Atmel AVR 8-bit Instruction Set

Atmel AVR 8-bit Instruction Set
Instruction Set Manual
Instruction Set Nomenclature
Status Register (SREG)
SREG: Status Register
C:
Carry Flag
Z:
Zero Flag
N:
Negative Flag
V:
Two’s complement overflow indicator
S:
N  V, For signed tests
H:
Half Carry Flag
T:
Transfer bit used by BLD and BST instructions
I:
Global Interrupt Enable/Disable Flag
Registers and Operands
Rd:
Destination (and source) register in the Register File
Rr:
Source register in the Register File
R:
Result after instruction is executed
K:
Constant data
k:
Constant address
b:
Bit in the Register File or I/O Register (3-bit)
s:
Bit in the Status Register (3-bit)
X,Y,Z:
Indirect Address Register
(X=R27:R26, Y=R29:R28 and Z=R31:R30)
A:
I/O location address
q:
Displacement for direct addressing (6-bit)
Rev. 0856J–AVR–07/2014
Instruction Set Manual_AVR_07/2014
1.
I/O Registers
1.1
RAMPX, RAMPY, RAMPZ
Registers concatenated with the X-, Y-, and Z-registers enabling indirect addressing of the whole data space on
MCUs with more than 64KB data space, and constant data fetch on MCUs with more than 64KB program
space.
1.2
RAMPD
Register concatenated with the Z-register enabling direct addressing of the whole data space on MCUs with
more than 64KB data space.
1.3
EIND
Register concatenated with the Z-register enabling indirect jump and call to the whole program space on MCUs
with more than 64K words (128KB) program space.
1.4
1.5
2
Stack
STACK:
Stack for return address and pushed registers
SP:
Stack Pointer to STACK
Flags
:
Flag affected by instruction
0:
Flag cleared by instruction
1:
Flag set by instruction
-:
Flag not affected by instruction
Instruction Set Manual
0856J-AVR-07/2014
2.
The Program and Data Addressing Modes
The AVR® Enhanced RISC microcontroller supports powerful and efficient addressing modes for access to the
Program memory (Flash) and Data memory (SRAM, Register file, I/O Memory, and Extended I/O Memory). This
section describes the various addressing modes supported by the AVR architecture. In the following figures, OP
means the operation code part of the instruction word. To simplify, not all figures show the exact location of the
addressing bits. To generalize, the abstract terms RAMEND and FLASHEND have been used to represent the
highest location in data and program space, respectively.
Note:
2.1
Not all addressing modes are present in all devices. Refer to the device specific instruction summary.
Register Direct, Single Register Rd
Figure 2-1.
Direct Single Register Addressing
The operand is contained in register d (Rd).
2.2
Register Direct, Two Registers Rd and Rr
Figure 2-2.
Direct Register Addressing, Two Registers
Operands are contained in register r (Rr) and d (Rd). The result is stored in register d (Rd).
Instruction Set Manual
0856J-AVR-07/2014
3
2.3
I/O Direct
Figure 2-3.
I/O Direct Addressing
Operand address is contained in six bits of the instruction word. n is the destination or source register address.
Note:
2.4
Some complex AVR Microcontrollers have more peripheral units than can be supported within the 64 locations
reserved in the opcode for I/O direct addressing. The extended I/O memory from address 64 to 255 can only be
reached by data addressing, not I/O addressing.
Data Direct
Figure 2-4.
Direct Data Addressing
Data Space
20 19
31
OP
16
0x0000
Rr/Rd
Data Address
15
0
RAMEND
A 16-bit Data Address is contained in the 16 LSBs of a two-word instruction. Rd/Rr specify the destination or
source register.
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0856J-AVR-07/2014
2.5
Data Indirect with Displacement
Figure 2-5.
Data Indirect with Displacement
Data Space
0x0000
15
0
Y OR Z - REGISTER
15
10
OP
6 5
Rr/Rd
0
q
RAMEND
Operand address is the result of the Y- or Z-register contents added to the address contained in six bits of the
instruction word. Rd/Rr specify the destination or source register.
2.6
Data Indirect
Figure 2-6.
Data Indirect Addressing
Data Space
0x0000
15
0
X, Y OR Z - REGISTER
RAMEND
Operand address is the contents of the X-, Y-, or the Z-register. In AVR devices without SRAM, Data Indirect
Addressing is called Register Indirect Addressing. Register Indirect Addressing is a subset of Data Indirect
Addressing since the data space form 0 to 31 is the Register File.
Instruction Set Manual
0856J-AVR-07/2014
5
2.7
Data Indirect with Pre-decrement
Figure 2-7.
Data Indirect Addressing with Pre-decrement
Data Space
0x0000
15
0
X, Y OR Z - REGISTER
-1
RAMEND
The X,- Y-, or the Z-register is decremented before the operation. Operand address is the decremented
contents of the X-, Y-, or the Z-register.
2.8
Data Indirect with Post-increment
Figure 2-8.
Data Indirect Addressing with Post-increment
Data Space
0x0000
15
0
X, Y OR Z - REGISTER
1
RAMEND
The X-, Y-, or the Z-register is incremented after the operation. Operand address is the content of the X-, Y-, or
the Z-register prior to incrementing.
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Instruction Set Manual
0856J-AVR-07/2014
2.9
Program Memory Constant Addressing using the LPM, ELPM, and SPM Instructions
Figure 2-9.
Program Memory Constant Addressing
0x0000
LSB
FLASHEND
Constant byte address is specified by the Z-register contents. The 15 MSBs select word address. For LPM, the
LSB selects low byte if cleared (LSB = 0) or high byte if set (LSB = 1). For SPM, the LSB should be cleared. If
ELPM is used, the RAMPZ Register is used to extend the Z-register.
2.10
Program Memory with Post-increment using the LPM Z+ and ELPM Z+ Instruction
Figure 2-10.
Program Memory Addressing with Post-increment
0x0000
LSB
1
FLASHEND
Constant byte address is specified by the Z-register contents. The 15 MSBs select word address. The LSB
selects low byte if cleared (LSB = 0) or high byte if set (LSB = 1). If ELPM Z+ is used, the RAMPZ Register is
used to extend the Z-register.
Instruction Set Manual
0856J-AVR-07/2014
7
2.11
Direct Program Addressing, JMP, and CALL
Figure 2-11.
Direct Program Memory Addressing
31
16
OP
0x0000
6 MSB
16 LSB
15
0
21
0
PC
FLASHEND
Program execution continues at the address immediate in the instruction word.
2.12
Indirect Program Addressing, IJMP, and ICALL
Figure 2-12.
Indirect Program Memory Addressing
0x0000
15
0
PC
FLASHEND
Program execution continues at address contained by the Z-register (i.e., the PC is loaded with the contents of
the Z-register).
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2.13
Relative Program Addressing, RJMP, and RCALL
Figure 2-13.
Relative Program Memory Addressing
0x0000
1
FLASHEND
Program execution continues at address PC + k + 1. The relative address k is from -2048 to 2047.
Instruction Set Manual
0856J-AVR-07/2014
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3.
Conditional Branch Summary
Test
Mnemonic
(1)
Complementary
Boolean
Mnemonic
Comment
BRGE*
Signed
Rd > Rr
Z(N  V) = 0
BRLT
Rd  Rr
Z+(N  V) = 1
Rd  Rr
(N  V) = 0
BRGE
Rd < Rr
(N  V) = 1
BRLT
Signed
Rd = Rr
Z=1
BREQ
Rd  Rr
Z=0
BRNE
Signed
BRGE
Rd > Rr
Z(N  V) = 0
BRLT*
Signed
BRLT
Rd  Rr
(N  V) = 0
BRGE
Signed
Rd  Rr
C+Z=1
BRSH*
Unsigned
Rd  Rr
Z+(N  V) = 1
Rd < Rr
(N  V) = 1
(1)
(1)
Rd > Rr
C+Z=0
Rd  Rr
C=0
BRSH/BRCC
Rd < Rr
C=1
BRLO/BRCS
Unsigned
Rd = Rr
Z=1
BREQ
Rd  Rr
Z=0
BRNE
Unsigned
BRLO
Rd > Rr
C+Z=0
BRLO*
Unsigned
(1)
Rd  Rr
C+Z=1
Rd < Rr
C=1
BRLO/BRCS
Rd  Rr
C=0
BRSH/BRCC
Unsigned
Carry
C=1
BRCS
No carry
C=0
BRCC
Simple
Negative
N=1
BRMI
Positive
N=0
BRPL
Simple
Overflow
V=1
BRVS
No overflow
V=0
BRVC
Simple
Zero
Z=1
BREQ
Not zero
Z=0
BRNE
Simple
Note:
10
Boolean
1.
BRSH
Interchange Rd and Rr in the operation before the test, i.e., CP Rd,Rr  CP Rr,Rd.
Instruction Set Manual
0856J-AVR-07/2014
4.
Complete Instruction Set Summary
4.1
Instruction Set Summary
Mnemonics
Operands
Description
Operation
Flags
#Clocks
ADD
Rd, Rr
Add without Carry
Rd
←
Rd + Rr
Z,C,N,V,S,H
1
ADC
Rd, Rr
Add with Carry
Rd
ADIW(1)
Rd, K
Add Immediate to Word
Rd
←
Rd + Rr + C
Z,C,N,V,S,H
1
←
Rd + 1:Rd + K
Z,C,N,V,S
SUB
Rd, Rr
Subtract without Carry
2
Rd
←
Rd - Rr
Z,C,N,V,S,H
1
SUBI
Rd, K
SBC
Rd, Rr
Subtract Immediate
Rd
←
Rd - K
Z,C,N,V,S,H
1
Subtract with Carry
Rd
←
Rd - Rr - C
Z,C,N,V,S,H
1
SBCI
Rd, K
SBIW(1)
Rd, K
Subtract Immediate with Carry
Rd
←
Rd - K - C
Z,C,N,V,S,H
1
Subtract Immediate from Word
Rd + 1:Rd
←
Rd + 1:Rd - K
Z,C,N,V,S
2
AND
Rd, Rr
ANDI
Rd, K
Logical AND
Rd
←
Rd  Rr
Z,N,V,S
1
Logical AND with Immediate
Rd
←
Rd  K
Z,N,V,S
1
OR
ORI
Rd, Rr
Logical OR
Rd
←
Rd v Rr
Z,N,V,S
1
Rd, K
Logical OR with Immediate
Rd
←
Rd v K
Z,N,V,S
1
EOR
Rd, Rr
Exclusive OR
Rd
←
Rd  Rr
Z,N,V,S
1
COM
Rd
One’s Complement
Rd
←
$FF - Rd
Z,C,N,V,S
1
NEG
Rd
Two’s Complement
Rd
←
$00 - Rd
Z,C,N,V,S,H
1
SBR
Rd,K
Set Bit(s) in Register
Rd
←
Rd v K
Z,N,V,S
1
CBR
Rd,K
Clear Bit(s) in Register
Rd
←
Rd  ($FFh - K)
Z,N,V,S
1
INC
Rd
Increment
Rd
←
Rd + 1
Z,N,V,S
1
DEC
Rd
Decrement
Rd
←
Rd - 1
Z,N,V,S
1
TST
Rd
Test for Zero or Minus
Rd
←
Rd  Rd
Z,N,V,S
1
CLR
Rd
Clear Register
Rd
←
Rd  Rd
Z,N,V,S
1
SER
Rd
Set Register
Rd
←
$FF
None
1
MUL(1)
Rd,Rr
Multiply Unsigned
R1:R0
←
Rd x Rr (UU)
Z,C
2
#Clocks
XMEGA
Arithmetic and Logic Instructions
MULS
(1)
Rd,Rr
Multiply Signed
R1:R0
←
Rd x Rr (SS)
Z,C
2
MULSU(1)
Rd,Rr
Multiply Signed with Unsigned
R1:R0
←
Rd x Rr (SU)
Z,C
2
FMUL(1)
Rd,Rr
Fractional Multiply Unsigned
R1:R0
←
Rd x Rr<<1 (UU)
Z,C
2
FMULS
(1)
Rd,Rr
Fractional Multiply Signed
R1:R0
←
Rd x Rr<<1 (SS)
Z,C
2
FMULSU(1)
Rd,Rr
Fractional Multiply Signed with Unsigned
R1:R0
←
Rd x Rr<<1 (SU)
Z,C
2
DES
K
Data Encryption
if (H = 0) then R15:R0
else if (H = 1) then R15:R0
←
←
Encrypt(R15:R0, K)
Decrypt(R15:R0, K)
RJMP
k
Relative Jump
PC
←
PC + k + 1
None
2
1/2
Branch Instructions
(1)
IJMP
Indirect Jump to (Z)
PC(15:0)
PC(21:16)
←
←
Z,
0
None
2
EIJMP(1)
Extended Indirect Jump to (Z)
PC(15:0)
PC(21:16)
←
←
Z,
EIND
None
2
JMP(1)
k
Jump
PC
←
k
None
3
RCALL
k
Relative Call Subroutine
PC
←
PC + k + 1
None
3 / 4(3)(5)
ICALL
(1)
Indirect Call to (Z)
PC(15:0)
PC(21:16)
←
←
Z,
0
None
3/4
(3)
2 / 3(3)
2 / 3(3)
Instruction Set Manual
0856J-AVR-07/2014
11
Mnemonics
Operands
EICALL(1)
Description
Operation
Flags
#Clocks
#Clocks
XMEGA
PC(15:0)
PC(21:16)
←
←
Z,
EIND
None
4 (3)
3 (3)
call Subroutine
PC
←
k
None
4 / 5(3)
3 / 4(3)
RET
Subroutine Return
PC
←
STACK
None
4 / 5(3)
RETI
Interrupt Return
PC
←
STACK
I
4 / 5(3)
if (Rd = Rr) PC
←
PC + 2 or 3
None
1/2/3
Rd - Rr
Z,C,N,V,S,H
1
Rd - Rr - C
Z,C,N,V,S,H
1
CALL(1)
Extended Indirect Call to (Z)
k
CPSE
Rd,Rr
Compare, Skip if Equal
CP
Rd,Rr
Compare
CPC
Rd,Rr
Compare with Carry
CPI
Rd,K
Compare with Immediate
SBRC
Rr, b
Skip if Bit in Register Cleared
SBRS
Rr, b
Skip if Bit in Register Set
SBIC
A, b
Skip if Bit in I/O Register Cleared
SBIS
A, b
Skip if Bit in I/O Register Set
BRBS
s, k
Branch if Status Flag Set
BRBC
s, k
Branch if Status Flag Cleared
BREQ
k
Branch if Equal
BRNE
k
BRCS
BRCC
Z,C,N,V,S,H
1
if (Rr(b) = 0) PC
Rd - K
←
PC + 2 or 3
None
1/2/3
if (Rr(b) = 1) PC
←
PC + 2 or 3
None
1/2/3
if (I/O(A,b) = 0) PC
←
PC + 2 or 3
None
1/2/3
2/3/4
If (I/O(A,b) =1) PC
←
PC + 2 or 3
None
1/2/3
2/3/4
if (SREG(s) = 1) then PC
←
PC + k + 1
None
1/2
if (SREG(s) = 0) then PC
←
PC + k + 1
None
1/2
if (Z = 1) then PC
←
PC + k + 1
None
1/2
Branch if Not Equal
if (Z = 0) then PC
←
PC + k + 1
None
1/2
k
Branch if Carry Set
if (C = 1) then PC
←
PC + k + 1
None
1/2
k
Branch if Carry Cleared
if (C = 0) then PC
←
PC + k + 1
None
1/2
BRSH
k
Branch if Same or Higher
if (C = 0) then PC
←
PC + k + 1
None
1/2
BRLO
k
Branch if Lower
if (C = 1) then PC
←
PC + k + 1
None
1/2
BRMI
k
Branch if Minus
if (N = 1) then PC
←
PC + k + 1
None
1/2
BRPL
k
Branch if Plus
if (N = 0) then PC
←
PC + k + 1
None
1/2
BRGE
k
Branch if Greater or Equal, Signed
if (N  V= 0) then PC
←
PC + k + 1
None
1/2
BRLT
k
Branch if Less Than, Signed
if (N  V= 1) then PC
←
PC + k + 1
None
1/2
BRHS
k
Branch if Half Carry Flag Set
if (H = 1) then PC
←
PC + k + 1
None
1/2
BRHC
k
Branch if Half Carry Flag Cleared
if (H = 0) then PC
←
PC + k + 1
None
1/2
BRTS
k
Branch if T Flag Set
if (T = 1) then PC
←
PC + k + 1
None
1/2
BRTC
k
Branch if T Flag Cleared
if (T = 0) then PC
←
PC + k + 1
None
1/2
BRVS
k
Branch if Overflow Flag is Set
if (V = 1) then PC
←
PC + k + 1
None
1/2
BRVC
k
Branch if Overflow Flag is Cleared
if (V = 0) then PC
←
PC + k + 1
None
1/2
BRIE
k
Branch if Interrupt Enabled
if (I = 1) then PC
←
PC + k + 1
None
1/2
BRID
k
Branch if Interrupt Disabled
if (I = 0) then PC
←
PC + k + 1
None
1/2
Data Transfer Instructions
MOV
Rd, Rr
Copy Register
MOVW(1)
Rd, Rr
Copy Register Pair
LDI
Rd, K
LDS
LD(2)
(1)
LD
(2)
Rd
←
Rr
None
1
Rd+1:Rd
←
Rr+1:Rr
None
1
Load Immediate
Rd
←
K
None
1
Rd, k
Load Direct from data space
Rd
←
(k)
None
1(5)/2(3)
2(3)(4)
Rd, X
Load Indirect
Rd
←
(X)
None
1(5)2(3)
1(3)(4)
(3)
1(3)(4)
Rd, X+
Load Indirect and Post-Increment
Rd
X
←
←
(X)
X+1
None
2
LD(2)
Rd, -X
Load Indirect and Pre-Decrement
X  X - 1,
Rd  (X)
←
←
X-1
(X)
None
2(3)/3(5)
2(3)(4)
LD(2)
Rd, Y
Load Indirect
Rd  (Y)
←
(Y)
None
1(5)/2(3)
1(3)(4)
LD(2)
Rd, Y+
Load Indirect and Post-Increment
Rd
Y
←
←
(Y)
Y+1
None
2(3)
1(3)(4)
LD(2)
Rd, -Y
Load Indirect and Pre-Decrement
Y
Rd
←
←
Y-1
(Y)
None
2(3)/3(5)
2(3)(4)
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Instruction Set Manual
0856J-AVR-07/2014
Mnemonics
Operands
Description
LDD(1)
Rd, Y+q
Load Indirect with Displacement
Rd
←
LD(2)
Rd, Z
Load Indirect
Rd
←
LD
(2)
Flags
#Clocks
#Clocks
XMEGA
(Y + q)
None
2(3)
2(3)(4)
(Z)
None
1(5)/2(3)
1(3)(4)
Operation
(3)
1(3)(4)
Rd, Z+
Load Indirect and Post-Increment
Rd
Z
←
←
(Z),
Z+1
None
2
LD(2)
Rd, -Z
Load Indirect and Pre-Decrement
Z
Rd
←
←
Z - 1,
(Z)
None
2(3)/3(5)
2(3)(4)
LDD(1)
Rd, Z+q
Load Indirect with Displacement
Rd
←
(Z + q)
None
2(3)
2(3)(4)
STS(1)
k, Rr
Store Direct to Data Space
(k)
←
Rd
None
1(5)/2(3)
(2)
(5)
2(3)
(3)
1(3)
ST
X, Rr
Store Indirect
(X)
←
Rr
None
1 /2
ST(2)
X+, Rr
Store Indirect and Post-Increment
(X)
X
←
←
Rr,
X+1
None
1(5)/2(3)
1(3)
ST(2)
-X, Rr
Store Indirect and Pre-Decrement
X
(X)
←
←
X - 1,
Rr
None
2(3)
2(3)
ST(2)
Y, Rr
Store Indirect
(Y)
←
Rr
None
1(5)/2(3)
1(3)
ST(2)
Y+, Rr
Store Indirect and Post-Increment
(Y)
Y
←
←
Rr,
Y+1
None
1(5)/2(3)
1(3)
ST(2)
-Y, Rr
Store Indirect and Pre-Decrement
Y
(Y)
←
←
Y - 1,
Rr
None
2(3)
2(3)
STD(1)
Y+q, Rr
Store Indirect with Displacement
(Y + q)
←
Rr
None
2(3)
(5)
(2)
2(3)
(3)
1(3)
ST
Z, Rr
Store Indirect
(Z)
←
Rr
None
1 /2
ST(2)
Z+, Rr
Store Indirect and Post-Increment
(Z)
Z
←
←
Rr
Z+1
None
1(5)/2(3)
1(3)
ST(2)
-Z, Rr
Store Indirect and Pre-Decrement
Z
←
Z-1
None
2(3)
2(3)
(3)
2(3)
STD
(1)
Z+q,Rr
LPM(1)(2)
Store Indirect with Displacement
(Z + q)
←
Rr
None
2
Load Program Memory
R0
←
(Z)
None
3
3
LPM(1)(2)
Rd, Z
Load Program Memory
Rd
←
(Z)
None
3
3
LPM(1)(2)
Rd, Z+
Load Program Memory and PostIncrement
Rd
Z
←
←
(Z),
Z+1
None
3
3
ELPM(1)
Extended Load Program Memory
R0
←
(RAMPZ:Z)
None
3
ELPM(1)
Rd, Z
Extended Load Program Memory
Rd
←
(RAMPZ:Z)
None
3
ELPM(1)
Rd, Z+
Extended Load Program Memory and
Post-Increment
Rd
Z
←
←
(RAMPZ:Z),
Z+1
None
3
SPM(1)
Store Program Memory
(RAMPZ:Z)
←
R1:R0
None
-
-
SPM(1)
Z+
Store Program Memory and PostIncrement by 2
(RAMPZ:Z)
Z
←
←
R1:R0,
Z+2
None
-
-
IN
Rd, A
In From I/O Location
Rd
←
I/O(A)
None
1
OUT
A, Rr
Out To I/O Location
PUSH(1)
Rr
Push Register on Stack
POP(1)
Rd
XCH
I/O(A)
←
Rr
None
1
STACK
←
Rr
None
2
1(3)
Pop Register from Stack
Rd
←
STACK
None
2
2(3)
Z, Rd
Exchange
(Z)
Rd
←
←
Rd,
(Z)
None
1
LAS
Z, Rd
Load and Set
(Z)
Rd
←
←
Rd v (Z)
(Z)
None
1
LAC
Z, Rd
Load and Clear
(Z)
Rd
←
←
($FF – Rd)  (Z)
(Z)
None
1
LAT
Z, Rd
Load and Toggle
(Z)
Rd
←
←
Rd  (Z)
(Z)
None
1
LSL
Rd
Logical Shift Left
Rd(n+1)
Rd(0)
C
←
←
←
Rd(n),
0,
Rd(7)
Z,C,N,V,H
1
LSR
Rd
Logical Shift Right
Rd(n)
Rd(7)
C
←
←
←
Rd(n+1),
0,
Rd(0)
Z,C,N,V
1
Bit and Bit-test Instructions
Instruction Set Manual
0856J-AVR-07/2014
13
Mnemonics
Operands
Description
ROL
Rd
Rotate Left Through Carry
ROR
Rd
Rotate Right Through Carry
ASR
Rd
Arithmetic Shift Right
SWAP
Rd
Swap Nibbles
BSET
s
BCLR
s
SBI
A, b
Operation
Flags
#Clocks
Rd(0)
Rd(n+1)
C
←
←
←
C,
Rd(n),
Rd(7)
Z,C,N,V,H
1
Rd(7)
Rd(n)
C
←
←
←
C,
Rd(n+1),
Rd(0)
Z,C,N,V
1
#Clocks
XMEGA
Rd(n)
←
Rd(n+1), n=0..6
Z,C,N,V
1
Rd(3..0)
↔
Rd(7..4)
None
1
Flag Set
SREG(s)
←
1
SREG(s)
1
Flag Clear
SREG(s)
←
0
SREG(s)
1
Set Bit in I/O Register
I/O(A, b)
←
1
None
1(5)2
1
(5)
1
CBI
A, b
Clear Bit in I/O Register
BST
Rr, b
Bit Store from Register to T
BLD
Rd, b
Bit load from T to Register
I/O(A, b)
←
0
None
1 /2
T
←
Rr(b)
T
1
Rd(b)
←
T
None
1
SEC
Set Carry
C
←
1
C
1
CLC
Clear Carry
C
←
0
C
1
SEN
Set Negative Flag
N
←
1
N
1
CLN
Clear Negative Flag
N
←
0
N
1
SEZ
Set Zero Flag
Z
←
1
Z
1
CLZ
Clear Zero Flag
Z
←
0
Z
1
SEI
Global Interrupt Enable
I
←
1
I
1
CLI
Global Interrupt Disable
I
←
0
I
1
SES
Set Signed Test Flag
S
←
1
S
1
CLS
Clear Signed Test Flag
S
←
0
S
1
SEV
Set Two’s Complement Overflow
V
←
1
V
1
CLV
Clear Two’s Complement Overflow
V
←
0
V
1
SET
Set T in SREG
T
←
1
T
1
CLT
Clear T in SREG
T
←
0
T
1
SEH
Set Half Carry Flag in SREG
H
←
1
H
1
CLH
Clear Half Carry Flag in SREG
H
←
0
H
1
None
1
None
1
MCU Control Instructions
BREAK(1)
Break
NOP
No Operation
SLEEP
Sleep
(see specific descr. for Sleep)
None
1
WDR
Watchdog Reset
(see specific descr. for WDR)
None
1
(See specific descr. for BREAK)
Notes:
1. This instruction is not available in all devices. Refer to the device specific instruction set summary.
2. Not all variants of this instruction are available in all devices. Refer to the device specific instruction set summary.
3. Cycle times for Data memory accesses assume internal memory accesses, and are not valid for accesses via the
external RAM interface.
4. One extra cycle must be added when accessing Internal SRAM.
5. Number of clock cycles for Reduced Core tinyAVR®.
14
Instruction Set Manual
0856J-AVR-07/2014
5.
ADC – Add with Carry
5.1
Description
Adds two registers and the contents of the C Flag and places the result in the destination register Rd.
Operation:
Rd  Rd + Rr + C
(i)
(i)
Syntax:
Operands:
Program Counter:
ADC Rd,Rr
0  d  31, 0  r  31
PC  PC + 1
16-bit Opcode:
0001
5.2
11rd
dddd
rrrr
Status Register (SREG) Boolean Formula:
I
T
H
S
V
N
Z
C
–
–






