the
other half of the sector. From the perspective of the external
bus, the two cache-line fills typically appear as two 32-byte
burst read cycles occurring back-to-back or, if allowed, as
p i pe l in e d cy cl e s . Th e b u rs t re a d cy cl e s d o n o t o c c u r
back-to-back (wait states occur) if the processor is not ready to
start a new cycle, if higher priority data read or write requests
exist, or if NA# (next address) was sampled negated. Wait states
can also exist between burst cycles if the processor samples
AHOLD or BOFF# asserted.
Software Prefetching
The 3DNow! technology includes an instruction called
PREFETCH that allows a cache line to be prefetched into the
L1 data cache. Unlike prefetching under hardware control,
software prefetching only fetches the cache line specified by
the operand of the PREFETCH instruction, and does not
attempt to fetch the other cache line in the sector. The
PREFETCH instruction format is defined in Table 15,
“3DNow!™ Instructions,” on page 81. For more detailed
information, see the 3DNow!™ Technology Manual, order#
21928.
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Cache States
Table 34 shows all the possible cache-line states before and
after program-generated accesses to individual cache lines. The
table includes the correspondence between MESI states and
Writethrough or Writeback states for lines in the data cache.
Table 34. Data Cache States for Read and Write Accesses
Type
Read miss
Cache
Read
Read hit
Access Type
Invalid
Write hit
1
MESI State2
Writeback/
Writethrough State
Single read from bus
Invalid
Not applicable or none
Invalid
Burst read from bus, fill
cache3
Shared or
exclusive4
Writethrough or writeback4
Exclusive
Not applicable or none
Exclusive
Writeback
Modified
Not applicable or none
Modified
Writeback
Shared
Not applicable or none
Shared
Writethrough
Invalid
Single write to bus5
Invalid
Not applicable or none
Invalid
Burst read from bus, fill
cache, write to cache6
Modified7
Not applicable or none
Invalid
Burst read from bus, fill
cache, write to cache,
single write to bus6
Shared8
Not applicable or none
Exclusive or modified
Write to cache
Modified
Writeback
Shared
Write to cache, single write
to bus
Shared or
exclusive4
Writethrough or writeback4
Write miss
Cache
Write
Cache State After Access
Cache State Before
Access
Notes:
1.
2.
3.
4.
5.
6.
7.
8.
Single read, single write, cache update, and writethrough = 1 to 8 bytes. Line fill = 32-byte burst read.
The final MESI state assumes that the state of the WB/WT# signal remains the same for all accesses to a particular cache line.
If CACHE# is driven Low and KEN# is sampled asserted.
If PWT is driven Low and WB/WT# is sampled High, the line is cached in the exclusive (writeback) state. If PWT is driven High or
WB/WT# is sampled Low, the line is cached in the shared (writethrough) state.
Assumes the write allocate conditions as specified in “Write Allocate” on page 192 are not met.
Assumes the write allocate conditions as specified in “Write Allocate” on page 192 are met.
Assumes PWT is driven Low and WB/WT# is sampled High.
Assumes PWT is driven High or WB/WT # is sampled Low.
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8.10
Cache Coherency
Different methods exist to maintain coherency between the
system memory and cache memories. Inquire cycles, internal
snoops, FLUSH#, WBINVD, INVD, and line replacements all
prevent inconsistencies between memories.
Inquire Cycles
Inquire cycles are bus cycles initiated by system logic. These
inquiries ensure coherency between the caches and main
memory. In systems with multiple caching masters, system logic
maintains cache coherency by driving inquire cycles to the
processor. System logic initiates inquire cycles by asserting
AHOLD, BOFF#, or HOLD to obtain control of the address bus
and then driving EADS#, INV (optional), and an inquire
address (A[31:5]).
This type of bus cycle causes the processor to compare the tags
for both its instruction and data caches with the inquire
address.
■
■
■
■
If there is a hit to a shared or exclusive line in the data cache
or a valid line in the instruction cache, the processor asserts
HIT#.
If the compare hits a modified line in the data cache, the
processor asserts HIT# and HITM#. If HITM# is asserted, the
processor writes the modified line back to memory.
If INV was sampled asserted with EADS#, a hit invalidates
the line.
If INV was sampled negated with EADS#, a hit leaves the
line in the Shared state or transitions it from the Exclusive
or Modified to Shared state.
Table 35 on page 202 shows the effects of inquire cycles—
performed with INV equal to 0 (non-validating) and INV equal
to 1 (invalidating) snoops and invalidations.
Internal Snooping
Internal snooping is initiated by the processor (rather than
system logic) during certain cache accesses. It is used to
maintain coherency between the L1 instruction and data
caches.
The processor automatically snoops its instruction cache during
read or write misses to its data cache, and it snoops its data
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cache during read misses to its instruction cache. Table 35
summarizes the actions taken during this internal snooping.
If an internal snoop hits its target, the processor does the
following:
■
■
Data Cache Snoop During an Instruction-Cache Read
Miss—If modified, the line in the data cache is written back
on the system bus to external memory. Regardless of its
state, the data-cache line is invalidated and the instruction
cache performs a burst read cycle from external memory.
Instruction Cache Snoop During a Data-Cache Miss—The
line in the instruction cache is marked invalid, and the
data-cache read or write is performed from memory.
FLUSH#
In response to sampling FLUSH# asserted, the processor writes
back any data cache lines that are in the Modified state and
then marks all lines in the instruction and data caches as
invalid.
Page Flush/Invalidate
Register (PFIR)
The AMD-K6-2E processor contains the page flush/invalidate
register (PFIR) (see Figure 78) that allows cache invalidation
and optional flushing of a specific 4-Kbyte page from the linear
address space. When the PFIR is written to (using the WRMSR
instruction), the invalidation and the flushing (optional) begin.
The total amount of cache in the AMD-K6-2E processor is 64
Kbytes. Using this register can result in a much lower cycle
count for flushing particular pages versus flushing the entire
cache.
32 31
63
12 11
LINPAGE
9 8 7
P
F
1 0
F
/
I
Reserved
Symbol
LINPAGE
PF
F/I
Description
20-bit Linear Page Address
Page Fault Occurred
Flush/Invalidate Command
Bit
31-12
8
0
Figure 78. Page Flush/Invalidate Register (PFIR)—MSR C000_0088h
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LINPAGE Field. This 20-bit field must be written with bits 31:12 of
the linear address of the 4-Kbyte page that is to be invalidated
and optionally flushed from the L1 cache.
PF Bit. If an attempt to invalidate or flush a page results in a
page fault, the processor sets the PF bit to 1, and the invalidate
or flush operation is not performed (even though invalidate
operations do not normally generate page faults). In this case,
an actual page fault exception is not generated. If the PF bit
equals 0 after an invalidate or flush operation, then the
operation executed successfully. The PF bit must be read after
every write to the PFIR register to determine if the invalidate
or flush operation executed successfully.
F/I Bit. This bit is used to control the type of action that occurs to
the specified linear page. If a 0 is written to this bit, the
operation is a flush, in which case all cache lines in the
modified state within the specified page are written back to
memory, after which the entire page is invalidated. If a 1 is
written to this bit, the operation is an invalidation, in which
case the entire page is invalidated without the occurrence of
any writebacks.
WBINVD and INVD
Instructions
These x86 instructions cause all cache lines to be marked as
invalid. WBINVD writes back modified lines before marking all
cache lines invalid. INVD does not write back modified lines.
Cache-Line
Replacement
Replacing lines in the instruction or data cache, according to
the line replacement algorithms described in “Cache-Line
Fills” on page 191, ensures coherency between external
memory and the caches.
Table 35 on page 202 shows all possible cache-line states before
and after various cache-related operations.
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Table 35. Cache States for Inquire Cycles, Snoops, Flushes, and Invalidation
Cache State
Type of Operation
Before Operation
Cache State After Operation
Memory Access
Shared or exclusive
Not applicable or none
Modified
Writeback to bus
Shared or exclusive
Not applicable or none
Modified
Writeback to bus
Shared or
exclusive
Not applicable or none
Modified
Writeback to bus
Shared or exclusive
Not applicable or none
Modified
Writeback to bus
Inquire Cycle
Internal Snoop
FLUSH# Signal
PFIR
(F/I = 0)
PFIR
(F/I = 1)
WBINVD Instruction
INVD Instruction
Not applicable or none Not applicable or none
Shared or exclusive
Not applicable or none
Modified
Writeback to bus
Not applicable or none Not applicable or none
MESI State
Writeback/
Writethrough State
INV=0
Shared
Writethrough
INV=1
Invalid
Invalid
INV=0
Shared
Writethrough
INV=1
Invalid
Invalid
Invalid
Invalid
Invalid
Invalid
Invalid
Invalid
Invalid
Invalid
Invalid
Invalid
Invalid
Invalid
Notes:
All writebacks are 32-byte burst write cycles.
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Cache Snooping
Table 36 shows the conditions under which snooping occurs in
the AMD-K6-2E processor and the resources that are snooped.
Table 36. Snoop Action
Type of Event
Type of Access
Inquire Cycle
System Logic
Instruction Cache
Internal Snoop
Data Cache
Snooping Action
Instruction Cache
Data Cache
Yes1
Yes1
Read
Miss
Not applicable
Yes2
Read
Hit
Not applicable
No
Read
Miss
Yes3
Not applicable
Read
Hit
No
Not applicable
Write
Miss
Yes3
Not applicable
Write
Hit
No
Not applicable
Notes:
1. The processor’s response to an inquire cycle depends on the state of the INV input signal and the state of the cache line as
follows:
For the instruction cache, if INV is sampled negated, the line remains invalid or valid, but if INV is sampled asserted, the line is
invalidated.
For the data cache, if INV is sampled negated, valid lines remain in or transition to the Shared state, a modified data cache line
is written back before the line is marked shared (with HITM# asserted), and invalid lines remain invalid. For the data cache, if
INV is sampled asserted, the line is marked invalid. Modified lines are written back before invalidation.
2. If an internal snoop hits a modified line in the data cache, the line is written back and invalidated. Then the instruction cache
performs a burst read from memory.
3. If an internal snoop hits a line in the instruction cache, the instruction cache line is invalidated and the data-cache read or write
is performed from memory.
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Writethrough and Writeback Coherency States
The terms writethrough and writeback apply to two related
concepts in a read-write cache like the AMD-K6-2E processor’s
L1 data cache. The following conditions apply to both the
writethrough and writeback modes:
■
■
8.12
Memory Writes—A relationship exists between external
memory writes and their concurrence with cache updates:
• An external memory write that occurs concurrently with
a cache update to the same location is a writethrough.
Writethroughs are driven as single cycles on the bus.
• An external memory write that occurs after the processor
has modified a cache line is a writeback. Writebacks are
driven as burst cycles on the bus.
Coherency State—A relationship exists between MESI
coherency states and writethrough-writeback coherency
states of lines in the cache as follows:
• Shared and invalid MESI lines are in writethrough state.
• Modified and exclusive MESI lines are in writeback state.
A20M# Masking of Cache Accesses
Although the processor samples A20M# as a level-sensitive
input on every clock edge, it should only be asserted in real
mode. The processor applies the A20M# masking to its tags,
through which all programs access the caches. Therefore,
assertion of A20M# affects all addresses (cache and external
memory), including the following:
■
■
Cache-line fills (caused by read misses or write allocates)
Cache writethroughs (caused by write misses or write hits to
lines in the Shared state)
However, A20M# does not mask writebacks or invalidations
caused by the following actions:
■
■
■
■
■
204
Internal snoops
Inquire cycles
The FLUSH# signal
The WBINVD instruction
Writing to the page flush/invalidate register (PFIR)
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9
Write Merge Buffer
The AMD-K6-2E processor contains an 8-byte write merge
buffer that allows the processor to conditionally combine data
from multiple noncacheable write cycles into this merge buffer.
The merge buffer operates in conjunction with the Memory
Type Range Registers (MTRRs). Refer to “Memory Type Range
Registers” on page 207 for a description of the MTRRs.
Merging multiple write cycles into a single write cycle reduces
processor bus utilization and processor stalls, thereby
increasing the overall system performance.
9.1
EWBE# Control
The presence of the merge buffer creates the potential to
perform out-of-order write cycles relative to the processor’s L1
cache. In general, the ordering of write cycles that are driven
externally on the system bus and those that hit the processor’s
cache can be controlled by the EWBE# signal. See “EWBE#
(External Write Buffer Empty)” on page 102 for more
information.
If EWBE# is sampled negated, the processor delays the
commitment of write cycles to cache lines in the Modified state
or Exclusive state in the processor’s cache. Therefore, the
system logic can enforce strong ordering by negating EWBE#
until the external write cycle is complete, thereby ensuring that
a subsequent write cycle that hits the cache does not complete
ahead of the external write cycle.
However, the addition of the write merge buffer introduces the
potential for out-of-order write cycles to occur between writes
to the merge buffer and writes to the processor’s cache. Because
these writes occur entirely within the processor and are not
sent out to the processor bus, the system logic is not able to
enforce strong ordering with the EWBE# signal.
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The EWBE control (EWBEC) bits in the EFER register provide
a mechanism for enforcing three different levels of write
ordering in the presence of the write merge buffer:
■
EFER[3] is defined as the Global EWBE# Disable
(GEWBED). When GEWBED equals 1, the processor does
not attempt to enforce any write ordering internally or
externally (the EWBE# signal is ignored). This is the
maximum performance setting.
■
EFER[2] is defined as the Speculative EWBE# Disable
(SEWBED). SEWBED only affects the processor when
GEWBED equals 0. If GEWBED equals 0 and SEWBED
equals 1, the processor enforces strong ordering for all
internal write cycles with the exception of write cycles
addressed to a range of memory defined as uncacheable
(UC) or write-combining (WC) by the MTRRs. In addition,
the processor samples the EWBE# signal. If EWBE# is
sampled negated, the processor delays the commitment of
write cycles to processor cache lines in the Modified state or
Exclusive state until EWBE# is sampled asserted.
This setting provides performance comparable to, but
slightly less than, the performance obtained when
GEWBED equals 1 because some degree of write ordering is
maintained.
If GEWBED equals 0 and SEWBED equals 0, the processor
enforces strong ordering for all internal and external write
cycles. In this setting, the processor assumes, or speculates,
that strong order must be maintained between writes to the
merge buffer and writes that hit the processor’s cache. Once
the merge buffer is written out to the processor’s bus, the
EWBE# signal is sampled. If EWBE# is sampled negated, the
processor delays the commitment of write cycles to
processor cache lines in the Modified state or Exclusive
state until EWBE# is sampled asserted.
This setting is the default after RESET and provides the
lowest performance of the three settings because full write
ordering is maintained.
■
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Table 37 summarizes the three settings of the EWBEC field for
the EFER register, along with the effect of write ordering and
performance. For more information on the EFER register, see
“Extended Feature Enable Register (EFER)” on page 43.
Table 37. EWBEC Settings
9.2
EFER[3]
(GEWBED)
EFER[2]
(SEWBED)
1
0 or 1
0
0
Write Ordering
Performance
None
Best
1
All except UC/WC
Close-to-Best
0
All
Slowest
Memory Type Range Registers
The AMD-K6-2E processor provides two variable-range Memory
Type Range registers (MTRRs), MTRR0 and MTRR1, each of
which specifies a range of memory. Each range can be defined
as one of the following memory types:
■
■
Chapter 9
Uncacheable (UC) Memory—Memory read cycles are
sourced directly from the specified memory address and the
processor does not allocate a cache line. Memory write
cycles are targeted at the specified memory address and a
write allocation does not occur.
Write-Combining (WC) Memory—Memory read cycles are
sourced directly from the specified memory address and the
processor does not allocate a cache line. The processor
conditionally combines data from multiple noncacheable
write cycles that are addressed within this range into a
merge buffer. Merging multiple write cycles into a single
write cycle reduces processor bus utilization and processor
stalls, thereby increasing the overall system performance.
This memory type is applicable for linear video frame
buffers.
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UC/WC Cacheability
Control Register
(UWCCR)
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The MTRRs are accessed by addressing the 64-bit MSR known
as the UC/WC Cacheability Control Register (UWCCR). The
MSR address of the UWCCR is C000_0085h. Following reset, all
bits in the UWCCR register are 0. MTRR0 (lower 32 bits of the
UWCCR register) defines the size and memory type of range 0
and MTRR1 (upper 32 bits) defines the size and memory type of
range 1 (see Figure 79 on page 208).
.
Symbol
UC1
WC1
63
Description
Uncacheable Memory Type
Write-Combining Memory Type
49
Physical Base Address 1
48
Bits
32
33
Symbol
UC0
WC0
Description
Uncacheable Memory Type
Write-Combining Memory Type
34 33 32 31
W U
Physical Address Mask 1 C C
1 1
17 16
Physical Base Address 0
MTRR1
Bits
0
1
2
1
0
W
Physical Address Mask 0 C
0
U
C
0
MTRR0
Figure 79. UC/WC Cacheability Control Register (UWCCR)—MSR C000_0085h
Physical Base Address n (n=0, 1). T h i s a d d re s s i s t h e 1 5 m o s t significant bits of the physical base address of the memory
range. The least-significant 17 bits of the base address are not
needed because the base address is by definition always aligned
on a 128-Kbyte boundary.
Physical Address Mask n (n=0, 1). T h i s v a l u e i s t h e 1 5 m o s t significant bits of a physical address mask that is used to define
the size of the memory range. This mask is logically ANDed
with both the physical base address field of the UWCCR
register and the physical address generated by the processor. If
the results of the two AND operations are equal, then the
generated physical address is considered within the range.
That is, if:
Mask & Physical Base Address = Mask & Physical Address Generated
then, the physical address generated by the processor is in the
range.
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WCn (n=0, 1). When set to 1, this memory range is defined as
write combinable (see Table 38 on page 209). Write-combinable
memory is uncacheable.
UCn (n=0, 1). When set to 1, this memory range is defined as
uncacheable (see Table 38).
Table 38. WC/UC Memory Type
9.3
WCn
UCn
0
0
No effect on cacheability or write combining
1
0
Write-combining memory range (uncacheable)
0 or 1
1
Uncacheable memory range
Memory Type
Memory-Range Restrictions
The following rules regarding the address alignment and size of
each range must be adhered to when programming the physical
base address and physical address mask fields of the UWCCR
register:
■
■
■
■
Chapter 9
The minimum size of each range is 128 Kbytes.
The physical base address must be aligned on a 128-Kbyte
boundary.
The physical base address must be range-size aligned. For
example, if the size of the range is 1 Mbyte, then the
physical base address must be aligned on a 1-Mbyte
boundary.
All bits set to 1 in the physical address mask must be
contiguous. Likewise, all bits cleared to 0 in the physical
address mask must be contiguous. For example:
111_1111_1100_0000b is a valid physical address mask
111_1111_1101_0000b is invalid
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Table 39 lists the valid physical address masks and the resulting
range sizes that can be programmed in the UWCCR register.
Table 39. Valid Masks and Range Sizes
210
Masks
Size
111_1111_1111_1111b
128 Kbytes
111_1111_1111_1110b
256 Kbytes
111_1111_1111_1100b
512 Kbytes
111_1111_1111_1000b
1 Mbyte
111_1111_1111_0000b
2 Mbytes
111_1111_1110_0000b
4 Mbytes
111_1111_1100_0000b
8 Mbytes
111_1111_1000_0000b
16 Mbytes
111_1111_0000_0000b
32 Mbytes
111_1110_0000_0000b
64 Mbytes
111_1100_0000_0000b
128 Mbytes
111_1000_0000_0000b
256 Mbytes
111_0000_0000_0000b
512 Mbytes
110_0000_0000_0000b
1 Gbyte
100_0000_0000_0000b
2 Gbytes
000_0000_0000_0000b
4 Gbytes
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9.4
Examples
Suppose that the range of memory from 16 Mbytes to 32 Mbytes
is uncacheable, and the 8-Mbyte range of memory on top of 1
Gbyte is writ e-com binable . Range 0 is def ined as t he
uncacheable range, and range 1 is defined as the writecombining range.
■
■
Chapter 9
Extracting the 15 most-significant bits of the 32-bit physical
base address that corresponds to 16 Mbytes (0100_0000h)
yields
a
physical
base
address
0
field
of
000_0000_1000_0000b. Because the uncacheable range size
is 16 Mbytes, the physical mask value 0 field is
111_1111_1000_0000b, according to Table 39. Bit 1 of the
UWCCR register (WC0) is cleared to 0 and bit 0 of the
UWCCR register is set to 1 (UC0).
Extracting the 15 most-significant bits of the 32-bit physical
base address that corresponds to 1 Gbyte (4000_0000h)
yields
a
physical
base
address
1
field
of
010_0000_0000_0000b. Because the write-combining range
size is 8 Mbytes, the physical mask value 1 field is
111_1111_1100_0000b, according to Table 39. Bit 33 of the
UWCCR register (WC1) is set to 1 and bit 32 of the UWCCR
register is cleared to 0 (UC1).
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10
Floating-Point and Multimedia Execution Units
10.1
Floating-Point Execution Unit
The AMD-K6-2E processor contains an IEEE 754-compatible
and IEEE 854-compatible floating-point execution unit
designed to accelerate the performance of software that utilizes
the x86 floating-point instruction set. Floating-point software is
typically written to manipulate numbers that are very large or
very small, that require a high degree of precision, or that result
f r o m c o m p l e x m a t h e m a t i c a l o p e ra t i o n s s u c h a s
transce ndentals. Applications t hat t ake advantage of
floating-point operations include geometric calculations for
graphics acceleration, scientific, statistical, and engineering
applications, and business applications that use large amounts
of high-precision data.
The high-performance floating-point execution unit contains an
adder unit, a multiplier unit, and a divide/square root unit.
These low-latency units can execute floating-point instructions
in as few as two processor clocks. To increase performance, the
proce sso r is de sig ned to simul ta neo usly de code mo st
floating-point instructions with most short-decodeable
instructions.
See “Software Environment” on page 23 for a description of the
floating-point data types, registers, and instructions.
Handling
Floating-Point
Exceptions
The AMD-K6-2E processor provides the following two types of
exception handling for floating-point exceptions:
■
■
External Logic
Support of
Floating-Point
Exceptions
Chapter 10
If the numeric error (NE) bit in CR0 is 1, the processor
invokes the interrupt 10h handler. In this manner, the
floating-point exception is completely handled by software.
If the NE bit in CR0 is 0, the processor requires external
logic to generate an interrupt on the INTR signal in order to
handle the exception.
The processor provides the FERR# (Floating-Point Error) and
IGNNE# (Ignore Numeric Error) signals to allow the external
logic to generate the interrupt in a manner consistent with
PC/AT-compatible systems. The assertion of FERR# indicates
the occurrence of an unmasked floating-point exception
resulting from the execution of a floating-point instruction.
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IGNNE# is used by the external hardware to control the effect
of an unmasked floating-point exception. Under certain
circumstances, if IGNNE# is sampled asserted, the processor
ignores the floating-point exception.
Figure 80 illustrates an implementation of external logic for
supporting floating-point exceptions. The following example
explains the operation of the external logic in Figure 80:
1. As the result of a floating-point exception, the processor
asserts FERR#.
2. The assertion of FERR# and the sampling of IGNNE#
negated indicates the processor has stopped instruction
execution and is waiting for an interrupt.
3. The assertion of FERR# leads to the assertion of INTR by
the interrupt controller.
4. The processor acknowledges the interrupt and jumps to the
corresponding interrupt service routine in which an I/O
write cycle to address port F0h leads to the assertion of
IGNNE#.
5. When IGNNE# is sampled asserted, the processor ignores
the floating-point exception and continues instruction
execution.
6. When the processor negates FERR#, the external logic
negates IGNNE#.
See “FERR# (Floating-Point Error)” on page 103 and “IGNNE#
(Ignore Numeric Exception)” on page 108 for more details.
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AMD-K6™-2E
Processor
I/O Address
Port F0h
IGNNE#
Flip-Flop
CLOCKQ
RESET
“1”
FERR#
DATAQ
CLEAR
FERR#
Flip-Flop
CLOCKQ
Interrupt
Controller
IRQ13
DATAQ
CLEAR
INTR
IGNNE#
Figure 80. External Logic for Supporting Floating-Point Exceptions
10.2
Multimedia and 3DNow!™ Execution Units
The multimedia and 3DNow! execution units of the AMD-K6-2E
processor are designed to accelerate the performance of
software written using the industry-standard MMX instructions
and the 3DNow! instructions. Applications that can take
advantage of the MMX and 3DNow! instructions include
graphics, video and audio compression and decompression,
speech recognition, and telephony applications.
The multimedia execution unit can execute MMX instructions
in a single processor clock. All MMX and 3DNow! arithmetic
instructions are pipelined for higher performance. To increase
performance, the processor is designed to simultaneously
decode all MMX and 3DNow! instructions with most other
instructions.
For more information on MMX instructions, see the AMD-K6®
Processor Multimedia Technology Manual, order #20726. For
more information on 3DNow! instructions, see the 3DNow!™
Technology Manual, order #21928.
Chapter 10
Floating-Point and Multimedia Execution Units
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Floating-Point and MMX™/3DNow!™ Instruction Compatibility
Registers
The eight 64-bit MMX registers (which are also utilized by
3DNow! instructions) are mapped on the floating-point stack.
This enables backward compatibility with all existing software.
For example, the register saving event that is performed by
operating systems during task switching requires no changes to
the operating system. The same support provided in an
operating system’s interrupt 7 handler (Device Not Available)
for saving and restoring the floating-point registers also
supports saving and restoring the MMX registers.
Exceptions
There are no new exceptions defined for supporting the MMX
and 3DNow! instructions. All exceptions that occur while
decoding or executing an MMX or 3DNow! instruction are
handled in existing exception handlers without modification.
FERR# and IGNNE#
MMX instructions and 3DNow! instructions do not generate
f l o a t i n g -p o i n t e x c e p t i o n s . H oweve r, i f a n u n m a s ke d
floating-point exception is pending, the processor asserts
FERR# at the instruction boundary of the next floating-point
instruction, MMX instruction, 3DNow! instruction or WAIT
instruction.
The sampling of IGNNE# asserted only affects processor
o p e ra t i o n d u r i n g t h e ex e c u t i o n o f a n e r ro r -s e n s i t ive
f l oa t i n g -po i n t i n st r u c ti on , MMX i n st r u c t i on , 3D N ow !
instruction or WAIT instruction when the NE bit in CR0 is
cleared to 0.
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11
System Management Mode (SMM)
SMM is an alternate operating mode entered by way of a system
management interrupt (SMI) and handled by an interrupt
service routine. SMM is designed for system control activities
s u ch a s p owe r m a n a g e m e n t . Th e s e a c t iv i t i e s a p p e a r
transparent to conventional operating systems like DOS and
Windows. SMM is primarily targeted for use by the Basic Input
Output System (BIOS) and specialized low-level device drivers.
The code and data for SMM are stored in the SMM memory
area, which is isolated from main memory.
The processor enters SMM by the system logic’s assertion of the
SMI# interrupt and the processor’s acknowledgment by the
assertion of SMIACT#. At this point the processor saves its state
into the SMM memory state-save area and jumps to the SMM
service routine. The processor returns from SMM when it
executes the resume (RSM) instruction from within the SMM
service routine. Subsequently, the processor restores its state
from the SMM save area, negates SMIACT#, and resumes
execution with the instruction following the point where it
entered SMM.
The following sections summarize the SMM state-save area,
entry into and exit from SMM, exceptions and interrupts in
SMM, memory allocation and addressing in SMM, and the SMI#
and SMIACT# signals.
11.1
SMM Operating Mode and Default Register Values
The software environment within SMM has the following
characteristics:
■
■
■
■
■
Chapter 11
Addressing and operation in real mode
4-Gbyte segment limits
Default 16-bit operand, address, and stack sizes, although
instruction prefixes can override these defaults
Control transfers that do not override the default operand
size truncate the EIP to 16 bits
Far jumps or calls cannot transfer control to a segment with
a base address requiring more than 20 bits, as in real mode
segment-base addressing
System Management Mode (SMM)
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■
■
■
■
■
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A20M# is masked
Interrupt vectors use the real-mode interrupt vector table
The IF flag in EFLAGS is cleared (INTR not recognized)
The TF flag in EFLAGS is cleared
The NMI and INIT interrupts are disabled
Debug register DR7 is cleared (debug traps disabled)
Figure 81 shows the default map of the SMM memory area. It
c on si st s of a 64 -Kbyt e a re a, b et we en 00 03 _ 00 00 h a n d
0003_FFFFh, of which the top 32 Kbytes (0003_8000h to
0003_FFFFh) must be populated with RAM. The default
code-segment (CS) base address for the area—called the SMM
b a s e a d d re s s — i s a t 0 0 0 3 _ 0 0 0 0 h . Th e t o p 5 1 2 by t e s
(0003_FE00h to 0003_FFFFh) contain a fill-down SMM
state-save area. The default entry point for the SMM service
routine is 0003_8000h.
Fill Down
SMM
State-Save
Area
0003_FFFFh
0003_FE00h
32-Kbyte
Minimum RAM
SMM
Service Routine
Service Routine Entry Point
0003_8000h
SMM Base Address (CS)
0003_0000h
Figure 81. SMM Memory
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Table 40 shows the initial state of registers when entering SMM.
Table 40. Initial State of Registers in System Management Mode (SMM)
Register
SMM Initial State
General-Purpose Registers
Unmodified
EFLAGs
0000_0002h
CR0
PE, EM, TS, and PG are cleared (bits 0, 2, 3, and 31).
The other bits are unmodified.
DR7
0000_0400h
GDTR, LDTR, IDTR, TSSR, DR6 Unmodified
11.2
EIP
0000_8000h
CS
0003_0000h
DS, ES, FS, GS, SS
0000_0000h
SMM State-Save Area
When the processor acknowledges an SMI# interrupt by
asserting SMIACT#, it saves its state in a 512-byte SMM
state-save area shown in Table 41. The save begins at the top of
the SMM memory area (SMM base address + FFFFh) and fills
down to SMM base address + FE00h.
Table 41 shows the offsets in the SMM state-save area relative
to the SMM base address. The SMM service routine can alter
any of the read/write values in the state-save area.
Table 41. SMM State-Save Area Map
Chapter 11
Address Offset
Contents Saved
FFFCh
CR0
FFF8h
CR3
FFF4h
EFLAGS
FFF0h
EIP
FFECh
EDI
FFE8h
ESI
FFE4h
EBP
FFE0h
ESP
FFDCh
EBX
FFD8h
EDX
FFD4h
ECX
FFD0h
EAX
System Management Mode (SMM)
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Table 41. SMM State-Save Area Map (continued)
220
Address Offset
Contents Saved
FFCCh
DR6
FFC8h
DR7
FFC4h
TR
FFC0h
LDTR Base
FFBCh
GS
FFB8h
FS
FFB4h
DS
FFB0h
SS
FFACh
CS
FFA8h
ES
FFA4h
I/O Trap Doubleword
FFA0h
No data dump at that address
FF9Ch
I/O Trap EIP1
FF98h
No data dump at that address
FF94h
No data dump at that address
FF90h
IDT Base
FF8Ch
IDT Limit
FF88h
GDT Base
FF84h
GDT Limit
FF80h
TSS Attr
FF7Ch
TSS Base
FF78h
TSS Limit
FF74h
No data dump at that address
FF70h
LDT High
FF6Ch
LDT Low
FF68h
GS Attr
FF64h
GS Base
FF60h
GS Limit
FF5Ch
FS Attr
FF58h
FS Base
FF54h
FS Limit
FF50h
DS Attr
FF4Ch
DS Base
FF48h
DS Limit
FF44h
SS Attr
FF40h
SS Base
System Management Mode (SMM)
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Table 41. SMM State-Save Area Map (continued)
Address Offset
Contents Saved
FF3Ch
SS Limit
FF38h
CS Attr
FF34h
CS Base
FF30h
CS Limit
FF2Ch
ES Attr
FF28h
ES Base
FF24h
ES Limit
FF20h
No data dump at this address
FF1Ch
No data dump at this address
FF18h
No data dump at this address
FF14h
CR2
FF10h
CR4
FF0Ch
I/O restart ESI1
FF08h
I/O restart ECX1
FF04h
I/O restart EDI1
FF02h
HALT Restart Slot
FF00h
I/O Trap Restart Slot
FEFCh
SMM RevID
FEF8h
SMM BASE
FEF7h–FE00h
No data dump at these addresses
Notes:
1. Only contains information if SMI# is asserted during a valid I/O bus cycle.
11.3
SMM Revision Identifier
The SMM revision identifier at offset FEFCh in the SMM
state-save area specifies the version of SMM and the extensions
that are available on the processor. The SMM revision identifier
fields are as follows:
■
■
■
■
Chapter 11
Bits 31–18—Reserved
Bit 17—SMM base address relocation (1 = enabled)
Bit 16—I/O trap restart (1 = enabled)
Bits 15–0—SMM revision level for the AMD-K6-2E processor
= 0002h
System Management Mode (SMM)
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Table 42 shows the format of the SMM revision identifier.
Table 42. SMM Revision Identifier
11.4
31–18
17
16
15–0
Reserved
SMM Base Relocation
I/O Trap Extension
SMM Revision Level
0
1
1
0002h
SMM Base Address
During RESET, the processor sets the base address of the
code-segment (CS) for the SMM memory area—the SMM base
address—to its default, 0003_0000h. The SMM base address at
offset FEF8h in the SMM state-save area can be changed by the
SMM service routine to any address that is aligned to a
32-Kbyte boundary. (Locations not aligned to a 32-Kbyte
boundary cause the processor to enter the Shutdown state when
executing the RSM instruction.)
In some operating environments it may be desirable to relocate
the 64-Kbyte SMM memory area to a high memory area in order
to provide more low memory for legacy software. During system
initialization, the base of the 64-Kbyte SMM memory area is
relocated by the BIOS. To relocate the SMM base address, the
system enters the SMM handler at the default address. This
handler changes the SMM base address location in the SMM
state-save area, copies the SMM handler to the new location,
and exits SMM.
The next time SMM is entered, the processor saves its state at
the new base address. This new address is used for every SMM
entry until the SMM base address in the SMM state-save area is
changed or a hardware reset occurs.
11.5
Halt Restart Slot
During entry into SMM, the halt restart slot at offset FF02h in
the SMM state-save area indicates if SMM was entered from the
Halt state. Before returning from SMM, the halt restart slot
(offset FF02h) can be written to by the SMM service routine to
specify whether the return from SMM takes the processor back
to the Halt state or to the next instruction after the HLT
instruction.
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Upon entry into SMM, the halt restart slot is defined as follows:
■
■
Bits 15–1—Reserved
Bit 0—Point of entry to SMM:
1 = entered from Halt state
0 = not entered from Halt state
After entry into the SMI handler and before returning from
SMM, the halt restart slot can be written using the following
definition:
■
■
Bits 15–1—Reserved
Bit 0—Point of return when exiting from SMM:
1 = return to Halt state
0 = return to next instruction after the HLT instruction
If the return from SMM takes the processor back to the Halt
state, the HLT instruction is not re-executed, but the Halt
special bus cycle is driven on the bus after the return.
11.6
I/O Trap Doubleword
If the assertion of SMI# is recognized during the execution of an
I/O instruction, the I/O trap doubleword at offset FFA4h in the
S M M s t a t e -s ave a re a c o n t a i n s i n fo r m a t i o n ab o ut t h e
instruction. The fields of the I/O trap doubleword are
configured as follows:
■
■
■
■
■
■
Chapter 11
Bits 31–16—I/O port address
Bits 15–4—Reserved
Bit 3—REP (repeat) string operation (1 = REP string, 0 = not
a REP string)
Bit 2—I/O string operation (1 = I/O string, 0 = not a I/O
string)
Bit 1—Valid I/O instruction (1 = valid, 0 = invalid)
Bit 0—Input or output instruction (1 = INx, 0 = OUTx)
System Management Mode (SMM)
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Table 43 shows the format of the I/O trap doubleword.
Table 43. I/O Trap Doubleword Configuration
31—16
15—4
3
2
1
0
I/O Port
Address
Reserved
REP String
Operation
I/O String
Operation
Valid I/O
Instruction
Input or
Output
The I/O trap doubleword is related to the I/O trap restart slot
(see “I/O Trap Restart Slot” on page 224). If bit 1 of the I/O
trap doubleword is set by the processor, it means that SMI#
was asserted during the execution of an I/O instruction. The
SMI handler tests bit 1 to see if there is a valid I/O instruction
trapped. If the I/O instruction is valid, the SMI handler is
required to ensure the I/O trap restart slot is set properly. The
I/O trap restart slot informs the CPU whether it should
re-execute the I/O instruction after the RSM or execute the
instruction following the trapped I/O instruction.
Note: If SMI# is sampled asserted during an I/O bus cycle a minimum of three clock edges before BRDY# is sampled asserted,
the associated I/O instruction is guaranteed to be trapped by
the SMI handler.
11.7
I/O Trap Restart Slot
The I/O trap restart slot at offset FF00h in the SMM state-save
area specifies whether the trapped I/O instruction should be
re-executed on return from SMM. This slot in the state-save area
is called the I/O instruction restart function. Re-executing a
trapped I/O instruction is useful, for example, if an I/O write
occurs to a disk that is powered down. The system logic
monitoring such an access can assert SMI#. Then the SMM
service routine would query the system logic, detect a failed I/O
write, take action to power-up the I/O device, enable the I/O
trap restart slot feature, and return from SMM.
The fields of the I/O trap restart slot are defined as follows:
■
■
224
Bits 31–16—Reserved
Bits 15–0—I/O instruction restart on return from SMM:
0000h = execute the next instruction after the trapped
I/O instruction
00FFh = re-execute the trapped I/O instruction
System Management Mode (SMM)
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Table 44 shows the format of the I/O trap restart slot.
Table 44. I/O Trap Restart Slot
31–16
Reserved
15–0
I/O Instruction restart on return from SMM:
■
0000h = Execute the next instruction after the trapped I/O
■
00FFh = Re-execute the trapped I/O instruction
The processor initializes the I/O trap restart slot to 0000h upon
entry into SMM. If SMM was entered due to a trapped I/O
instruction, the processor indicates the validity of the I/O
instruction by setting or clearing bit 1 of the I/O trap
doubleword at offset FFA4h in the SMM state-save area. The
S MM se rvice ro u tine should t es t b it 1 of the I/ O t ra p
doubleword to determine if a valid I/O instruction was being
executed when entering SMM and before writing the I/O trap
restart slot. If the I/O instruction is valid, the SMM service
routine can safely rewrite the I/O trap restart slot with the value
00FFh, which causes the processor to re-execute the trapped I/O
instruction when the RSM instruction is executed. If the I/O
instruction is invalid, writing the I/O trap restart slot has
undefined results.
If a second SMI# is asserted and a valid I/O instruction was
trapped by the first SMM handler, the CPU services the second
SMI# prior to re-executing the trapped I/O instruction. The
second entry into SMM never has bit 1 of the I/O trap
doubleword set, and the second SMM service routine must not
rewrite the I/O trap restart slot.
During a simultaneous SMI# I/O instruction trap and debug
breakpoint trap, the AMD-K6-2E processor first responds to the
SMI# and postpones recognizing the debug exception until
after returning from SMM via the RSM instruction. If the debug
registers DR3–DR0 are used while in SMM, they must be saved
and restored by the SMM handler. The processor automatically
saves and restores DR7–DR6. If the I/O trap restart slot in the
SMM state-save area contains the value 00FFh when the RSM
instruction is executed, the debug trap does not occur until
after the I/O instruction is re-executed.
Chapter 11
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Exceptions, Interrupts, and Debug in SMM
During an SMI# I/O trap, the exception/interrupt priority of the
AMD-K6-2E processor changes from its normal priority. The
normal priority places the debug traps at a priority higher than
the sampling of the FLUSH# or SMI# signals. However, during
an SMI# I/O trap, the sampling of the FLUSH# or SMI# signals
takes precedence over debug traps.
The processor recognizes the assertion of NMI within SMM
immediately after the completion of an IRET instruction. Once
NMI is recognized within SMM, NMI recognition remains
enabled until SMM is exited, at which point NMI masking is
restored to the state it was in before entering SMM.
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12
Test and Debug
The AMD-K6-2E processor implements various test and debug
modes to enable the functional and manufacturing testing of
systems and boards that use the processor. In addition, the
debug features of the processor allow designers to debug the
instruction execution of software components. This chapter
describes the following test and debug features:
■
■
■
■
■
12.1
Built-In Self-Test (BIST)—The BIST, which is invoked after
the falling transition of RESET, runs internal tests that
exercise most on-chip RAM structures.
Three-State Test Mode—A test mode that causes the
processor to float its output and bidirectional pins.
Boundary-Scan Test Access Port (TAP) —The Joint Test
Action Group (JTAG) test access function defined by the
IEEE Standard Test Access Port and Boundary-Scan
Architecture (IEEE 1149.1-1990) specification.
Level-One (L1) Cache Inhibit—A feature that disables the
processor’s internal L1 instruction and data caches.
Debug Support—Consists of all x86-compatible software
debug features, including the debug extensions.
Built-In Self-Test (BIST)
Following the falling transition of RESET, the processor
unconditionally runs its built-in self test (BIST). The internal
resources tested during BIST include the following:
■
■
L1 instruction and data caches
Instruction and Data Translation Lookaside Buffers (TLBs)
The contents of the EAX general-purpose register after the
completion of reset indicate if the BIST was successful.
■
■
If EAX contains 0000_0000h, then BIST was successful.
If EAX is non-zero, the BIST failed.
Following the completion of the BIST, the processor jumps to
address FFFF_FFF0h to start instruction execution, regardless
of the outcome of the BIST. The BIST takes approximately
295,000 processor clocks to complete.
Chapter 12
Test and Debug
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Three-State Test Mode
The three-state test mode causes the processor to float its
output and bidirectional pins, which is useful for board-level
manufac turing t esting . I n t his m ode, t he processo r is
electrically isolated from other components on a system board,
allowing automated test equipment (ATE) to test components
that drive the same signals as those the processor floats.
If the FLUSH# signal is sampled Low during the falling
transition of RESET, the processor enters the three-state test
mode. (See “FLUSH# (Cache Flush)” on page 104 for the
specific sampling requirements.) The signals floated in the
three-state test mode are as follows:
■
■
■
■
■
■
■
■
A[31:3]
ADS#
ADSC#
AP
APCHK#
BE[7:0]#
BREQ
CACHE#
■
■
■
■
■
■
■
■
D/C#
D[63:0]
DP[7:0]
FERR#
HIT#
HITM#
HLDA
LOCK#
■
■
■
■
■
■
■
M/IO#
PCD
PCHK#
PWT
SCYC
SMIACT#
W/R#
The VCC2DET, VCC2H/L#, and TDO signals are the only
outputs not floated in the three-state test mode.
■
■
VCC2DET and VCC2H/L# must remain Low to ensure the
system continues to supply the specified processor core
voltage to the VCC2 pins.
TDO is never floated because the boundary-scan Test Access
Port must remain enabled at all times, including during the
three-state test mode.
The three-state test mode is exited when the processor samples
RESET asserted.
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12.3
Boundary-Scan Test Access Port (TAP)
The boundary-scan Test Access Port (TAP) is an IEEE standard
that defines synchronous scanning test methods for complex
logic circuits, such as boards containing a processor. The
AMD-K6-2E processor supports the TAP standard defined in
the I EEE Standard Test Acces s Port and Boundary-Scan
Architecture (IEEE 1149.1-1990) specification.
Boundary scan testing uses a shift register consisting of the
serial interconnection of boundary-scan cells that correspond to
each I/O buffer of the processor. This non-inverting register
chain, called a Boundary Scan register (BSR), can be used to
capture the state of every processor pin and to drive every
processor output and bidirectional pin to a known state.
Each BSR of every component on a board that implements the
boundary-scan architecture can be serially interconnected to
enable component interconnect testing.
Test Access Port
The Test Access Port (TAP) consists of the following:
■
■
■
Chapter 12
Test Access Port (TAP) Controller—The TAP controller is a
synchronous, finite state machine that uses the TMS and
TDI input signals to control a sequence of test operations.
See “TAP Controller State Machine” on page 236 for a list
of TAP states and their definition.
Instruction Register (IR)—The IR contains the instructions
that select the test operation to be performed and the Test
Data Register (TDR) to be selected. See “TAP Registers” on
page 231 for more details on the IR.
Test Data Registers (TDR)—The three TDRs are used to
process the test data. Each TDR is selected by an
instruction in the Instruction Register (IR). See “TAP
Registers” on page 231 for a list of these registers and their
functions.
Test and Debug
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The test signals associated with the TAP controller are as
follows:
■
■
■
■
■
TCK—The Test Clock for all TAP operations. The rising
edge of TCK is used for sampling TAP signals, and the
falling edge of TCK is used for asserting TAP signals. The
state of the TMS signal sampled on the rising edge of TCK
causes the state transitions of the TAP controller to occur.