H:
Rd3 Rr3 + Rr3R3 + R3Rd3
Set if there was a carry from bit 3; cleared otherwise.
S:
N  V, For signed tests.
V:
Rd7 Rr7R7 + Rd7Rr7 R7
Set if two’s complement overflow resulted from the operation; cleared otherwise.
N:
R7
Set if MSB of the result is set; cleared otherwise.
Z:
R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $00; cleared otherwise.
C:
Rd7 Rr7 Rr7R7R7 Rd7
Set if there was carry from the MSB of the result; cleared otherwise.
R (Result) equals Rd after the operation.
Example:
; Add R1:R0 to R3:R2
add
r2,r0
; Add low byte
adc
r3,r1
; Add with carry high byte
Words: 1 (2 bytes)
Cycles: 1
Instruction Set Manual
0856J-AVR-07/2014
15
6.
ADD – Add without Carry
6.1
Description
Adds two registers without the C Flag and places the result in the destination register Rd.
Operation:
Rd  Rd + Rr
(i)
(i)
Syntax:
Operands:
Program Counter:
ADD Rd,Rr
0  d  31, 0  r  31
PC  PC + 1
16-bit Opcode:
0000
6.2
11rd
dddd
rrrr
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–






H:
Rd3 Rr3 + Rr3R3 + R3 Rd3
Set if there was a carry from bit 3; cleared otherwise.
S:
N  V, for signed tests.
V:
Rd7 Rr7R7 + Rd7Rr7 R7
Set if two’s complement overflow resulted from the operation; cleared otherwise.
N:
R7
Set if MSB of the result is set; cleared otherwise.
Z:
R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $00; cleared otherwise.
C:
Rd7  Rr7 + Rr7 R7 + R7 Rd7
Set if there was carry from the MSB of the result; cleared otherwise.
R (Result) equals Rd after the operation.
Example:
add
r1,r2
; Add r2 to r1 (r1=r1+r2)
add
r28,r28
; Add r28 to itself (r28=r28+r28)
Words: 1 (2 bytes)
Cycles: 1
16
Instruction Set Manual
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7.
ADIW – Add Immediate to Word
7.1
Description
Adds an immediate value (0 - 63) to a register pair and places the result in the register pair. This instruction
operates on the upper four register pairs, and is well suited for operations on the pointer registers.
This instruction is not available in all devices. Refer to the device specific instruction set summary.
Operation:
Rd+1:Rd  Rd+1:Rd + K
(i)
(i)
Syntax:
Operands:
Program Counter:
ADIW Rd+1:Rd,K
d  {24,26,28,30}, 0  K  63
PC  PC + 1
16-bit Opcode:
1001
7.2
0110
KKdd
KKKK
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–





S:
N  V, For signed tests.
V:
Rdh7 R15
Set if two’s complement overflow resulted from the operation; cleared otherwise.
N:
R15
Set if MSB of the result is set; cleared otherwise.
Z:
R15 R14 R13 R12 R11 R10 R9 R8 R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $0000; cleared otherwise.
C:
R15  Rdh7
Set if there was carry from the MSB of the result; cleared otherwise.
R (Result) equals Rdh:Rdl after the operation (Rdh7-Rdh0 = R15-R8, Rdl7-Rdl0=R7-R0).
Example:
adiw r25:24,1 ; Add 1 to r25:r24
adiw ZH:ZL,63 ; Add 63 to the Z-pointer(r31:r30)
Words: 1 (2 bytes)
Cycles: 2
Instruction Set Manual
0856J-AVR-07/2014
17
8.
AND – Logical AND
8.1
Description
Performs the logical AND between the contents of register Rd and register Rr and places the result in the
destination register Rd.
Operation:
Rd  Rd  Rr
(i)
(i)
Syntax:
Operands:
Program Counter:
AND Rd,Rr
0  d  31, 0  r  31
PC  PC + 1
16-bit Opcode:
0010
8.2
00rd
dddd
rrrr
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–

0


–
S:
N  V, For signed tests.
V:
0
Cleared.
N:
R7
Set if MSB of the result is set; cleared otherwise.
Z:
R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $00; cleared otherwise.
R (Result) equals Rd after the operation.
Example:
and
r2,r3
; Bitwise and r2 and r3, result in r2
ldi
r16,1
; Set bitmask 0000 0001 in r16
and
r2,r16
; Isolate bit 0 in r2
Words: 1 (2 bytes)
Cycles: 1
18
Instruction Set Manual
0856J-AVR-07/2014
9.
ANDI – Logical AND with Immediate
9.1
Description
Performs the logical AND between the contents of register Rd and a constant and places the result in the
destination register Rd.
Operation:
Rd  Rd  K
(i)
(i)
Syntax:
Operands:
Program Counter:
ANDI Rd,K
16  d  31, 0  K  255
PC  PC + 1
16-bit Opcode:
0111
9.2
KKKK
dddd
KKKK
Status Register (SREG) and Boolean Formula
I
T
H
S
–
–
–

V
0
N
Z
C


–
S:
N  V, for signed tests.
V:
0
Cleared.
N:
R7
Set if MSB of the result is set; cleared otherwise.
Z:
R7 R6 R5R4 R3 R2 R1 R0
Set if the result is $00; cleared otherwise.
R (Result) equals Rd after the operation.
Example:
andi r17,$0F
; Clear upper nibble of r17
andi r18,$10
; Isolate bit 4 in r18
andi r19,$AA
; Clear odd bits of r19
Words: 1 (2 bytes)
Cycles: 1
Instruction Set Manual
0856J-AVR-07/2014
19
10.
ASR – Arithmetic Shift Right
10.1
Description
Shifts all bits in Rd one place to the right. Bit 7 is held constant. Bit 0 is loaded into the C Flag of the SREG. This
operation effectively divides a signed value by two without changing its sign. The Carry Flag can be used to
round the result.
Operation:
(i)
b7-------------------b0
(i)
C
Syntax:
Operands:
Program Counter:
ASR Rd
0  d  31
PC  PC + 1
16-bit Opcode:
1001
10.2
010d
dddd
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–





S:
N  V, for signed tests.
V:
N  C, for N and C after the shift.
N:
R7
Set if MSB of the result is set; cleared otherwise.
Z:
R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $00; cleared otherwise.
C:
Rd0
Set if, before the shift, the LSB of Rd was set; cleared otherwise.
R (Result) equals Rd after the operation.
Example:
ldi
r16,$10
; Load decimal 16 into r16
asr
r16
; r16=r16 / 2
ldi
r17,$FC
; Load -4 in r17
asr
r17
; r17=r17/2
Words: 1 (2 bytes)
Cycles: 1
20
0101
Instruction Set Manual
0856J-AVR-07/2014
11.
BCLR – Bit Clear in SREG
11.1
Description
Clears a single Flag in SREG.
Operation:
SREG(s)  0
(i)
(i)
Syntax:
Operands:
Program Counter:
BCLR s
0s7
PC  PC + 1
16-bit Opcode:
1001
11.2
0100
1sss
1000
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C