TCK can be stopped in the logic 0 or 1 state.
TDI—The Test Data Input represents the input to the most
significant bit of all TAP registers, including the IR and all
test data registers. Test data and instructions are serially
shifted by one bit into their respective registers on the rising
edge of TCK.
TDO—The Test Data Output represents the output of the
least significant bit of all TAP registers, including the IR and
all test data registers. Test data and instructions are serially
shifted by one bit out of their respective registers on the
falling edge of TCK.
TMS—The Test Mode Select input specifies the test
function and sequence of state changes for boundary-scan
testing. If TMS is sampled High for five or more consecutive
clocks, the TAP controller enters its reset state.
TRST#—The Test Reset signal is an asynchronous reset that
unconditionally causes the TAP controller to enter its reset
state.
Refer to “Electrical Data” on page 253 and “Signal Switching
Charact erist ics” on pa ge 26 7 t o obta in t he ele ct rical
specifications of the test signals.
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TAP Registers
The AMD-K6-2E processor provides an Instruction register (IR)
a n d t h re e Te s t D a t a re g i s t e rs ( T D R ) t o s u p p o r t t h e
boundary-scan architecture. The IR and one of the TDRs—the
Boundary-Scan register (BSR) —consist of a shift register and
an output register. The shift register is loaded in parallel in the
Capture states. (See “TAP Controller State Machine” on page
236 for a description of the TAP controller states.) In addition,
the shift register is loaded and shifted serially in the Shift
states. The output register is loaded in parallel from its
corresponding shift register in the Update states.
Instruction Register (IR). The IR is a 5-bit register, without parity,
that determines which instruction to run and which test data
register to select. When the TAP controller enters the
Capture-IR state, the processor loads the following bits into the
IR shift register:
■
■
01b—Loaded into the two least significant bits, as specified
by the IEEE 1149.1 standard
000b—Loaded into the three most significant bits
Loading 00001b into the IR shift register during the Capture-IR
state results in loading the SAMPLE/PRELOAD instruction.
For each entry into the Shift-IR state, the IR shift register is
serially shifted by one bit toward the TDO pin. During the shift,
the most significant bit of the IR shift register is loaded from
the TDI pin.
The IR output register is loaded from the IR shift register in the
Update-IR state, and the current instruction is defined by the IR
output register. See “TAP Instructions” on page 235 for a list and
definition of the instructions supported by the AMD-K6-2E
processor.
Boundary Scan Register (BSR). The Boundary Scan Register is a Test
Data register consisting of the interconnection of 152
boundary-scan cells. Each output and bidirectional pin of the
processor requires a two-bit cell, where one bit corresponds to
the pin and the other bit is the output enable for the pin. When
a 0 is shifted into the enable bit of a cell, the corresponding pin
is floated, and when a 1 is shifted into the enable bit, the pin is
driven valid. Each input pin requires a one-bit cell that
corresponds to the pin. The last cell of the BSR is reserved and
does not correspond to any processor pin.
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The total number of bits that comprise the BSR is 281. Table 45
on page 233 lists the order of these bits, where TDI is the input
to bit 280, and TDO is driven from the output of bit 0. The
entries listed as pin_E (where pin is an output or bidirectional
signal) are the enable bits.
If the BSR is the register selected by the current instruction
and the TAP controller is in the Capture-DR state, the processor
loads the BSR shift register as follows:
■
■
If the current instruction is SAMPLE/PRELOAD, then the
current state of each input, output, and bidirectional pin is
loaded. A bidirectional pin is treated as an output if its
enable bit equals 1, and it is treated as an input if its enable
bit equals 0.
If the current instruction is EXTEST, then the current state
of each input pin is loaded. A bidirectional pin is treated as
an input, regardless of the state of its enable.
While in the Shift-DR state, the BSR shift register is serially
shifted toward the TDO pin. During the shift, bit 280 of the BSR
is loaded from the TDI pin.
The BSR output register is loaded with the contents of the BSR
shift register in the Update-DR state. If the current instruction
is EXTEST, the processor’s output pins, as well as those
bidirectional pins that are enabled as outputs, are driven with
their corresponding values from the BSR output register.
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Table 45. Boundary Scan Bit Definitions1
Bit Pin/Enable Bit Pin/Enable Bit Pin/Enable Bit Pin/Enable Bit Pin/Enable Bit
Pin/Enable
280 D35_E
247 D19
214
BF1
181 A24
148 A14
115 BE7#
279 D35
246 D16_E
213
BF2
180 A18_E
147 A17_E
114 PCD_E
278 D29_E
245 D16
212
RESET
179 A18
146 A17
113 PCD
277 D29
244 D17_E
211
BF0
178 A5_E
145 A16_E
112 DC_E
276 D33_E
243 D17
210
FLUSH#
177 A5
144 A16
111 D/C#
275 D33
242 D15_E
209 INTR
176 EADS#
143 HIT_E
110 WR_E
274 D27_E
241 D15
208 NMI
175 A22_E
142 HIT#
109 W/R#
273 D27
240 DP1_E
207 SMI#
174
141
108 NA#
272 DP0_E
239 DP1
206 A25_E
173 AHOLD
140 ADS#
107 PWT_E
271 DP0
238 D13_E
205 A25
172 HITM_E
139 CLK
106 PWT
270 DP3_E
237 D13
204 A26_E
171
138 ADSC_E
105 CACHE_E
269 DP3
236 D6_E
203 A26
170 A4_E
137 ADSC#
104 CACHE#
268 D25_E
235 D6
202 A29_E
169 A4
136 BE0_E
103 WB/WT#
267 D25
234 D14_E
201 A29
168 A9_E
135 BE0#
102 MIO_E
266 D0_E
233 D14
200 A28_E
167 A9
134 AP_E
101 M/IO#
265 D0
232 D11_E
199 A28
166 A8_E
133 AP
100 BREQ_E
264 D30_E
231 D11
198 A23_E
165 A8
132 BE1_E
99
BREQ
263 D30
230 D1_E
197 A23
164 A19_E
131 BE1#
98
SCYC_E
262 DP2_E
229 D1
196 A27_E
163 A19
130 BE2_E
97
SCYC
261 DP2
228 D12_E
195 A27
162 BOFF#
129 BE2#
96
LOCK_E
260 D2_E
227 D12
194 A11_E
161 A6_E
128 BRDY#
95
LOCK#
259 D2
226 D10_E
193 A11
160 A6
127 BE3_E
94
APCHK_E
258 D28_E
225 D10
192 A3_E
159 A20_E
126 BE3#
93
APCHK#
257 D28
224 D7_E
191 A3
158 A20
125 BE4_E
92
PCHK_E
256 D24_E
223 D7
190 A31_E
157 A13_E
124 BE4#
91
PCHK#
255 D24
222 D8_E
189 A31
156 A13
123 BRDYC#
90
EWBE#
254 D26_E
221 D8
188 A21_E
155 A12_E
122 BE5_E
89
SMIACT_E
253 D26
220 D9_E
187 A21
154 A12
121 BE5#
88
SMIACT#
252 D21_E
219
D9
186 A30_E
153 A10_E
120 BE6_E
87
FERR_E
251 D21
218
HOLD
185 A30
152 A10
119
BE6#
86
FERR#
250 D18_E
217
STPCLK#
184 A7_E
151 A15_E
118
KEN#
85
D20_E
249 D18
216
INIT
183 A7
150 A15
117
INV
84
D20
248 D19_E
215
IGNNE#
182 A24_E
149 A14_E
116
BE7_E
83
D22_E
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Table 45. Boundary Scan Bit Definitions1 (continued)
Bit Pin/Enable Bit Pin/Enable Bit Pin/Enable Bit Pin/Enable Bit Pin/Enable Bit
Pin/Enable
82
D22
68
D54_E
54
D47_E
40
D62_E
26
D38_E
12
D3_E
81
D23_E
67
D54
53
D47
39
D62
25
D38
11
D3
80
D23
66
D50_E
52
D59_E
38
D49_E
24
D58_E
10
D39_E
79
A20M#
65
D50
51
D59
37
D49
23
D58
9
D39
78
HLDA_E
64
D56_E
50
D51_E
36
DP4_E
22
D42_E
8
D32_E
77
HLDA
63
D56
49
D51
35
DP4
21
D42
7
D32
76
DP7_E
62
D55_E
48
D45_E
34
D4_E
20
D36_E
6
D5_E
75
DP7
61
D55
47
D45
33
D4
19
D36
5
D5
74
D63_E
60
D48_E
46
D61_E
32
D46_E
18
D60_E
4
D37_E
73
D63
59
D48
45
D61
31
D46
17
D60
3
D37
72
D52_E
58
D57_E
44
DP5_E
30
D41_E
16
D40_E
2
D31_E
71
D52
57
D57
43
DP5
29
D41
15
D40
1
D31
70
DP6_E
56
D53_E
42
D43_E
28
D44_E
14
D34_E
0
Reserved
69
DP6
55
D53
41
D43
27
D44
13
D34
Notes:
1.
TDI is the input to bit 280, and TDO is driven from the output of bit 0. The entries listed as pin_E (where pin is an output or
bidirectional signal) are the enable bits.
Device Identification Register (DIR). The DIR is a 32-bit Test Data
register selected during the execution of the IDCODE
instruction. The fields of the DIR and their values are shown in
Table 46 and are defined as follows:
■
■
■
■
Version Code—This 4-bit field is incremented by AMD
manufacturing for each major revision of silicon.
Part Number—This 16-bit field identifies the specific
processor model.
Manufacturer—This 11-bit field identifies the manufacturer
of the component (AMD).
LSB—The least significant bit (LSB) of the DIR is always 1,
as specified by the IEEE 1149.1 standard.
Table 46. Device Identification Register
234
Version Code
(Bits 31–28)
Part Number
(Bits 27–12)
Manufacturer
(Bits 11–1)
LSB
(Bit 0)
Xh
0580h
00000000001b
1b
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Bypass Register (BR). The BR is a Test Data register consisting of a
1-bit shift register that provides the shortest path between TDI
and TDO. When the processor is not involved in a test
operation, the BR can be selected by an instruction to allow the
transfer of test data through the processor without having to
serially scan the test data through the BSR. This functionality
preserves the state of the BSR and significantly reduces test
time.
The BR register is selected by the BYPASS and HIGHZ
instructions as well as by any instructions not supported by the
AMD-K6-2E processor.
TAP Instructions
The processor supports the three instructions required by the
IEEE 1149.1 standard — EXTEST, SAMPLE/PRELOAD, and
BYPASS — as well as two additional optional instructions —
IDCODE and HIGHZ.
Table 47 shows the complete set of TAP instructions supported
by the processor along with the 5-bit Instruction Register
encoding and the register selected by each instruction.
Table 47. Supported Test Access Port (TAP) Instructions
Instruction
Encoding
Register
00000b
BSR
Sample inputs and drive outputs
SAMPLE / PRELOAD
00001b
BSR
Sample inputs and outputs, then load the BSR
IDCODE
00010b
DIR
Read DIR
HIGHZ
00011b
BR
Float outputs and bidirectional pins
BYPASS2
00100b–11110b
BR
Undefined instruction, execute the BYPASS instruction
BYPASS3
11111b
BR
Connect TDI to TDO to bypass the BSR
EXTEST
1
Description
Notes:
1. Following the execution of the EXTEST instruction, the processor must be reset to return to normal, non-test operation.
2. These instruction encodings are undefined on the AMD-K6-2E processor and default to the BYPASS instruction.
3. Because the TDI input contains an internal pullup, the BYPASS instruction is executed if the TDI input is not connected or open
during an instruction scan operation. The BYPASS instruction does not affect the normal operational state of the processor.
EXTEST Instruction. When the EXTEST instruction is executed,
the processor loads the BSR shift register with the current state
of the input and bidirectional pins in the Capture-DR state and
drives the output and bidirectional pins with the corresponding
values from the BSR output register in the Update-DR state.
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SAMPLE/PRELOAD Instruction. The SAMPLE/PRELOAD instruction
performs two functions. These functions are as follows:
■
■
During the Capture-DR state, the processor loads the BSR
shift register with the current state of every input, output,
and bidirectional pin.
During the Update-DR state, the BSR output register is
loaded from the BSR shift register in preparation for the
next EXTEST instruction.
The SAMPLE/PRELOAD instruction does not affect the normal
operational state of the processor.
BYPASS Instruction. The BYPASS instruction selects the BR
register, which reduces the boundary-scan length through the
processor from 281 to one (TDI to BR to TDO). The BYPASS
instruction does not affect the normal operational state of the
processor.
IDCODE Instruction. The IDCODE instruction selects the DIR
register, allowing the device identification code to be shifted
out of the processor. This instruction is loaded into the IR when
the TAP controller is reset. The IDCODE instruction does not
affect the normal operational state of the processor.
HIGHZ Instruction. The HIGHZ instruction forces all output and
bidirectional pins to be floated. During this instruction, the BR
is selected and the normal operational state of the processor is
not affected.
TAP Controller State
Machine
236
The TAP controller state diagram is shown in Figure 82 on page
237. State transitions occur on the rising edge of TCK. The logic
0 or 1 next to the states represents the value of the TMS signal
sampled by the processor on the rising edge of TCK.
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Test-Logic-Reset
1
0
Run-Test/Idle
1
1
Select-DR-Scan
1
Select-IR-Scan
0
0
0
1
Capture-DR
1
Capture-IR
0
0
Shift-DR
Shift-IR
0
0
1
1
1
Exit1-DR
Exit1-IR
0
0
Pause-DR
1
Pause-IR
0
0
1
1
Exit2-IR
Exit2-DR
0
0
1
1
Update-IR
Update-DR
0
1
1
0
IEEE Std 1149.1-1990, Copyright © 1990. IEEE. All rights reserved
Figure 82. TAP State Diagram
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The states of the TAP controller are described as follows:
Test-Logic-Reset. This state represents the initial reset state of the
TAP controller and is entered when the processor samples
RESET asserted, when TRST# is asynchronously asserted, and
when TMS is sampled High for five or more consecutive clocks.
In addition, this state can be entered from the Select-IR-Scan
state. The IR is initialized with the IDCODE instruction, and
the processor’s normal operation is not affected in this state.
Capture-DR. During the SAMPLE/PRELOAD instruction, the
processor loads the BSR shift register with the current state of
every input, output, and bidirectional pin. During the EXTEST
instruction, the processor loads the BSR shift register with the
current state of every input and bidirectional pin.
Capture-IR. When the TAP controller enters the Capture-IR state,
the processor loads 01b into the two least significant bits of the
IR shift register and loads 000b into the three most significant
bits of the IR shift register.
Shift-DR. While in the Shift-DR state, the selected TDR shift
register is serially shifted toward the TDO pin. During the shift,
the most significant bit of the TDR is loaded from the TDI pin.
Shift-IR. While in the Shift-IR state, the IR shift register is
serially shifted toward the TDO pin. During the shift, the most
significant bit of the IR is loaded from the TDI pin.
Update-DR. During the SAMPLE/PRELOAD instruction, the BSR
output register is loaded with the contents of the BSR shift
register. During the EXTEST instruction, the output pins, as
well as those bidirectional pins defined as outputs, are driven
with their corresponding values from the BSR output register.
Update-IR. In this state, the IR output register is loaded from the
IR shift register, and the current instruction is defined by the
IR output register.
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The following states have no effect on the normal or test
operation of the processor other than as shown in Figure 82 on
page 237:
■
Run-Test/Idle—This state is an idle state between scan
operations.
■
Select-DR-Scan—This is the initial state of the test data
register state transitions.
Select-IR-Scan—This is the initial state of the Instruction
Register state transitions.
Exit1-DR—This state is entered to terminate the shifting
process and enter the Update-DR state.
■
■
■
Exit1-IR—This state is entered to terminate the shifting
process and enter the Update-IR state.
■
Pause-DR—This state is entered to temporarily stop the
shifting process of a test data register.
Pause-IR—This state is entered to temporarily stop the
shifting process of the instruction register.
Exit2-DR—This state is entered in order to either terminate
the shifting process and enter the Update-DR state or to
resume shifting following the exit from the Pause-DR state.
Exit2-IR—This state is entered in order to either terminate
the shifting process and enter the Update-IR state or to
resume shifting following the exit from the Pause-IR state.
■
■
■
12.4
L1 Cache Inhibit
The AMD-K6-2E processor provides a means for inhibiting the
normal operation of its L1 instruction and data caches while
still supporting an external level-2 (L2) cache. This capability
allows system designers to disable the L1 cache during the
testing and debug of an L2 cache.
If the Cache Inhibit bit (bit 3) of test register 12 (TR12) is 0, the
processor’s L1 cache is enabled and operates as described in
“Cache Organization” on page 185. If the Cache Inhibit bit is 1,
the L1 cache is disabled and no new cache lines are allocated.
Even though new allocations do not occur, valid L1 cache lines
remain valid and are read by the processor when a requested
address hits a cache line. In addition, the processor continues to
support inquire cycles initiated by the system logic, including
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the execution of writeback cycles when a modified cache line is
hit.
While the L1 is inhibited, the processor continues to drive the
PCD output signal appropriately, which system logic can use to
control external L2 caching.
In order to completely disable the L1 cache so that no valid
lines exist in the cache, the Cache Inhibit bit must be set to 1
and the cache must be flushed in one of the following ways:
■
■
■
■
12.5
By asserting the FLUSH# input signal
By executing the WBINVD instruction
By executing the INVD instruction (modified cache lines are
not written back to memory)
By using the Page Flush/Invalidate register (PFIR) (see
“Page Flush/Invalidate Register (PFIR)” on page 200)
Debug
The AMD-K6-2E processor implements the standard x86 debug
functions, registers, and exceptions. In addition, the processor
supports the I/O breakpoint debug extension. The debug
feature assists programmers and system designers during
software execution tracing by generating exceptions when one
or more events occur during processor execution. The exception
handler, or debugger, can be written to perform various tasks,
such as displaying the conditions that caused the breakpoint to
occur, displaying and modifying register or memory contents, or
single-stepping through program execution.
The following sections describe the debug registers and the
various types of breakpoints and exceptions that the processor
supports.
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Debug Registers
Figures 83 through 86 show the 32-bit debug registers
supported by the processor.
Symbol
LEN 3
R/W 3
LEN 2
R/W 2
LEN 1
R/W 1
LEN 0
R/W 0
Description
Length of Breakpoint #3
Type of Transaction(s) to Trap
Length of Breakpoint #2
Type of Transaction(s) to Trap
Length of Breakpoint #1
Type of Transaction(s) to Trap
Length of Breakpoint #0
Type of Transaction(s) to Trap
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
LEN
3
R/W
3
LEN
2
R/W
2
LEN
1
R/W
1
LEN
0
R/W
0
G
D
G
E
8
7
6
5
L G L G
E 3 3 2
4
3
L G
2 1
2
Bits
31–30
29–28
27–26
25–24
23–22
21–20
19–18
17–16
1
0
L G
1 0
L
0
Reserved
Symbol
GD
GE
LE
G3
L3
G2
L2
G1
L1
G0
L0
Description
Bit
General Detect Enabled
13
Global Exact Breakpoint Enabled
9
Local Exact Breakpoint Enabled
8
Global Exact Breakpoint # 3 Enabled 7
Local Exact Breakpoint # 3 Enabled 6
Global Exact Breakpoint # 2 Enabled 5
Local Exact Breakpoint # 2 Enabled 4
Global Exact Breakpoint # 1 Enabled 3
Local Exact Breakpoint # 1 Enabled 2
Global Exact Breakpoint # 0 Enabled 1
Local Exact Breakpoint # 0 Enabled 0
Figure 83. Debug Register DR7
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31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
8
7
6
5
4
B B B
T S D
3
2
1
0
B
3
B
2
B
1
B
0
Reserved
Symbol
BT
BS
BD
B3
B2
B1
B0
Description
Breakpoint Task Switch
Breakpoint Single Step
Breakpoint Debug Access Detected
Breakpoint #3 Condition Detected
Breakpoint #2 Condition Detected
Breakpoint #1 Condition Detected
Breakpoint #0 Condition Detected
Bit
15
14
13
3
2
1
0
Figure 84. Debug Register DR6
DR5
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
8
7
6
5
4
3
2
1
0
8
7
6
5
4
3
2
1
0
Reserved
DR4
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
Reserved
Figure 85. Debug Registers DR5 and DR4
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DR3
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
8
7
6
5
4
3
2
1
0
8
7
6
5
4
3
2
1
0
8
7
6
4
3
2
1
0
8
7
6
4
3
2
1
0
Breakpoint 3 32-bit Linear Address
DR2
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
Breakpoint 2 32-bit Linear Address
DR1
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
5
Breakpoint 1 32-bit Linear Address
DR0
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
5
Breakpoint 0 32-bit Linear Address
Figure 86. Debug Registers DR3, DR2, DR1, and DR0
DR3–DR0. The processor allows the setting of up to four
breakpoints. DR3–DR0 contain the linear addresses for
breakpoint 3 through breakpoint 0, respectively, and are
compared to the linear addresses of processor cycles to
determine if a breakpoint occurs. Debug register DR7 defines
the specific type of cycle that must occur in order for the
breakpoint to occur.
DR5–DR4. When debugging extensions are disabled (bit 3 of CR4
is 0), the DR5 and DR4 registers are mapped to DR7 and DR6,
respectively, in order to be software compatible with previous
generations of x86 processors. When debugging extensions are
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enabled (bit 3 of CR4 is 1), any attempt to load DR5 or DR4
results in an undefined opcode exception. Likewise, any
attempt to store DR5 or DR4 also results in an undefined
opcode exception.
DR6. If a breakpoint is enabled in DR7, and the breakpoint
conditions as defined in DR7 occur, then the corresponding B
bit (B3–B0) in DR6 is set to 1. In addition, any other breakpoints
defined using these particular breakpoint conditions are
reported by the processor by setting the appropriate B bits in
DR6, regardless of whether these breakpoints are enabled or
disabled. However, if a breakpoint is not enabled, a debug
exception does not occur for that breakpoint.
If the processor decodes an instruction that writes or reads DR7
through DR0, the BD bit (bit 13) in DR6 is set to 1 (if enabled in
DR7) and the processor generates a debug exception. This
operation allows control to pass to the debugger prior to debug
register access by software.
If the Trap Flag (bit 8) of the EFLAGS register is 1, the
processor generates a debug exception after the successful
execution of every instruction (single-step operation) and sets
the BS bit (bit 14) in DR6 to indicate the source of the
exception.