I:
0 if s = 7; Unchanged otherwise.
T:
0 if s = 6; Unchanged otherwise.
H:
0 if s = 5; Unchanged otherwise.
S:
0 if s = 4; Unchanged otherwise.
V:
0 if s = 3; Unchanged otherwise.
N:
0 if s = 2; Unchanged otherwise.
Z:
0 if s = 1; Unchanged otherwise.
C:
0 if s = 0; Unchanged otherwise.
Example:
bclr
0
; Clear Carry Flag
bclr
7
; Disable interrupts
Words: 1 (2 bytes)
Cycles: 1
Instruction Set Manual
0856J-AVR-07/2014
21
12.
BLD – Bit Load from the T Flag in SREG to a Bit in Register
12.1
Description
Copies the T Flag in the SREG (Status Register) to bit b in register Rd.
Operation:
Rd(b)  T
(i)
(i)
Syntax:
Operands:
Program Counter:
BLD Rd,b
0  d  31, 0  b  7
PC  PC + 1
16 bit Opcode:
1111
12.2
100d
dddd
0bbb
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
; Copy bit
bst
r1,2
; Store bit 2 of r1 in T Flag
bld
r0,4
; Load T Flag into bit 4 of r0
Words: 1 (2 bytes)
Cycles: 1
22
Instruction Set Manual
0856J-AVR-07/2014
13.
BRBC – Branch if Bit in SREG is Cleared
13.1
Description
Conditional relative branch. Tests a single bit in SREG and branches relatively to PC if the bit is cleared. This
instruction branches relatively to PC in either direction (PC - 63 destination PC + 64). The parameter k is the
offset from PC and is represented in two’s complement form.
Operation:
If SREG(s) = 0 then PC  PC + k + 1, else PC  PC + 1
(i)
(i)
Syntax:
Operands:
Program Counter:
BRBC s,k
0  s  7, -64  k  +63
PC  PC + k + 1
PC  PC + 1, if condition is false
16-bit Opcode:
1111
13.2
01kk
kkkk
ksss
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
cpi
r20,5
brbc 1,noteq
; Compare r20 to the value 5
; Branch if Zero Flag cleared
...
noteq:nop
; Branch destination (do nothing)
Words: 1 (2 bytes)
Cycles: 1 if condition is false
2 if condition is true
Instruction Set Manual
0856J-AVR-07/2014
23
14.
BRBS – Branch if Bit in SREG is Set
14.1
Description
Conditional relative branch. Tests a single bit in SREG and branches relatively to PC if the bit is set. This
instruction branches relatively to PC in either direction (PC - 63 destinationPC + 64). The parameter k is the
offset from PC and is represented in two’s complement form.
Operation:
If SREG(s) = 1 then PC  PC + k + 1, else PC  PC + 1
(i)
(i)
Syntax:
Operands:
Program Counter:
BRBS s,k
0  s  7, -64  k  +63
PC  PC + k + 1
PC  PC + 1, if condition is false
16-bit Opcode:
1111
14.2
00kk
kkkk
ksss
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
bst
r0,3
; Load T bit with bit 3 of r0
brbs 6,bitset ; Branch T bit was set
...
bitset: nop
Words: 1 (2 bytes)
Cycles: 1 if condition is false
2 if condition is true
24
Instruction Set Manual
0856J-AVR-07/2014
; Branch destination (do nothing)
15.
BRCC – Branch if Carry Cleared
15.1
Description
Conditional relative branch. Tests the Carry Flag (C) and branches relatively to PC if C is cleared. This
instruction branches relatively to PC in either direction (PC - 63 destination PC + 64). The parameter k is the
offset from PC and is represented in two’s complement form. (Equivalent to instruction BRBC 0,k).
Operation:
If C = 0 then PC  PC + k + 1, else PC  PC + 1
(i)
(i)
Syntax:
Operands:
Program Counter:
BRCC k
-64  k  +63
PC  PC + k + 1
PC  PC + 1, if condition is false
16-bit Opcode:
1111
15.2
01kk
kkkk
k000
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
add
r22,r23
brcc nocarry
; Add r23 to r22
; Branch if carry cleared
...
nocarry: nop
; Branch destination (do nothing)
Words: 1 (2 bytes)
Cycles: 1 if condition is false
2 if condition is true
Instruction Set Manual
0856J-AVR-07/2014
25
16.
BRCS – Branch if Carry Set
16.1
Description
Conditional relative branch. Tests the Carry Flag (C) and branches relatively to PC if C is set. This instruction
branches relatively to PC in either direction (PC - 63 destinationPC + 64). The parameter k is the offset from
PC and is represented in two’s complement form. (Equivalent to instruction BRBS 0,k).
Operation:
If C = 1 then PC  PC + k + 1, else PC  PC + 1
(i)
(i)
Syntax:
Operands:
Program Counter:
BRCS k
-64  k  +63
PC  PC + k + 1
PC  PC + 1, if condition is false
16-bit Opcode:
1111
16.2
00kk
kkkk
k000
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
cpi
r26,$56
brcs carry
; Compare r26 with $56
; Branch if carry set
...
carry: nop
Words: 1 (2 bytes)
Cycles: 1 if condition is false
2 if condition is true
26
Instruction Set Manual
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; Branch destination (do nothing)
17.
BREAK – Break
17.1
Description
The BREAK instruction is used by the On-chip Debug system, and is normally not used in the application
software. When the BREAK instruction is executed, the AVR CPU is set in the Stopped Mode. This gives the
On-chip Debugger access to internal resources.
If any Lock bits are set, or either the JTAGEN or OCDEN Fuses are unprogrammed, the CPU will treat the
BREAK instruction as a NOP and will not enter the Stopped mode.
This instruction is not available in all devices. Refer to the device specific instruction set summary.
Operation:
(i)
On-chip Debug system break.
(i)
Syntax:
Operands:
Program Counter:
BREAK
None
PC  PC + 1
16-bit Opcode:
1001
17.2
0101
1001
1000
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Words: 1 (2 bytes)
Cycles: 1
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27
18.
BREQ – Branch if Equal
18.1
Description
Conditional relative branch. Tests the Zero Flag (Z) and branches relatively to PC if Z is set. If the instruction is
executed immediately after any of the instructions CP, CPI, SUB, or SUBI, the branch will occur if and only if the
unsigned or signed binary number represented in Rd was equal to the unsigned or signed binary number
represented in Rr. This instruction branches relatively to PC in either direction (PC - 63 destination PC + 64).
The parameter k is the offset from PC and is represented in two’s complement form. (Equivalent to instruction
BRBS 1,k).
Operation:
(i)
If Rd = Rr (Z = 1) then PC  PC + k + 1, else PC  PC + 1
Syntax:
Operands:
Program Counter:
(i)
BREQ k
-64  k  +63
PC  PC + k + 1
PC  PC + 1, if condition is false
16-bit Opcode:
1111
18.2
00kk
kkkk
k001
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
cp
r1,r0
Example:
breq equal
; Compare registers r1 and r0
; Branch if registers equal
...
equal: nop
Words: 1 (2 bytes)
Cycles: 1 if condition is false
2 if condition is true
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; Branch destination (do nothing)
19.
BRGE – Branch if Greater or Equal (Signed)
19.1
Description
Conditional relative branch. Tests the Signed Flag (S) and branches relatively to PC if S is cleared. If the
instruction is executed immediately after any of the instructions CP, CPI, SUB, or SUBI, the branch will occur if
and only if the signed binary number represented in Rd was greater than or equal to the signed binary number
represented in Rr. This instruction branches relatively to PC in either direction (PC - 63 destination PC + 64).
The parameter k is the offset from PC and is represented in two’s complement form. (Equivalent to instruction
BRBC 4,k).
Operation:
(i)
If Rd  Rr (N  V = 0) then PC  PC + k + 1, else PC  PC + 1
Syntax:
Operands:
Program Counter:
(i)
BRGE k
-64  k  +63
PC  PC + k + 1
PC  PC + 1, if condition is false
16-bit Opcode:
1111
19.2
01kk
kkkk
k100
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
cp
r11,r12
brge greateq
; Compare registers r11 and r12
; Branch if r11  r12 (signed)
...
greateq: nop
; Branch destination (do nothing)
Words: 1 (2 bytes)
Cycles: 1 if condition is false
2 if condition is true
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29
20.
BRHC – Branch if Half Carry Flag is Cleared
20.1
Description
Conditional relative branch. Tests the Half Carry Flag (H) and branches relatively to PC if H is cleared. This
instruction branches relatively to PC in either direction (PC - 63 destination PC + 64). The parameter k is the
offset from PC and is represented in two’s complement form. (Equivalent to instruction BRBC 5,k).
Operation:
If H = 0 then PC  PC + k + 1, else PC  PC + 1
(i)
(i)
Syntax:
Operands:
Program Counter:
BRHC k
-64  k  +63
PC  PC + k + 1
PC  PC + 1, if condition is false
16-bit Opcode:
1111
20.2
01kk
kkkk
k101
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
brhc hclear
; Branch if Half Carry Flag cleared
...
hclear:
nop
Words: 1 (2 bytes)
Cycles: 1 if condition is false
2 if condition is true
30
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; Branch destination (do nothing)
21.
BRHS – Branch if Half Carry Flag is Set
21.1
Description
Conditional relative branch. Tests the Half Carry Flag (H) and branches relatively to PC if H is set. This
instruction branches relatively to PC in either direction (PC - 63 destination PC + 64). The parameter k is the
offset from PC and is represented in two’s complement form. (Equivalent to instruction BRBS 5,k).
Operation:
If H = 1 then PC  PC + k + 1, else PC  PC + 1
(i)
(i)
Syntax:
Operands:
Program Counter:
BRHS k
-64  k  +63
PC  PC + k + 1
PC  PC + 1, if condition is false
16-bit Opcode:
1111
21.2
00kk
kkkk
k101
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
brhs
hset
; Branch if Half Carry Flag set
...
hset:
nop
; Branch destination (do nothing)
Words: 1 (2 bytes)
Cycles: 1 if condition is false
2 if condition is true
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31
22.
BRID – Branch if Global Interrupt is Disabled
22.1
Description
Conditional relative branch. Tests the Global Interrupt Flag (I) and branches relatively to PC if I is cleared. This
instruction branches relatively to PC in either direction (PC - 63 destination PC + 64). The parameter k is the
offset from PC and is represented in two’s complement form. (Equivalent to instruction BRBC 7,k).
Operation:
(i)
If I = 0 then PC  PC + k + 1, else PC  PC + 1
Syntax:
Operands:
Program Counter:
(i)
BRID k
-64  k  +63
PC  PC + k + 1
PC  PC + 1, if condition is false
16-bit Opcode:
1111
22.2
01kk
kkkk
k111
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
brid intdis
; Branch if interrupt disabled
...
intdis:
nop
Words: 1 (2 bytes)
Cycles: 1 if condition is false
2 if condition is true
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; Branch destination (do nothing)
23.
BRIE – Branch if Global Interrupt is Enabled
23.1
Description
Conditional relative branch. Tests the Global Interrupt Flag (I) and branches relatively to PC if I is set. This
instruction branches relatively to PC in either direction (PC - 63 destination PC + 64). The parameter k is the
offset from PC and is represented in two’s complement form. (Equivalent to instruction BRBS 7,k).
Operation:
(i)
If I = 1 then PC  PC + k + 1, else PC  PC + 1
Syntax:
Operands:
Program Counter:
(i)
BRIE k
-64  k  +63
PC  PC + k + 1
PC  PC + 1, if condition is false
16-bit Opcode:
1111
23.2
00kk
kkkk
k111
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
brie
inten
; Branch if interrupt enabled
...
inten:
nop
; Branch destination (do nothing)
Words: 1 (2 bytes)
Cycles: 1 if condition is false
2 if condition is true
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33
24.
BRLO – Branch if Lower (Unsigned)
24.1
Description
Conditional relative branch. Tests the Carry Flag (C) and branches relatively to PC if C is set. If the instruction is
executed immediately after any of the instructions CP, CPI, SUB, or SUBI, the branch will occur if and only if,
the unsigned binary number represented in Rd was smaller than the unsigned binary number represented in Rr.
This instruction branches relatively to PC in either direction (PC - 63 destinationPC + 64). The parameter k
is the offset from PC and is represented in two’s complement form. (Equivalent to instruction BRBS 0,k).
Operation:
If Rd < Rr (C = 1) then PC  PC + k + 1, else PC  PC + 1
(i)
(i)
Syntax:
Operands:
Program Counter:
BRLO k
-64  k  +63
PC  PC + k + 1
PC  PC + 1, if condition is false
16-bit Opcode:
1111
24.2
00kk
kkkk
k000
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
loop:
eor
r19,r19
; Clear r19
inc
r19
; Increase r19
...
cpi
r19,$10
; Branch if r19 < $10 (unsigned)
nop
; Exit from loop (do nothing)
Words: 1 (2 bytes)
Cycles: 1 if condition is false
2 if condition is true
34
; Compare r19 with $10
brlo loop
Instruction Set Manual
0856J-AVR-07/2014
25.
BRLT – Branch if Less Than (Signed)
25.1
Description
Conditional relative branch. Tests the Signed Flag (S) and branches relatively to PC if S is set. If the instruction
is executed immediately after any of the instructions CP, CPI, SUB, or SUBI, the branch will occur if and only if,
the signed binary number represented in Rd was less than the signed binary number represented in Rr. This
instruction branches relatively to PC in either direction (PC - 63 destination PC + 64). The parameter k is the
offset from PC and is represented in two’s complement form. (Equivalent to instruction BRBS 4,k).
Operation:
If Rd < Rr (N  V = 1) then PC  PC + k + 1, else PC  PC + 1
(i)
(i)
Syntax:
Operands:
Program Counter:
BRLT k
-64  k  +63
PC  PC + k + 1
PC  PC + 1, if condition is false
16-bit Opcode:
1111
25.2
00kk
kkkk
k100
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
cp
r16,r1
brlt less
; Compare r16 to r1
; Branch if r16 < r1 (signed)
...
less:
nop
; Branch destination (do nothing)
Words: 1 (2 bytes)
Cycles: 1 if condition is false
2 if condition is true
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35
26.
BRMI – Branch if Minus
26.1
Description
Conditional relative branch. Tests the Negative Flag (N) and branches relatively to PC if N is set. This instruction
branches relatively to PC in either direction (PC - 63 destinationPC + 64). The parameter k is the offset from
PC and is represented in two’s complement form. (Equivalent to instruction BRBS 2,k.)
Operation:
(i)
If N = 1 then PC  PC + k + 1, else PC  PC + 1
Syntax:
Operands:
Program Counter:
(i)
BRMI k
-64  k  +63
PC  PC + k + 1
PC  PC + 1, if condition is false
16-bit Opcode:
1111
26.2
00kk
kkkk
k010
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
subi
r18,4
; Subtract 4 from r18
brmi
negative
; Branch if result negative
...
negative:
nop
Words: 1 (2 bytes)
Cycles: 1 if condition is false
2 if condition is true
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; Branch destination (do nothing)
27.
BRNE – Branch if Not Equal
27.1
Description
Conditional relative branch. Tests the Zero Flag (Z) and branches relatively to PC if Z is cleared. If the
instruction is executed immediately after any of the instructions CP, CPI, SUB, or SUBI, the branch will occur if
and only if, the unsigned or signed binary number represented in Rd was not equal to the unsigned or signed
binary number represented in Rr. This instruction branches relatively to PC in either direction (PC - 63 
destinationPC + 64). The parameter k is the offset from PC and is represented in two’s complement form.
(Equivalent to instruction BRBC 1,k.)
Operation:
If Rd  Rr (Z = 0) then PC  PC + k + 1, else PC  PC + 1
(i)
(i)
Syntax:
Operands:
Program Counter:
BRNE k
-64  k  +63
PC  PC + k + 1
PC  PC + 1, if condition is false
16-bit Opcode:
1111
27.2
01kk
kkkk
k001
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
loop:
eor
r27,r27
; Clear r27
inc
r27
; Increase r27
cpi
r27,5
; Compare r27 to 5
brne
loop
; Branch if r27<>5
...
nop
; Loop exit (do nothing)
Words: 1 (2 bytes)
Cycles: 1 if condition is false
2 if condition is true
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37
28.
BRPL – Branch if Plus
28.1
Description
Conditional relative branch. Tests the Negative Flag (N) and branches relatively to PC if N is cleared. This
instruction branches relatively to PC in either direction (PC - 63 destination PC + 64). The parameter k is the
offset from PC and is represented in two’s complement form. (Equivalent to instruction BRBC 2,k.)
Operation:
(i)
If N = 0 then PC  PC + k + 1, else PC  PC + 1
Syntax:
Operands:
Program Counter:
(i)
BRPL k
-64  k  +63
PC  PC + k + 1
PC  PC + 1, if condition is false
16-bit Opcode:
1111
28.2
01kk
kkkk
k010
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
subi r26,$50
; Subtract $50 from r26
brpl positive
; Branch if r26 positive
...
positive:
nop
Words: 1 (2 bytes)
Cycles: 1 if condition is false
2 if condition is true
38
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; Branch destination (do nothing)
29.
BRSH – Branch if Same or Higher (Unsigned)
29.1
Description
Conditional relative branch. Tests the Carry Flag (C) and branches relatively to PC if C is cleared. If the
instruction is executed immediately after execution of any of the instructions CP, CPI, SUB, or SUBI the branch
will occur if and only if, the unsigned binary number represented in Rd was greater than or equal to the unsigned
binary number represented in Rr. This instruction branches relatively to PC in either direction (PC - 63 
destination PC + 64). The parameter k is the offset from PC and is represented in two’s complement form.
(Equivalent to instruction BRBC 0,k.)
Operation:
(i)
If Rd Rr (C = 0) then PC  PC + k + 1, else PC  PC + 1
Syntax:
Operands:
Program Counter:
(i)
BRSH k
-64  k  +63
PC  PC + k + 1
PC  PC + 1, if condition is false
16-bit Opcode:
1111
29.2
01kk
kkkk
k000
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
subi r19,4
; Subtract 4 from r19
brsh highsm
; Branch if r19 >= 4 (unsigned)
...
highsm:
nop
; Branch destination (do nothing)
Words: 1 (2 bytes)
Cycles: 1 if condition is false
2 if condition is true
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39
30.
BRTC – Branch if the T Flag is Cleared
30.1
Description
Conditional relative branch. Tests the T Flag and branches relatively to PC if T is cleared. This instruction
branches relatively to PC in either direction (PC - 63 destination PC + 64). The parameter k is the offset from
PC and is represented in two’s complement form. (Equivalent to instruction BRBC 6,k.)
Operation:
If T = 0 then PC  PC + k + 1, else PC  PC + 1
(i)
(i)
Syntax:
Operands:
Program Counter:
BRTC k
-64  k  +63
PC  PC + k + 1
PC  PC + 1, if condition is false
16-bit Opcode:
1111
30.2
01kk
kkkk
k110
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
bst
r3,5
; Store bit 5 of r3 in T Flag
brtc
tclear
; Branch if this bit was cleared
...
tclear:
nop
Words: 1 (2 bytes)
Cycles: 1 if condition is false
2 if condition is true
40
Instruction Set Manual
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; Branch destination (do nothing)
31.
BRTS – Branch if the T Flag is Set
31.1
Description
Conditional relative branch. Tests the T Flag and branches relatively to PC if T is set. This instruction branches
relatively to PC in either direction (PC - 63 destination PC + 64). The parameter k is the offset from PC and
is represented in two’s complement form. (Equivalent to instruction BRBS 6,k.)
Operation:
(i)
If T = 1 then PC  PC + k + 1, else PC  PC + 1
Syntax:
Operands:
Program Counter:
(i)
BRTS k
-64  k  +63
PC  PC + k + 1
PC  PC + 1, if condition is false
16-bit Opcode:
1111
31.2
00kk
kkkk
k110
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
bst
r3,5
brts tset
; Store bit 5 of r3 in T Flag
; Branch if this bit was set
...
tset:
nop
; Branch destination (do nothing)
Words: 1 (2 bytes)
Cycles: 1 if condition is false
2 if condition is true
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41
32.
BRVC – Branch if Overflow Cleared
32.1
Description
Conditional relative branch. Tests the Overflow Flag (V) and branches relatively to PC if V is cleared. This
instruction branches relatively to PC in either direction (PC - 63 destinationPC + 64). The parameter k is the
offset from PC and is represented in two’s complement form. (Equivalent to instruction BRBC 3,k.)
Operation:
(i)
If V = 0 then PC  PC + k + 1, else PC  PC + 1
Syntax:
Operands:
Program Counter:
(i)
BRVC k
-64  k  +63
PC  PC + k + 1
PC  PC + 1, if condition is false
16-bit Opcode:
1111
32.2
01kk
kkkk
k011
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
add
r3,r4
brvc noover
; Add r4 to r3
; Branch if no overflow
...
noover:
nop
Words: 1 (2 bytes)
Cycles: 1 if condition is false
2 if condition is true
42
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; Branch destination (do nothing)
33.
BRVS – Branch if Overflow Set
33.1
Description
Conditional relative branch. Tests the Overflow Flag (V) and branches relatively to PC if V is set. This instruction
branches relatively to PC in either direction (PC - 63 destinationPC + 64). The parameter k is the offset from
PC and is represented in two’s complement form. (Equivalent to instruction BRBS 3,k.)
Operation:
If V = 1 then PC  PC + k + 1, else PC  PC + 1
(i)
(i)
Syntax:
Operands:
Program Counter:
BRVS k
-64  k  +63
PC  PC + k + 1
PC  PC + 1, if condition is false
16-bit Opcode:
1111
33.2
00kk
kkkk
k011
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
add
r3,r4
; Add r4 to r3
brvs
overfl
; Branch if overflow
...
overfl:
nop
; Branch destination (do nothing)
Words: 1 (2 bytes)
Cycles: 1 if condition is false
2 if condition is true
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43
34.
BSET – Bit Set in SREG
34.1
Description
Sets a single Flag or bit in SREG.
Operation:
SREG(s)  1
(i)
(i)
Syntax:
Operands:
Program Counter:
BSET s
0s7
PC  PC + 1
16-bit Opcode:
1001
34.2
0100
0sss
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C








I:
1 if s = 7; Unchanged otherwise.
T:
1 if s = 6; Unchanged otherwise.
H:
1 if s = 5; Unchanged otherwise.
S:
1 if s = 4; Unchanged otherwise.
V:
1 if s = 3; Unchanged otherwise.
N:
1 if s = 2; Unchanged otherwise.
Z:
1 if s = 1; Unchanged otherwise.
C:
1 if s = 0; Unchanged otherwise.
Example:
bset
6
; Set T Flag
bset
7
; Enable interrupt
Words: 1 (2 bytes)
Cycles: 1
44
1000
Instruction Set Manual
0856J-AVR-07/2014
35.
BST – Bit Store from Bit in Register to T Flag in SREG
35.1
Description
Stores bit b from Rd to the T Flag in SREG (Status Register).
Operation:
T  Rd(b)
(i)
(i)
Syntax:
Operands:
Program Counter:
BST Rd,b
0  d  31, 0  b  7
PC  PC + 1
16-bit Opcode:
1111
35.2
101d
dddd
0bbb
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–

–
–
–
–
–
–
T:
0 if bit b in Rd is cleared. Set to 1 otherwise.
Example:
; Copy bit
bst
r1,2
; Store bit 2 of r1 in T Flag
bld
r0,4
; Load T into bit 4 of r0
Words: 1 (2 bytes)
Cycles: 1
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45
36.
CALL – Long Call to a Subroutine
36.1
Description
Calls to a subroutine within the entire Program memory. The return address (to the instruction after the CALL)
will be stored onto the Stack. (See also RCALL). The Stack Pointer uses a post-decrement scheme during
CALL.
This instruction is not available in all devices. Refer to the device specific instruction set summary.
Operation:
PC  k
PC  k
(i)
(ii)
Devices with 16 bits PC, 128KB Program memory maximum.
Devices with 22 bits PC, 8MB Program memory maximum.
Syntax:
Operands:
Program CounterStack:
(i)
CALL k
0  k  64K
PC  k
STACK  PC+2
SP  SP-2, (2 bytes, 16 bits)
(ii)
CALL k
0  k  4M
PC  k
STACK  PC+2
SP  SP-3 (3 bytes, 22 bits)
32-bit Opcode:
1001
kkkk
36.2
010k
kkkk
kkkk
kkkk
111k
kkkk
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
mov
r16,r0
call
check
nop
; Copy r0 to r16
; Call subroutine
; Continue (do nothing)
...
check: cpi
breq
r16,$42
error
ret
; Check if r16 has a special value
; Branch if equal
; Return from subroutine
...
error: rjmp
error
Words:
Cycles:
Cycles XMEGA®:
46
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; Infinite loop
2 (4 bytes)
4 devices with 16 bit PC
5 devices with 22 bit PC
3 devices with 16 bit PC
4 devices with 22 bit PC
37.
CBI – Clear Bit in I/O Register
37.1
Description
Clears a specified bit in an I/O Register. This instruction operates on the lower 32 I/O Registers – addresses 031.
Operation:
I/O(A,b)  0
(i)
(i)
Syntax:
Operands:
Program Counter:
CBI A,b
0  A  31, 0  b  7
PC  PC + 1
16-bit Opcode:
1001
37.2
1000
AAAA
Abbb
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
cbi
$12,7
Words:
Cycles:
Cycles XMEGA:
Cycles Reduced Core tinyAVR:
; Clear bit 7 in Port D
1 (2 bytes)
2
1
1
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47
38.
CBR – Clear Bits in Register
38.1
Description
Clears the specified bits in register Rd. Performs the logical AND between the contents of register Rd and the
complement of the constant mask K. The result will be placed in register Rd.
Operation:
Rd  Rd  ($FF - K)
(i)
(i)
Syntax:
Operands:
Program Counter:
CBR Rd,K
16  d  31, 0  K  255
PC  PC + 1
16-bit Opcode: (see ANDI with K complemented)
38.2
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–

0


–
S:
N  V, For signed tests.
V:
0
Cleared.
N:
R7
Set if MSB of the result is set; cleared otherwise.
Z:
R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $00; cleared otherwise.
R (Result) equals Rd after the operation.
Example:
cbr
r16,$F0
; Clear upper nibble of r16
cbr
r18,1
; Clear bit 0 in r18
Words: 1 (2 bytes)
Cycles: 1
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39.
CLC – Clear Carry Flag
39.1
Description
Clears the Carry Flag (C) in SREG (Status Register).
Operation:
C0
(i)
(i)
Syntax:
Operands:
Program Counter:
CLC
None
PC  PC + 1
16-bit Opcode:
1001
39.2
0100
1000
1000
Status Register (SREG) and Boolean Formula
C:
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
0
0
Carry Flag cleared.
Example:
add
r0,r0
clc
; Add r0 to itself
; Clear Carry Flag
Words: 1 (2 bytes)
Cycles: 1
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49
40.
CLH – Clear Half Carry Flag
40.1
Description
Clears the Half Carry Flag (H) in SREG (Status Register).
Operation:
H0
(i)
(i)
Syntax:
Operands:
Program Counter:
CLH
None
PC  PC + 1
16-bit Opcode:
1001
40.2
0100
1101
1000
Status Register (SREG) and Boolean Formula
H:
I
T
H
S
V
N
Z
C
–
–
0
–
–
–
–
–
0
Half Carry Flag cleared.
Example:
clh
Words: 1 (2 bytes)
Cycles: 1
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; Clear the Half Carry Flag
41.
CLI – Clear Global Interrupt Flag
41.1
Description
Clears the Global Interrupt Flag (I) in SREG (Status Register). The interrupts will be immediately disabled. No
interrupt will be executed after the CLI instruction, even if it occurs simultaneously with the CLI instruction.
Operation:
I0
(i)
(i)
Syntax:
Operands:
Program Counter:
CLI
None
PC  PC + 1
16-bit Opcode:
1001
41.2
0100
1111
1000
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
0
–
–
–
–
–
–
–
I:
0
Global Interrupt Flag cleared.
Example:
in
temp, SREG ; Store SREG value (temp must be defined by user)
cli
sbi
sbi
; Disable interrupts during timed sequence
EECR, EEMWE ; Start EEPROM write
EECR, EEWE
out
SREG, temp ; Restore SREG value (I-Flag)
Words: 1 (2 bytes)
Cycles: 1
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51
42.
CLN – Clear Negative Flag
42.1
Description
Clears the Negative Flag (N) in SREG (Status Register).
Operation:
N0
(i)
(i)
Syntax:
Operands:
Program Counter:
CLN
None
PC  PC + 1
16-bit Opcode:
1001
42.2
0100
1010
1000
Status Register (SREG) and Boolean Formula
N:
I
T
H
S
V
N
Z
C
–
–
–
–
–
0
–
–
0
Negative Flag cleared.
Example:
add
r2,r3
cln
Words: 1 (2 bytes)
Cycles: 1
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; Add r3 to r2
; Clear Negative Flag
43.
CLR – Clear Register
43.1
Description
Clears a register. This instruction performs an Exclusive OR between a register and itself. This will clear all bits
in the register.
Operation:
(i)
Rd  Rd  Rd
Syntax:
Operands:
Program Counter:
(i)
CLR Rd
0  d  31
PC  PC + 1
16-bit Opcode: (see EOR Rd,Rd)
0010
43.2
01dd
dddd
dddd
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
0
0
0
1
–
S:
0
Cleared.
V:
0
Cleared.
N:
0
Cleared.
Z:
1
Set.
R (Result) equals Rd after the operation.
Example:
loop:
clr
r18
; clear r18
inc
r18
; increase r18
r18,$50
; Compare r18 to $50
...
cpi
brne loop
Words: 1 (2 bytes)
Cycles: 1
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53
44.
CLS – Clear Signed Flag
44.1
Description
Clears the Signed Flag (S) in SREG (Status Register).
Operation:
S0
(i)
(i)
Syntax:
Operands:
Program Counter:
CLS
None
PC  PC + 1
16-bit Opcode:
1001
44.2
0100
1100
1000
Status Register (SREG) and Boolean Formula
S:
I
T
H
S
V
N
Z
C
–
–
–
0
–
–
–
–
0
Signed Flag cleared.
Example:
add
r2,r3
cls
Words: 1 (2 bytes)
Cycles: 1
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; Add r3 to r2
; Clear Signed Flag
45.
CLT – Clear T Flag
45.1
Description
Clears the T Flag in SREG (Status Register).
Operation:
T0
(i)
(i)
Syntax:
Operands:
Program Counter:
CLT
None
PC  PC + 1
16-bit Opcode:
1001
45.2
0100
1110
1000
Status Register (SREG) and Boolean Formula
T:
I
T
H
S
V
N
Z
C
–
0
–
–
–
–
–
–
0
T Flag cleared.
Example:
clt
; Clear T Flag
Words: 1 (2 bytes)
Cycles: 1
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55
46.
CLV – Clear Overflow Flag
46.1
Description
Clears the Overflow Flag (V) in SREG (Status Register).
Operation:
V0
(i)
(i)
Syntax:
Operands:
Program Counter:
CLV
None
PC  PC + 1
16-bit Opcode:
1001
46.2
0100
1011
1000
Status Register (SREG) and Boolean Formula
V:
I
T
H
S
V
N
Z
C
–
–
–
–
0
–
–
–
0
Overflow Flag cleared
Example:
add
r2,r3
clv
Words: 1 (2 bytes)
Cycles: 1
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; Add r3 to r2
; Clear Overflow Flag
47.
CLZ – Clear Zero Flag
47.1
Description
Clears the Zero Flag (Z) in SREG (Status Register).
Operation:
Z0
(i)
(i)
Syntax:
Operands:
Program Counter:
CLZ
None
PC  PC + 1
16-bit Opcode:
1001
47.2
0100
1001
1000
Status Register (SREG) and Boolean Formula
Z:
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
0
–
0
Zero Flag cleared.
Example:
add
clz
r2,r3
; Add r3 to r2
; Clear zero
Words: 1 (2 bytes)
Cycles: 1
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48.
COM – One’s Complement
48.1
Description
This instruction performs a One’s Complement of register Rd.
Operation:
Rd  $FF - Rd
(i)
(i)
Syntax:
Operands:
Program Counter:
COM Rd
0  d  31
PC  PC + 1
16-bit Opcode:
1001
48.2
010d
dddd
0000
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–

0


1
S:
NV
For signed tests.
V:
0
Cleared.
N:
R7
Set if MSB of the result is set; cleared otherwise.
Z:
R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $00; Cleared otherwise.
C:
1
Set.
R (Result) equals Rd after the operation.
Example:
com
r4
; Take one’s complement of r4
breq
zero
; Branch if zero
...
zero:
nop
Words: 1 (2 bytes)
Cycles: 1
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; Branch destination (do nothing)
49.
CP – Compare
49.1
Description
This instruction performs a compare between two registers Rd and Rr. None of the registers are changed. All
conditional branches can be used after this instruction.
Operation:
(i)
Rd - Rr
(i)
Syntax:
Operands:
Program Counter:
CP Rd,Rr
0  d  31, 0  r  31
PC  PC + 1
16-bit Opcode:
0001
49.2
01rd
dddd
rrrr
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–






H:
Rd3  Rr3 + Rr3  R3 + R3 Rd3
Set if there was a borrow from bit 3; cleared otherwise.
S:
N  V, For signed tests.
V:
Rd7 Rr7 R7 + Rd7  Rr7 R7
Set if two’s complement overflow resulted from the operation; cleared otherwise.
N:
R7
Set if MSB of the result is set; cleared otherwise.
Z:
R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $00; cleared otherwise.
C:
Rd7  Rr7 + Rr7 R7 + R7 Rd7
Set if the absolute value of the contents of Rr is larger than the absolute value of Rd; cleared otherwise.
R (Result) after the operation.
Example:
cp
r4,r19
brne noteq
; Compare r4 with r19
; Branch if r4 <> r19
...
noteq: nop
; Branch destination (do nothing)
Words: 1 (2 bytes)
Cycles: 1
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59
50.
50.1
CPC – Compare with Carry
Description
This instruction performs a compare between two registers Rd and Rr and also takes into account the previous
carry. None of the registers are changed. All conditional branches can be used after this instruction.
Operation:
(i)
Rd - Rr - C
(i)
Syntax:
Operands:
Program Counter:
CPC Rd,Rr
0  d  31, 0  r  31
PC  PC + 1
16-bit Opcode:
0000
50.2
01rd
dddd
rrrr
Status Register (SREG) and Boolean Formula
I
–
T
H
S
V
N
Z
C
–






H:
Rd3  Rr3 + Rr3  R3 + R3 Rd3
Set if there was a borrow from bit 3; cleared otherwise.
S:
N  V, For signed tests.
V:
Rd7 Rr7 R7 + Rd7 Rr7 R7
Set if two’s complement overflow resulted from the operation; cleared otherwise.
N:
R7
Set if MSB of the result is set; cleared otherwise.
Z:
R7 R6 R5 R4 R3 R2 R1 R0 Z
Previous value remains unchanged when the result is zero; cleared otherwise.
C:
Rd7  Rr7 + Rr7 R7 + R7 Rd7
Set if the absolute value of the contents of Rr plus previous carry is larger than the absolute value of Rd;
cleared otherwise.
R (Result) after the operation.
Example:
; Compare r3:r2 with r1:r0
cp
r2,r0
; Compare low byte
cpc
r3,r1
; Compare high byte
brne
noteq
; Branch if not equal
...
noteq: nop
Words: 1 (2 bytes)
Cycles: 1
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; Branch destination (do nothing)
51.
CPI – Compare with Immediate
51.1
Description
This instruction performs a compare between register Rd and a constant. The register is not changed. All
conditional branches can be used after this instruction.
Operation:
(i)
Rd - K
Syntax:
Operands:
Program Counter:
(i)
CPI Rd,K
16  d  31, 0  K  255
PC  PC + 1
16-bit Opcode:
0011
51.2
KKKK
dddd
KKKK
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–






H:
Rd3  K3 + K3 R3 + R3 Rd3
Set if there was a borrow from bit 3; cleared otherwise.
S:
N  V, For signed tests.
V:
Rd7 K7 R7 + Rd7  K7 R7
Set if two’s complement overflow resulted from the operation; cleared otherwise.
N:
R7
Set if MSB of the result is set; cleared otherwise.
Z:
R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $00; cleared otherwise.
C:
Rd7  K7 + K7 R7 + R7 Rd7
Set if the absolute value of K is larger than the absolute value of Rd; cleared otherwise.
R (Result) after the operation.
Example:
cpi
r19,3
; Compare r19 with 3
brne
error
; Branch if r19<>3
...
error:
nop
; Branch destination (do nothing)
Words: 1 (2 bytes)
Cycles: 1
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52.
CPSE – Compare Skip if Equal
52.1
Description
This instruction performs a compare between two registers Rd and Rr, and skips the next instruction if Rd = Rr.
Operation:
If Rd = Rr then PC  PC + 2 (or 3) else PC  PC + 1
(i)
(i)
Syntax:
Operands:
Program Counter:
CPSE Rd,Rr
0  d  31, 0  r  31
PC  PC + 1, Condition false - no skip
PC  PC + 2, Skip a one word instruction
PC  PC + 3, Skip a two word instruction
16-bit Opcode:
0001
52.2
00rd
dddd
rrrr
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
inc
r4
; Increase r4
cpse
r4,r0
; Compare r4 to r0
neg
r4
; Only executed if r4<>r0
nop
; Continue (do nothing)
Words: 1 (2 bytes)
Cycles: 1 if condition is false (no skip)
2 if condition is true (skip is executed) and the instruction skipped is 1 word
3 if condition is true (skip is executed) and the instruction skipped is 2 words
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53.
DEC – Decrement
53.1
Description
Subtracts one -1- from the contents of register Rd and places the result in the destination register Rd.
The C Flag in SREG is not affected by the operation, thus allowing the DEC instruction to be used on a loop
counter in multiple-precision computations.
When operating on unsigned values, only BREQ and BRNE branches can be expected to perform consistently.
When operating on two’s complement values, all signed branches are available.
Operation:
Rd  Rd - 1
(i)
(i)
Syntax:
Operands:
Program Counter:
DEC Rd
0  d  31
PC  PC + 1
16-bit Opcode:
1001
53.2
010d
dddd
1010
Status Register and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–




–
S:
NV
For signed tests.
V:
R7  R6  R5 R4 R3 R2 R1  R0
Set if two’s complement overflow resulted from the operation; cleared otherwise. Two’s complement
overflow occurs if and only if Rd was $80 before the operation.
N:
R7
Set if MSB of the result is set; cleared otherwise.
Z:
R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $00; Cleared otherwise.
R (Result) equals Rd after the operation.
Example:
loop:
ldi
r17,$10
; Load constant in r17
add
r1,r2
; Add r2 to r1
dec
r17
; Decrement r17
brne loop
; Branch if r17<>0
nop
; Continue (do nothing)
Words: 1 (2 bytes)
Cycles: 1
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54.
DES – Data Encryption Standard
54.1
Description
The module is an instruction set extension to the AVR CPU, performing DES iterations. The 64-bit data block
(plaintext or ciphertext) is placed in the CPU register file, registers R0-R7, where LSB of data is placed in LSB of
R0 and MSB of data is placed in MSB of R7. The full 64-bit key (including parity bits) is placed in registers R8R15, organized in the register file with LSB of key in LSB of R8 and MSB of key in MSB of R15. Executing one
DES instruction performs one round in the DES algorithm. Sixteen rounds must be executed in increasing order
to form the correct DES ciphertext or plaintext. Intermediate results are stored in the register file (R0-R15) after
each DES instruction. The instruction's operand (K) determines which round is executed, and the half carry flag
(H) determines whether encryption or decryption is performed.
The DES algorithm is described in “Specifications for the Data Encryption Standard” (Federal Information
Processing Standards Publication 46). Intermediate results in this implementation differ from the standard
because the initial permutation and the inverse initial permutation are performed each iteration. This does not
affect the result in the final ciphertext or plaintext, but reduces execution time.
Operation:
(i)
(i)
If H = 0 then
If H = 1 then
Encrypt round (R7-R0, R15-R8, K)
Decrypt round (R7-R0, R15-R8, K)
Syntax:
Operands:
Program Counter:
DES K
0x00K 0x0F
PC  PC + 1
16-bit Opcode:
1001
0100
KKKK
1011
Example:
DES 0x00
DES 0x01
…
DES 0x0E
DES 0x0F
Words: 1
Cycles: 1 (2(1))
Note:
1. If the DES instruction is succeeding a non-DES instruction, an extra cycle is inserted.
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55.
EICALL – Extended Indirect Call to Subroutine
55.1
Description
Indirect call of a subroutine pointed to by the Z (16 bits) Pointer Register in the Register File and the EIND
Register in the I/O space. This instruction allows for indirect calls to the entire 4M (words) Program memory
space. See also ICALL. The Stack Pointer uses a post-decrement scheme during EICALL.
This instruction is not available in all devices. Refer to the device specific instruction set summary.
Operation:
(i)
PC(15:0)  Z(15:0)
PC(21:16) EIND
Syntax:
Operands:
Program Counter:
Stack:
(i)
EICALL
None
See Operation
STACK  PC + 1
SP  SP - 3 (3 bytes, 22 bits)
16-bit Opcode:
1001
55.2
0101
0001
1001
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
ldi
r16,$05
out
EIND,r16
ldi
r30,$00
ldi
r31,$10
eicall
Words:
Cycles:
Cycles XMEGA:
; Set up EIND and Z-pointer
; Call to $051000
1 (2 bytes)
4 (only implemented in devices with 22 bit PC)
3 (only implemented in devices with 22 bit PC)
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56.
EIJMP – Extended Indirect Jump
56.1
Description
Indirect jump to the address pointed to by the Z (16 bits) Pointer Register in the Register File and the EIND
Register in the I/O space. This instruction allows for indirect jumps to the entire 4M (words) Program memory
space. See also IJMP.
This instruction is not available in all devices. Refer to the device specific instruction set summary.
Operation:
(i)
PC(15:0)  Z(15:0)
PC(21:16) EIND
(i)
EIJMP
Syntax:
Operands:
None
Program Counter:
Stack:
See Operation
Not Affected
16-bit Opcode:
1001
56.2
0100
0001
1001
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
ldi
r16,$05
out
EIND,r16
ldi
r30,$00
ldi
r31,$10
eijmp
Words: 1 (2 bytes)
Cycles: 2
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; Set up EIND and Z-pointer
; Jump to $051000
57.
ELPM – Extended Load Program Memory
57.1
Description
Loads one byte pointed to by the Z-register and the RAMPZ Register in the I/O space, and places this byte in
the destination register Rd. This instruction features a 100% space effective constant initialization or constant
data fetch. The Program memory is organized in 16-bit words while the Z-pointer is a byte address. Thus, the
least significant bit of the Z-pointer selects either low byte (ZLSB = 0) or high byte (ZLSB = 1). This instruction can
address the entire Program memory space. The Z-pointer Register can either be left unchanged by the
operation, or it can be incremented. The incrementation applies to the entire 24-bit concatenation of the RAMPZ
and Z-pointer Registers.
Devices with Self-Programming capability can use the ELPM instruction to read the Fuse and Lock bit value.
Refer to the device documentation for a detailed description.
This instruction is not available in all devices. Refer to the device specific instruction set summary.
The result of these combinations is undefined:
ELPM r30, Z+
ELPM r31, Z+
Operation:
Comment:
(i) R0  (RAMPZ:Z) RAMPZ:Z: Unchanged, R0 implied destination register
(ii) Rd  (RAMPZ:Z) RAMPZ:Z: Unchanged
(iii) Rd  (RAMPZ:Z)(RAMPZ:Z)  (RAMPZ:Z) + 1RAMPZ:Z: Post incremented
Syntax:Operands:
Program Counter:
(i) ELPMNone, R0 impliedPC  PC + 1
(ii) ELPM Rd, Z0  d  31PC  PC + 1
(iii) ELPM Rd, Z+0  d  31PC  PC + 1
16 bit Opcode:
(i)
(ii)
(iii)
1001
1001
1001
0101
000d
000d
1101
dddd
dddd
1000
0110
0111
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57.2
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
ldi
ZL, byte3(Table_1<<1); Initialize Z-pointer
out
RAMPZ, ZL
ldi
ZH, byte2(Table_1<<1)
ldi
ZL, byte1(Table_1<<1)
elpm r16, Z+
; Load constant from Program
; memory pointed to by RAMPZ:Z (Z is r31:r30)
...
Table_1:
.dw 0x3738
; 0x38 is addressed when ZLSB = 0
; 0x37 is addressed when ZLSB = 1
...
Words: 1 (2 bytes)
Cycles: 3
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58.
EOR – Exclusive OR
58.1
Description
Performs the logical EOR between the contents of register Rd and register Rr and places the result in the
destination register Rd.
Operation:
Rd  Rd  Rr
(i)
(i)
Syntax:
Operands:
Program Counter:
EOR Rd,Rr
0  d  31, 0  r  31
PC  PC + 1
16-bit Opcode:
0010
58.2
01rd
dddd
rrrr
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–

0


–
S:
N  V, For signed tests.
V:
0
Cleared.
N:
R7
Set if MSB of the result is set; cleared otherwise.
Z:
R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $00; cleared otherwise.
R (Result) equals Rd after the operation.
Example:
eor
r4,r4
; Clear r4
eor
r0,r22
; Bitwise exclusive or between r0 and r22
Words: 1 (2 bytes)
Cycles: 1
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59.
FMUL – Fractional Multiply Unsigned
59.1
Description
This instruction performs 8-bit  8-bit  16-bit unsigned multiplication and shifts the result one bit left.
Rd
Rr

Multiplicand
8
Multiplier

8
R1
R0
Product High
Product Low
16
Let (N.Q) denote a fractional number with N binary digits left of the radix point, and Q binary digits right of the
radix point. A multiplication between two numbers in the formats (N1.Q1) and (N2.Q2) results in the format
((N1+N2).(Q1+Q2)). For signal processing applications, the format (1.7) is widely used for the inputs, resulting
in a (2.14) format for the product. A left shift is required for the high byte of the product to be in the same format
as the inputs. The FMUL instruction incorporates the shift operation in the same number of cycles as MUL.
The (1.7) format is most commonly used with signed numbers, while FMUL performs an unsigned multiplication.
This instruction is therefore most useful for calculating one of the partial products when performing a signed
multiplication with 16-bit inputs in the (1.15) format, yielding a result in the (1.31) format. Note: the result of the
FMUL operation may suffer from a 2’s complement overflow if interpreted as a number in the (1.15) format. The
MSB of the multiplication before shifting must be taken into account, and is found in the carry bit. See the
following example.
The multiplicand Rd and the multiplier Rr are two registers containing unsigned fractional numbers where the
implicit radix point lies between bit 6 and bit 7. The 16-bit unsigned fractional product with the implicit radix point
between bit 14 and bit 15 is placed in R1 (high byte) and R0 (low byte).
This instruction is not available in all devices. Refer to the device specific instruction set summary.
Operation:
(i)
R1:R0  Rd  Rr
(unsigned (1.15)  unsigned (1.7) unsigned (1.7))
Syntax:
Operands:
Program Counter:
(i)
FMUL Rd,Rr
16  d  23, 16  r  23
PC  PC + 1
16-bit Opcode:
0000
70
0011
Instruction Set Manual
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0ddd
1rrr
59.2
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–


C:
R16
Set if bit 15 of the result before left shift is set; cleared otherwise.
Z:
R15 R14 R13 R12 R11 R10 R9 R8 R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $0000; cleared otherwise.
R (Result) equals R1,R0 after the operation.
Example:
;******************************************************************************
;* DESCRIPTION
;*Signed fractional multiply of two 16-bit numbers with 32-bit result.
;* USAGE
;*r19:r18:r17:r16 = ( r23:r22 * r21:r20 ) << 1
;******************************************************************************
fmuls16x16_32:
clrr2
fmulsr23, r21;((signed)ah * (signed)bh) << 1
movwr19:r18, r1:r0
fmulr22, r20;(al * bl) << 1
adcr18, r2
movwr17:r16, r1:r0
fmulsur23, r20;((signed)ah * bl) << 1
sbcr19, r2
addr17, r0
adcr18, r1
adcr19, r2
fmulsur21, r22;((signed)bh * al) << 1
sbcr19, r2
addr17, r0
adcr18, r1
adcr19, r2
Words: 1 (2 bytes)
Cycles: 2
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60.
FMULS – Fractional Multiply Signed
60.1
Description
This instruction performs 8-bit  8-bit  16-bit signed multiplication and shifts the result one bit left.
Rd
Rr

Multiplicand
R1

Multiplier
8
R0
Product High
8
Product Low
16
Let (N.Q) denote a fractional number with N binary digits left of the radix point, and Q binary digits right of the
radix point. A multiplication between two numbers in the formats (N1.Q1) and (N2.Q2) results in the format
((N1+N2).(Q1+Q2)). For signal processing applications, the format (1.7) is widely used for the inputs, resulting
in a (2.14) format for the product. A left shift is required for the high byte of the product to be in the same format
as the inputs. The FMULS instruction incorporates the shift operation in the same number of cycles as MULS.
The multiplicand Rd and the multiplier Rr are two registers containing signed fractional numbers where the
implicit radix point lies between bit 6 and bit 7. The 16-bit signed fractional product with the implicit radix point
between bit 14 and bit 15 is placed in R1 (high byte) and R0 (low byte).
Note that when multiplying 0x80 (-1) with 0x80 (-1), the result of the shift operation is 0x8000 (-1). The shift
operation thus gives a two’s complement overflow. This must be checked and handled by software.
This instruction is not available in all devices. Refer to the device specific instruction set summary.
Operation:
(i)
R1:R0  Rd  Rr
(signed (1.15)  signed (1.7) signed (1.7))
Syntax:
Operands:
Program Counter:
(i)
FMULS Rd,Rr
16  d  23, 16  r  23
PC  PC + 1
16-bit Opcode:
0000
60.2
0011
1ddd
0rrr
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–


C:
R16
Set if bit 15 of the result before left shift is set; cleared otherwise.
Z:
R15 R14 R13 R12 R11 R10 R9 R8 R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $0000; cleared otherwise.
R (Result) equals R1,R0 after the operation.
Example:
fmuls r23,r22
; Multiply signed r23 and r22 in (1.7) format, result in (1.15) format
movw r23:r22,r1:r0
; Copy result back in r23:r22
Words: 1 (2 bytes)
Cycles: 2
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61.
FMULSU – Fractional Multiply Signed with Unsigned
61.1
Description
This instruction performs 8-bit  8-bit  16-bit signed multiplication and shifts the result one bit left.
Rd
Multiplicand
Rr

8
Multiplier
R1

8
R0
Product High
Product Low
16
Let (N.Q) denote a fractional number with N binary digits left of the radix point, and Q binary digits right of the
radix point. A multiplication between two numbers in the formats (N1.Q1) and (N2.Q2) results in the format
((N1+N2).(Q1+Q2)). For signal processing applications, the format (1.7) is widely used for the inputs, resulting
in a (2.14) format for the product. A left shift is required for the high byte of the product to be in the same format
as the inputs. The FMULSU instruction incorporates the shift operation in the same number of cycles as
MULSU.
The (1.7) format is most commonly used with signed numbers, while FMULSU performs a multiplication with
one unsigned and one signed input. This instruction is therefore most useful for calculating two of the partial
products when performing a signed multiplication with 16-bit inputs in the (1.15) format, yielding a result in the
(1.31) format. Note: the result of the FMULSU operation may suffer from a 2's complement overflow if
interpreted as a number in the (1.15) format. The MSB of the multiplication before shifting must be taken into
account, and is found in the carry bit. See the following example.
The multiplicand Rd and the multiplier Rr are two registers containing fractional numbers where the implicit radix
point lies between bit 6 and bit 7. The multiplicand Rd is a signed fractional number, and the multiplier Rr is an
unsigned fractional number. The 16-bit signed fractional product with the implicit radix point between bit 14 and
bit 15 is placed in R1 (high byte) and R0 (low byte).
This instruction is not available in all devices. Refer to the device specific instruction set summary.
Operation:
(i)
(i)
R1:R0  Rd  Rr
(signed (1.15)  signed (1.7) unsigned (1.7))
Syntax:
Operands:
Program Counter:
FMULSU Rd,Rr
16  d  23, 16  r  23
PC  PC + 1
16-bit Opcode:
0000
0011
1ddd
1rrr
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61.2
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–