When the processor switches to a new task and the debug trap
bit (T bit) in the corresponding Task State Segment (TSS) is 1,
the processor sets the BT bit (bit 15) in DR6 and generates a
debug exception.
DR7. When set to 1, L3–L0 locally enable breakpoints 3 through
0, respectively. L3–L0 are cleared to 0 whenever the processor
executes a task switch. Clearing L3–L0 to 0 disables the
breakpoints and ensures that these particular debug exceptions
are only generated for a specific task.
When set to 1, G3–G0 globally enable breakpoints 3 through 0,
respectively. Unlike L3–L0, G3–G0 are not cleared to 0
whenever the processor executes a task switch. Not clearing
G3–G0 to 0 allows breakpoints to remain enabled across all
tasks. If a breakpoint is enabled globally but disabled locally,
the global enable overrides the local enable.
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The LE (bit 8) and GE (bit 9) bits in DR7 have no effect on the
operation of the processor and are provided to be softwarecompatible with previous generations of x86 processors.
When set to 1, the GD bit in DR7 (bit 13) enables the debug
exception associated with the BD bit (bit 13) in DR6. This bit is
cleared to 0 when a debug exception is generated.
LEN3–LEN0 and RW3–RW0 are two-bit fields in DR7 that
specify the length and type of each breakpoint as defined in
Table 48.
Table 48. DR7 LEN and RW Definitions
LEN Bits1
RW Bits
00b
00b2
Instruction Execution
00b
01b
One-byte Data Write
01b
Breakpoint
Two-byte Data Write
11b
Four-byte Data Write
00b
10b
3
One-byte I/O Read or Write
01b
Two-byte I/O Read or Write
11b
Four-byte I/O Read or Write
00b
11b
One-byte Data Read or Write
01b
Two-byte Data Read or Write
11b
Four-byte Data Read or Write
Notes:
1. LEN bits equal to 10b is undefined.
2. When RW equals 00b, LEN must be equal to 00b.
3. When RW equals 10b, debugging extensions (DE) must be enabled (bit 3 of CR4 must be set
to 1). If DE is cleared to 0, then RW equal to 10b is undefined.
Debug Exceptions
A debug exception is categorized as either a debug trap or a
debug fault.
■
■
A debug trap calls the debugger following the execution of
the instruction that caused the trap.
A debug fault calls the debugger prior to the execution of the
instruction that caused the fault.
All debug traps and faults generate either an Interrupt 01h or
an Interrupt 03h exception.
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Interrupt 01h. The following events are considered debug traps
that cause the processor to generate an Interrupt 01h
exception:
■
■
■
Enabled breakpoints for data and I/O cycles
Single-step trap
Task-switch trap
The following events are considered debug faults that cause the
processor to generate an Interrupt 01h exception:
■
■
Enabled breakpoints for instruction execution
BD bit in DR6 set to 1
Interrupt 03h. The INT 3 instruction is defined in the x86
architecture as a breakpoint instruction. This instruction
causes the processor to generate an Interrupt 03h exception.
This exception is a debug trap because the debugger is called
following the execution of the INT 3 instruction.
The INT 3 instruction is a one-byte instruction (opcode CCh)
typically used to insert a breakpoint in software by writing CCh
to the address of the first byte of the instruction to be trapped
(the target instruction). Following the trap, if the target
instruction is to be executed, the debugger must replace the
INT 3 instruction with the first byte of the target instruction.
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13
13.1
Clock Control
Clock Control States
The AMD-K6-2E processor supports five modes of clock control.
The processor can transition between these modes to maximize
performance, to minimize power dissipation, or to provide a
balance between performance and power. (See “Power
Dissipation” on page 258 for the maximum power dissipation of
t h e A M D -K 6 -2 E p ro c e s s o r w it h in t h e n o r m a l a n d t h e
reduced-power states.)
The five clock-control states supported are:
■
Normal State—The processor is running in real mode,
virtual-8086 mode, protected mode, or system management
mode (SMM). In this state, all clocks are running— including
the external bus clock, CLK, and the internal processor
clock—and the full features and functions of the processor
are available.
■
Halt State—This low-power state is entered following the
successful execution of the HLT instruction. During this
state, the internal processor clock is stopped.
Stop Grant State—This low-power state is entered following
the recognition of the assertion of the STPCLK# signal.
During this state, the internal processor clock is stopped.
Stop Grant Inquire State—This state is entered from the
Halt state and the Stop Grant state as the result of a
system-initiated inquire cycle.
Stop Clock State—This low-power state is entered from the
Stop Grant state when the CLK signal is stopped.
■
■
■
Figure 87 on page 248 illustrates the clock control state
transitions. Each of the four reduced-power states are described
in the following sections.
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HLT Instruction
RESET, SMI#, INIT,
or INTR Asserted
Halt
State
EADS# Asserted
Writeback
Completed
22529B/0—January 2000
Normal Mode
– Real
– Virtual-8086
– Protected
– SMM
Stop Grant
Inquire
State
STPCLK# Asserted
STPCLK# Negated,
or RESET Asserted
EADS# Asserted
Stop Grant
State
Writeback
Completed
CLK
Started
CLK
Stopped
Stop Clock
State
Figure 87. Clock Control State Transitions
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13.2
Halt State
Enter Halt State
During the execution of the HLT instruction, the AMD-K6-2E
processor executes a Halt special cycle. After BRDY# is
sampled asserted during this cycle, and then EWBE# is also
sampled asserted (if not masked off), the processor enters the
Halt state in which the processor disables most of its internal
clock distribution.
To support the following operations, the internal phase-lock
loop (PLL) continues to run, and some internal resources are
still clocked in the Halt state:
■
■
■
■
Inquire Cycles—The processor continues to sample AHOLD,
BOFF#, and HOLD to support inquire cycles that are
initiated by the system logic. The processor transitions to
the Stop Grant Inquire state during the inquire cycle. After
returning to the Halt state following the inquire cycle, the
processor does not execute another Halt special cycle.
Flush Cycles—The processor continues to sample FLUSH#.
If FLUSH# is sampled asserted, the processor performs the
flush operation in the same manner as it is performed in the
Normal state. Upon completing the flush operation, the
processor executes the Halt special cycle which indicates
the processor is in the Halt state.
Time Stamp Counter (TSC)—The TSC continues to count in
the Halt state.
Signal Sampling—The processor continues to sample INIT,
INTR, NMI, RESET, and SMI#.
After entering the Halt state, all signals driven by the processor
retain their state as they existed following the completion of
the Halt special cycle.
Exit Halt State
Chapter 13
The AMD-K6-2E processor remains in the Halt state until it
samples INIT, INTR (if interrupts are enabled), NMI, RESET, or
SMI# asserted. If any of these signals is sampled asserted, the
processor returns to the Normal state and performs the
corresponding operation. All of the normal requirements for
recognition of these input signals apply within the Halt state.
Clock Control
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Stop Grant State
Enter Stop Grant
State
After recognizing the assertion of STPCLK#, the AMD-K6-2E
processor flushes its instruction pipelines, completes all
pending and in-progress bus cycles, and acknowledges the
STPCLK# assertion by executing a Stop Grant special bus cycle.
After BRDY# is sampled asserted during this cycle, and after
EWBE# is also sampled asserted (if not masked off), the
processor enters the Stop Grant state.
The Stop Grant state is like the Halt state in that the processor
disables most of its internal clock distribution in the Stop Grant
state.
In order to support the following operations, the internal PLL
still runs, and some internal resources are still clocked in the
Stop Grant state:
■
■
■
Inquire cycles—The processor transitions to the Stop Grant
Inquire state during an inquire cycle. After returning to the
Stop Grant state following the inquire cycle, the processor
does not execute another Stop Grant special cycle.
Time Stamp Counter (TSC)—The TSC continues to count in
the Stop Grant state.
Signal Sampling—The processor continues to sample INIT,
INTR, NMI, RESET, and SMI#.
FLUSH# is not recognized in the Stop Grant state (unlike while
in the Halt state).
Upon entering the Stop Grant state, all signals driven by the
processor retain their state as they existed following the
completion of the Stop Grant special cycle.
Exit Stop Grant State
The AMD-K6-2E processor remains in the Stop Grant state until
it samples STPCLK# negated or RESET asserted. If STPCLK#
is sampled negated, the processor returns to the Normal state in
less than 10 bus clock (CLK) periods. After the transition to the
Norm al state, the processor resumes execution at the
instruction boundary on which STPCLK# was initially
recognized.
If STPCLK# is recognized as negated in the Stop Grant state
and subsequently sampled asserted prior to returning to the
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Normal state, a minimum of one instruction is executed prior to
re-entering the Stop Grant state.
If INIT, INTR (if interrupts are enabled), FLUSH#, NMI, or
SMI# are sampled asserted in the Stop Grant state, the
processor latches the edge-sensitive signals (INIT, FLUSH#,
NMI, and SMI#), but otherwise does not exit the Stop Grant
state to service the interrupt. When the processor returns to the
Normal state due to sampling STPCLK# negated, any pending
interrupts are recognized after returning to the Normal state.
To ensure their recognition, all of the normal requirements for
these input signals apply within the Stop Grant state.
If RESET is sampled asserted in the Stop Grant state, the
processor immediately returns to the Normal state and the
reset process begins.
13.4
Stop Grant Inquire State
Enter Stop Grant
Inquire State
The Stop Grant Inquire state is entered from the Stop Grant
state or the Halt state when EADS# is sampled asserted during
an inquire cycle initiated by the system logic. The AMD-K6-2E
processor responds to an inquire cycle in the same manner as in
the Normal state by driving HIT# and HITM#. If the inquire
cycle hits a modified data cache line, the processor performs a
writeback cycle.
Exit Stop Grant
Inquire State
Following the completion of any writeback, the processor
returns to the state from which it entered the Stop Grant
Inquire state.
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Stop Clock State
Enter Stop Clock
State
If the CLK signal is stopped while the AMD-K6-2E processor is
in the Stop Grant state, the processor enters the Stop Clock
state. Because all internal clocks and the PLL are not running
in the Stop Clock state, the Stop Clock state represents the
minimum-power state of all clock control states. The CLK signal
must be held Low while it is stopped.
The Stop Clock state cannot be entered from the Halt state.
INTR is the only input signal that is allowed to change states
while the processor is in the Stop Clock state. However, INTR is
not sampled until the processor returns to the Stop Grant state.
All other input signals must remain unchanged in the Stop
Clock state.
Exit Stop Clock State
The AMD-K6-2E processor returns to the Stop Grant state from
the Stop Clock state after the CLK signal is started and the
internal PLL has stabilized. PLL stabilization is achieved after
the CLK signal has been running within its specification for a
minimum of 1.0 ms.
The frequency of CLK when exiting the Stop Clock state can be
different than the frequency of CLK when entering the Stop
Clock state.
The state of the BF[2:0] signals when exiting the Stop Clock
state is ignored because the BF[2:0] signals are only sampled
during the falling transition of RESET.
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14
Electrical Data
This chapter includes specifications for the operating ranges,
absolute ratings, and DC characteristics of the AMD-K6-2E
embedded processor. Typical and maximum power dissipation
values for the AMD-K6-2E processor during normal and
reduced power states are listed, as are example power derating
values based on lower CPU frequencies. The derating data may
be of special interest to embedded customers who want to use
A M D ’s s t a n d a rd - o r l ow - p owe r d ev i c e s a t l owe r C P U
frequencies. The chapter concludes with a discussion of power
and grounding requirements and I/O buffer characteristics.
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Operating Ranges
The AMD-K6-2E processor is designed to provide functional
operation if the voltage and temperature parameters are within
the limits defined in Table 49.
Table 49. Operating Ranges
Parameter
VCC2
1
Parameter Description
Minimum
Typical
Maximum
Core Supply Voltage—Low Power
1.8 V
1.9 V
2.0 V
Core Supply Voltage—Standard Power3
2.1 V
2.2 V
2.3 V
3.135 V
3.3 V
3.6 V
2
VCC31
I/O Supply Voltage—Standard and Low Power
TCASE
Case Temperature—Low Power4
0•C
–
85•C
Case Temperature—Standard Power5
0•C
–
70•C
Notes:
1.
2.
3.
4.
VCC2 and VCC3 are referenced from VSS.
VCC2 specification for 1.9-V component.
VCC2 specification for 2.2-V component.
Case temperature range required for AMD-K6-2E/xxxAMZ valid ordering part number combinations, where xxx represents the
processor core frequency.
5. Case temperature range required for AMD-K6-2E/xxxAFR valid ordering part number combinations, where xxx represents the
processor core frequency.
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14.2
Absolute Ratings
The AMD-K6-2E processor is not designed to be operated
beyond the operating ranges listed in Table 49. Exposure to
conditions outside these operating ranges for extended periods
of time can affect long-term reliability. Permanent damage can
occur if the absolute ratings listed in Table 50 are exceeded.
Note: If the AMD-K6-2E processor shows a “7” after the date code,
refer to the numbers in the last (rightmost) column of Table
50. The AMD-K6®-2 Revision Guide (order #21641)
available on AMD’s web site contains package marking
details, including the location of the date code
Table 50. Absolute Ratings
Parameter
Minimum
Maximum for OPN
Suffixes: 233AFR,
233AMZ, 266AFR,
266AMZ, 300AFR1
VCC2
–0.5 V
2.6 V
2.4 V
VCC3
–0.5 V
3.6 V
3.6 V
VPIN3
–0.5 V
VCC3 + 0.5 V and < 4.0 V
VCC3 + 0.5 V and < 4.0 V
TCASE (under bias)
–65•C
+110•C
+110•C
TSTORAGE
–65•C
+150•C
+150•C
Maximum for All OPNs2
Notes:
1. The data in this column applies to OPN suffixes 233AFR, 233AMZ, 266AFR, 266AMZ, and
300AFR, provided that the processor is not marked with “7” following the date code (i.e., is
blank).
2. The data in this column applies to all OPNs listed in Table 73, “Valid Ordering Part Number
Combinations,” on page 306 (including 233AFR, 233AMZ, 266AFR, 266AMZ, and 300AFR
when the processor is marked with a “7” following the date code).
3. VPIN (the voltage on any I/O pin) must not be greater than 0.5 V above the voltage being
applied to VCC3. In addition, the VPIN voltage must never exceed 4.0 V.
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DC Characteristics
The DC characteristics of the AMD-K6-2E processor are shown
in Table 51.
Table 51. DC Characteristics
Symbol
Parameter Description
Min
Max
VIL
Input Low Voltage
–0.3 V
+0.8 V
VIH1
Input High Voltage
2.0 V
VCC3 +0.3 V
VOL
Output Low Voltage
VOH
Output High Voltage
ICC2
Low Power
0.4 V
ICC2
Standard
Power
2.2 V Power Supply Current
6
ICC3
Standard
and
Low Power
256
3.3 V Power Supply Current
7
4.75 A
233 MHz2,3
5.35 A
266 MHz2,3
5.50 A
300 MHz2,3,5
5.65 A
333 MHz2,3,4
6.25 A
350 MHz2,5
6.50 A
233 MHz3,6
7.35 A
266 MHz3,6
8.45 A
300 MHz3,5,6
9.40 A
333 MHz3,4,6
9.85 A
350 MHz5,6
10.00 A
400 MHz3,5,6
0.52 A
233 MHz3,7
0.54 A
266 MHz3,7
0.56 A
300 MHz3,5,7
0.58 A
333 MHz3,4,7
0.60 A
350 MHz5,7
0.62 A
400 MHz3,5,7
ILI8
Input Leakage Current
–15 mA
ILO8
Output Leakage Current
–15 mA
IIL9
Input Leakage Current Bias with Pullup
–400 mA
Electrical Data
IOL = 4.0-mA load
IOH = 3.0-mA load
2.4 V
1.9 V Power Supply Current2
Comments
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AMD-K6™-2E Processor Data Sheet
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Table 51. DC Characteristics (continued)
Symbol
Parameter Description
Min
Max
IIH10
Input Leakage Current Bias with Pulldown
200 mA
CIN
Input Capacitance
10 pF
COUT
Output Capacitance
15 pF
COUT
I/O Capacitance
20 pF
CCLK
CLK Capacitance
10 pF
CTIN
Test Input Capacitance (TDI, TMS, TRST#)
10 pF
CTOUT
Test Output Capacitance (TDO)
15 pF
CTCK
TCK Capacitance
10 pF
Comments
Notes:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
VCC3 refers to the voltage being applied to VCC3 during functional operation.
VCC2=2.0 V —The maximum power supply current must be taken into account when designing a power supply.
This specification applies to components using a CLK frequency of 66 MHz.
This specification applies to components using a CLK frequency of 95 MHz.
This specification applies to components using a CLK frequency of 100 MHz.
VCC2=2.3 V —The maximum power supply current must be taken into account when designing a power supply.
VCC3=3.6 V —The maximum power supply current must be taken into account when designing a power supply.
Refers to inputs and I/O without an internal pullup resistor and 0 ˆ VIN ˆ VCC3.
Refers to inputs with an internal pullup and VIL=0.4 V.
Refers to inputs with an internal pulldown and VIH=2.4 V.
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Power Dissipation
Table 52 and Table 53 list the typical and maximum power
dissipation of the AMD-K6-2E processor during normal and
reduced power states.
.
Table 52. Typical and Maximum Power Dissipation for OPN Suffix AMZ (Low-Power Devices)
Clock Control State
233 MHz1
266 MHz1
300 MHz1,3
333 MHz1,2
350 MHz3
Thermal Power
(Maximum)4,5
9.00 W
10.00 W
10.00 W
10.00 W
11.00 W
Thermal Power
(Typical)6
6.30 W
7.00 W
7.00 W
7.00 W
7.70 W
Stop Grant/Halt
(Maximum)7
1.20 W
1.20 W
1.20 W
1.20 W
1.20 W
Stop Clock
(Maximum)8
1.00 W
1.00 W
1.00 W
1.00 W
1.00 W
Notes:
1.
2.
3.
4.
5.
6.
7.
8.
This specification applies to components using a CLK frequency of 66 MHz.
This specification applies to components using a CLK frequency of 95 MHz.
This specification applies to components using a CLK frequency of 100 MHz.
The maximum power dissipated in the normal clock control state must be taken into account when designing a solution for
thermal dissipation for the AMD-K6-2E processor.
Maximum power is determined for the worst-case instruction sequence or function for the listed clock control states with
VCC2 = 1.9 V, and VCC3 = 3.3 V.
Typical power is determined for the typical instruction sequences or functions associated with normal system operation with
VCC2 = 1.9 V, and VCC3 = 3.3 V.
The CLK signal and the internal PLL are still running but most internal clocking has stopped.
The CLK signal, the internal PLL, and all internal clocking has stopped.
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Table 53. Typical and Maximum Power Dissipation for OPN Suffix AFR (Standard-Power Devices)
Clock Control State
233 MHz1
266 MHz1
300 MHz1,3
333 MHz1,2
350 MHz3
400 MHz1,3
Thermal Power
(Maximum)4,5
13.50 W
14.70 W
17.20 W
19.00 W
19.95 W
16.90 W
Thermal Power
(Typical)6
8.10
8.85 W
10.35 W
11.40 W
11.98 W
10.15 W
Stop Grant/Halt
(Maximum)7
2.46 W
2.48 W
2.50 W
3.94 W
3.96 W
4.40 W
Stop Clock
(Maximum)8
2.25 W
2.25
2.25 W
3.50 W
3.50 W
4.00 W
Notes:
1.
2.
3.
4.
5.
6.
7.
8.
This specification applies to components using a CLK frequency of 66 MHz.
This specification applies to components using a CLK frequency of 95 MHz.
This specification applies to components using a CLK frequency of 100 MHz.
The maximum power dissipated in the normal clock control state must be taken into account when designing a solution for
thermal dissipation for the AMD-K6-2E processor.
Maximum power is determined for the worst-case instruction sequence or function for the listed clock control states with
VCC2 = 2.2 V, and VCC3 = 3.3 V.
Typical power is determined for the typical instruction sequences or functions associated with normal system operation with
VCC2 = 2.2 V, and VCC3 = 3.3 V.
The CLK signal and the internal PLL are still running but most internal clocking has stopped.
The CLK signal, the internal PLL, and all internal clocking has stopped.
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Power Derating Based on Lower CPU Frequencies
This section provides standard- and low-power product
specification power derating based on lower CPU frequencies.
Note: The 166-MHz and 200-MHz data provided in Table 54 and
Table 55 was derived from the standard- and low-power
AMD-K6-2E/233AFR (and AMZ) and AMD-K6-2E/266AFR
(and AMZ) products and is solely for informational
purposes. The guaranteed electrical and thermal
specification data for the AMD-K6-2E/233AFR (and AMZ)
and AMD-K6-2E/266AFR (and AMZ) is also included here
for convenience. The derating data may be of interest to
customers who want to use AMD’s standard- or low-power
devices at lower CPU frequencies. AMD does not guarantee
the 166-MHz and 200-MHz CPU frequency derating data
and does not provide devices with these lower CPU
frequencies. Only devices listed in Table 73, “Valid Ordering
Part Number Combinations,” on page 306 are available.
Table 54. Power Derating Specification for Standard-Power Devices (AMD-K6-2E/233AFR and 266AFR)
166.7 MHz1
200.0 MHz1
233.3 MHz1
266.7 MHz1
5.31 A
6.00 A
6.50 A
7.35 A
0.48 A
0.50 A
0.52 A
0.54 A
Thermal Power (Maximum)4
11.10 W
12.50 W
13.50 W
14.70 W
Thermal Power (Typical)5
6.65 W
7.50 W
8.10 W
8.85 W
Clock Multiple
2.5x
3.0x
3.5x
4.0x
BF[2:0] Inputs
100b
101b
111b
010b
Clock Control State
Maximum ICC2 (core)
VCC2 = 2.2 V ± 100 mV2
Maximum ICC3 (I/O)
VCC3 = 3.3 V +300 mV, –165 mV3
Notes:
1. This specification applies to components using a clock and bus frequency of 66 MHz.
2. The maximum ICC2 specification is taken at VCC2 = 2.3 V. (The maximum power supply current must be taken into account when
designing a power supply.)
3. The maximum ICC3 specification is taken at VCC3 = 3.6 V. (The maximum power supply current must be taken into account when
designing a power supply.)
4. Maximum thermal power is determined for the worst-case instruction sequence or functions for the listed clock control states
with VCC2 = 2.2 V and VCC3 = 3.3 V.
5. Typical thermal power is determined for the typical instruction sequence or functions associated with normal system operation
with VCC2 = 2.2 V and VCC3 = 3.3 V.
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Table 55. Power Derating Specification for Low-Power Devices (AMD-K6-2E/233AMZ and 266AMZ)
Clock Control State
166.7 MHz1
200.0 MHz1
233.3 MHz1
266.7 MHz1
3.79 A
4.37 A
4.75 A
5.35 A
0.48 A
0.50 A
0.52 A
0.54 A
Thermal Power (Maximum)4
7.07 W
8.10 W
9.00 W
10.00 W
Thermal Power (Typical)5
4.95 W
5.67 W
6.30 W
7.00 W
Clock Multiple
2.5x
3.0x
3.5x
4.0x
BF[2:0] Inputs
100b
101b
111b
010b
Maximum ICC2 (core)
VCC2 = 1.9 V ± 100 mV2
Maximum ICC3 (I/O)
VCC3 = 3.3 V +300 mV, –165 mV3
Notes:
1. This specification applies to components using a clock and bus frequency of 66 MHz.
2. The maximum ICC2 specification is taken at VCC2 = 2.0 V. (The maximum power supply current must be taken into account when
designing a power supply.)
3. The maximum ICC3 specification is taken at VCC3 = 3.6 V. (The maximum power supply current must be taken into account when
designing a power supply.)
4. Maximum thermal power is determined for the worst-case instruction sequence or functions for the listed clock control states
with VCC2 = 1.9 V and VCC3 = 3.3 V.
5. Typical thermal power is determined for the typical instruction sequence or functions associated with normal system operation
with VCC2 = 1.9 V and VCC3 = 3.3 V.
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Power and Grounding
Power Connections
The AMD-K6-2E processor is a dual voltage device. Two
separate supply voltages are required: VCC2 and VCC3.
■
■
VCC2 provides the core voltage for the processor.
VCC3 provides the I/O voltage.
See “Electrical Data” on page 253 for the value and range of
VCC2 and VCC3.
There are 28 VCC2, 32 VCC3, and 68 VSS pins on the AMD-K6-2E
processor. (See Chapter 17, “Pin Designation Diagrams” on
page 299 for all power and ground pin designations.) The large
number of power and ground pins are provided to ensure that
the processor and package maintain a clean and stable power
distribution network.
For proper operation and functionality, all VCC2, VCC3, and VSS
pins must be connected to the appropriate planes in the circuit
board. The power planes have been arranged in a pattern to
simplify routing and minimize crosstalk on the circuit board.
The isolation region between two voltage planes must be at
least 0.254 mm if they are in the same layer of the circuit board.
(See Figure 88 on page 263.) To maintain low-impedance
current sink and reference, the ground plane must never be
split.
Although the AMD-K6-2E processor has two separate supply
voltages, there are no special power sequencing requirements.
The best procedure is to minimize the time between which VCC2
and VCC3 are either both on or both off.
262
Electrical Data
Chapter 14
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
C19
C21
C2
C11
CC4
+
+
CC5
CC6
C12
C13
VCC3 (I/O) Plane
C26
CC10
C22
C23
C24
CC8
C1
+
+
+
C25
C29
C27
C30
C28
C31
CC7
CC3
C15
C7
C9
C20
C16
C6
C10
C17
C18
C5
CC9
C8
C14
0.254mm (min.) for
isolation region
VCC2 (Core) Plane
CC1
CC2
Figure 88. Suggested Component Placement
Decoupling
Recommendations
In addition to the isolation region mentioned in “Power
Connections” on page 262, adequate decoupling capacitance is
required between the two system power planes and the ground
plane to minimize ringing and to provide a low-impedance path
for return currents. Suggested decoupling capacitor placement
is shown in Figure 88.
Surface mounted capacitors should be used as close as possible
to the processor to minimize resistance and inductance in the
lead lengths while maintaining minimal height.
For recommendations about the specific value, quantity, and
location of the capacitors illustrated in Figure 88, see the AMDK6® Processor Power Supply Design Application Note, order
#21103.
Chapter 14
Electrical Data
263
Preliminary Information
AMD-K6™-2E Processor Data Sheet
Pin Connection
Requirements
For proper operation, the following requirements for signal pin
connections must be met:
■
■
■
■
■
14.7
22529B/0—January 2000
Do not drive address and data signals into large capacitive
loads at high frequencies. If necessary, use buffer chips to
drive large capacitive loads.
Leave all NC (no-connect) pins unconnected.
Unused inputs should always be connected to an
appropriate signal level.
• Active Low inputs that are not being used should be
connected to VCC3 through a 20-kW pullup resistor.
• Active High inputs that are not being used should be
connected to GND through a pulldown resistor.
Reserved signals can be treated in one of the following ways:
• As no-connect (NC) pins, in which case these pins are left
unconnected
• As pins connected to the system logic as defined by the
industry-standard Socket 7 and Super7 interfaces
• Any combination of NC and Socket 7 pins
Keep trace lengths to a minimum.
I/O Buffer Characteristics
All of the AMD-K6-2E process or inputs , outputs, and
bidirectional buffers are implemented using a 3.3 V buffer
design. AMD has developed a model that represents the
characteristics of the actual I/O buffer to allow system
designers to perform analog simulations of AMD-K6-2E
processor signals that interface with the system logic. Analog
simulations are used to determine a signal’s time of flight from
source to destination and to ensure that the system’s signal
quality requirements are met. Signal quality measurements
include overshoot, undershoot, slope reversal, and ringing.
I/O Buffer Model
264
AMD provides a model of the AMD-K6-2E processor I/O buffer
for system designers to use in board-level simulations. This I/O
b u f f e r m o d e l c o n fo r m s t o t h e I / O B u f f er I nf o r m at i o n
Specification (IBIS). The I/O model contains voltage versus
current (V/I) and voltage versus time (V/T) data tables for
accurate modeling of I/O buffer behavior.
Electrical Data
Chapter 14
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
The following list characterizes the properties of the I/O buffer
model:
■
■
■
■
■
■
■
■
All data tables contain minimum, typical, and maximum
values to allow for worst-case, typical, and best-case
simulations, respectively.
The pullup, pulldown, power clamp, and ground clamp
device V/I tables contain enough data points to accurately
represent the nonlinear nature of the V/I curves. In addition,
the voltage ranges provided in these tables extend beyond
the normal operating range of the AMD-K6-2E processor for
those simulators that yield more accurate results based on
this wider range.
The rising and falling ramp rates are specified.
The min/typ/max VCC3 operating range is specified as
3.135V, 3.3V, and 3.6V, respectively.
VIL = 0.8V, VIH = 2.0V, and VMEAS = 1.5V.
The R/L/C of the package is modeled.
The capacitance of the silicon die is modeled.
The model assumes a test load resistance of 50 W.
I/O Model
Application Note
For the AMD-K6-2E processor I/O Buffer IBIS Models and their
application, refer to the AMD-K6® Processor I/O Model (IBIS)
Application Note, order #21084.
I/O Buffer AC and DC
Characteristics
See “Signal Switching Characteristics” on page 267 for the
AMD-K6-2E processor AC timing specifications.
U s e t h i s c h a p t e r f o r t h e A M D -K 6 -2 E p r o c e s s o r D C
specifications.
Chapter 14
Electrical Data
265
Preliminary Information
AMD-K6™-2E Processor Data Sheet
266
22529B/0—January 2000
Electrical Data
Chapter 14
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
15
Signal Switching Characteristics
The AMD-K6-2E processor signal switching characteristics are
presented in tables 56 through 65. Valid delay, float, setup, and
hold timing specifications are listed. These specifications are
provided for the system designer to determine if the timings
necessary for the processor to interface with the system logic
are met.
■
■
■
■
Table 56 and Table 57 on page 268 contain the switching
characteristics of the CLK input.
Table 58 through Table 61, beginning on page 270, contain
the timings for the normal operation signals.
Table 62 on page 278 and Table 63 on page 279 contain the
timings for RESET and the configuration signals.
Table 64 and Table 65 on page 280 contain the timings for
the test operation signals.
All signal timings provided are:
■
■
■
■
15.1
Measured between CLK, TCK, or RESET at 1.5 V and the
corresponding signal at 1.5 V—this applies to input and
output signals that are switching from Low to High, or from
High to Low
Based on input signals applied at a slew rate of 1 V/ns
between 0 V and 3 V (rising) and 3 V to 0 V (falling)
Valid within the operating ranges given in “Operating
Ranges” on page 254
Based on a load capacitance (CL) of 0 pF
CLK Switching Characteristics
Table 56 and Table 57 contain the switching characteristics of
the CLK input to the AMD-K6-2E processor for 100-MHz and
66-MHz bus operation, respectively, as measured at the voltage
levels indicated by Figure 89 on page 269.
The CLK Period Stability parameter specifies the variance
(jitter) allowed between successive periods of the CLK input
measured at 1.5 V. This parameter must be considered as one of
the elements of clock skew between the AMD-K6-2E and the
system logic.
Chapter 15
Signal Switching Characteristics
267
Preliminary Information
AMD-K6™-2E Processor Data Sheet
15.2
22529B/0—January 2000
Clock Switching Characteristics for 100-MHz Bus Operation
Table 56. CLK Switching Characteristics for 100-MHz Bus Operation
Symbol
Parameter Description
Preliminary Data
Figure
Comments
100 MHz
–
In Normal Mode
10.0 ns
–
89
In Normal Mode
CLK High Time
3.0 ns
–
89
–
t3
CLK Low Time
3.0 ns
–
89
–
t4
CLK Fall Time
0.15 ns
1.5 ns
89
–
t5
CLK Rise Time
0.15 ns
1.5 ns
89
–
–
– 250 ps
–
Note
Min
Max
Frequency
33.3 MHz
t1
CLK Period
t2
CLK Period Stability
Notes:
The jitter frequency power spectrum peaking must occur at frequencies greater than (Frequency of CLK)/3 or less than 500 kHz.
15.3
Clock Switching Characteristics for 66-MHz Bus Operation
Table 57. CLK Switching Characteristics for 66-MHz Bus Operation
Symbol
Parameter Description
Preliminary Data
Figure
Min
Max
Frequency
33.3 MHz
66.6 MHz
t1
CLK Period
15.0 ns
30.0 ns
t2
CLK High Time
4.0 ns
89
t3
CLK Low Time
4.0 ns
89
t4
CLK Fall Time
0.15 ns
1.5 ns
89
t5
CLK Rise Time
0.15 ns
1.5 ns
89
CLK Period Stability
– 250 ps
Comments
In Normal Mode
89
In Normal Mode
Note
Notes:
The jitter frequency power spectrum peaking must occur at frequencies greater than (Frequency of CLK)/3 or less than 500 KHz.
268
Signal Switching Characteristics
Chapter 15
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
t2
2.0 V
1.5 V
t3
0.8 V
t4
t5
t1
Figure 89. CLK Waveform
15.4
Valid Delay, Float, Setup, and Hold Timings
Valid Delay and Float
Timing
Setup and Hold
Timing
The maximum valid delay timings are provided to allow a
system designer to determine if setup times to the system logic
can be met. Likewise, the minimum valid delay timings are used
to analyze hold times to the system logic.
■
Valid delay and float timings are given for output signals
during functional operation and are given relative to the
rising edge of CLK.
■
During boundary-scan testing, valid delay and float timings
for output signals are with respect to the falling edge of
TCK.
The setup and hold time requirements for the AMD-K6-2E
processor input signals must be met by the system logic to
assure the proper operation of the processor.
■
Chapter 15
The setup and hold timings during functional and
boundary-scan test mode are given relative to the rising
edge of CLK and TCK, respectively.
Signal Switching Characteristics
269
Preliminary Information
AMD-K6™-2E Processor Data Sheet
15.5
22529B/0—January 2000
Output Delay Timings for 100-MHz Bus Operation
Table 58. Output Delay Timings for 100-MHz Bus Operation
Symbol
270
Preliminary Data
Parameter Description
Figure
Min
Max
1.1 ns
4.0 ns
91
7.0 ns
92
4.0 ns
91
7.0 ns
92
4.0 ns
91
7.0 ns
92
5.5 ns
91
7.0 ns
92
t6
A[31:3] Valid Delay
t7
A[31:3] Float Delay
t8
ADS# Valid Delay
t9
ADS# Float Delay
t10
ADSC# Valid Delay
t11
ADSC# Float Delay
t12
AP Valid Delay
t13
AP Float Delay
t14
APCHK# Valid Delay
1.0 ns
4.5 ns
91
t15
BE[7:0]# Valid Delay
1.0 ns
4.0 ns
91
t16
BE[7:0]# Float Delay
7.0 ns
92
t17
BREQ Valid Delay
1.0 ns
4.0 ns
91
t18
CACHE# Valid Delay
1.0 ns
4.0 ns
91
t19
CACHE# Float Delay
7.0 ns
92
t20
D/C# Valid Delay
4.0 ns
91
t21
D/C# Float Delay
7.0 ns
92
t22
D[63:0] Write Data Valid Delay
4.5 ns
91
t23
D[63:0] Write Data Float Delay
7.0 ns
92
t24
DP[7:0] Write Data Valid Delay
4.5 ns
91
t25
DP[7:0] Write Data Float Delay
7.0 ns
92
t26
FERR# Valid Delay
1.0 ns
4.5 ns
91
t27
HIT# Valid Delay
1.0 ns
4.0 ns
91
t28
HITM# Valid Delay
1.1 ns
4.0 ns
91
t29
HLDA Valid Delay
1.0 ns
4.0 ns
91
t30
LOCK# Valid Delay
1.1 ns
4.0 ns
91
t31
LOCK# Float Delay
7.0 ns
92
t32
M/IO# Valid Delay
4.0 ns
91
t33
M/IO# Float Delay
7.0 ns
92
t34
PCD Valid Delay
4.0 ns
91
1.0 ns
1.0 ns
1.0 ns
1.0 ns
1.3 ns
1.3 ns
1.0 ns
1.0 ns
Signal Switching Characteristics
Chapter 15
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 58. Output Delay Timings for 100-MHz Bus Operation (continued)
Symbol
Parameter Description
t35
PCD Float Delay
t36
PCHK# Valid Delay
t37
PWT Valid Delay
t38
PWT Float Delay
t39
SCYC Valid Delay
t40
SCYC Float Delay
t41
SMIACT# Valid Delay
t42
W/R# Valid Delay
t43
W/R# Float Delay
Chapter 15
Preliminary Data
Min
Max
Figure
7.0 ns
92
1.0 ns
4.5 ns
91
1.0 ns
4.0 ns
91
7.0 ns
92
4.0 ns
91
7.0 ns
92
1.0 ns
4.0 ns
91
1.0 ns
4.0 ns
91
7.0 ns
92
1.0 ns
Signal Switching Characteristics
271
Preliminary Information
AMD-K6™-2E Processor Data Sheet
15.6
22529B/0—January 2000
Input Setup and Hold Timings for 100-MHz Bus Operation
Table 59. Input Setup and Hold Timings for 100-MHz Bus Operation
Symbol
272
Preliminary Data
Parameter Description
Min
Max
Figure
t44
A[31:5] Setup Time
3.0 ns
93
t45
A[31:5] Hold Time
1.0 ns
93
t461
A20M# Setup Time
3.0 ns
93
t471
A20M# Hold Time
1.0 ns
93
t48
AHOLD Setup Time
3.5 ns
93
t49
AHOLD Hold Time
1.0 ns
93
t50
AP Setup Time
1.7 ns
93
t51
AP Hold Time
1.0 ns
93
t52
BOFF# Setup Time
3.5 ns
93
t53
BOFF# Hold Time
1.0 ns
93
t54
BRDY# Setup Time
3.0 ns
93
t55
BRDY# Hold Time
1.0 ns
93
t56
BRDYC# Setup Time
3.0 ns
93
t57
BRDYC# Hold Time
1.0 ns
93
t58
D[63:0] Read Data Setup Time
1.7 ns
93
t59
D[63:0] Read Data Hold Time
1.5 ns
93
t60
DP[7:0] Read Data Setup Time
1.7 ns
93
t61
DP[7:0] Read Data Hold Time
1.5 ns
93
t62
EADS# Setup Time
3.0 ns
93
t63
EADS# Hold Time
1.0 ns
93
t64
EWBE# Setup Time
1.7 ns
93
t65
EWBE# Hold Time
1.0 ns
93
t662
FLUSH# Setup Time
1.7 ns
93
t672
FLUSH# Hold Time
1.0 ns
93
t68
HOLD Setup Time
1.7 ns
93
t69
HOLD Hold Time
1.5 ns
93
t701
IGNNE# Setup Time
1.7 ns
93
t711
IGNNE# Hold Time
1.0 ns
93
Signal Switching Characteristics
Chapter 15
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 59. Input Setup and Hold Timings for 100-MHz Bus Operation (continued)
Symbol
Parameter Description
Preliminary Data
Min
Max
Figure
t722
INIT Setup Time
1.7 ns
93
t732
INIT Hold Time
1.0 ns
93
t741
INTR Setup Time
1.7 ns
93
t751
INTR Hold Time
1.0 ns
93
t76
INV Setup Time
1.7 ns
93
t77
INV Hold Time
1.0 ns
93
t78
KEN# Setup Time
3.0 ns
93
t79
KEN# Hold Time
1.0 ns
93
t80
NA# Setup Time
1.7 ns
93
t81
NA# Hold Time
1.0 ns
93
t822
NMI Setup Time
1.7 ns
93
t832
NMI Hold Time
1.0 ns
93
t842
SMI# Setup Time
1.7 ns
93
t852
SMI# Hold Time
1.0 ns
93
t861
STPCLK# Setup Time
1.7 ns
93
t871
STPCLK# Hold Time
1.0 ns
93
t88
WB/WT# Setup Time
1.7 ns
93
t89
WB/WT# Hold Time
1.0 ns
93
Notes:
1. These level-sensitive signals can be asserted synchronously or asynchronously. To be sampled on a specific clock edge, setup
and hold times must be met. If asserted asynchronously, they must be asserted for a minimum pulse width of two clocks.
2. These edge-sensitive signals can be asserted synchronously or asynchronously. To be sampled on a specific clock edge, setup
and hold times must be met. If asserted asynchronously, they must have been negated at least two clocks prior to assertion and
must remain asserted at least two clocks.
Chapter 15
Signal Switching Characteristics
273
Preliminary Information
AMD-K6™-2E Processor Data Sheet
15.7
22529B/0—January 2000
Output Delay Timings for 66-MHz Bus Operation
Table 60. Output Delay Timings for 66-MHz Bus Operation
Symbol
274
Preliminary Data
Parameter Description
Figure
Min
Max
1.1 ns
6.3 ns
91
10.0 ns
92
6.0 ns
91
10.0 ns
92
7.0 ns
91
10.0 ns
92
8.5 ns
91
10.0 ns
92
t6
A[31:3] Valid Delay
t7
A[31:3] Float Delay
t8
ADS# Valid Delay
t9
ADS# Float Delay
t10
ADSC# Valid Delay
t11
ADSC# Float Delay
t12
AP Valid Delay
t13
AP Float Delay
t14
APCHK# Valid Delay
1.0 ns
8.3 ns
91
t15
BE[7:0]# Valid Delay
1.0 ns
7.0 ns
91
t16
BE[7:0]# Float Delay
10.0 ns
92
t17
BREQ Valid Delay
1.0 ns
8.0 ns
91
t18
CACHE# Valid Delay
1.0 ns
7.0 ns
91
t19
CACHE# Float Delay
10.0 ns
92
t20
D/C# Valid Delay
7.0 ns
91
t21
D/C# Float Delay
10.0 ns
92
t22
D[63:0] Write Data Valid Delay
7.5 ns
91
t23
D[63:0] Write Data Float Delay
10.0 ns
92
t24
DP[7:0] Write Data Valid Delay
7.5 ns
91
t25
DP[7:0] Write Data Float Delay
10.0 ns
92
t26
FERR# Valid Delay
1.0 ns
8.3 ns
91
t27
HIT# Valid Delay
1.0 ns
6.8 ns
91
t28
HITM# Valid Delay
1.1 ns
6.0 ns
91
t29
HLDA Valid Delay
1.0 ns
6.8 ns
91
t30
LOCK# Valid Delay
1.1 ns
7.0 ns
91
t31
LOCK# Float Delay
10.0 ns
92
t32
M/IO# Valid Delay
5.9 ns
91
t33
M/IO# Float Delay
10.0 ns
92
t34
PCD Valid Delay
7.0 ns
91
1.0 ns
1.0 ns
1.0 ns
1.0 ns
1.3 ns
1.3 ns
1.0 ns
1.0 ns
Signal Switching Characteristics
Chapter 15
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 60. Output Delay Timings for 66-MHz Bus Operation (continued)
Symbol
Parameter Description
t35
PCD Float Delay
t36
PCHK# Valid Delay
t37
PWT Valid Delay
t38
PWT Float Delay
t39
SCYC Valid Delay
t40
SCYC Float Delay
t41
SMIACT# Valid Delay
t42
W/R# Valid Delay
t43
W/R# Float Delay
Chapter 15
Preliminary Data
Min
Max
Figure
10.0 ns
92
1.0 ns
7.0 ns
91
1.0 ns
7.0 ns
91
10.0 ns
92
7.0 ns
91
10.0 ns
92
1.0 ns
7.3 ns
91
1.0 ns
7.0 ns
91
10.0 ns
92
1.0 ns
Signal Switching Characteristics
275
Preliminary Information
AMD-K6™-2E Processor Data Sheet
15.8
22529B/0—January 2000
Input Setup and Hold Timings for 66-MHz Bus Operation
Table 61. Input Setup and Hold Timings for 66-MHz Bus Operation
Symbol
276
Preliminary Data
Parameter Description
Min
Max
Figure
t44
A[31:5] Setup Time
6.0 ns
93
t45
A[31:5] Hold Time
1.0 ns
93
t461
A20M# Setup Time
5.0 ns
93
t471
A20M# Hold Time
1.0 ns
93
t48
AHOLD Setup Time
5.5 ns
93
t49
AHOLD Hold Time
1.0 ns
93
t50
AP Setup Time
5.0 ns
93
t51
AP Hold Time
1.0 ns
93
t52
BOFF# Setup Time
5.5 ns
93
t53
BOFF# Hold Time
1.0 ns
93
t54
BRDY# Setup Time
5.0 ns
93
t55
BRDY# Hold Time
1.0 ns
93
t56
BRDYC# Setup Time
5.0 ns
93
t57
BRDYC# Hold Time
1.0 ns
93
t58
D[63:0] Read Data Setup Time
2.8 ns
93
t59
D[63:0] Read Data Hold Time
1.5 ns
93
t60
DP[7:0] Read Data Setup Time
2.8 ns
93
t61
DP[7:0] Read Data Hold Time
1.5 ns
93
t62
EADS# Setup Time
5.0 ns
93
t63
EADS# Hold Time
1.0 ns
93
t64
EWBE# Setup Time
5.0 ns
93
t65
EWBE# Hold Time
1.0 ns
93
t662
FLUSH# Setup Time
5.0 ns
93
t672
FLUSH# Hold Time
1.0 ns
93
t68
HOLD Setup Time
5.0 ns
93
t69
HOLD Hold Time
1.5 ns
93
t701
IGNNE# Setup Time
5.0 ns
93
t711
IGNNE# Hold Time
1.0 ns
93
Signal Switching Characteristics
Chapter 15
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 61. Input Setup and Hold Timings for 66-MHz Bus Operation (continued)
Symbol
Parameter Description
Preliminary Data
Min
Max
Figure
t722
INIT Setup Time
5.0 ns
93
t732
INIT Hold Time
1.0 ns
93
t741
INTR Setup Time
5.0 ns
93
t751
INTR Hold Time
1.0 ns
93
t76
INV Setup Time
5.0 ns
93
t77
INV Hold Time
1.0 ns
93
t78
KEN# Setup Time
5.0 ns
93
t79
KEN# Hold Time
1.0 ns
93
t80
NA# Setup Time
4.5 ns
93
t81
NA# Hold Time
1.0 ns
93
t822
NMI Setup Time
5.0 ns
93
t832
NMI Hold Time
1.0 ns
93
t842
SMI# Setup Time
5.0 ns
93
t852
SMI# Hold Time
1.0 ns
93
t861
STPCLK# Setup Time
5.0 ns
93
t871
STPCLK# Hold Time
1.0 ns
93
t88
WB/WT# Setup Time
4.5 ns
93
t89
WB/WT# Hold Time
1.0 ns
93
Notes:
1. These level-sensitive signals can be asserted synchronously or asynchronously. To be sampled on a specific clock edge, setup
and hold times must be met. If asserted asynchronously, they must be asserted for a minimum pulse width of two clocks.