C:
R16
Set if bit 15 of the result before left shift is set; cleared otherwise.
Z:
R15 R14 R13 R12 R11 R10 R9 R8 R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $0000; cleared otherwise.
R (Result) equals R1,R0 after the operation.
Example:
;******************************************************************************
;* DESCRIPTION
;*Signed fractional multiply of two 16-bit numbers with 32-bit result.
;* USAGE
;*r19:r18:r17:r16 = ( r23:r22 * r21:r20 ) << 1
;******************************************************************************
fmuls16x16_32:
clrr2
fmulsr23, r21;((signed)ah * (signed)bh) << 1
movwr19:r18, r1:r0
fmulr22, r20;(al * bl) << 1
adcr18, r2
movwr17:r16, r1:r0
fmulsur23, r20;((signed)ah * bl) << 1
sbcr19, r2
addr17, r0
adcr18, r1
adcr19, r2
fmulsur21, r22;((signed)bh * al) << 1
sbcr19, r2
addr17, r0
adcr18, r1
adcr19, r2
Words: 1 (2 bytes)
Cycles: 2
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62.
ICALL – Indirect Call to Subroutine
62.1
Description
Calls to a subroutine within the entire 4M (words) Program memory. The return address (to the instruction after
the CALL) will be stored onto the Stack. See also RCALL. The Stack Pointer uses a post-decrement scheme
during CALL.
This instruction is not available in all devices. Refer to the device specific instruction set summary.
Operation:
(i)
(ii)
PC(15:0)  Z(15:0) Devices with 16 bits PC, 128KB Program memory maximum.
PC(15:0)  Z(15:0) Devices with 22 bits PC, 8MB Program memory maximum.
PC(21:16)  0
Syntax:
Operands:
Program Counter:
Stack:
(i)
ICALL
None
See Operation
STACK  PC + 1
SP  SP - 2 (2 bytes, 16 bits)
(ii)
ICALL
None
See Operation
STACK  PC + 1
SP  SP - 3 (3 bytes, 22 bits)
16-bit Opcode:
1001
62.2
0101
0000
1001
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
mov
icall
Words :
Cycles :
Cycles XMEGA:
r30,r0
; Set offset to call table
; Call routine pointed to by r31:r30
1 (2 bytes)
3 devices with 16 bit PC
4 devices with 22 bit PC
2 devices with 16 bit PC
3 devices with 22 bit PC
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63.
IJMP – Indirect Jump
63.1
Description
Indirect jump to the address pointed to by the Z (16 bits) Pointer Register in the Register File. The Z-pointer
Register is 16 bits wide and allows jump within the lowest 64K words (128KB) section of Program memory.
This instruction is not available in all devices. Refer to the device specific instruction set summary.
Operation:
(i)
(ii)
PC  Z(15:0)
Devices with 16 bits PC, 128KB Program memory maximum.
PC(15:0)  Z(15:0) Devices with 22 bits PC, 8MBMB Program memory maximum.
PC(21:16)  0
Syntax:
Operands:
Program Counter:
Stack:
(i), (ii)
IJMP
None
See Operation
Not Affected
16-bit Opcode:
1001
63.2
0100
0000
1001
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
mov
r30,r0
ijmp
Words: 1 (2 bytes)
Cycles: 2
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; Set offset to jump table
; Jump to routine pointed to by r31:r30
64.
IN - Load an I/O Location to Register
64.1
Description
Loads data from the I/O Space (Ports, Timers, Configuration Registers, etc.) into register Rd in the Register
File.
Operation:
Rd  I/O(A)
(i)
(i)
Syntax:
Operands:
Program Counter:
IN Rd,A
0  d  31, 0 A  63
PC  PC + 1
16-bit Opcode:
1011
64.2
0AAd
dddd
AAAA
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
in
r25,$16
; Read Port B
cpi
r25,4
; Compare read value to constant
breq
exit
; Branch if r25=4
...
exit:
nop
; Branch destination (do nothing)
Words: 1 (2 bytes)
Cycles: 1
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65.
INC – Increment
65.1
Description
Adds one -1- to the contents of register Rd and places the result in the destination register Rd.
The C Flag in SREG is not affected by the operation, thus allowing the INC instruction to be used on a loop
counter in multiple-precision computations.
When operating on unsigned numbers, only BREQ and BRNE branches can be expected to perform
consistently. When operating on two’s complement values, all signed branches are available.
Operation:
Rd  Rd + 1
(i)
(i)
Syntax:
Operands:
Program Counter:
INC Rd
0  d  31
PC  PC + 1
16-bit Opcode:
1001
65.2
010d
dddd
0011
Status Register and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–




–
S:
NV
For signed tests.
V:
R7 R6 R5 R4 R3 R2 R1 R0
Set if two’s complement overflow resulted from the operation; cleared otherwise. Two’s complement
overflow occurs if and only if Rd was $7F before the operation.
N:
R7
Set if MSB of the result is set; cleared otherwise.
Z:
R7 R6 R5 R4R3 R2 R1 R0
Set if the result is $00; Cleared otherwise.
R (Result) equals Rd after the operation.
Example:
loop:
clr
r22
; clear r22
inc
r22
; increment r22
cpi
r22,$4F
; Compare r22 to $4f
brne
loop
; Branch if not equal
...
nop
; Continue (do nothing)
Words:
Cycles: 1
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1 (2 bytes)
66.
JMP – Jump
66.1
Description
Jump to an address within the entire 4M (words) Program memory. See also RJMP.
This instruction is not available in all devices. Refer to the device specific instruction set summary.
Operation:
(i)
PC  k
Syntax:
Operands:
Program Counter:
Stack:
(i)
JMP k
0  k  4M
PC  k
Unchanged
32-bit Opcode:
1001
kkkk
66.2
010k
kkkk
kkkk
kkkk
110k
kkkk
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
mov
r1,r0
; Copy r0 to r1
jmp
farplc
; Unconditional jump
...
farplc: nop
; Jump destination (do nothing)
Words: 2 (4 bytes)
Cycles: 3
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67.
LAC – Load and Clear
67.1
Description
Load one byte indirect from data space to register and stores an clear the bits in data space specified by the
register. The instruction can only be used towards internal SRAM.
The data location is pointed to by the Z (16 bits) Pointer Register in the Register File. Memory access is limited
to the current data segment of 64KB. To access another data segment in devices with more than 64KB data
space, the RAMPZ in register in the I/O area has to be changed.
The Z-pointer Register is left unchanged by the operation. This instruction is especially suited for clearing status
bits stored in SRAM.
Operation:
(Z)  ($FF – Rd)  (Z), Rd (Z)
(i)
(i)
Syntax:
Operands:
Program Counter:
LAC Z,Rd
0  d  31
PC  PC + 1
16-bit Opcode:
1001
67.2
001r
0110
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Words: 1 (2 bytes)
Cycles: 2
80
rrrr
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68.
LAS – Load and Set
68.1
Description
Load one byte indirect from data space to register and set bits in data space specified by the register. The
instruction can only be used towards internal SRAM.
The data location is pointed to by the Z (16 bits) Pointer Register in the Register File. Memory access is limited
to the current data segment of 64KB. To access another data segment in devices with more than 64KB data
space, the RAMPZ in register in the I/O area has to be changed.
The Z-pointer Register is left unchanged by the operation. This instruction is especially suited for setting status
bits stored in SRAM.
Operation:
(Z)  Rd v (Z), Rd  (Z)
(i)
(i)
Syntax:
Operands:
Program Counter:
LAS Z,Rd
0  d  31
PC  PC + 1
16-bit Opcode:
1001
68.2
001r
rrrr
0101
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Words: 1 (2 bytes)
Cycles: 2
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69.
LAT – Load and Toggle
69.1
Description
Load one byte indirect from data space to register and toggles bits in the data space specified by the register.
The instruction can only be used towards SRAM.
The data location is pointed to by the Z (16 bits) Pointer Register in the Register File. Memory access is limited
to the current data segment of 64KB. To access another data segment in devices with more than 64KB data
space, the RAMPZ in register in the I/O area has to be changed.
The Z-pointer Register is left unchanged by the operation. This instruction is especially suited for changing
status bits stored in SRAM.
Operation:
(i)
(Z)  Rd (Z), Rd  (Z)
Syntax:
Operands:
Program Counter:
(i)
LAT Z,Rd
0  d  31
PC  PC + 1
16-bit Opcode:
1001
69.2
001r
0111
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Words: 1 (2 bytes)
Cycles: 2
82
rrrr
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70.
LD – Load Indirect from Data Space to Register using Index X
70.1
Description
Loads one byte indirect from the data space to a register. For parts with SRAM, the data space consists of the
Register File, I/O memory and internal SRAM (and external SRAM if applicable). For parts without SRAM, the
data space consists of the Register File only. In some parts the Flash Memory has been mapped to the data
space and can be read using this command. The EEPROM has a separate address space.
The data location is pointed to by the X (16 bits) Pointer Register in the Register File. Memory access is limited
to the current data segment of 64KB. To access another data segment in devices with more than 64KB data
space, the RAMPX in register in the I/O area has to be changed.
The X-pointer Register can either be left unchanged by the operation, or it can be post-incremented or predecremented. These features are especially suited for accessing arrays, tables, and Stack Pointer usage of the
X-pointer Register. Note that only the low byte of the X-pointer is updated in devices with no more than 256
bytes data space. For such devices, the high byte of the pointer is not used by this instruction and can be used
for other purposes. The RAMPX Register in the I/O area is updated in parts with more than 64KB data space or
more than 64KB Program memory, and the increment/decrement is added to the entire 24-bit address on such
devices.
Not all variants of this instruction is available in all devices. Refer to the device specific instruction set summary.
In the Reduced Core tinyAVR the LD instruction can be used to achieve the same operation as LPM since the
program memory is mapped to the data memory space.
The result of these combinations is undefined:
LD r26, X+
LD r27, X+
LD r26, -X
LD r27, -X
Using the X-pointer:
(i)
(ii)
(iii)
(i)
(ii)
(iii)
Operation:
Comment:
Rd  (X)
Rd  (X)
XX-1
XX+1
Rd  (X)
X: Unchanged
X: Post incremented
X: Pre decremented
Syntax:
Operands:
Program Counter:
LD Rd, X
LD Rd, X+
LD Rd, -X
0  d  31
0  d  31
0  d  31
PC  PC + 1
PC  PC + 1
PC  PC + 1
16-bit Opcode:
(i)
(ii)
(iii)
1001
1001
1001
000d
000d
000d
dddd
dddd
dddd
1100
1101
1110
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70.2
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
clr
r27
; Clear X high byte
ldi
r26,$60
; Set X low byte to $60
ld
r0,X+
; Load r0 with data space loc. $60(X post inc)
ld
r1,X
; Load r1 with data space loc. $61
ldi
r26,$63
; Set X low byte to $63
ld
r2,X
; Load r2 with data space loc. $63
ld
r3,–X
; Load r3 with data space loc. $62(X pre dec)
Words: 1 (2 bytes)
Cycles:
(i) 1(2)
(ii) 2
(iii) 3(2)
Cycles XMEGA:
(i) 1(1)
(ii) 1(1)
(iii) 2(1)
Notes: 1. IF the LD instruction is accessing internal SRAM, one extra cycle is inserted.
2. LD instruction can load data from program memory since the flash is memory mapped. Loading data from the
data memory takes one clock cycle, and loading from the program memory takes two clock cycles. But if an
interrupt occur (before the last clock cycle) no additional clock cycles is necessary when loading from the program memory. Hence, the instruction takes only one clock cycle to execute.
LD instruction with pre-decrement can load data from program memory since the flash is memory mapped.
Loading data from the data memory takes two clock cycles, and loading from the program memory takes three
clock cycles. But if an interrupt occur (before the last clock cycle) no additional clock cycles is necessary when
loading from the program memory. Hence, the instruction takes only one clock cycle to execute.
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71.
LD (LDD) – Load Indirect from Data Space to Register using Index Y
71.1
Description
Loads one byte indirect with or without displacement from the data space to a register. For parts with SRAM, the
data space consists of the Register File, I/O memory and internal SRAM (and external SRAM if applicable). For
parts without SRAM, the data space consists of the Register File only. In some parts the Flash Memory has
been mapped to the data space and can be read using this command. The EEPROM has a separate address
space.
The data location is pointed to by the Y (16 bits) Pointer Register in the Register File. Memory access is limited
to the current data segment of 64KB. To access another data segment in devices with more than 64KB data
space, the RAMPY in register in the I/O area has to be changed.
The Y-pointer Register can either be left unchanged by the operation, or it can be post-incremented or predecremented. These features are especially suited for accessing arrays, tables, and Stack Pointer usage of the
Y-pointer Register. Note that only the low byte of the Y-pointer is updated in devices with no more than 256
bytes data space. For such devices, the high byte of the pointer is not used by this instruction and can be used
for other purposes. The RAMPY Register in the I/O area is updated in parts with more than 64KB data space or
more than 64KB Program memory, and the increment/decrement/displacement is added to the entire 24-bit
address on such devices.
Not all variants of this instruction is available in all devices. Refer to the device specific instruction set summary.
In the Reduced Core tinyAVR the LD instruction can be used to achieve the same operation as LPM since the
program memory is mapped to the data memory space.
The result of these combinations is undefined:
LD r28, Y+
LD r29, Y+
LD r28, -Y
LD r29, -Y
Using the Y-pointer:
Operation:
(i)
(ii)
(iii)
(iv)
(i)
(ii)
(iii)
(iv)
Comment:
Rd  (Y)
Rd  (Y)
YY-1
Rd  (Y+q)
YY+1
Rd  (Y)
Y: Unchanged
Y: Post incremented
Y: Pre decremented
Y: Unchanged, q: Displacement
Syntax:
Operands:
Program Counter:
LD Rd, Y
LD Rd, Y+
LD Rd, -Y
LDD Rd, Y+q
0  d  31
0  d  31
0  d  31
0  d  31, 0  q  63
PC  PC + 1
PC  PC + 1
PC  PC + 1
PC  PC + 1
16-bit Opcode:
(i)
(ii)
(iii)
(iv)
1000
1001
1001
10q0
000d
000d
000d
qq0d
dddd
dddd
dddd
dddd
1000
1001
1010
1qqq
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71.2
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
clr
r29
; Clear Y high byte
ldi
r28,$60
; Set Y low byte to $60
ld
r0,Y+
; Load r0 with data space loc. $60(Y post inc)
ld
r1,Y
; Load r1 with data space loc. $61
ldi
r28,$63
; Set Y low byte to $63
ld
r2,Y
; Load r2 with data space loc. $63
ld
r3,-Y
; Load r3 with data space loc. $62(Y pre dec)
ldd
r4,Y+2
; Load r4 with data space loc. $64
Words: 1 (2 bytes)
Cycles:
(i) 1(2)
(ii) 2
(iii) 3(2)
Cycles XMEGA:
(i) 1(1)
(ii) 1(1)
(iii) 2(1)
(iv) 2(1)
Notes: 1. IF the LD instruction is accessing internal SRAM, one extra cycle is inserted.
2. LD instruction can load data from program memory since the flash is memory mapped. Loading data from the
data memory takes one clock cycle, and loading from the program memory takes two clock cycles. But if an
interrupt occur (before the last clock cycle) no additional clock cycles is necessary when loading from the program memory. Hence, the instruction takes only one clock cycle to execute.
LD instruction with pre-decrement can load data from program memory since the flash is memory mapped.
Loading data from the data memory takes two clock cycles, and loading from the program memory takes three
clock cycles. But if an interrupt occur (before the last clock cycle) no additional clock cycles is necessary when
loading from the program memory. Hence, the instruction takes only one clock cycle to execute.
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72.
LD (LDD) – Load Indirect From Data Space to Register using Index Z
72.1
Description
Loads one byte indirect with or without displacement from the data space to a register. For parts with SRAM, the
data space consists of the Register File, I/O memory and internal SRAM (and external SRAM if applicable). For
parts without SRAM, the data space consists of the Register File only. In some parts the Flash Memory has
been mapped to the data space and can be read using this command. The EEPROM has a separate address
space.
The data location is pointed to by the Z (16 bits) Pointer Register in the Register File. Memory access is limited
to the current data segment of 64KB. To access another data segment in devices with more than 64KB data
space, the RAMPZ in register in the I/O area has to be changed.
The Z-pointer Register can either be left unchanged by the operation, or it can be post-incremented or predecremented. These features are especially suited for Stack Pointer usage of the Z-pointer Register, however
because the Z-pointer Register can be used for indirect subroutine calls, indirect jumps and table lookup, it is
often more convenient to use the X or Y-pointer as a dedicated Stack Pointer. Note that only the low byte of the
Z-pointer is updated in devices with no more than 256 bytes data space. For such devices, the high byte of the
pointer is not used by this instruction and can be used for other purposes. The RAMPZ Register in the I/O area
is updated in parts with more than 64KB data space or more than 64KB Program memory, and the
increment/decrement/displacement is added to the entire 24-bit address on such devices.
Not all variants of this instruction is available in all devices. Refer to the device specific instruction set summary.
In the Reduced Core tinyAVR the LD instruction can be used to achieve the same operation as LPM since the
program memory is mapped to the data memory space.
For using the Z-pointer for table lookup in Program memory see the LPM and ELPM instructions.
The result of these combinations is undefined:
LD r30, Z+
LD r31, Z+
LD r30, -Z
LD r31, -Z
Using the Z-pointer:
Operation:
(i)
(ii)
(iii)
(iv)
(i)
(ii)
(iii)
(iv)
Comment:
Rd  (Z)
Rd  (Z)
Z  Z -1
Rd  (Z+q)
ZZ+1
Rd  (Z)
Z: Unchanged
Z: Post increment
Z: Pre decrement
Z: Unchanged, q: Displacement
Syntax:
Operands:
Program Counter:
LD Rd, Z
LD Rd, Z+
LD Rd, -Z
LDD Rd, Z+q
0  d  31
0  d  31
0  d  31
0  d  31, 0  q  63
PC  PC + 1
PC  PC + 1
PC  PC + 1
PC  PC + 1
16-bit Opcode:
(i)
(ii)
(iii)
(iv)
1000
1001
1001
10q0
000d
000d
000d
qq0d
dddd
dddd
dddd
dddd
0000
0001
0010
0qqq
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72.2
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
clr
r31
; Clear Z high byte
ldi
r30,$60
; Set Z low byte to $60
ld
r0,Z+
; Load r0 with data space loc. $60(Z post inc)
ld
r1,Z
; Load r1 with data space loc. $61
ldi
r30,$63
; Set Z low byte to $63
ld
r2,Z
; Load r2 with data space loc. $63
ld
r3,-Z
; Load r3 with data space loc. $62(Z pre dec)
ldd
r4,Z+2
; Load r4 with data space loc. $64
Words: 1 (2 bytes)
Cycles:
(i) 1(2)
(ii) 2
(iii) 3(2)
Cycles XMEGA:
(i) 1(1)
(ii) 1(1)
(iii) 2(1)
(iv) 2(1)
Notes: 1. IF the LD instruction is accessing internal SRAM, one extra cycle is inserted.
2. LD instruction can load data from program memory since the flash is memory mapped. Loading data from the
data memory takes one clock cycle, and loading from the program memory takes two clock cycles. But if an
interrupt occur (before the last clock cycle) no additional clock cycles is necessary when loading from the program memory. Hence, the instruction takes only one clock cycle to execute.
LD instruction with pre-decrement can load data from program memory since the flash is memory mapped.
Loading data from the data memory takes two clock cycles, and loading from the program memory takes three
clock cycles. But if an interrupt occur (before the last clock cycle) no additional clock cycles is necessary when
loading from the program memory. Hence, the instruction takes only one clock cycle to execute.
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73.
LDI – Load Immediate
73.1
Description
Loads an 8 bit constant directly to register 16 to 31.
Operation:
Rd  K
(i)
(i)
Syntax:
Operands:
Program Counter:
LDI Rd,K
16  d  31, 0  K  255
PC  PC + 1
16-bit Opcode:
1110
73.2
KKKK
dddd
KKKK
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
clr
r31
; Clear Z high byte
ldi
r30,$F0
; Set Z low byte to $F0
lpm
; Load constant from Program
; memory pointed to by Z
Words: 1 (2 bytes)
Cycles: 1
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74.
LDS – Load Direct from Data Space
74.1
Description
Loads one byte from the data space to a register. For parts with SRAM, the data space consists of the Register
File, I/O memory and internal SRAM (and external SRAM if applicable). For parts without SRAM, the data space
consists of the register file only. The EEPROM has a separate address space.
A 16-bit address must be supplied. Memory access is limited to the current data segment of 64KB. The LDS
instruction uses the RAMPD Register to access memory above 64KB. To access another data segment in
devices with more than 64KB data space, the RAMPD in register in the I/O area has to be changed.
This instruction is not available in all devices. Refer to the device specific instruction set summary.
Operation:
Rd  (k)
(i)
(i)
Syntax:
Operands:
Program Counter:
LDS Rd,k
0  d  31, 0  k  65535
PC  PC + 2
32-bit Opcode:
1001
kkkk
74.2
000d
kkkk
dddd
kkkk
0000
kkkk
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
lds
r2,$FF00
; Load r2 with the contents of data space location $FF00
add
r2,r1
; add r1 to r2
sts
$FF00,r2
; Write back
Words:
Cycles:
Cycles XMEGA:
90
2 (4 bytes)
2
2 If the LDS instruction is accessing internal SRAM, one extra cycle is inserted
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75.
LDS (16-bit) – Load Direct from Data Space
75.1
Description
Loads one byte from the data space to a register. For parts with SRAM, the data space consists of the Register
File, I/O memory and internal SRAM (and external SRAM if applicable). For parts without SRAM, the data space
consists of the register file only. In some parts the Flash memory has been mapped to the data space and can
be read using this command. The EEPROM has a separate address space.
A 7-bit address must be supplied. The address given in the instruction is coded to a data space address as
follows:
ADDR[7:0] = (INST[8], INST[8], INST[10], INST[9], INST[3], INST[2], INST[1], INST[0])
Memory access is limited to the address range 0x40...0xbf.
This instruction is not available in all devices. Refer to the device specific instruction set summary.
Operation:
Rd  (k)
(i)
(i)
Syntax:
Operands:
Program Counter:
LDS Rd,k
16  d  31, 0  k  127
PC  PC + 1
16-bit Opcode:
1010
75.2
0kkk
dddd
kkkk
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
lds
r16,$00
; Load r16 with the contents of data space location $00
add
r16,r17
; add r17 to r16
sts
$00,r16
; Write result to the same address it was fetched from
Words: 1 (2 bytes)
Cycles: 1
Note:
Registers r0...r15 are remapped to r16...r31.
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76.
LPM – Load Program Memory
76.1
Description
Loads one byte pointed to by the Z-register into the destination register Rd. This instruction features a 100%
space effective constant initialization or constant data fetch. The Program memory is organized in 16-bit words
while the Z-pointer is a byte address. Thus, the least significant bit of the Z-pointer selects either low byte (ZLSB
= 0) or high byte (ZLSB = 1). This instruction can address the first 64KB (32K words) of Program memory. The Zpointer Register can either be left unchanged by the operation, or it can be incremented. The incrementation
does not apply to the RAMPZ Register.
Devices with Self-Programming capability can use the LPM instruction to read the Fuse and Lock bit values.
Refer to the device documentation for a detailed description.
The LPM instruction is not available in all devices. Refer to the device specific instruction set summary.
The result of these combinations is undefined:
LPM r30, Z+
LPM r31, Z+
(i)
(ii)
(iii)
(i)
(ii)
(iii)
Operation:
Comment:
R0  (Z)
Rd  (Z)
Rd  (Z)
ZZ+1
Z: Unchanged, R0 implied destination register
Z: Unchanged
Z: Post incremented
Syntax:
Operands:
Program Counter:
LPM
LPM Rd, Z
LPM Rd, Z+
None, R0 implied
0  d  31
0  d  31
PC  PC + 1
PC  PC + 1
PC  PC + 1
16-bit Opcode:
(i)
(ii)
(iii)
1001
1001
1001
0101
000d
000d
1100
dddd
dddd
1000
0100
0101
Status Register (SREG) and Boolean Formula:
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
ldi
ZH, high(Table_1<<1); Initialize Z-pointer
ldi
ZL, low(Table_1<<1)
lpm
r16, Z
; Load constant from Program
; Memory pointed to by Z (r31:r30)
...
Table_1:
.dw 0x5876
; 0x76 is addresses when ZLSB = 0
; 0x58 is addresses when ZLSB = 1
...
Words: 1 (2 bytes)
Cycles: 3
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77.
LSL – Logical Shift Left
77.1
Description
Shifts all bits in Rd one place to the left. Bit 0 is cleared. Bit 7 is loaded into the C Flag of the SREG. This
operation effectively multiplies signed and unsigned values by two.
Operation:
(i)