2. These edge-sensitive signals can be asserted synchronously or asynchronously. To be sampled on a specific clock edge, setup
and hold times must be met. If asserted asynchronously, they must have been negated at least two clocks prior to assertion and
must remain asserted at least two clocks.
Chapter 15
Signal Switching Characteristics
277
Preliminary Information
AMD-K6™-2E Processor Data Sheet
15.9
22529B/0—January 2000
RESET and Test Signal Timing
Table 62. RESET and Configuration Signals for 100-MHz Bus Operation
Symbol
Preliminary Data
Parameter Description
Min
Max
Figure
t90
RESET Setup Time
1.7 ns
94
t91
RESET Hold Time
1.0 ns
94
t92
RESET Pulse Width, VCC and CLK Stable
15 clocks
94
t93
RESET Active After VCC and CLK Stable
1.0 ms
94
t941
BF[2:0] Setup Time
1.0 ms
94
t951
BF[2:0] Hold Time
2 clocks
94
t96
intentionally left blank
t97
intentionally left blank
t98
intentionally left blank
t992
FLUSH# Setup Time
1.7 ns
94
t1003
FLUSH# Hold Time
1.0 ns
94
t1013
FLUSH# Setup Time
2 clocks
94
t1023
FLUSH# Hold Time
2 clocks
94
Notes:
1. BF[2:0] must meet a minimum setup time of 1.0 ms and a minimum hold time of two clocks relative to the negation of RESET.
2. To be sampled on a specific clock edge, setup and hold times must be met the clock edge before the clock edge on which RESET
is sampled negated.
3. If asserted asynchronously, these signals must meet a minimum setup and hold time of two clocks relative to the negation of
RESET.
278
Signal Switching Characteristics
Chapter 15
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 63. RESET and Configuration Signals for 66-MHz Bus Operation
Symbol
Preliminary Data
Parameter Description
Min
Max
Figure
t90
RESET Setup Time
5.0 ns
94
t91
RESET Hold Time
1.0 ns
94
t92
RESET Pulse Width, VCC and CLK Stable
15 clocks
94
t93
RESET Active After VCC and CLK Stable
1.0 ms
94
t941
BF[2:0] Setup Time
1.0 ms
94
t951
BF[2:0] Hold Time
2 clocks
94
t96
intentionally left blank
t97
intentionally left blank
t98
intentionally left blank
t992
FLUSH# Setup Time
5.0 ns
94
t1002
FLUSH# Hold Time
1.0 ns
94
t1013
FLUSH# Setup Time
2 clocks
94
t1023
FLUSH# Hold Time
2 clocks
94
Notes:
1. BF[2:0] must meet a minimum setup time of 1.0 ms and a minimum hold time of two clocks relative to the negation of RESET.
2. To be sampled on a specific clock edge, setup and hold times must be met the clock edge before the clock edge on which RESET
is sampled negated.
3. If asserted asynchronously, these signals must meet a minimum setup and hold time of two clocks relative to the negation of
RESET.
Chapter 15
Signal Switching Characteristics
279
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 64. TCK Waveform and TRST# Timing at 25 MHz
Symbol
Parameter Description
Preliminary Data
Min
Max
TCK Frequency
Figure
25 MHz
95
t103
TCK Period
40.0 ns
95
t104
TCK High Time
14.0 ns
95
t105
TCK Low Time
14.0 ns
95
t1061,2
TCK Fall Time
5.0 ns
95
t1071,2
TCK Rise Time
5.0 ns
95
t1083
TRST# Pulse Width
30.0 ns
96
Notes:
1. Rise/Fall times can be increased by 1.0 ns for each 10 MHz that TCK is run below its maximum frequency of 25 MHz.
2. Rise/Fall times are measured between 0.8 V and 2.0 V.
3. Asynchronous.
Table 65. Test Signal Timing at 25 MHz
Symbol
Preliminary Data
Parameter Description
Min
Max
Figure
t1091
TDI Setup Time
5.0 ns
97
t1101
TDI Hold Time
9.0 ns
97
t1111
TMS Setup Time
5.0 ns
97
t1121
TMS Hold Time
9.0 ns
97
t1132
TDO Valid Delay
3.0 ns
t1142
TDO Float Delay
t1152
All Outputs (Non-Test) Valid Delay
t1162
All Outputs (Non-Test) Float Delay
t1171
All Inputs (Non-Test) Setup Time
5.0 ns
97
t1181
All Inputs (Non-Test) Hold Time
9.0 ns
97
3.0 ns
13.0 ns
97
16.0 ns
97
13.0 ns
97
16.0 ns
97
Notes:
1. Parameter is measured from the TCK rising edge.
2. Parameter is measured from the TCK falling edge.
280
Signal Switching Characteristics
Chapter 15
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
15.10
Timing Diagrams
WAVEFORM
INPUTS
OUTPUTS
Must be steady
Steady
Can change from
High to Low
Changing from High to Low
Can change
from Low to High
Changing from Low to High
Don’t care, any
change permitted
Changing, State Unknown
(Does not apply)
Center line is high
impedance state
Figure 90. Key to Timing Diagrams
Tx
Tx
CLK
1.5 V
Max
tv
Output Signal
Min
Valid n
Valid n +1
Note: For symbols tv listed in Table 58 on page 270 and Table 60 on page 274, where:
v = 6, 8, 10, 12, 14, 15, 17, 18, 20, 22, 24, 26, 27, 28, 29, 30, 32, 34, 36, 37, 39, 41, 42
Figure 91. Output Valid Delay Timing
Chapter 15
Signal Switching Characteristics
281
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
1.5 V
CLK
Tx
Tx
Tx
Tx
tf
Output Signal
Valid
tv
Min
Note: For symbols tv and tf listed in Table 58 on page 270 and Table 60 on page 274, where:
v = 6, 8, 10, 12, 15, 18, 20, 22, 24, 30, 32, 34, 37, 39, 42
f = 7, 9, 11, 13, 16, 19, 21, 23, 25, 31, 33, 35, 38, 40, 43
Figure 92. Maximum Float Delay Timing
Tx
Tx
Tx
Tx
1.5 V
CLK
ts
th
Input Signal
Note: For symbols ts and th listed in Table 59 on page 272 and Table 61 on page 276, where:
s = 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88
h = 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 85, 87, 89
Figure 93. Input Setup and Hold Timing
282
Signal Switching Characteristics
Chapter 15
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Tx
Tx
CLK
1.5 V
•••
t90
RESET
1.5 V
t91
•••
1.5 V
t92, 93
t99
FLUSH#
(Synchronous)
•••
FLUSH#
(Asynchronous)
•••
t101
t100
t102
•••
BF[2:0]
(Asynchronous)
t94
t95
Figure 94. Reset and Configuration Timing
Chapter 15
Signal Switching Characteristics
283
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
t104
2.0 V
1.5 V
t105
0.8 V
t106
t107
t103
Figure 95. TCK Timing
t108
1.5 V
Figure 96. TRST# Timing
t103
TCK
1.5 V
t109, 111
t110, 112
TDI, TMS
t114
t113
TDO
Output
Signals
t116
t115
Input
Signals
t117
t118
Figure 97. Test Signal Timing
284
Signal Switching Characteristics
Chapter 15
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
16
Thermal Design
16.1
Package Thermal Specifications
The AMD-K6-2E processor operating specification calls for the
case temperature (TC) to be in the range of 0°C to 70°C (for the
standard-power 2.2-V component) or 0°C to 85°C (for the lowpower 1.9-V component). The ambient temperature (TA) is not
specified as long as the case temperature is not violated. The
case temperature must be measured on the top center of the
package. Table 66 and Table 67 show the package thermal
specifications for the AMD-K6-2E processor.
Table 66. Package Thermal Specification for OPN Suffix AMZ (Low-Power Devices)
qJC
Junction-Case
Maximum Thermal Power
233 MHz
266 MHz
300 MHz
333 MHz
350 MHz
1.0 °C/W
9.00 W
10.00 W
10.00 W
10.00 W
11.00 W
Stop Grant Mode
1.20 W
1.20 W
1.20 W
1.20 W
1.20 W
Stop Clock Mode
1.00 W
1.00 W
1.00 W
1.00 W
1.00 W
0°C–85°C
TC Case Temperature
Table 67. Package Thermal Specification for OPN Suffix AFR (Standard-Power Devices)
qJC
Junction-Case
Maximum Thermal Power
233 MHz
266 MHz
300 MHz
333 MHz
350 MHz
400 MHz
1.0 °C/W
13.50 W
14.70 W
17.20 W
19.00 W
19.95 W
16.90 W
Stop Grant Mode
2.46 W
2.48 W
2.50 W
3.94 W
3.96 W
4.40 W
Stop Clock Mode
2.25 W
2.25 W
2.25 W
3.50 W
3.50 W
4.00 W
0°C–70°C
TC Case Temperature
Chapter 16
Thermal Design
285
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Figure 98 shows the thermal model of a processor with a passive
thermal solution. The ambient temperature (TA) is guaranteed
as long as TC is not violated. The case-to-ambient temperature
(TCA) can be calculated from the following equation:
TCA
= PMAX • qCA
= PMAX • ( qIF + qSA)
Where:
PMAX
qCA
qIF
qSA
=
=
=
=
Maximum Power Consumption
Case-to-Ambient Thermal Resistance
Interface Material Thermal Resistance
Sink-to-Ambient Thermal Resistance
Thermal
Resistance
(°C/W)
Temperature
(Ambient)
TCA
qSA
qCA
Sink
Case
qIF
Figure 98. Thermal Model
Figure 99 illustrates the case-to-ambient temperature
(T CA=T C – TA) in relation to the power consumption (X-axis)
and the thermal resistance (Y-axis). If the power consumption
and case temperature are known, the thermal resistance (qCA)
requirement can be calculated for a given ambient temperature
(TA) value.
286
Thermal Design
Chapter 16
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
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Figure 99. Power Consumption v. Thermal Resistance
The thermal resistance of a heatsink is determined by the heat
dissipation surface area, the material and shape of the
heatsink, and the airflow volume across the heatsink. In
general, the larger the surface area the lower the thermal
resistance.
The required thermal resistance of a heatsink ( q SA ) can be
calculated using the following example:
If:
TC = 70°C
TA = 45°C
PMAX = 19.95 W at 350 MHz (Standard-power AMD-K6-2E/350AFR)
Then:
Ë T C – T AÛ
25•C = 1.25 ( •C ‰ W )
q CA ˆ Ì --------------------Ü = --------------------19.95W
Í P MAX Ý
Chapter 16
Thermal Design
287
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Thermal grease is recommended as interface material because
it provides the lowest thermal resistance (@ 0.20°C/W). The
required thermal resistance ( q SA ) of the heatsink in this
example is calculated as follows:
qSA = qCA – qIF = 1.25 – 0.20 = 1.05(°C/W)
Heat Dissipation Path
Figure 100 illustrates the heat dissipation path of the processor.
Due to the lower thermal resistance between the processor die
junction and case, most of the heat generated by the processor
is transferred from the top surface of the case. The small
amount of heat generated from the bottom side of the processor
where the processor socket blocks the convection can be safely
ignored.
Ambient Temperature
Thin Lid
Case temperature
Figure 100. Processor Heat Dissipation Path
16.2
Measuring Case Temperature
The processor case temperature is measured to ensure that the
t h e r m a l s o l u t i o n m e e t s t h e p ro c e s s o r ’s o p e ra t i o n a l
specification. This temperature should be measured on the top
center of the package, where most of the heat is dissipated.
Figure 101 on page 289 shows the correct location for measuring
the case temperature. The tip of the thermocouple should be
secured to the package surface with a small amount of
thermally conductive epoxy. A second location along the
thermocouple should also be secured to avoid any movement
during testing.
If a heatsink is installed while measuring, the thermocouple
must be installed into the heatsink via a small hole drilled
through the heatsink base (e.g., 1/16 of an inch). Secure the
thermocouple to the base of the heatsink by filling the small
hole with thermal epoxy, allowing the tip of the thermocouple
to protrude the epoxy and touch the top of the processor case.
288
Thermal Design
Chapter 16
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Thermally Conductive Epoxy
Thermocouple
Figure 101. Measuring Case Temperature
16.3
Sample Heatsink Measured Data
The example measured data (provided in tables 69 through 72
and figures 105 through 108) shows case-to-ambient thermal
resistance and maximum ambient temperature for both
socketed and soldered processors using three passive heatsink
samples with different height profiles (see Table 68) and
different levels of airflow in the system. This data is based on
the following specification assumptions:
TC = 85°C = TC(MAX) for 1.9-V low-power K6-2E processors
Pd = 10 W
qCA = qSA + qIF
TA(MAX) = TC(MAX) – (qCA ·Pd)
TA(MAX) = 85 - (qSA + qIF)·Pd
Note: AMD does not guarantee the example measured heatsink
data provided in tables 69 through 72 and figures 105
through 108. This data is supplied for informational
purposes only to facilitate the selection of an appropriate
thermal solution.
Example Heatsinks
Table 68 describes the three heatsinks tested. Figure 102,
Figure 103, and Figure 104 show the actual heatsinks.
Table 68. Passive Heatsink Samples
Chapter 16
Identifier
Size X (mm)
Size Y (mm)
Size Z Height (mm)
A
52
50
15
B
52
50
20
C
50
50
30
Thermal Design
289
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Figure 102. Heatsink A (15 mm height)
Figure 103. Heatsink B (20 mm height)
Figure 104. Heatsink C (30 mm height)
290
Thermal Design
Chapter 16
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Socketed Installation:
Case-to-Ambient
Thermal Resistance
Table 69 and Figure 105 show the measured values for the caseto-ambient thermal resistance ( q CA in ° C/watt) at different
levels of airflow in the system for the low-power embedded
AMD-K6-2E processors with a maximum thermal power
dissipation of 10.0 watts (OPNs: AMD-K6-2E/266AMZ,
AM D-K6 -2E/ 300 AMZ , and AMD - K6 -2 E/ 33 3A MZ) and a
maximum case temperature rating of 85 ° C, in the 321-pin
Ceramic Pin Grid Array package (CPGA) when installed into a
socket.
Table 69. Socketed CPGA Package: Measured Thermal Resistance (°C/W) qJC and qCA
qCA (°C/W) v. Airflow (m/s)
Heatsink Type
qJC (°C/W)
0.0 m/s
1.0 m/s
2.0 m/s
3.0 m/s
4.0 m/s
No Heatsink
1.0
9.1
7.5
6.1
4.7
4.0
A (15 mm)
1.0
6.5
4.3
3.1
2.6
2.3
B (20 mm)
1.0
5.7
3.8
2.7
2.3
2.0
C (30 mm)
1.0
4.7
2.8
1.8
1.5
1.3
10
9
8
q ca (°C/W)
7
None
A
B
C
6
5
4
3
2
1
0
0
1
2
3
4
Airflow Rate (m/s)
Figure 105. Measured Thermal Resistance v. Airflow (Socketed 321-Pin CPGA Package)
Chapter 16
Thermal Design
291
Preliminary Information
AMD-K6™-2E Processor Data Sheet
Socketed Installation:
Maximum Ambient
Temperature
22529B/0—January 2000
Table 70 and Figure 106 show the measured maximum ambient
temperature (TA) values in °C at different levels of airflow in
the system for the low-power embedded AMD-K6-2E processors
with a maximum thermal power dissipation of 10.0 watts (for
OPNs: AMD-K6-2E/266AMZ, AMD-K6-2E/300AMZ, and
AMD-K6-2E/333AMZ) and a maximum case temperature rating
of 85 °C, in the 321-pin Ceramic Pin Grid Array package (CPGA)
when installed into a socket.
Table 70. Socketed CPGA Package: Measured Maximum Ambient Temperature (°C)
Maximum TA (°C) v. Airflow (m/s)
Heatsink Type
0.0 m/s
1.0 m/s
2.0 m/s
3.0 m/s
4.0 m/s
No Heatsink
-10°C
6°C
21°C
36°C
43°C
A (15 mm)
20°C
42°C
54°C
59°C
62°C
B (20 mm)
28°C
47°C
58°C
62°C
65°C
C (30mm)
38°C
57°C
67°C
70°C
72°C
TC = 85°C, Pd = 10 W
80
Maximum Ambient
Temperature (°C)
70
60
50
1RQH
$
%
&
40
30
20
10
0
-10
-20
0
1
2
3
4
Airflow Rate (m/s)
Figure 106. Measured Maximum Ambient Temperature (Socketed 321-Pin CPGA Package)
292
Thermal Design
Chapter 16
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Soldered Installation:
Case-to-Ambient
Thermal Resistance
Table 71 and Figure 107 show the measured values for the caseto-ambient thermal resistance (q CA in ° C/watt) at different
levels of airflow in the system for the low-power embedded
AMD-K6-2E processors with a maximum thermal power
dissipation of 10.0 watts (OPNs: AMD-K6-2E/266AMZ,
AM D-K6 -2E/ 300 AMZ , and AMD - K6 -2 E/ 33 3A MZ) and a
maximum case temperature rating of 85 ° C, in the 321-pin
Ceramic Pin Grid Array package (CPGA) when soldered into a
printed circuit board.
.
Table 71. Soldered CPGA Package: Measured Thermal Resistance (°C/W) qJC and qCA
qCA (°C/W) v. Airflow (m/s)
qJC (°C/W)
Heatsink Type
0.0 m/s
1.0 m/s
2.0 m/s
3.0 m/s
4.0 m/s
No Heatsink
1.0
7.0
5.2
4.2
3.3
2.7
A (15 mm)
1.0
5.2
3.4
2.4
1.9
1.7
B (20 mm)
1.0
4.9
2.9
2.0
1.5
1.3
C (30 mm)
1.0
4.3
2.5
1.6
1.4
1.2
8
7
q ca (°C/W)
6
1RQH
$
%
&
5
4
3
2
1
0
0
1
2
3
4
Airflow Rate (m/s)
Figure 107. Measured Thermal Resistance v. Airflow (Soldered 321-Pin CPGA Package)
Chapter 16
Thermal Design
293
Preliminary Information
AMD-K6™-2E Processor Data Sheet
Soldered Installation:
Maximum Ambient
Temperature
22529B/0—January 2000
Table 72 and Figure 108 show the measured maximum ambient
temperature (TA) values in °C at different levels of airflow in
the system for the low-power embedded AMD-K6-2E processors
with a maximum thermal power dissipation of 10.0 watts (for
OPNs: AMD-K6-2E/266AMZ, AMD-K6-2E/300AMZ, and
AMD-K6-2E/333AMZ) and a maximum case temperature rating
of 85 °C, in the 321-pin Ceramic Pin Grid Array package (CPGA)
when soldered into a printed circuit board.
.
Table 72. Soldered CPGA Package: Measured Maximum Ambient Temperature (°C)
Maximum TA (°C) v. Airflow (m/s)
Heatsink Type
0.0 m/s
1.0 m/s
2.0 m/s
3.0 m/s
4.0 m/s
No Heatsink
14°C
31°C
42°C
53°C
58°C
A (15 mm)
33°C
51°C
61°C
66°C
68°C
B (20 mm)
36°C
56°C
65°C
70°C
72°C
C (30 mm)
42°C
60°C
69°C
71°C
73°C
TC = 85°C, Pd = 10 W
80
Maximum Ambient
Temperature (°C)
70
60
1RQH
$
%
&
50
40
30
20
10
0
0
1
2
3
4
Airflow Rate (m/s)
Figure 108. Measured Maximum Ambient Temperature (Soldered, 321-Pin CPGA Package)
294
Thermal Design
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Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
16.4
Layout and Airflow Considerations
Voltage Regulator
A voltage regulator is required to support the lower voltage
(3.3 V and lower) to the processor. In most applications, the
voltage regulator is designed with power transistors. As a
result, additional heatsinks are required to dissipate the heat
from the power transistors. Figure 109 shows the voltage
regulator placed parallel to the processor with the airflow
aligned with the devices. With this alignment, the heat
generated by the voltage regulator has minimal effect on the
processor.
Voltage Regulator
Processor
Airflow
Figure 109. Voltage Regulator Placement
A heatsink and fan combination can deliver much better
thermal performance than a heatsink alone. More importantly,
with a fan/sink, the airflow requirements in a system design are
not as critical. A unidirectional heatsink with a fan moves air
from the top of the heatsink to the side. In this case, the best
location for the voltage regulator is on the side of the processor
in the path of the airflow exiting the fan sink (see Figure 110 on
page 296). This location guarantees that the heatsinks on both
t he pro cess or a nd t he re gula to r rece ive ade quat e ai r
circulation.