C
(i)
 0
b7 - - - - - - - - - - - - - - - - - - b0
Syntax:
Operands:
Program Counter:
LSL Rd
0  d  31
PC  PC + 1
16-bit Opcode: (see ADD Rd,Rd)
0000
77.2
11dd
dddd
dddd
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–






H:
Rd3
S:
N  V, for signed tests.
V:
N  C, for N and C after the shift.
N:
R7
Set if MSB of the result is set; cleared otherwise.
Z:
R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $00; cleared otherwise.
C:
Rd7
Set if, before the shift, the MSB of Rd was set; cleared otherwise.
R (Result) equals Rd after the operation.
Example:
add
r0,r4
; Add r4 to r0
lsl
r0
; Multiply r0 by 2
Words: 1 (2 bytes)
Cycles: 1
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78.
LSR – Logical Shift Right
78.1
Description
Shifts all bits in Rd one place to the right. Bit 7 is cleared. Bit 0 is loaded into the C Flag of the SREG. This
operation effectively divides an unsigned value by two. The C Flag can be used to round the result.
Operation:

0 
(i)
b7 - - - - - - - - - - - - - - - - - - b0
 C
Syntax:
Operands:
Program Counter:
LSR Rd
0  d  31
PC  PC + 1
16-bit Opcode:
1001
78.2
010d
dddd
0110
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–


0


S:
N  V, for signed tests.
V:
N  C, for N and C after the shift.
N:
0
Z:
R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $00; cleared otherwise.
C:
Rd0
Set if, before the shift, the LSB of Rd was set; cleared otherwise.
R (Result) equals Rd after the operation.
Example:
add
r0,r4
; Add r4 to r0
lsr
r0
; Divide r0 by 2
Words: 1 (2 bytes)
Cycles: 1
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79.
MOV – Copy Register
79.1
Description
This instruction makes a copy of one register into another. The source register Rr is left unchanged, while the
destination register Rd is loaded with a copy of Rr.
Operation:
(i)
Rd  Rr
Syntax:
Operands:
Program Counter:
(i)
MOV Rd,Rr
0  d  31, 0  r  31
PC  PC + 1
16-bit Opcode:
0010
79.2
11rd
dddd
rrrr
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
mov
r16,r0
; Copy r0 to r16
call
check
; Call subroutine
r16,$11
; Compare r16 to $11
...
check:
cpi
...
ret
; Return from subroutine
Words: 1 (2 bytes)
Cycles: 1
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80.
MOVW – Copy Register Word
80.1
Description
This instruction makes a copy of one register pair into another register pair. The source register pair Rr+1:Rr is
left unchanged, while the destination register pair Rd+1:Rd is loaded with a copy of Rr + 1:Rr.
This instruction is not available in all devices. Refer to the device specific instruction set summary.
Operation:
Rd+1:Rd  Rr+1:Rr
(i)
Syntax:
Operands:
Program Counter:
MOVW Rd+1:Rd,Rr+1Rrd  {0,2,...,30}, r  {0,2,...,30}
(i)
PC  PC + 1
16-bit Opcode:
0000
80.2
0001
dddd
rrrr
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
movw
r17:16,r1:r0 ; Copy r1:r0 to r17:r16
call
check
; Call subroutine
r16,$11
; Compare r16 to $11
r17,$32
; Compare r17 to $32
...
check:
cpi
...
cpi
...
ret
Words: 1 (2 bytes)
Cycles: 1
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; Return from subroutine
81.
MUL – Multiply Unsigned
81.1
Description
This instruction performs 8-bit  8-bit  16-bit unsigned multiplication.
Rd
Rr
Multiplicand


Multiplier
8
R1
R0
Product High
Product Low
8
16
The multiplicand Rd and the multiplier Rr are two registers containing unsigned numbers. The 16-bit unsigned
product is placed in R1 (high byte) and R0 (low byte). Note that if the multiplicand or the multiplier is selected
from R0 or R1 the result will overwrite those after multiplication.
This instruction is not available in all devices. Refer to the device specific instruction set summary.
Operation:
(i)
(i)
R1:R0  Rd  Rr
(unsigned  unsignedunsigned)
Syntax:
Operands:
Program Counter:
MUL Rd,Rr
0  d  31, 0  r  31
PC  PC + 1
16-bit Opcode:
1001
81.2
11rd
dddd
rrrr
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–


C:
R15
Set if bit 15 of the result is set; cleared otherwise.
Z:
R15 R14 R13 R12 R11 R10 R9 R8 R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $0000; cleared otherwise.
R (Result) equals R1,R0 after the operation.
Example:
mul
r5,r4
movw r4,r0
; Multiply unsigned r5 and r4
; Copy result back in r5:r4
Words: 1 (2 bytes)
Cycles: 2
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82.
MULS – Multiply Signed
82.1
Description
This instruction performs 8-bit  8-bit  16-bit signed multiplication.
Rd
Rr

Multiplicand
R1

Multiplier
8
R0
Product High
8
Product Low
16
The multiplicand Rd and the multiplier Rr are two registers containing signed numbers. The 16-bit signed
product is placed in R1 (high byte) and R0 (low byte).
This instruction is not available in all devices. Refer to the device specific instruction set summary.
Operation:
(i)
(i)
R1:R0  Rd  Rr
(signed  signedsigned)
Syntax:
Operands:
Program Counter:
MULS Rd,Rr
16  d  31, 16  r  31
PC  PC + 1
16-bit Opcode:
0000
82.2
0010
dddd
rrrr
Status Register (SREG) and Boolean Formula
I
T
–
–
H
–
S
–
V
–
N
Z
C
–


C:
R15
Set if bit 15 of the result is set; cleared otherwise.
Z:
R15 R14 R13 R12 R11 R10 R9 R8 R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $0000; cleared otherwise.
R (Result) equals R1,R0 after the operation.
Example:
muls r21,r20
; Multiply signed r21 and r20
movw r20,r0
; Copy result back in r21:r20
Words: 1 (2 bytes)
Cycles: 2
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83.
MULSU – Multiply Signed with Unsigned
83.1
Description
This instruction performs 8-bit  8-bit  16-bit multiplication of a signed and an unsigned number.
Rd
Rr
Multiplicand


Multiplier
8
R1
R0
Product High
Product Low
8
16
The multiplicand Rd and the multiplier Rr are two registers. The multiplicand Rd is a signed number, and the
multiplier Rr is unsigned. The 16-bit signed product is placed in R1 (high byte) and R0 (low byte).
This instruction is not available in all devices. Refer to the device specific instruction set summary.
Operation:
(i)
(i)
R1:R0  Rd  Rr
(signed  signedunsigned)
Syntax:
Operands:
Program Counter:
MULSU Rd,Rr
16  d  23, 16  r  23
PC  PC + 1
16-bit Opcode:
0000
83.2
0011
0ddd
0rrr
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–


C:
R15
Set if bit 15 of the result is set; cleared otherwise.
Z:
R15 R14 R13 R12 R11 R10 R9 R8 R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $0000; cleared otherwise.
R (Result) equals R1,R0 after the operation.
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Example:
;******************************************************************************
;* DESCRIPTION
;*Signed multiply of two 16-bit numbers with 32-bit result.
;* USAGE
;*r19:r18:r17:r16 = r23:r22 * r21:r20
;******************************************************************************
muls16x16_32:
clrr2
mulsr23, r21; (signed)ah * (signed)bh
movwr19:r18, r1:r0
mulr22, r20; al * bl
movwr17:r16, r1:r0
mulsur23, r20; (signed)ah * bl
sbcr19, r2
addr17, r0
adcr18, r1
adcr19, r2
mulsur21, r22; (signed)bh * al
sbcr19, r2
addr17, r0
adcr18, r1
adcr19, r2
ret
Words: 1 (2 bytes)
Cycles: 2
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84.
NEG – Two’s Complement
84.1
Description
Replaces the contents of register Rd with its two’s complement; the value $80 is left unchanged.
Operation:
Rd  $00 - Rd
(i)
(i)
Syntax:
Operands:
Program Counter:
NEG Rd
0  d  31
PC  PC + 1
16-bit Opcode:
1001
84.2
010d
dddd
0001
Status Register (SREG) and Boolean Formula
I
–
T
H
S
V
N
Z
C
–






H:
R3 + Rd3
Set if there was a borrow from bit 3; cleared otherwise.
S:
NV
For signed tests.
V:
R7 R6 R5 R4 R3 R2R1 R0
Set if there is a two’s complement overflow from the implied subtraction from zero; cleared otherwise. A
two’s complement overflow will occur if and only if the contents of the Register after operation (Result) is
$80.
N:
R7
Set if MSB of the result is set; cleared otherwise.
Z:
R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $00; Cleared otherwise.
C:
R7 + R6 + R5 + R4 + R3 + R2 + R1 + R0
Set if there is a borrow in the implied subtraction from zero; cleared otherwise. The C Flag will be set in
all cases except when the contents of Register after operation is $00.
R (Result) equals Rd after the operation.
Example:
sub
positive:
r11,r0
; Subtract r0 from r11
brpl positive
; Branch if result positive
neg
; Take two’s complement of r11
nop
r11
; Branch destination (do nothing)
Words: 1 (2 bytes)
Cycles: 1
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85.
NOP – No Operation
85.1
Description
This instruction performs a single cycle No Operation.
Operation:
(i)
No
(i)
Syntax:
Operands:
Program Counter:
NOP
None
PC  PC + 1
16-bit Opcode:
0000
85.2
0000
0000
0000
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
clr
r16
; Clear r16
ser
r17
; Set r17
out
$18,r16
; Write zeros to Port B
nop
out
; Wait (do nothing)
$18,r17
Words: 1 (2 bytes)
Cycles: 1
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; Write ones to Port B
86.
OR – Logical OR
86.1
Description
Performs the logical OR between the contents of register Rd and register Rr and places the result in the
destination register Rd.
Operation:
Rd  Rd v Rr
(i)
(i)
Syntax:
Operands:
Program Counter:
OR Rd,Rr
0  d  31, 0  r  31
PC  PC + 1
16-bit Opcode:
0010
86.2
10rd
dddd
rrrr
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–

0


–
S:
N  V, For signed tests.
V:
0
Cleared.
N:
R7
Set if MSB of the result is set; cleared otherwise.
Z:
R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $00; cleared otherwise.
R (Result) equals Rd after the operation.
Example:
or
r15,r16
; Do bitwise or between registers
bst
r15,6
; Store bit 6 of r15 in T Flag
brts
ok
; Branch if T Flag set
...
ok:
nop
; Branch destination (do nothing)
Words: 1 (2 bytes)
Cycles: 1
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103
87.
ORI – Logical OR with Immediate
87.1
Description
Performs the logical OR between the contents of register Rd and a constant and places the result in the
destination register Rd.
Operation:
(i)
Rd  Rd v K
Syntax:
Operands:
Program Counter:
(i)
ORI Rd,K
16  d  31, 0  K  255
PC  PC + 1
16-bit Opcode:
0110
87.2
KKKK
dddd
KKKK
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–

0


–
S:
N  V, For signed tests.
V:
0
Cleared.
N:
R7
Set if MSB of the result is set; cleared otherwise.
Z:
R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $00; cleared otherwise.
R (Result) equals Rd after the operation.
Example:
ori
r16,$F0
; Set high nibble of r16
ori
r17,1
; Set bit 0 of r17
Words: 1 (2 bytes)
Cycles: 1
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88.
OUT – Store Register to I/O Location
88.1
Description
Stores data from register Rr in the Register File to I/O Space (Ports, Timers, Configuration Registers, etc.).
Operation:
I/O(A)  Rr
(i)
(i)
Syntax:
Operands:
Program Counter:
OUT A,Rr
0  r  31, 0  A  63
PC  PC + 1
16-bit Opcode:
1011
88.2
1AAr
rrrr
AAAA
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
clr
r16
; Clear r16
ser
r17
; Set r17
out
$18,r16
; Write zeros to Port B
nop
out
; Wait (do nothing)
$18,r17
; Write ones to Port B
Words: 1 (2 bytes)
Cycles: 1
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105
89.
POP – Pop Register from Stack
89.1
Description
This instruction loads register Rd with a byte from the STACK. The Stack Pointer is pre-incremented by 1 before
the POP.
This instruction is not available in all devices. Refer to the device specific instruction set summary.
Operation:
(i)
Rd  STACK
Syntax:
Operands:
Program Counter:
Stack:
(i)
POP Rd
0  d  31
PC  PC + 1
SP  SP + 1
16-bit Opcode:
1001
89.2
000d
dddd
1111
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
call
routine
; Call subroutine
...
routine:
push
r14
; Save r14 on the Stack
push
r13
; Save r13 on the Stack
pop
r13
; Restore r13
pop
r14
...
ret
Words: 1 (2 bytes)
Cycles: 2
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; Restore r14
; Return from subroutine
90.
PUSH – Push Register on Stack
90.1
Description
This instruction stores the contents of register Rr on the STACK. The Stack Pointer is post-decremented by 1
after the PUSH.
This instruction is not available in all devices. Refer to the device specific instruction set summary.
Operation:
STACK  Rr
(i)
Syntax:
(i)
PUSH Rr
Operands:
Program Counter:
Stack:
0  r  31
PC  PC + 1
SP  SP - 1
16-bit Opcode:
1001
90.2
001d
dddd
1111
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
call
routine ; Call subroutine
...
routine:
push
r14
; Save r14 on the Stack
push
r13
; Save r13 on the Stack
pop
r13
; Restore r13
pop
r14
...
ret
Words:
Cycles:
Cycles XMEGA:
; Restore r14
; Return from subroutine
1 (2 bytes)
2
1
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107
91.
RCALL – Relative Call to Subroutine
91.1
Description
Relative call to an address within PC - 2K + 1 and PC + 2K (words). The return address (the instruction after the
RCALL) is stored onto the Stack. See also CALL. For AVR microcontrollers with Program memory not
exceeding 4K words (8KB) this instruction can address the entire memory from every address location. The
Stack Pointer uses a post-decrement scheme during RCALL.
Operation:
(i)
(ii)
PC  PC + k + 1
PC  PC + k + 1
Devices with 16 bits PC, 128KB Program memory maximum.
Devices with 22 bits PC, 8MB Program memory maximum.
Syntax:
Operands:
Program Counter:
Stack:
(i)
RCALL k
-2K  k  2K
PC  PC + k + 1
STACK  PC + 1
SP  SP - 2 (2 bytes, 16 bits)
(ii)
RCALL k
-2K  k  2K
PC  PC + k + 1
STACK  PC + 1
SP  SP - 3 (3 bytes, 22 bits)
16-bit Opcode:
1101
91.2
kkkk
kkkk
kkkk
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
rcall
routine
; Call subroutine
r14
; Save r14 on the Stack
r14
; Restore r14
...
routine:
push
...
pop
ret
Words:
Cycles:
; Return from subroutine
1 (2 bytes)
3 devices with 16 bit PC
4 devices with 22 bit PC
Cycles XMEGA:
2 devices with 16 bit PC
3 devices with 22 bit PC
Cycles Reduced Core tinyAVR:4
108
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92.
RET – Return from Subroutine
92.1
Description
Returns from subroutine. The return address is loaded from the STACK. The Stack Pointer uses a preincrement scheme during RET.
Operation:
PC(15:0)  STACK Devices with 16 bits PC, 128KB Program memory maximum.
PC(21:0)  STACKDevices with 22 bits PC, 8MB Program memory maximum.
(i)
(ii)
Syntax:
Operands:
Program Counter:
Stack:
(i)
RET
None
See Operation
SP SP + 2, (2 bytes,16 bits)
(ii)
RET
None
See Operation
SP SP + 3, (3 bytes,22 bits)
16-bit Opcode:
1001
92.2
0101
0000
1000
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
call
routine
; Call subroutine
r14
; Save r14 on the Stack
r14
; Restore r14
Example:
...
routine:
push
...
pop
ret
; Return from subroutine
Words: 1 (2 bytes)
Cycles: 4 devices with 16-bit PC
5 devices with 22-bit PC
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93.
RETI – Return from Interrupt
93.1
Description
Returns from interrupt. The return address is loaded from the STACK and the Global Interrupt Flag is set.
Note that the Status Register is not automatically stored when entering an interrupt routine, and it is not restored
when returning from an interrupt routine. This must be handled by the application program. The Stack Pointer
uses a pre-increment scheme during RETI.
Operation:
PC(15:0)  STACK Devices with 16 bits PC, 128KB Program memory maximum.
PC(21:0)  STACK Devices with 22 bits PC, 8MB Program memory maximum.
(i)
(ii)
Syntax:
Operands:
Program Counter:
Stack
(i)
RETI
None
See Operation
SP  SP + 2 (2 bytes, 16 bits)
(ii)
RETI
None
See Operation
SP  SP + 3 (3 bytes, 22 bits)
16-bit Opcode:
1001
93.2
0101
0001
1000
Status Register (SREG) and Boolean Formula
I:
I
T
H
S
V
N
Z
C
1
–
–
–
–
–
–
–
1
The I Flag is set.
Example:
...
extint:
push
r0
; Save r0 on the Stack
r0
; Restore r0
...
pop
reti
Words: 1 (2 bytes)
Cycles: 4 devices with 16-bit PC
5 devices with 22-bit PC
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; Return and enable interrupts
94.
RJMP – Relative Jump
94.1
Description
Relative jump to an address within PC - 2K +1 and PC + 2K (words). For AVR microcontrollers with Program
memory not exceeding 4K words (8KB) this instruction can address the entire memory from every address
location. See also JMP.
Operation:
PC  PC + k + 1
(i)
(i)
Syntax:
Operands:
Program Counter:
Stack
RJMP k
-2K  k  2K
PC  PC + k + 1
Unchanged
16-bit Opcode:
1100
94.2
kkkk
kkkk
kkkk
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
error:
ok:
cpi
r16,$42
; Compare r16 to $42
brne
error
; Branch if r16 <> $42
rjmp
ok
; Unconditional branch
add
r16,r17
; Add r17 to r16
inc
r16
; Increment r16
nop
; Destination for rjmp (do nothing)
Words: 1 (2 bytes)
Cycles: 2
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111
95.
ROL – Rotate Left trough Carry
95.1
Description
Shifts all bits in Rd one place to the left. The C Flag is shifted into bit 0 of Rd. Bit 7 is shifted into the C Flag. This
operation, combined with LSL, effectively multiplies multi-byte signed and unsigned values by two.
Operation:

C
¨
(i)
 C
b7 - - - - - - - - - - - - - - - - - - b0
Syntax:
Operands:
Program Counter:
ROL Rd
0  d  31
PC  PC + 1
16-bit Opcode: (see ADC Rd,Rd)
0001
95.2
11dd
dddd
dddd
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–






H:
Rd3
S:
N  V, for signed tests.
V:
N  C, for N and C after the shift.
N:
R7
Set if MSB of the result is set; cleared otherwise.
Z:
R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $00; cleared otherwise.
C:
Rd7
Set if, before the shift, the MSB of Rd was set; cleared otherwise.
R (Result) equals Rd after the operation.
Example:
lsl
r18
rol
r19
brcs oneenc
; Multiply r19:r18 by two
; r19:r18 is a signed or unsigned two-byte integer
; Branch if carry set
...
oneenc:
nop
Words: 1 (2 bytes)
Cycles: 1
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; Branch destination (do nothing)
96.
ROR – Rotate Right through Carry
96.1
Description
Shifts all bits in Rd one place to the right. The C Flag is shifted into bit 7 of Rd. Bit 0 is shifted into the C Flag.
This operation, combined with ASR, effectively divides multi-byte signed values by two. Combined with LSR it
effectively divides multi-byte unsigned values by two. The Carry Flag can be used to round the result.
Operation:


C
(i)
 C
b7 - - - - - - - - - - - - - - - - - - b0
Syntax:
Operands:
Program Counter:
ROR Rd
0  d  31
PC  PC + 1
16-bit Opcode:
1001
96.2
010d
dddd
0111
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–





S:
N  V, for signed tests.
V:
N  C, for N and C after the shift.
N:
R7
Set if MSB of the result is set; cleared otherwise.
Z:
R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $00; cleared otherwise.
C:
Rd0
Set if, before the shift, the LSB of Rd was set; cleared otherwise.
R (Result) equals Rd after the operation.
Example:
lsr
r19
ror
r18
; Divide r19:r18 by two
; r19:r18 is an unsigned two-byte integer
brcc zeroenc1
; Branch if carry cleared
asr
r17
; Divide r17:r16 by two
ror
r16
brcc zeroenc2
; r17:r16 is a signed two-byte integer
; Branch if carry cleared
...
zeroenc1:
nop
; Branch destination (do nothing)
...
zeroenc1:
nop
; Branch destination (do nothing)
Words: 1 (2 bytes)
Cycles: 1
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97.
SBC – Subtract with Carry
97.1
Description
Subtracts two registers and subtracts with the C Flag and places the result in the destination register Rd.
Operation:
Rd  Rd - Rr - C
(i)
(i)
Syntax:
Operands:
Program Counter:
SBC Rd,Rr
0  d  31, 0  r  31
PC  PC + 1
16-bit Opcode:
0000
97.2
10rd
dddd
rrrr
Status Register and Boolean Formula
I
T
H
S
V
N
Z
C
–
–






H:
Rd3  Rr3 + Rr3  R3 + R3 Rd3
Set if there was a borrow from bit 3; cleared otherwise.
S:
N  V, for signed tests.
V:
Rd7 Rr7  R7 Rd7 Rr7 R7
Set if two’s complement overflow resulted from the operation; cleared otherwise.
N:
R7
Set if MSB of the result is set; cleared otherwise.
Z:
R7  R6 R5  R4  R3 R2  R1  R0 Z
Previous value remains unchanged when the result is zero; cleared otherwise.
C:
Rd7 Rr7 + Rr7 R7 + R7 Rd7
Set if the absolute value of the contents of Rr plus previous carry is larger than the absolute value of the
Rd; cleared otherwise.
R (Result) equals Rd after the operation.
Example:
; Subtract r1:r0 from r3:r2
sub
r2,r0
; Subtract low byte
sbc
r3,r1
; Subtract with carry high byte
Words: 1 (2 bytes)
Cycles: 1
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98.
SBCI – Subtract Immediate with Carry
98.1
Description
Subtracts a constant from a register and subtracts with the C Flag and places the result in the destination
register Rd.
Operation:
Rd  Rd - K - C
(i)
(i)
Syntax:
Operands:
Program Counter:
SBCI Rd,K
16  d  31, 0  K  255
PC  PC + 1
16-bit Opcode:
0100
98.2
KKKK
dddd
KKKK
Status Register and Boolean Formula
I
T
H
S
V
N
Z
C
–
–






H:
Rd3 K3 + K3  R3 + R3 Rd3
Set if there was a borrow from bit 3; cleared otherwise.
S:
N  V, for signed tests.
V:
Rd7 K7 R7 Rd7 K7 R7
Set if two’s complement overflow resulted from the operation; cleared otherwise.
N:
R7
Set if MSB of the result is set; cleared otherwise.
Z:
R7 R6 R5 R4 R3 R2 R1 R0 Z
Previous value remains unchanged when the result is zero; cleared otherwise.
C:
Rd7 K7 + K7 R7 + R7 Rd7
Set if the absolute value of the constant plus previous carry is larger than the absolute value of Rd;
cleared otherwise.
R (Result) equals Rd after the operation.
Example:
; Subtract $4F23 from r17:r16
subi r16,$23
; Subtract low byte
sbci r17,$4F
; Subtract with carry high byte
Words: 1 (2 bytes)
Cycles: 1
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115
99.
SBI – Set Bit in I/O Register
99.1
Description
Sets a specified bit in an I/O Register. This instruction operates on the lower 32 I/O Registers – addresses 0-31.
Operation:
I/O(A,b)  1
(i)
(i)
Syntax:
Operands:
Program Counter:
SBI A,b
0  A  31, 0  b  7
PC  PC + 1
16-bit Opcode:
1001
99.2
1010
AAAA
Abbb
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
out
$1E,r0
; Write EEPROM address
sbi
$1C,0
; Set read bit in EECR
in
r1,$1D
; Read EEPROM data
Words:
1 (2 bytes)
Cycles:
2
Cycles XMEGA:
1
Cycles Reduced Core tinyAVR:1
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100. SBIC – Skip if Bit in I/O Register is Cleared
100.1 Description
This instruction tests a single bit in an I/O Register and skips the next instruction if the bit is cleared. This
instruction operates on the lower 32 I/O Registers – addresses 0-31.
Operation:
If I/O(A,b) = 0 then PC  PC + 2 (or 3) else PC  PC + 1
(i)
(i)
Syntax:
Operands:
Program Counter:
SBIC A,b
0  A  31, 0  b  7
PC  PC + 1, Condition false - no skip
PC  PC + 2, Skip a one word instruction
PC  PC + 3, Skip a two word instruction
16-bit Opcode:
1001
1001
AAAA
Abbb
100.2 Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
e2wait:
Words:
Cycles:
Cycles XMEGA:
sbic $1C,1
; Skip next inst. if EEWE cleared
rjmp e2wait
; EEPROM write not finished
nop
; Continue (do nothing)
1 (2 bytes)
1 if condition is false (no skip)
2 if condition is true (skip is executed) and the instruction skipped is 1 word
3 if condition is true (skip is executed) and the instruction skipped is 2 words
2 if condition is false (no skip)
3 if condition is true (skip is executed) and the instruction skipped is 1 word
4 if condition is true (skip is executed) and the instruction skipped is 2 words
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101. SBIS – Skip if Bit in I/O Register is Set
101.1 Description
This instruction tests a single bit in an I/O Register and skips the next instruction if the bit is set. This instruction
operates on the lower 32 I/O Registers – addresses 0-31.
Operation:
If I/O(A,b) = 1 then PC  PC + 2 (or 3) else PC  PC + 1
(i)
(i)
Syntax:
Operands:
Program Counter:
SBIS A,b
0  A  31, 0  b  7
PC  PC + 1, Condition false - no skip
PC  PC + 2, Skip a one word instruction
PC  PC + 3, Skip a two word instruction
16-bit Opcode:
1001
1011
AAAA
Abbb
101.2 Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
waitset: sbis $10,0
; Bit not set
nop
; Continue (do nothing)
Words:
Cycles:
Cycles XMEGA:
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; Skip next inst. if bit 0 in Port D set
rjmp waitset
1 (2 bytes)
1 if condition is false (no skip)
2 if condition is true (skip is executed) and the instruction skipped is 1 word
3 if condition is true (skip is executed) and the instruction skipped is 2 words
2 if condition is false (no skip)
3 if condition is true (skip is executed) and the instruction skipped is 1 word
4 if condition is true (skip is executed) and the instruction skipped is 2 words
102. SBIW – Subtract Immediate from Word
102.1 Description
Subtracts an immediate value (0-63) from a register pair and places the result in the register pair. This
instruction operates on the upper four register pairs, and is well suited for operations on the Pointer Registers.
This instruction is not available in all devices. Refer to the device specific instruction set summary.
Operation:
Rd+1:Rd  Rd+1:Rd - K
(i)
(i)
Syntax:
Operands:
Program Counter:
SBIW Rd+1:Rd,K
d  {24,26,28,30}, 0  K  63
PC  PC + 1
16-bit Opcode:
1001
0111
KKdd
KKKK
102.2 Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–





S:
N  V, for signed tests.
V:
Rdh7 R15
Set if two’s complement overflow resulted from the operation; cleared otherwise.
N:
R15
Set if MSB of the result is set; cleared otherwise.
Z:
R15 R14 R13 R12 R11 R10 R9 R8 R7 R6  R5 R4 R3  R2 R1 R0
Set if the result is $0000; cleared otherwise.
C:
R15  Rdh7
Set if the absolute value of K is larger than the absolute value of Rd; cleared otherwise.
R (Result) equals Rdh:Rdl after the operation (Rdh7-Rdh0 = R15-R8, Rdl7-Rdl0=R7-R0).
Example:
sbiw
r25:r24,1
; Subtract 1 from r25:r24
sbiw
YH:YL,63
; Subtract 63 from the Y-pointer(r29:r28)
Words: 1 (2 bytes)
Cycles: 2
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119
103. SBR – Set Bits in Register
103.1 Description
Sets specified bits in register Rd. Performs the logical ORI between the contents of register Rd and a constant
mask K and places the result in the destination register Rd.
Operation:
Rd  Rd v K
(i)
(i)
Syntax:
Operands:
Program Counter:
SBR Rd,K
16  d  31, 0  K  255
PC  PC + 1
16-bit Opcode:
0110
KKKK
dddd
KKKK
103.2 Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–