Chapter 16
Thermal Design
295
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Airflow
Ideal areas for voltage regulator
Figure 110. Airflow for a Heatsink with Fan
Airflow Management
in a System Design
Complete airflow management in a system is important. In
addition to the volume of air, the path of the air is also
important. Figure 111 shows the airflow in a dual-fan system.
The fan in the front end pulls cool air into the system through
intake slots in the chassis. The power supply fan forces the hot
air out of the chassis. The thermal performance of the heatsink
can be maximized if it is located in the shaded area, where it
receives greatest benefit from this air exchange system.
Fan
P/S
Main Board
V
e
n
t
s
Drive Bays
Fan
Vents
Front
Figure 111. Airflow Path in a Dual-Fan System
296
Thermal Design
Chapter 16
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Figure 112 shows the airflow management in a system using the
ATX form-factor. The orientation of the power supply fan and
the motherboard are modified in the ATX platform design. The
power supply fan pulls cool air through the chassis and across
the processor. The processor is located near the power supply
fan, where it can receive adequate airflow without an auxiliary
fan. The arrangement significantly improves the airflow across
the processor with minimum installation cost.
Main Board
F
a
n
P/S
Drive Bays
Figure 112. Airflow Path in an ATX Form-Factor System
For more information about thermal design considerations, see
the AMD-K6 ® Processor Thermal Solution Design Application
Note, order #21085.
Chapter 16
Thermal Design
297
Preliminary Information
AMD-K6™-2E Processor Data Sheet
298
22529B/0—January 2000
Thermal Design
Chapter 16
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
17
Pin Designation Diagrams
Figure 113. AMD-K6™-2E Processor Connection Diagram (Top-Side View CPGA)
Chapter 17
Pin Designation Diagrams
299
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Figure 114. AMD-K6™-2E Processor Connection Diagram (Bottom-Side View CPGA)
300
Pin Designation Diagrams
Chapter 17
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
17.1
Pin Designations by Functional Grouping
Pin Name
Pin Number
Control
A20M#
ADS#
ADSC#
AHOLD
APCHK#
BE0#
BE1#
BE2#
BE3#
BE4#
BE5#
BE6#
BE7#
BF0
BF1
BF2
BOFF#
BRDY#
BRDYC#
BREQ
CACHE#
CLK
D/C#
EADS#
EWBE#
FERR#
FLUSH#
HIT#
HITM#
HLDA
HOLD
IGNNE#
INIT
INTR
INV
KEN#
LOCK#
M/IO#
NA#
NMI
PCD
PCHK#
PWT
RESET
SCYC
SMI#
SMIACT#
STPCLK#
VCC2DET
VCC2H/L#
W/R#
WB/WT#
Chapter 17
AK-08
AJ-05
AM-02
V-04
AE-05
AL-09
AK-10
AL-11
AK-12
AL-13
AK-14
AL-15
AK-16
Y-33
X-34
W-35
Z-04
X-04
Y-03
AJ-01
U-03
AK-18
AK-04
AM-04
W-03
Q-05
AN-07
AK-06
AL-05
AJ-03
AB-04
AA-35
AA-33
AD-34
U-05
W-05
AH-04
T-04
Y-05
AC-33
AG-05
AF-04
AL-03
AK-20
AL-17
AB-34
AG-03
V-34
AL-01
AN-05
AM-06
AA-05
Pin Name
Pin Number
Address
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12
A13
A14
A15
A16
A17
A18
A19
A20
A21
A22
A23
A24
A25
A26
A27
A28
A29
A30
A31
AL-35
AM-34
AK-32
AN-33
AL-33
AM-32
AK-30
AN-31
AL-31
AL-29
AK-28
AL-27
AK-26
AL-25
AK-24
AL-23
AK-22
AL-21
AF-34
AH-36
AE-33
AG-35
AJ-35
AH-34
AG-33
AK-36
AK-34
AM-36
AJ-33
Pin Name
Pin Number
Data
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
D10
D11
D12
D13
D14
D15
D16
D17
D18
D19
D20
D21
D22
D23
D24
D25
D26
D27
D28
D29
D30
D31
D32
D33
D34
D35
D36
D37
D38
D39
D40
D41
D42
D43
D44
D45
D46
D47
D48
D49
D50
D51
Pin Designation Diagrams
K-34
G-35
J-35
G-33
F-36
F-34
E-35
E-33
D-34
C-37
C-35
B-36
D-32
B-34
C-33
A-35
B-32
C-31
A-33
D-28
B-30
C-29
A-31
D-26
C-27
C-23
D-24
C-21
D-22
C-19
D-20
C-17
C-15
D-16
C-13
D-14
C-11
D-12
C-09
D-10
D-08
A-05
E-09
B-04
D-06
C-05
E-07
C-03
D-04
E-05
D-02
F-04
Pin Name
D52
D53
D54
D55
D56
D57
D58
D59
D60
D61
D62
D63
Pin Number
Data
E-03
G-05
E-01
G-03
H-04
J-03
J-05
K-04
L-05
L-03
M-04
N-03
Test
TCK
TDI
TDO
TMS
TRST#
M-34
N-35
N-33
P-34
Q-33
Parity
AP
DP0
DP1
DP2
DP3
DP4
DP5
DP6
DP7
AK-02
D-36
D-30
C-25
D-18
C-07
F-06
F-02
N-05
301
Preliminary Information
AMD-K6™-2E Processor Data Sheet
No Connect (NC)
VCC2
A-37
E-17
E-25
R-34
S-33
S-35
W-33
AJ-15
AJ-23
AL-19
AN-35
A-07
A-09
A-11
A-13
A-15
A-17
B-02
E-15
G-01
J-01
L-01
N-01
Q-01
S-01
U-01
W-01
Y-01
AA-01
AC-01
AE-01
AG-01
AJ-11
AN-09
AN-11
AN-13
AN-15
AN-17
AN-19
Internal No Connect (INC)
C-01
H-34
Y-35
Z-34
AC-35
AL-07
AN-01
AN-03
Reserved (RSVD)
J-33
L-35
P-04
Q-03
Q-35
R-04
S-03
S-05
AA-03
AC-03
AC-05
AD-04
AE-03
AE-35
Key
AH-32
302
22529B/0—January 2000
Pin Numbers
VCC3
A-19
A-21
A-23
A-25
A-27
A-29
E-21
E-27
E-37
G-37
J-37
L-33
L-37
N-37
Q-37
S-37
T-34
U-33
U-37
W-37
Y-37
AA-37
AC-37
AE-37
AG-37
AJ-19
AJ-29
AN-21
AN-23
AN-25
AN-27
AN-29
VSS
VSS
A-03
B-06
B-08
B-10
B-12
B-14
B-16
B-18
B-20
B-22
B-24
B-26
B-28
E-11
E-13
E-19
E-23
E-29
E-31
H-02
H-36
K-02
K-36
M-02
M-36
P-02
P-36
R-02
R-36
T-02
T-36
U-35
V-02
V-36
X-02
X-36
Z-02
Z-36
AB-02
AB-36
AD-02
AD-36
AF-02
AF-36
AH-02
AJ-07
AJ-09
AJ-13
AJ-17
AJ-21
AJ-25
AJ-27
AJ-31
AJ-37
AL-37
AM-08
AM-10
AM-12
AM-14
AM-16
AM-18
AM-20
AM-22
AM-24
AM-26
AM-28
AM-30
AN-37
Pin Designation Diagrams
Chapter 17
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
18
Package Specifications
18.1
321-Pin Staggered CPGA Package Specification
1.940
1.960
1.795
1.805
B
A
.100
.050
1.940
1.960
1.795
1.805
.064 MAX
.060
(45¡ Chamfer)
.090
Index Corner
C
.005
F
B
.120
.130
321 x
.030
.010
1.940
1.960
1.768
1.776
1.221
1.295
A
.017
.020
M
M
C A
C
M
B
M
1.221
1.295
1.768
1.776
1.940 1.768 1.221
1.960 1.776 1.295
.100
Lid
.050
.051
.060
.115
.143
.060
.090
Index Corner
(45¡ Chamfer)
SIDE VIEW OF CPGA
SIDE VIEW OF CGF PGA
ALL MEASUREMENTS ARE IN INCHES UNLESS OTHERWISE NOTED.
16-038-CP-5_AC
CGF321
EU160
4.27.99 lv
Figure 115. 321-Pin Staggered CPGA Package Specification
Chapter 18
Package Specifications
303
Preliminary Information
AMD-K6™-2E Processor Data Sheet
304
22529B/0—January 2000
Package Specifications
Chapter 18
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
19
Ordering Information
AMD standard- and low-power products are available in several operating ranges. The
ordering part number (OPN) is formed by a combination of the elements below. See
Table 73 on page 306 for valid ordering part number combinations.
AMD-K6-2E/ 400
A F R
Case Temperature
R = 0°C–70°C
Z = 0°C–85°C
Operating Voltage
F = 2.1 V–2.3 V (Core) / 3.135 V–3.6 V (I/O)
M = 1.8 V–2.0 V (Core) / 3.135 V–3.6 V (I/O)
Package Type
A = 321-pin Ceramic Pin Grid Array (CPGA)
Performance Rating
/400 = 400 MHz
/350 = 350 MHz
/333 = 333 MHz
/300 = 300 MHz
/266 = 266 MHz
/233 = 233 MHz
Family/Core
AMD-K6-2E Embedded Processor
Chapter 19
Ordering Information
305
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Table 73. Valid Ordering Part Number Combinations1
Device
Type
OPN
AMD-K6-2E/350AMZ
Low
Power
Package Type Operating Voltage
321-pin CPGA
1.8V–2.0V (Core)
Case
Temperature
Maximum CPU/Bus
Frequency
0°C–85°C
350 MHz/100 MHz
0°C–85°C
333 MHz/95 MHz2
0°C–85°C
300 MHz/100 MHz2
0°C–85°C
266 MHz/66 MHz
0°C–85°C
233 MHz/66 MHz
0°C–70°C
400 MHz/100 MHz2
0°C–70°C
350 MHz/100 MHz
0°C–70°C
333 MHz/95 MHz2
0°C–70°C
300 MHz/100 MHz2
0°C–70°C
266 MHz/66 MHz
0°C–70°C
233 MHz/66 MHz
3.135V–3.6V (I/O)
AMD-K6-2E/333AMZ
321-pin CPGA
1.8V–2.0V (Core)
3.135V–3.6V (I/O)
AMD-K6-2E/300AMZ
321-pin CPGA
1.8V–2.0V (Core)
3.135V–3.6V (I/O)
AMD-K6-2E/266AMZ
321-pin CPGA
1.8V–2.0V (Core)
3.135V–3.6V (I/O)
AMD-K6-2E/233AMZ
321-pin CPGA
1.8V–2.0V (Core)
3.135V–3.6V (I/O)
AMD-K6-2E/400AFR
Standard
Power
321-pin CPGA
2.1V–2.3V (Core)
3.135V–3.6V (I/O)
AMD-K6-2E/350AFR
321-pin CPGA
2.1V–2.3V (Core)
3.135V–3.6V (I/O)
AMD-K6-2E/333AFR
321-pin CPGA
2.1V–2.3V (Core)
3.135V–3.6V (I/O)
AMD-K6-2E/300AFR
321-pin CPGA
2.1V–2.3V (Core)
3.135V–3.6V (I/O)
AMD-K6-2E/266AFR
321-pin CPGA
2.1V–2.3V (Core)
3.135V–3.6V (I/O)
AMD-K6-2E/233AFR
321-pin CPGA
2.1V–2.3V (Core)
3.135V–3.6V (I/O)
Notes:
1. This table lists configurations planned to be supported in volume for this device. Consult the local AMD sales office to confirm
availability of specific valid combinations and to check on newly-released combinations.
2. Also supports 66-MHz bus operation.
306
Ordering Information
Chapter 19
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Index
Numerics
0.25-Micron Process Technology . . . . . . . . . . . . . . . . . . . . . . . 4
100-MHz Bus
clock switching characteristics . . . . . . . . . . . . . . . . . . . . 268
input setup and hold timings. . . . . . . . . . . . . . . . . . . . . . 272
output delay timings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270
321-Pin Staggered CPGA
package specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
3DNow!™ Technology. . . . . . . . . . . . . . . . . . . . . . . . . .3, 15–20
data types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
execution unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19–20
INIT state. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183
instruction compatibility, floating-point and . . . . . . . . . 216
instructions . . . . . . . . . . . . . . . . . . . . . . 13, 56, 81, 197, 216
PREFETCH instruction . . . . . . . . . . . . . . . . . . . . . . . . . . 197
registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
RESET state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118, 179
software prefetching. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
4-Kbyte Paging Mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . 49
4-Mbyte Paging Mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . 50
66-MHz Bus
clock switching characteristics . . . . . . . . . . . . . . . . . . . . 268
input setup and hold timings. . . . . . . . . . . . . . . . . . . . . . 276
output delay timings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274
A
A[31:3] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
A20M# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
masking cache accesses with . . . . . . . . . . . . . . . . . . . . . . 204
Absolute Ratings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255
Accelerated Graphic Port (AGP) . . . . . . . . . . . . . . . . . . . . . 4–5
Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
bus . . . . . . . . . . . . . . . . . . . .87–92, 101, 154, 158, 160, 199
generation sequence during bursts. . . . . . . . . . . . . . . . . 142
hold. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
parity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
parity check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
ADS# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
ADSC# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
AGP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4–5
AHOLD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
-initiated inquire hit to modified line. . . . . . . . . . . 158–159
-initiated inquire hit to shared or exclusive line . . 156 –157
-initiated inquire miss . . . . . . . . . . . . . . . . . . . . . . . 154–155
restriction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160–161
Airflow
consideration, layout and . . . . . . . . . . . . . . . . . . . . . . . . . 295
heatsink with fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296
management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296
path in a dual-fan system . . . . . . . . . . . . . . . . . . . . . . . . . 296
path in an ATX form-factor system . . . . . . . . . . . . . . . . . 297
Allocate, Write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
AMD-K6™-2E Processor
3DNow!™ technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
absolute ratings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255
block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
bus cycles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
cache organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
Index
clock control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247
configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
connection diagrams . . . . . . . . . . . . . . . . . . . . . . . . 299–300
DC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256
decode logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
electrical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253
features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
floating-point unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213
logic symbol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
low-power devices . . . . . . . . . . . . . . . . . . 255–256, 261, 306
microarchitecture overview . . . . . . . . . . . . . . . . . . . . . . . . 7
multimedia execution unit . . . . . . . . . . . . . . . . . . . . . . . 213
operating ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254
ordering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305
package specification . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
pin connection requirements . . . . . . . . . . . . . . . . . . . . . 264
pin designations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
power-on initialization. . . . . . . . . . . . . . . . . . . . . . . . . . . 179
process technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
scheduler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
signal descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
signal switching characteristics . . . . . . . . . . . . . . . . . . . 267
Socket 7 platform. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
software environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
standard-power devices . . . . . . . . . . . . . . 255–256, 260, 306
Super7 platform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
System Management Mode (SMM) . . . . . . . . . . . . . . . . 217
test and debug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
thermal design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285
write merge buffer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
AP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
APCHK# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Application Segment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Asserted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
B
Backoff . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
BE[7:0]# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
BF[2:0]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93, 179
BIST. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
BOFF# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94, 162–163
locked operation with . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
Boundary-Scan
bit definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233
register (BSR). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
test access port (TAP) . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
BR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
Branch
execution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
history table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
prediction . . . . . . . . . . . . . . . . . . . . . . . . . . . .1, 3, 11, 20–21
target cache . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
BRDY#. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
BRDYC# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
BREQ. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
BSR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
Built-In Self-Test (BIST) . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
307
Preliminary Information
AMD-K6™-2E Processor Data Sheet
Burst
pipelined burst reads . . . . . . . . . . . . . . . . . . . . . . . . 142–143
reads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142–143
ready. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
ready copy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
writeback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
writeback due to cache-line replacement. . . . . . . . . . . . 145
Bus
address . . . . . . . . . . . . . . . . .89–92, 101, 154, 158, 160, 199
arbitration cycles, inquire and . . . . . . . . . . . . . . . . . . . . 148
backoff (BOFF#) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
cycles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
order during misaligned I/O transfers . . . . . . . . . . . . 147
order during misaligned memory transfers . . . . . . . . 140
special . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
data. . . . 92, 95, 99–100, 116, 120, 136–138, 154, 160, 164
enables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
hold request. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
lock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
request . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
states
address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
data-NA# requested . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
idle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
pipeline address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
pipeline data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
state machine diagram . . . . . . . . . . . . . . . . . . . . . . . . . 135
transition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
BYPASS Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
Bypass Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
C
Cache . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
cacheable access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
coherency. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
writeback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
writethrough . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
disabling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
enable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
flushing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104, 190
inhibit, L1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
instruction prefetch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
L1 . . . . . . . . . . . . . . . . . . . 42, 185, 192, 196, 199, 204, 227
-line fills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
-line replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . 192, 201
masking cache accesses with A20M# . . . . . . . . . . . . . . . 204
MESI states in the data cache . . . . . . . . . . . . . . . . . . . . . 186
operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12, 185, 205
predecode bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
prefetching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
related signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
sector organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
snooping. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
states . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
write allocate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
write to cacheable page . . . . . . . . . . . . . . . . . . . . . . . . . . 193
writeback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8, 12, 204
writethrough . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
CACHE# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97, 189
308
22529B/0—January 2000
Capture-DR state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
Capture-IR state. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
Case Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285, 297
extended . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285
measuring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288–289
Centralized Scheduler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
CLK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97, 269
switching characteristics . . . . . . . . . . . . . . . . . . . . . . . . . 267
100-MHz bus operation . . . . . . . . . . . . . . . . . . . . . . . . 268
66-MHz bus operation . . . . . . . . . . . . . . . . . . . . . . . . . 268
Clock Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97, 247
states . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247
diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248
halt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249
stop clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173, 252
stop grant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173, 250
stop grant inquire . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
transitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248
switching characteristics
100-MHz bus operation . . . . . . . . . . . . . . . . . . . . . . . . 268
66-MHz bus operation . . . . . . . . . . . . . . . . . . . . . . . . . 268
Coherency
cache . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
writeback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
writethrough. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
Component Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263
Configuration
power-on initialization. . . . . . . . . . . . . . . . . . . . . . . . . . . 179
Control Register 0 (CR0) . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Control Register 1 (CR1) . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Control Register 2 (CR2) . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Control Register 3 (CR3) . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Control Register 4 (CR4) . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Counter, Time Stamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Customer Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Cycles
bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
hold and hold acknowledge . . . . . . . . . . . . . . . . . . . . . . 148
inquire. . . . 86–91, 101, 105–106, 122, 129, 144, 152, 154,
. . . 156–158, 160, 162, 166, 199, 202–204, 239, 247,
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249–251
inquire and bus arbitration. . . . . . . . . . . . . . . . . . . . . . . 148
interrupt acknowledge . . . . . 87, 90, 92, 98, 114, 128, 132
locked . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164
pipelined. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13, 88
pipelined write. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
shutdown. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
special . . . . . . . . . . . . . . . . . . . . . . . .132, 170, 223, 249–250
writeback . . 86, 88–89, 102, 105, 129, 144, 152, 156, 158,
. . . . . . . . . . . . 160, 162, 166, 188–189, 240, 248, 251
D
D/C#. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
D[63:0]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
bus . . . . 92, 95, 99–100, 116, 120, 136–138, 154, 160, 164
cache, MESI states in the . . . . . . . . . . . . . . . . . . . . . . . . 186
parity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Data Types
3DNow!™ technology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
floating-point register . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
integer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
MMX technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Index
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
Data/Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Data-NA# Requested . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
DC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256
Debug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240
exceptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
in System Management Mode (SMM). . . . . . . . . . . . . . . 226
registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37, 241
DR3, DR2, DR1, and DR0 . . . . . . . . . . . . . . . . . . . 39, 243
DR3–DR0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
DR5 and DR4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38, 242
DR5–DR4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
DR6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38, 242, 244
DR7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37, 241, 244
Decoders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1, 9
Decoupling Recommendations . . . . . . . . . . . . . . . . . . . . . . 263
Derating, Power. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260
Descriptors and Gates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Device Identification Register (DIR) . . . . . . . . . . . . . . . . . 234
Diagrams
key . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281
timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
waveform definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
DIR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
Disabling
cache . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
DP[7:0] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
DR3–DR0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
DR5–DR4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
DR6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
DR7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
LEN and RW definitions . . . . . . . . . . . . . . . . . . . . . . . . . 245
Driven. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Dual Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262
E
EADS# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
EAX Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
EFER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40, 43, 182, 206
EFLAGS Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Electrical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253
absolute ratings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255
DC characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256
I/O buffer characteristics . . . . . . . . . . . . . . . . . . . . . . . . . 264
operating ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254
power and grounding . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262
power derating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260
power dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258
Embedded Processor Features . . . . . . . . . . . . . . . . . . . . . . 1–2
EMMS Instruction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
EWBE# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102, 205
EWBE# Control (EWBEC) . . . . . . . . . . . . . . . . . . . . . . 205, 207
Exception. . . . . . . . 90–91, 100, 103, 116, 216, 226, 244–246
debug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225, 245
flags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28–29
floating-point. . . . . . . . . . . . . . . . . . 103, 108, 213–214, 216
handler. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240
machine-check. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
MMX technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216
shutdown cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
System Management Mode (SMM) . . . . . . . . . . . . . . . . . 226
Execution Latency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Index
Execution Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1, 18
3DNow!™ technology. . . . . . . . . . . . . . . . . . . . . . . . . . 19–20
floating-point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213
multimedia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19–20, 215
register X . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19–20
register Y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19–20
Extended Feature Enable Register (EFER) . 40 , 43, 182, 206
External
address strobe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
write buffer empty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
EXTEST Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
F
FEMMS Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
FERR#. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103, 214, 216
Float Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
Float Delay Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282
Floated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Floating-Point
and MMX/3DNow!™ instruction compatibility . . . . . . 216
and multimedia execution units. . . . . . . . . . . . . . . . . . . 213
error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
execution unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213
handling exceptions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213
instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
register data types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
FLUSH# . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104, 179, 200, 228
FPU
control word register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
status word register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
tag word register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268, 280
multiplier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
operating. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93, 97, 179
G
Gate Descriptor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52, 55
General-Purpose Registers . . . . . . . . . . . . . . . . . . . . . . . . . . 24
data types in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
doubleword, word, and byte names . . . . . . . . . . . . . . . . . 25
Global EWBE# Disable (GEWBED) . . . . . . . . . . . . . . . . . . 206
H
Halt
restart slot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
state. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hardware Prefetching . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Heat Dissipation Path . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Heatsink
examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
sample measured data. . . . . . . . . . . . . . . . . . . . . . . . . . .
thermal resistance calculation . . . . . . . . . . . . . . . . . . . .
HIGHZ Instruction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hit to
modified line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
modified line, AHOLD-initiated inquire . . . . . . . . . . . .
modified line, HOLD-initiated inquire . . . . . . . . . . . . .
shared or exclusive line, AHOLD-initiated inquire . . .
shared or exclusive line, HOLD-initiated inquire . . . .
HIT# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
HITM# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
222
249
197
288
289
289
287
236
105
158
152
156
150
105
105
309
Preliminary Information
AMD-K6™-2E Processor Data Sheet
HLDA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
HOLD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
-initiated inquire hit to modified line. . . . . . . . . . . . . . . 152
-initiated inquire hit to shared or exclusive line . . . . . . 150
Hold
acknowledge . . . . . . . . . . . . . . . . . . . . . . . . . . .106, 148–150
timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267, 282
I
I/O
buffer
AC and DC characteristics. . . . . . . . . . . . . . . . . . . . . . 265
characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264
model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264
misaligned read and write . . . . . . . . . . . . . . . . . . . . . . . . 147
read and write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
trap doubleword . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223–224
trap restart slot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224
I/O Buffer Information Specification (IBIS). . . . . . . . . . . . 264
IBIS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264
IDCODE Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
Idle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
IEEE 1149.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
IEEE 754 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27, 213
IEEE 854 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213
IGNNE# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108, 214, 216
Ignore Numeric Exception . . . . . . . . . . . . . . . . . . . . . . . . . . 108
INIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
-initiated transition from protected mode to real mode 176
state of processor after. . . . . . . . . . . . . . . . . . . . . . . . . . . 183
Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
output signal state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
power-on configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . 179
processor state after INIT . . . . . . . . . . . . . . . . . . . . . . . . 183
processor state after RESET . . . . . . . . . . . . . . . . . . . . . . 180
register state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
RESET requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
signals sampled during RESET . . . . . . . . . . . . . . . . . . . . 179
Input
pin types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
setup and hold timing. . . . . . . . . . . . . . . . . . . . . . . . . . . . 282
setup and hold timings for 100-MHz bus operation. . . . 272
setup and hold timings for 66-MHz bus operation. . . . . 276
Inquire
and bus arbitration cycles . . . . . . . . . . . . . . . . . . . . . . . . 148
cycle hit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
cycle hit to modified line . . . . . . . . . . . . . . . . . . . . . . . . . 105
cycles 86–91, 101, 105–106, 122, 129, 144, 148, 151–158,
. . . . 160, 162, 166, 199, 202–204, 239, 247, 249–251
miss, AHOLD-initiated . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
Instruction
buffer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
decode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
fetch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
pointer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Instructions
3DNow!™ technology . . . . . . . . . . . . . . . . . . . . . . . . . 81, 215
compatibility of floating-point, MMX technology, and
3DNow!™ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216
EMMS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
FEMMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
floating-point. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
integer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
INVD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
MMX technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78, 215
310
22529B/0—January 2000
PREFETCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16, 197
RSM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
supported by the AMD-K6™-2E processor . . . . . . . . . . . 56
test access port (TAP) . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
WBINVD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
Integer
data registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
data types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
01h . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246
03h . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246
10h . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213
acknowledge . . . . . . . . . . . . . . . . . . . 95, 110, 112, 116, 164
acknowledge cycle definition . . . . . . . . . . . . . . . . . . . . . 168
acknowledge cycles . . . . . . . . 87, 90, 92, 98, 114, 128, 132
clock grant state. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
descriptor table register . . . . . . . . . . . . . . . . . . . . . . . . . . 47
flag. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34, 110, 121
floating-point exceptions . . . . . . . . . . . . . . . . . . . . 213–214
gate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
INIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
INTR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
IRQ13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
MMX instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216
NMI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114, 183
redirection bitmap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
request . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
service routine . . . . . . . . . . . . . . . . . . . . . 110, 114, 214, 217
shutdown cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
STPCLK# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
system management . . . . . . . . . . . . . . . . . . . . 121, 217, 219
System Management Mode (SMM) . . . . . . . . . . . . . . . . 226
type of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
INTR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
INV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
Invalidation Request . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
INVD Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
K
KEN# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111, 192
L
L1 Cache . . . . . . . . . . . . . . . . . . . . 42, 185, 196, 199, 204, 227
inhibit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
Layout and Airflow Considerations . . . . . . . . . . . . . . . . . . 295
Literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
LOCK#. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
Locked
cycles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164
operation with BOFF# intervention . . . . . . . . . . . . 166–167
operation, basic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164
Logic
branch-prediction. . . . . . . . . . . . . . . . . . . . . . . . 3, 11, 20–21
external support of floating-point exceptions . . . . . . . 213
symbol diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Low-Power Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
valid ordering part numbers . . . . . . . . . . . . . . . . . . . . . . 306
Index
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
M
M/IO# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
Machine-Check Address Register (MCAR) . . . . . .40–41, 182
Machine-Check Exception . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Machine-Check Type Register (MCTR) . . . . . . . . .40–41, 182
Maskable Interrupt. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
MCAR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40–41, 182
MCTR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40–41, 182
Memory
management registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
or I/O . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
read and write, misaligned single-transfer . . . . . . . . . . 140
read and write, single-transfer . . . . . . . . . . . . . . . . . . . . 138
reads and writes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
type range registers (MTRR) . . . . . . . . . . . . . . . . . . . 45, 207
MESI. . . . . . . . . . . . . . . . . . . . . . . . . 1, 148, 152, 198, 202, 204
bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12, 186, 188
states in the data cache . . . . . . . . . . . . . . . . . . . . . . . . . . 186
Microarchitecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1, 7
branch prediction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
cache . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
centralized scheduler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
decoders. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
enhanced RISC86 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
execution units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
instruction fetching and decode . . . . . . . . . . . . . . . . . . . . 13
instruction prefetch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
predecode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Misaligned
I/O read and write. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
I/O transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
single-transfer memory read and write . . . . . . . . . 140–141
MMX Technology . . . . . . . . . . . . . . . . . . . . . 15–16, 18–20, 23
3DNow!™ registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
data types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
exceptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216
INIT state. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183
instruction compatibility, floating-point and . . . . . . . . . 216
instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56, 78, 216
registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
RESET state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118, 179
Model-Specific Registers (MSR) . . . . . . . . . . . . . . . . . . . . . . 40
MSR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
MTRR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45, 207
Multimedia
and 3DNow!™ execution units . . . . . . . . . . . . . . . . . . . . 215
execution unit . . . . . . . . . . . . . . . . . . . . . . . . . . . .19–20, 215
functional unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
N
NA#. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
Negated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Next Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
NMI. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
No-Connect Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Non-Maskable Interrupt. . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
Non-Pipelined Single-Transfer Memory Read/Write and
Write Delayed by EWBE# . . . . . . . . . . . . . . . . . . . . 139
O
Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ordering Part Number (OPN). . . . . . . . . . . . . . . . . . . . . . .
Output
delay timings for 100-MHz bus operation . . . . . . . . . . .
delay timings for 66-MHz bus operation . . . . . . . . . . . .
pin float conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
signal state after RESET. . . . . . . . . . . . . . . . . . . . . . . . .
signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
valid delay timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
305
305
270
274
131
180
180
281
P
Package
321-pin staggered CPGA . . . . . . . . . . . . . . . . . . . . . . . . . 303
Socket 7 platform. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
Super7™ platform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
thermal specification. . . . . . . . . . . . . . . . . . . . . . . . . . . . 285
Packed Decimal Data Register . . . . . . . . . . . . . . . . . . . . . . . 30
Page
cache disable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
directory entry (PDE) . . . . . . . . . . . . . . . . . . . . . 50–51, 188
flush/invalidate register (PFIR) . . . . .40, 46, 182, 200–201
table entry (PTE) . . . . . . . . . . . . . . . . . . . . . . . . . 50, 52, 188
writethrough. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Paging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Parity. . . . . . . . . . . . . . . . . . . . . . . . . 83, 90, 92, 100, 116, 138
bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90, 100, 116
check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90–91, 100, 116
error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91, 116, 154, 231
flags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Part Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305
PCD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115, 188–189, 196
PCHK# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
PFIR . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40, 46, 182, 200–201
Pins
connection requirements . . . . . . . . . . . . . . . . . . . . . . . . 264
designation diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . 299
designations by functional grouping . . . . . . . . . . . . . . . 301
float conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Pipeline. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136–137, 142
address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8, 10, 12, 19, 21
data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
register X and Y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Pipelined. . . . . . . . . . . . . . . . 19, 114, 137, 142–143, 160, 185
burst reads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
cycles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13, 88, 99
design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Pointer, Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Power
and grounding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262
connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262
consumption and thermal resistance . . . . . . . . . . . . . . . 287
derating based on lower CPU frequencies . . . . . . . . . . 260
dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258
low-power devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261
standard-power devices . . . . . . . . . . . . . . . . . . . . . . . 260
Power-on Configuration and Initialization . . . . . . . . . . . . 179
Precision Real Data Registers . . . . . . . . . . . . . . . . . . . . . . . 30
Predecode Bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13, 187
PREFETCH Instruction . . . . . . . . . . . . . . . . . . . . . . . . 16, 197
Operating Ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254
OPN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305
Index
311
Preliminary Information
AMD-K6™-2E Processor Data Sheet
Prefetching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
PREFETCH instruction . . . . . . . . . . . . . . . . . . . . . . . 16, 197
software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
Processor
heat dissipation path . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288
state observability register (PSOR) . . . . . . . . . 40, 45, 182
PSOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40, 45, 182
PWT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117, 188
R
Read and Write
basic I/O . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
misaligned I/O . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
Reads, Burst Reads and Pipelined Burst . . . . . . . . . . . . . . 142
Register X and Y
functional units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
pipelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10, 23, 44, 216
3DNow!™ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23, 31
boundary-scan (BSR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
bypass (BR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
control 0 (CR0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
control 1 (CR1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
control 2 (CR2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
control 3 (CR3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
control 4 (CR4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
data types, floating-point . . . . . . . . . . . . . . . . . . . . . . . . . . 30
debug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37, 241
descriptors and gates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
device identification (DIR) . . . . . . . . . . . . . . . . . . . . . . . 234
DR3–DR0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
DR5–DR4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
DR6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
DR7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
EAX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
EFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
extended feature enable (EFER) . . . . . . . . . . . . . . . . . . . 43
floating-point. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
general-purpose. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
IR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
machine-check address (MCAR) . . . . . . . . . . . . . . . . . . . . 41
machine-check type (MCTR) . . . . . . . . . . . . . . . . . . . . . . . 41
memory management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
memory type range (MTRR) . . . . . . . . . . . . . . . . . . . . . . . 45
MMX technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23, 31
model-specific (MSR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
packed decimal data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
PFIR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
precision real data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
PSOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
reset state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
segment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
SYSCALL/SYSRET target address (STAR) . . . . . . . . . . . 44
System Management Mode (SMM) initial state . . . . . . 219
test (TR12). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
test access port (TAP). . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
TR12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
UC/WC cacheability control (UWCCR) . . . . . . . . . . . . . . 45
write handling control (WHCR) . . . . . . . . . . . . . . . . . . . . 44
X and Y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18–19
Regulator, Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295
Reserved . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
312
22529B/0—January 2000
RESET. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118, 180
and configuration signals for 100-MHz bus operation . 278
and configuration signals for 66-MHz bus operation . . 279
and test signal timing . . . . . . . . . . . . . . . . . . . . . . . . . . . 278
requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
signals sampled during . . . . . . . . . . . . . . . . . . . . . . . . . . 179
state of processor after . . . . . . . . . . . . . . . . . . . . . . . . . . 180
Reset and Configuration Timing . . . . . . . . . . . . . . . . . . . . 283
Return Address Stack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
RISC86® Microarchitecture . . . . . . . . . . . . . . . . . . . . . . . . . . 8
RSM Instruction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222, 225
RSVD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
S
SAMPLE/PRELOAD Instruction . . . . . . . . . . . . . . . . . . . . 236
Sampled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Scheduler/Instruction Control Unit . . . . . . . . . . . . . . . . 10, 17
SCYC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Sector, Write to a . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193, 197
Segment
descriptor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26, 52–54
registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
task state. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Shift-DR state. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
Shift-IR state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
Shutdown Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
Signals
A[31:3]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
A20M# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86, 218
ADS# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
ADSC#. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
AHOLD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89, 249
AP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
APCHK# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
BE[7:0]# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
BF[2:0]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93, 252
BOFF# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94, 162, 249
BRDY#. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95, 224, 249–250
BRDYC# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
BREQ. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
CACHE# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97, 189
cache-related . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
CLK . . . . . . . . . . . . . . . . . . . . . . 97, 247, 250, 252, 267–268
D/C#. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
D[63:0]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
DP[7:0] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
EADS#. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101, 251
EWBE# . . . . . . . . . . . . . . . . . . . . . . . . . . . 102, 205, 249–250
FERR#. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103, 216
FLUSH# . . . . . . . . . 104, 132, 179, 200, 226, 228, 249–251
HIT# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105, 251
HITM# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105, 251
HLDA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
HOLD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107, 249
IGNNE#. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108, 216
INIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109, 218, 249–250
INTR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110, 249–250
INV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
KEN# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
LOCK#. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
Index
Preliminary Information
AMD-K6™-2E Processor Data Sheet
22529B/0—January 2000
logic symbol. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
M/IO# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
NA#. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
NMI. . . . . . . . . . . . . . . . . . . . . . . . . . 114, 218, 226, 249–250
output. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
PCD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
PCHK# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
pin connection requirements. . . . . . . . . . . . . . . . . . . . . . 264
pin designations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
PWT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
RESET . . . . . . . . . . . . . . . . . . . . . . . 118, 249–250, 252, 267
reset state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
RSVD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
sampled during RESET . . . . . . . . . . . . . . . . . . . . . . . . . . 179
SCYC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
SMI# . . . . . . . . . . . . . . . . . . . . . . . . . 121, 217, 224, 249–250
SMIACT# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122, 217
STPCLK# . . . . . . . . . . . . . . . . . . . . . . . . . 123, 247, 250–251
switching characteristics . . . . . . . . . . . . . . . . . . . . . . . . . 267
TCK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124, 267
TDI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
TDO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
test access port (TAP). . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
TMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
TRST# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
VCC2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262
VCC2DET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
VCC2H/L# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
VCC3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262
W/R#. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
WB/WT# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
SIMD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Single Instruction Multiple Data (SIMD) Operations . . . . . 11
Single-Transfer Memory Read and Write. . . . . . . . . . . . . . 138
SMI# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
SMIACT# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
Snoop . . . . . . . . . . . . . . . . . . . . . . 122, 129, 144, 200, 202–203
cache . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
internal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
Software Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
application segment types . . . . . . . . . . . . . . . . . . . . . . . . . 53
descriptors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
exceptions (summary) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
gates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
instructions supported . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
interrupts (summary) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
model-specific registers (MSR) . . . . . . . . . . . . . . . . . . . . . 41
paging. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Software Prefetching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
Special Bus Cycles . . . 95, 102, 104, 123, 170–173, 190, 223,
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249–250
definition (table). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
encodings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
summary (table) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
Speculative EWBE# Disable (SEWBED) . . . . . . . . . . . . . . 206
Split Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Standard-Power Devices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
valid ordering part numbers . . . . . . . . . . . . . . . . . . . . . . 306
State
cache . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
machine diagram, bus. . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
processor
after INIT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183
after RESET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
Index
Stop
clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
clock state. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173, 252
grant inquire state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
grant state. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173, 250
STPCLK# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
Super7™ Platform
enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
initiative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Switching Characteristics
CLK switching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
diagram key . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281
float delay timing diagram . . . . . . . . . . . . . . . . . . . . . . . 282
input setup and hold timing diagram . . . . . . . . . . . . . . 282
input setup and hold timings for 100-MHz bus . . . . . . . 272
input setup and hold timings for 66-MHz bus . . . . . . . . 276
output delay timings for 100-MHz bus. . . . . . . . . . . . . . 270
output delay timings for 66-MHz bus. . . . . . . . . . . . . . . 274
output valid delay timing diagram. . . . . . . . . . . . . . . . . 281
RESET and configuration signals for 100-MHz bus . . . 278
RESET and configuration signals for 66-MHz bus . . . . 279
RESET and configuration timing diagram . . . . . . . . . . 283
TCK timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284
test signal timing . . . . . . . . . . . . . . . . . . . . . . . . . . . 280, 284
TRST# timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284
valid delay, float, setup, and hold timings. . . . . . . . . . . 269
SYSCALL Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . 44, 73
SYSCALL/SYSRET Target Address Register (STAR) .40, 44,
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
SYSRET Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44, 73
System
design
airflow management . . . . . . . . . . . . . . . . . . . . . . . . . . 296
component placement . . . . . . . . . . . . . . . . . . . . . . . . . 263
decoupling recommendations. . . . . . . . . . . . . . . . . . . 263
I/O buffer characteristics . . . . . . . . . . . . . . . . . . . . . . 264
pin connection requirements . . . . . . . . . . . . . . . . . . . 264
power connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262
thermal considerations . . . . . . . . . . . . . . . . . . . . . . . . 285
segment and gate types. . . . . . . . . . . . . . . . . . . . . . . . . . . 54
segment descriptor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
System Management Mode (SMM)
base address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
debugging in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
default register values. . . . . . . . . . . . . . . . . . . . . . . . . . . 217
exceptions in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
halt restart slot. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
I/O trap doubleword. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224
I/O trap restart slot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224
initial register state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219
interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
interrupt active . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
interrupts in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218
operating mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217
revision identifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221
state-save area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219
T
TAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
Task State Segment (TSS). . . . . . . . . . . . . . . . . . . . . . . . . . . 48
TCK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124, 280, 284
TDI. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
TDO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
Technical Publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
313
Preliminary Information
AMD-K6™-2E Processor Data Sheet
Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254
ambient . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285
case. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285, 288
case-to-ambient . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286
extended rating for low-power devices . . . . . . . . . . . . . . 285
Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
boundary-scan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
built-in self-test (BIST). . . . . . . . . . . . . . . . . . . . . . . . . . . 227
clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
data input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
data output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
debug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240
L1 cache inhibit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
-logic-reset state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
mode select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
register 12 (TR12). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
switching characteristics of signals. . . . . . . . . . . . . . . . . 280
test access port (TAP). . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
three-state test mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228
Test Access Port (TAP)
instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
BYPASS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
EXTEST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
HIGHZ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
IDCODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
SAMPLE/PRELOAD. . . . . . . . . . . . . . . . . . . . . . . . . . . 236
registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
boundary-scan (BSR) . . . . . . . . . . . . . . . . . . . . . . . . . . 231
bypass (BR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
device identification (DIR) . . . . . . . . . . . . . . . . . . . . . 234
instruction register (IR) . . . . . . . . . . . . . . . . . . . . . . . . 231
signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
states
capture-DR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
capture-IR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
shift-DR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
shift-IR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
state machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236–237
test-logic-reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
update-DR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
update-IR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
Test Signal
timing at 25 MHz. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280
timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284
Thermal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .286, 295–296
design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285
extended temperature rating. . . . . . . . . . . . . . . . . . . . . . 285
heat dissipation path . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288
heatsink sample data . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289
layout and airflow consideration. . . . . . . . . . . . . . . . . . . 295
measuring case temperature . . . . . . . . . . . . . . . . . . . . . . 288
model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286
Third-Party Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
Three-State Test Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228
Time Stamp Counter (TSC) . . . . . . . . . . . . . . . . . . . . . . 42, 250
Timing Diagrams. . . . . . . . . . . . . . . . . . . . . . . . . .133, 139–177
waveform definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
TLB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
TMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
TR12 . . . . . . . . . . . . . . . . . . . . . . . . . 40, 42, 182, 188, 195, 239
Transition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
from protected mode to real mode . . . . . . . . . . . . . . . . . 176
Translation Lookaside Buffer (TLB) . . . . . . . . . . . . . . . . . . 185
314
22529B/0—January 2000
TRST# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125, 280, 284
TSC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40, 42, 182, 249–250
TSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48, 54–55, 244
Typical and Maximum Power Dissipation . . . . . . . . . 258–259
low-power devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261
standard-power devices . . . . . . . . . . . . . . . . . . . . . . . . . . 260
U
UC/WC Cacheability Control Register (UWCCR)40, 45, 180,
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182, 191, 208
Uncacheable Memory . . . . . . . . . . . . . . . . . . . . . . 45, 206–207
UWCCR. . . . . . . . . . . . . . . . . . . . . . 40, 45, 180, 182, 191, 208
V
Valid
delay, float, setup, and hold timings . . . . . . . . . . . . . . .
masks and range sizes . . . . . . . . . . . . . . . . . . . . . . . . . .
ordering part number combinations . . . . . . . . . . . . . . .
VCC2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VCC2DET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VCC2H/L#. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VCC3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Voltage . . . . . . . . . . . . . . . . . . . . 126–127, 134, 254, 256,
dual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
269
210
306
262
126
127
262
264
262
265
295
W
W/R# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
Waveform Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
WB/WT# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
WBINVD Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
WC/UC Memory Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209
WCDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
WHCR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40, 44, 182, 196
Write
handling control register (WHCR). . . . . . . 40, 44, 182, 196
to a cacheable page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
to a sector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193, 197
Write Allocate . . . . . . . . . . . . . . . . . . . . . . . 187, 192–193, 196
enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
enable limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
logic mechanisms and conditions . . . . . . . . . . . . . . . . . . 196
Write Merge Buffer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
EWBE# Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
memory type range registers (MTRR) . . . . . . . . . . . . . . 207
Write/Read . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
Writeback . . . 97, 99–100, 111, 117, 122, 129, 132, 144–145,
. . . . . . . . . . . . . . . . . . . . . . . . 170, 185, 191, 198, 204
burst . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
cache . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8, 12
cycles . 86, 88–89, 102, 105, 129, 144, 152, 156, 158, 160,
. . . . . . . . . . . . . . . . 162, 166, 188–189, 240, 248, 251
or writethrough . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
Write-Combining Memory. . . . . . . . . . . . . . . . . . . 45, 206–207
Writethrough and Writeback Coherency States . . . . . . . . 204
Index