0


–
S:
N  V, for signed tests.
V:
0
Cleared.
N:
R7
Set if MSB of the result is set; cleared otherwise.
Z:
R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $00; cleared otherwise.
R (Result) equals Rd after the operation.
Example:
sbr
r16,3
; Set bits 0 and 1 in r16
sbr
r17,$F0
; Set 4 MSB in r17
Words: 1 (2 bytes)
Cycles: 1
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104. SBRC – Skip if Bit in Register is Cleared
104.1 Description
This instruction tests a single bit in a register and skips the next instruction if the bit is cleared.
Operation:
If Rr(b) = 0 then PC  PC + 2 (or 3) else PC  PC + 1
(i)
(i)
Syntax:
Operands:
Program Counter:
SBRC Rr,b
0  r  31, 0  b  7
PC  PC + 1, Condition false - no skip
PC  PC + 2, Skip a one word instruction
PC  PC + 3, Skip a two word instruction
16-bit Opcode:
1111
110r
rrrr
0bbb
104.2 Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
sub
r0,r1
; Subtract r1 from r0
sbrc r0,7
; Skip if bit 7 in r0 cleared
sub
; Only executed if bit 7 in r0 not cleared
nop
r0,r1
; Continue (do nothing)
Words: 1 (2 bytes)
Cycles: 1 if condition is false (no skip)
2 if condition is true (skip is executed) and the instruction skipped is 1 word
3 if condition is true (skip is executed) and the instruction skipped is 2 words
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105. SBRS – Skip if Bit in Register is Set
105.1 Description
This instruction tests a single bit in a register and skips the next instruction if the bit is set.
Operation:
If Rr(b) = 1 then PC  PC + 2 (or 3) else PC  PC + 1
(i)
(i)
Syntax:
Operands:
Program Counter:
SBRS Rr,b
0  r  31, 0  b  7
PC  PC + 1, Condition false - no skip
PC  PC + 2, Skip a one word instruction
PC  PC + 3, Skip a two word instruction
16-bit Opcode:
1111
111r
rrrr
0bbb
105.2 Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
sub
r0,r1
; Subtract r1 from r0
sbrs
r0,7
; Skip if bit 7 in r0 set
neg
r0
; Only executed if bit 7 in r0 not set
nop
; Continue (do nothing)
Words: 1 (2 bytes)
Cycles: 1 if condition is false (no skip)
2 if condition is true (skip is executed) and the instruction skipped is 1 word
3 if condition is true (skip is executed) and the instruction skipped is 2 words
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106. SEC – Set Carry Flag
106.1 Description
Sets the Carry Flag (C) in SREG (Status Register).
Operation:
C1
(i)
(i)
Syntax:
Operands:
Program Counter:
SEC
None
PC  PC + 1
16-bit Opcode:
1001
0100
0000
1000
106.2 Status Register (SREG) and Boolean Formula
C:
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
1
1
Carry Flag set.
Example:
sec
adc
; Set Carry Flag
r0,r1
; r0=r0+r1+1
Words: 1 (2 bytes)
Cycles: 1
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123
107. SEH – Set Half Carry Flag
107.1 Description
Sets the Half Carry (H) in SREG (Status Register).
Operation:
H1
(i)
(i)
Syntax:
Operands:
Program Counter:
SEH
None
PC  PC + 1
16-bit Opcode:
1001
0100
0101
1000
107.2 Status Register (SREG) and Boolean Formula
H:
I
T
H
S
V
N
Z
C
–
–
1
–
–
–
–
–
1
Half Carry Flag set.
Example:
seh
; Set Half Carry Flag
Words: 1 (2 bytes)
Cycles: 1
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108. SEI – Set Global Interrupt Flag
108.1 Description
Sets the Global Interrupt Flag (I) in SREG (Status Register). The instruction following SEI will be executed
before any pending interrupts.
Operation:
I1
(i)
(i)
Syntax:
Operands:
Program Counter:
SEI
None
PC  PC + 1
16-bit Opcode:
1001
0100
0111
1000
108.2 Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
1
–
–
–
–
–
–
–
I:
1
Global Interrupt Flag set.
Example:
sei
; set global interrupt enable
sleep
; enter sleep, waiting for interrupt
; note: will enter sleep before any pending interrupt(s)
Words: 1 (2 bytes)
Cycles: 1
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125
109. SEN – Set Negative Flag
109.1 Description
Sets the Negative Flag (N) in SREG (Status Register).
Operation:
N1
(i)
(i)
Syntax:
Operands:
Program Counter:
SEN
None
PC  PC + 1
16-bit Opcode:
1001
0100
0010
1000
109.2 Status Register (SREG) and Boolean Formula
N:
I
T
H
S
V
N
Z
C
–
–
–
–
–
1
–
–
1
Negative Flag set.
Example:
add
r2,r19
sen
Words: 1 (2 bytes)
Cycles: 1
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; Add r19 to r2
; Set Negative Flag
110. SER – Set all Bits in Register
110.1 Description
Loads $FF directly to register Rd.
Operation:
Rd  $FF
(i)
(i)
Syntax:
Operands:
Program Counter:
SER Rd
16  d  31
PC  PC + 1
16-bit Opcode:
1110
1111
dddd
1111
110.2 Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
clr
r16
; Clear r16
ser
r17
; Set r17
out
$18,r16
; Write zeros to Port B
nop
out
; Delay (do nothing)
$18,r17
; Write ones to Port B
Words: 1 (2 bytes)
Cycles: 1
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127
111. SES – Set Signed Flag
111.1 Description
Sets the Signed Flag (S) in SREG (Status Register).
Operation:
S1
(i)
(i)
Syntax:
Operands:
Program Counter:
SES
None
PC  PC + 1
16-bit Opcode:
1001
0100
0100
1000
111.2 Status Register (SREG) and Boolean Formula
S:
I
T
H
S
V
N
Z
C
–
–
–
1
–
–
–
–
1
Signed Flag set.
Example:
add
r2,r19
ses
Words: 1 (2 bytes)
Cycles: 1
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; Add r19 to r2
; Set Negative Flag
112. SET – Set T Flag
112.1 Description
Sets the T Flag in SREG (Status Register).
Operation:
T1
(i)
(i)
Syntax:
Operands:
Program Counter:
SET
None
PC  PC + 1
16-bit Opcode:
1001
0100
0110
1000
112.2 Status Register (SREG) and Boolean Formula
T:
I
T
H
S
V
N
Z
C
–
1
–
–
–
–
–
–
1
T Flag set.
Example:
set
; Set T Flag
Words: 1 (2 bytes)
Cycles: 1
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129
113. SEV – Set Overflow Flag
113.1 Description
Sets the Overflow Flag (V) in SREG (Status Register).
Operation:
V1
(i)
(i)
Syntax:
Operands:
Program Counter:
SEV
None
PC  PC + 1
16-bit Opcode:
1001
0100
0011
1000
113.2 Status Register (SREG) and Boolean Formula
V:
I
T
H
S
V
N
Z
C
–
–
–
–
1
–
–
–
1
Overflow Flag set.
Example:
add
r2,r19
sev
Words: 1 (2 bytes)
Cycles: 1
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; Add r19 to r2
; Set Overflow Flag
114. SEZ – Set Zero Flag
114.1 Description
Sets the Zero Flag (Z) in SREG (Status Register).
Operation:
Z1
(i)
(i)
Syntax:
Operands:
Program Counter:
SEZ
None
PC  PC + 1
16-bit Opcode:
1001
0100
0001
1000
114.2 Status Register (SREG) and Boolean Formula
Z:
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
1
–
1
Zero Flag set.
Example:
add
sez
r2,r19
; Add r19 to r2
; Set Zero Flag
Words: 1 (2 bytes)
Cycles: 1
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131
115. SLEEP
115.1 Description
This instruction sets the circuit in sleep mode defined by the MCU Control Register.
Operation:
Refer to the device documentation for detailed description of SLEEP usage.
Syntax:
Operands:
Program Counter:
SLEEP
None
PC  PC + 1
16-bit Opcode:
1001
0101
1000
1000
115.2 Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
mov
r0,r11
; Copy r11 to r0
ldi
r16,(1<<SE)
; Enable sleep mode
out
MCUCR, r16
sleep
Words: 1 (2 bytes)
Cycles: 1
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; Put MCU in sleep mode
116. SPM – Store Program Memory
116.1 Description
SPM can be used to erase a page in the Program memory, to write a page in the Program memory (that is
already erased), and to set Boot Loader Lock bits. In some devices, the Program memory can be written one
word at a time, in other devices an entire page can be programmed simultaneously after first filling a temporary
page buffer. In all cases, the Program memory must be erased one page at a time. When erasing the Program
memory, the RAMPZ and Z-register are used as page address. When writing the Program memory, the RAMPZ
and Z-register are used as page or word address, and the R1:R0 register pair is used as data(1). When setting
the Boot Loader Lock bits, the R1:R0 register pair is used as data. Refer to the device documentation for
detailed description of SPM usage. This instruction can address the entire Program memory.
The SPM instruction is not available in all devices. Refer to the device specific instruction set summary.
Note:
1. R1 determines the instruction high byte, and R0 determines the instruction low byte.
Operation:
Comment:
(i)
(ii)
(iii)
(iv)
(v)
(RAMPZ:Z) $ffff
(RAMPZ:Z) R1:R0
(RAMPZ:Z) R1:R0
(RAMPZ:Z) TEMP
BLBITS R1:R0
Erase Program memory page
Write Program memory word
Write temporary page buffer
Write temporary page buffer to Program memory
Set Boot Loader Lock bits
Syntax:
Operands:
Program Counter:
SPM
Z+
PC  PC + 1
(i)-(v)
16-bit Opcode:
1001
0101
1110
1000
Status Register (SREG) and Boolean Formula:
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
;This example shows SPM write of one page for devices with page write
;- the routine writes one page of data from RAM to Flash
;
the first data location in RAM is pointed to by the Y-pointer
;
the first data location in Flash is pointed to by the Z-pointer
;- error handling is not included
;- the routine must be placed inside the boot space
;
(at least the do_spm sub routine)
;- registers used: r0, r1, temp1, temp2, looplo, loophi, spmcrval
;
(temp1, temp2, looplo, loophi, spmcrval must be defined by the user)
;
storing and restoring of registers is not included in the routine
;
register usage can be optimized at the expense of code size
.equPAGESIZEB = PAGESIZE*2;PAGESIZEB is page size in BYTES, not words
.org SMALLBOOTSTART
write_page:
;page erase
ldispmcrval, (1<<PGERS) + (1<<SPMEN)
calldo_spm
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133
;transfer data from RAM to Flash page buffer
ldilooplo, low(PAGESIZEB);init loop variable
ldiloophi, high(PAGESIZEB);not required for PAGESIZEB<=256
wrloop:ldr0, Y+
ldr1, Y+
ldispmcrval, (1<<SPMEN)
calldo_spm
adiwZH:ZL, 2
sbiwloophi:looplo, 2;use subi for PAGESIZEB<=256
brnewrloop
;execute page write
subiZL, low(PAGESIZEB);restore pointer
sbciZH, high(PAGESIZEB);not required for PAGESIZEB<=256
ldispmcrval, (1<<PGWRT) + (1<<SPMEN)
calldo_spm
;read back and check, optional
ldilooplo, low(PAGESIZEB);init loop variable
ldiloophi, high(PAGESIZEB);not required for PAGESIZEB<=256
subiYL, low(PAGESIZEB);restore pointer
sbciYH, high(PAGESIZEB)
rdloop:lpmr0, Z+
ldr1, Y+
cpser0, r1
jmperror
sbiwloophi:looplo, 2;use subi for PAGESIZEB<=256
brnerdloop
;return
ret
do_spm:
;input: spmcrval determines SPM action
;disable interrupts if enabled, store status
intemp2, SREG
cli
;check for previous SPM complete
wait:intemp1, SPMCR
sbrctemp1, SPMEN
rjmpwait
;SPM timed sequence
outSPMCR, spmcrval
spm
;restore SREG (to enable interrupts if originally enabled)
outSREG, temp2
ret
Words: 1 (2 bytes)
Cycles: depends on the operation
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117. SPM #2 – Store Program Memory
117.1 Description
SPM can be used to erase a page in the Program memory and to write a page in the Program memory (that is
already erased). An entire page can be programmed simultaneously after first filling a temporary page buffer.
The Program memory must be erased one page at a time. When erasing the Program memory, the RAMPZ and
Z-register are used as page address. When writing the Program memory, the RAMPZ and Z-register are used
as page or word address, and the R1:R0 register pair is used as data(1).
Refer to the device documentation for detailed description of SPM usage. This instruction can address the entire
Program memory.
Note:
1. R1 determines the instruction high byte, and R0 determines the instruction low byte.
Operation:
Comment:
(i)
(ii)
(iii)
(iv)
(v)
(vi)
(RAMPZ:Z)  $ffff
(RAMPZ:Z)  R1:R0
(RAMPZ:Z)  BUFFER
(RAMPZ:Z)  $fff
(RAMPZ:Z)  R1:R0
(RAMPZ:Z) BUFFER
Erase Program memory page
Load Page Buffer
Write Page Buffer to Program memory
Erase Program memory page, Z post incremented
Load Page Buffer, Z post incremented
Write Page Buffer to Program memory,
Z post incremented
Syntax:
(i)-(iii) SPM
(iv)-(vi) SPM Z+
ZZ+2
ZZ+2
ZZ+2
Operands:
Program Counter:
None
None
PC  PC + 1
PC  PC + 1
16-bit Opcode:
(i)-(iii)
(iv)-(vi)
1001
1001
0101
0101
1110
1111
1000
1000
Status Register (SREG) and Boolean Formula:
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
Words: 1 (2 bytes)
Cycles: Depends on the operation
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118. ST – Store Indirect From Register to Data Space using Index X
118.1 Description
Stores one byte indirect from a register to data space. For parts with SRAM, the data space consists of the
Register File, I/O memory and internal SRAM (and external SRAM if applicable). For parts without SRAM, the
data space consists of the Register File only. The EEPROM has a separate address space.
The data location is pointed to by the X (16 bits) Pointer Register in the Register File. Memory access is limited
to the current data segment of 64KB. To access another data segment in devices with more than 64KB data
space, the RAMPX in register in the I/O area has to be changed.
The X-pointer Register can either be left unchanged by the operation, or it can be post-incremented or predecremented. These features are especially suited for accessing arrays, tables, and Stack Pointer usage of the
X-pointer Register. Note that only the low byte of the X-pointer is updated in devices with no more than 256
bytes data space. For such devices, the high byte of the pointer is not used by this instruction and can be used
for other purposes. The RAMPX Register in the I/O area is updated in parts with more than 64KB data space or
more than 64KB Program memory, and the increment/ decrement is added to the entire 24-bit address on such
devices.
Not all variants of this instruction is available in all devices. Refer to the device specific instruction set summary.
The result of these combinations is undefined:
ST X+, r26
ST X+, r27
ST -X, r26
ST -X, r27
Using the X-pointer:
(i)
(ii)
(iii)
(i)
(ii)
(iii)
Operation:
Comment:
(X)  Rr
(X)  Rr
XX-1
X  X+1
(X)  Rr
X: Unchanged
X: Post incremented
X: Pre decremented
Syntax:
Operands:
Program Counter:
ST X, Rr
ST X+, Rr
ST -X, Rr
0  r  31
0  r  31
0  r  31
PC  PC + 1
PC  PC + 1
PC  PC + 1
16-bit Opcode:
(i)
(ii)
(iii)
136
1001
1001
1001
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001r
001r
001r
rrrr
rrrr
rrrr
1100
1101
1110
118.2 Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
clr
r27
; Clear X high byte
ldi
r26,$60
; Set X low byte to $60
st
X+,r0
; Store r0 in data space loc. $60(X post inc)
st
X,r1
; Store r1 in data space loc. $61
ldi
r26,$63
; Set X low byte to $63
st
X,r2
; Store r2 in data space loc. $63
st
-X,r3
; Store r3 in data space loc. $62(X pre dec)
Words:
Cycles:
Cycles XMEGA:
1 (2 bytes)
2
(i) 1
(ii) 1
(iii) 2
Cycles Reduced Core tinyAVR:(i) 1
(ii) 1
(iii) 2
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137
119. ST (STD) – Store Indirect From Register to Data Space using Index Y
119.1 Description
Stores one byte indirect with or without displacement from a register to data space. For parts with SRAM, the
data space consists of the Register File, I/O memory and internal SRAM (and external SRAM if applicable). For
parts without SRAM, the data space consists of the Register File only. The EEPROM has a separate address
space.
The data location is pointed to by the Y (16 bits) Pointer Register in the Register File. Memory access is limited
to the current data segment of 64KB. To access another data segment in devices with more than 64KB data
space, the RAMPY in register in the I/O area has to be changed.
The Y-pointer Register can either be left unchanged by the operation, or it can be post-incremented or predecremented. These features are especially suited for accessing arrays, tables, and Stack Pointer usage of the
Y-pointer Register. Note that only the low byte of the Y-pointer is updated in devices with no more than 256
bytes data space. For such devices, the high byte of the pointer is not used by this instruction and can be used
for other purposes. The RAMPY Register in the I/O area is updated in parts with more than 64KB data space or
more than 64KB Program memory, and the increment/ decrement/displacement is added to the entire 24-bit
address on such devices.
Not all variants of this instruction is available in all devices. Refer to the device specific instruction set summary.
The result of these combinations is undefined:
ST Y+, r28
ST Y+, r29
ST -Y, r28
ST -Y, r29
Using the Y-pointer:
Operation:
(i)
(ii)
(iii)
(iv)
(i)
(ii)
(iii)
(iv)
Comment:
(Y)  Rr
(Y)  Rr
YY-1
(Y+q)  Rr
Y  Y+1
(Y)  Rr
Y: Unchanged
Y: Post incremented
Y: Pre decremented
Y: Unchanged, q: Displacement
Syntax:
Operands:
Program Counter:
ST Y, Rr
ST Y+, Rr
ST -Y, Rr
STD Y+q, Rr
0  r  31
0  r  31
0  r  31
0  r  31, 0  q  63
PC  PC + 1
PC  PC + 1
PC  PC + 1
PC  PC + 1
16-bit Opcode:
(i)
(ii)
(iii)
(iv)
138
1000
1001
1001
10q0
Instruction Set Manual
0856J-AVR-07/2014
001r
001r
001r
qq1r
rrrr
rrrr
rrrr
rrrr
1000
1001
1010
1qqq
119.2
Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
clr
r29
; Clear Y high byte
ldi
r28,$60
; Set Y low byte to $60
st
Y+,r0
; Store r0 in data space loc. $60(Y post inc)
st
Y,r1
; Store r1 in data space loc. $61
ldi
r28,$63
; Set Y low byte to $63
st
Y,r2
; Store r2 in data space loc. $63
st
-Y,r3
; Store r3 in data space loc. $62(Y pre dec)
std
Y+2,r4
; Store r4 in data space loc. $64
Words: 1 (2 bytes)
Cycles:
Cycles XMEGA:
(i)
(ii)
(iii)
(iv)
Cycles Reduced Core tinyAVR:(i)
(ii)
(iii)
2
1
1
2
2
1
1
2
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139
120. ST (STD) – Store Indirect From Register to Data Space using Index Z
120.1 Description
Stores one byte indirect with or without displacement from a register to data space. For parts with SRAM, the
data space consists of the Register File, I/O memory and internal SRAM (and external SRAM if applicable). For
parts without SRAM, the data space consists of the Register File only. The EEPROM has a separate address
space.
The data location is pointed to by the Z (16 bits) Pointer Register in the Register File. Memory access is limited
to the current data segment of 64KB. To access another data segment in devices with more than 64KB data
space, the RAMPZ in register in the I/O area has to be changed.
The Z-pointer Register can either be left unchanged by the operation, or it can be post-incremented or predecremented. These features are especially suited for Stack Pointer usage of the Z-pointer Register, however
because the Z-pointer Register can be used for indirect subroutine calls, indirect jumps and table lookup, it is
often more convenient to use the X or Y-pointer as a dedicated Stack Pointer. Note that only the low byte of the
Z-pointer is updated in devices with no more than 256 bytes data space. For such devices, the high byte of the
pointer is not used by this instruction and can be used for other purposes. The RAMPZ Register in the I/O area
is updated in parts with more than 64KB data space or more than 64KB Program memory, and the
increment/decrement/displacement is added to the entire 24-bit address on such devices.
Not all variants of this instruction is available in all devices. Refer to the device specific instruction set summary.
The result of these combinations is undefined:
ST Z+, r30
ST Z+, r31
ST -Z, r30
ST -Z, r31
Using the Z-pointer:
Operation:
(i)
(ii)
(iii)
(iv)
(Z) Rr
(Z)  Rr
ZZ-1
(Z+q)  Rr
(i)
(ii)
(iii)
(iv)
Comment:
Z  Z+1
(Z)  Rr
Z: Unchanged
Z: Post incremented
Z: Pre decremented
Z: Unchanged, q: Displacement
Syntax:
Operands:
Program Counter:
ST Z, Rr
ST Z+, Rr
ST -Z, Rr
STD Z+q, Rr
0  r  31
0  r  31
0  r  31
0  r  31, 0  q  63
PC  PC + 1
PC  PC + 1
PC  PC + 1
PC  PC + 1
16-bit Opcode :
(i)
(ii)
(iii)
(iv)
140
1000
1001
1001
10q0
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0856J-AVR-07/2014
001r
001r
001r
qq1r
rrrr
rrrr
rrrr
rrrr
0000
0001
0010
0qqq
120.2 Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
clr
r31
; Clear Z high byte
ldi
r30,$60
; Set Z low byte to $60
st
Z+,r0
; Store r0 in data space loc. $60(Z post inc)
st
Z,r1
; Store r1 in data space loc. $61
ldi
r30,$63
; Set Z low byte to $63
st
Z,r2
; Store r2 in data space loc. $63
st
-Z,r3
; Store r3 in data space loc. $62(Z pre dec)
std
Z+2,r4
; Store r4 in data space loc. $64
Words: 1 (2 bytes)
Cycles:
Cycles XMEGA:
(i)
(ii)
(iii)
(iv)
Cycles Reduced Core tinyAVR:(i)
(ii)
(iii)
2
1
1
2
2
1
1
2
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141
121. STS – Store Direct to Data Space
121.1 Description
Stores one byte from a Register to the data space. For parts with SRAM, the data space consists of the Register
File, I/O memory and internal SRAM (and external SRAM if applicable). For parts without SRAM, the data space
consists of the Register File only. The EEPROM has a separate address space.
A 16-bit address must be supplied. Memory access is limited to the current data segment of 64KB. The STS
instruction uses the RAMPD Register to access memory above 64KB. To access another data segment in
devices with more than 64KB data space, the RAMPD in register in the I/O area has to be changed.
This instruction is not available in all devices. Refer to the device specific instruction set summary.
Operation:
(i)
(k)  Rr
Syntax:
Operands:
Program Counter:
(i)
STS k,Rr
0  r  31, 0  k  65535
PC  PC + 2
32-bit Opcode:
1001
kkkk
001d
kkkk
dddd
kkkk
0000
kkkk
121.2 Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
lds
r2,$FF00
; Load r2 with the contents of data space location $FF00
add
r2,r1
; add r1 to r2
sts
$FF00,r2
; Write back
Words: 2 (4 bytes)
Cycles: 2
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122. STS (16-bit) – Store Direct to Data Space
122.1 Description
Stores one byte from a Register to the data space. For parts with SRAM, the data space consists of the Register
File, I/O memory and internal SRAM (and external SRAM if applicable). For parts without SRAM, the data space
consists of the Register File only. In some parts the Flash memory has been mapped to the data space and can
be written using this command. The EEPROM has a separate address space.
A 7-bit address must be supplied. The address given in the instruction is coded to a data space address as
follows:
ADDR[7:0] = (INST[8], INST[8], INST[10], INST[9], INST[3], INST[2], INST[1], INST[0])
Memory access is limited to the address range 0x40...0xbf of the data segment.
This instruction is not available in all devices. Refer to the device specific instruction set summary.
Operation:
(k)  Rr
(i)
(i)
Syntax:
Operands:
Program Counter:
STS k,Rr
16  r  31, 0  k  127
PC  PC + 1
16-bit Opcode:
1010
1kkk
dddd
kkkk
122.2 Status Register (SREG) and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
lds
r16,$00
; Load r16 with the contents of data space location $00
add
r16,r17
; add r17 to r16
sts
$00,r16
; Write result to the same address it was fetched from
Words: 1 (2 bytes)
Cycles: 1
Note:
Registers r0...r15 are remaped to r16...r31
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143
123. SUB – Subtract without Carry
123.1 Description
Subtracts two registers and places the result in the destination register Rd.
Operation:
Rd  Rd - Rr
(i)
(i)
Syntax:
Operands:
Program Counter:
SUB Rd,Rr
0  d  31, 0  r  31
PC  PC + 1
16-bit Opcode:
0001
10rd
dddd
rrrr
123.2 Status Register and Boolean Formula
I
T
H
S
V
N
Z
C
–
–






H:
Rd3 Rr3 + Rr3  R3 + R3 Rd3
Set if there was a borrow from bit 3; cleared otherwise.
S:
N  V, For signed tests.
V:
Rd7 Rr7 R7 Rd7  Rr7 R7
Set if two’s complement overflow resulted from the operation; cleared otherwise.
N:
R7
Set if MSB of the result is set; cleared otherwise.
Z:
R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $00; cleared otherwise.
C:
Rd7 Rr7 + Rr7  R7 + R7 Rd7
Set if the absolute value of the contents of Rr is larger than the absolute value of Rd; cleared otherwise.
R (Result) equals Rd after the operation.
Example:
sub
r13,r12
; Subtract r12 from r13
brne
noteq
; Branch if r12<>r13
...
noteq:
nop
Words: 1 (2 bytes)
Cycles: 1
144
Instruction Set Manual
0856J-AVR-07/2014
; Branch destination (do nothing)
124. SUBI – Subtract Immediate
124.1 Description
Subtracts a register and a constant and places the result in the destination register Rd. This instruction is
working on Register R16 to R31 and is very well suited for operations on the X, Y, and Z-pointers.
Operation:
Rd  Rd - K
(i)
(i)
Syntax:
Operands:
Program Counter:
SUBI Rd,K
16  d  31, 0  K  255
PC  PC + 1
16-bit Opcode:
0101
KKKK
dddd
KKKK
124.2 Status Register and Boolean Formula
I
T
H
S
V
N
Z
C
–
–






H:
Rd3 K3 + K3  R3 + R3 Rd3
Set if there was a borrow from bit 3; cleared otherwise.
S:
N  V, for signed tests.
V:
Rd7 K7 R7 + Rd7 K7 R7
Set if two’s complement overflow resulted from the operation; cleared otherwise.
N:
R7
Set if MSB of the result is set; cleared otherwise.
Z:
R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $00; cleared otherwise.
C:
Rd7 K7 + K7  R7 + R7 Rd7
Set if the absolute value of K is larger than the absolute value of Rd; cleared otherwise.
R (Result) equals Rd after the operation.
Example:
subi
r22,$11
; Subtract $11 from r22
brne
noteq
; Branch if r22<>$11
...
noteq:
nop
; Branch destination (do nothing)
Words: 1 (2 bytes)
Cycles: 1
Instruction Set Manual
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145
125. SWAP – Swap Nibbles
125.1 Description
Swaps high and low nibbles in a register.
Operation:
R(7:4)  Rd(3:0), R(3:0)  Rd(7:4)
(i)
(i)
Syntax:
Operands:
Program Counter:
SWAP Rd
0  d  31
PC  PC + 1
16-bit Opcode:
1001
010d
dddd
0010
125.2 Status Register and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
R (Result) equals Rd after the operation.
Example:
inc
r1
; Increment r1
swap
r1
; Swap high and low nibble of r1
inc
r1
; Increment high nibble of r1
swap
r1
; Swap back
Words: 1 (2 bytes)
Cycles: 1
146
Instruction Set Manual
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126. TST – Test for Zero or Minus
126.1 Description
Tests if a register is zero or negative. Performs a logical AND between a register and itself. The register will
remain unchanged.
Operation:
(i)
Rd  Rd  Rd
Syntax:
Operands:
Program Counter:
(i)
TST Rd
0  d  31
PC  PC + 1
16-bit Opcode: (see AND Rd, Rd)
0010
00dd
dddd
dddd
126.2 Status Register and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–

0


–
S:
N  V, for signed tests.
V:
0
Cleared.
N:
R7
Set if MSB of the result is set; cleared otherwise.
Z:
R7 R6 R5 R4 R3 R2 R1 R0
Set if the result is $00; cleared otherwise.
R (Result) equals Rd.
Example:
tst
r0
breq zero
; Test r0
; Branch if r0=0
...
zero:
nop
; Branch destination (do nothing)
Words: 1 (2 bytes)
Cycles: 1
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147
127. WDR – Watchdog Reset
127.1 Description
This instruction resets the Watchdog Timer. This instruction must be executed within a limited time given by the
WD prescaler. See the Watchdog Timer hardware specification.
Operation:
(i)
WD timer restart.
(i)
Syntax:
Operands:
Program Counter:
WDR
None
PC  PC + 1
16-bit Opcode:
1001
0101
1010
1000
127.2 Status Register and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Example:
wdr
Words: 1 (2 bytes)
Cycles: 1
148
Instruction Set Manual
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; Reset watchdog timer
128. XCH – Exchange
128.1 Description
Exchanges one byte indirect between register and data space.
The data location is pointed to by the Z (16 bits) Pointer Register in the Register File. Memory access is limited
to the current data segment of 64KB. To access another data segment in devices with more than 64KB data
space, the RAMPZ in register in the I/O area has to be changed.
The Z-pointer Register is left unchanged by the operation. This instruction is especially suited for writing/reading
status bits stored in SRAM.
Operation:
(Z)  Rd, Rd  (Z)
(i)
(i)
Syntax:
Operands:
Program Counter:
XCH Z,Rd
0  d  31
PC  PC + 1
16-bit Opcode:
1001
001r
rrrr
0100
128.2 Status Register and Boolean Formula
I
T
H
S
V
N
Z
C
–
–
–
–
–
–
–
–
Words: 1 (2 bytes)
Cycles: 2
Instruction Set Manual
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149
129. Datasheet Revision History
Note that the referring page numbers in this section are referred to this document. The referring revision in this
section is referred to the document revision.
129.1 Rev.0856J - 07/2014
1. Section 3., “Conditional Branch Summary” on page 10 has been corrected.
2. The first table in Section 59.1, “Description” on page 70 has been corrected.
3. “TBD” in “Example” in Section 117.1, “Description” on page 135 has been removed.
4. The LAC operation in See “LAC – Load and Clear” on page 80 has been corrected.
5. New template has been added.
129.2 Rev.0856I – 07/2010
1. Updated Section 4., “Complete Instruction Set Summary” on page 11 with new instructions: LAC, LAS, LAT
and XCH.
Section 67., “LAC – Load and Clear” on page 80
Section 68., “LAS – Load and Set” on page 81
Section 69., “LAT – Load and Toggle” on page 82
Section 128., “XCH – Exchange” on page 149
2. Updated number of clock cycles column to include Reduced Core tinyAVR.
(ATtiny replaced by Reduced Core tinyAVR).
129.3 Rev.0856H – 04/2009
1. Updated Section 4., “Complete Instruction Set Summary” on page 11:
Updated number of clock cycles column to include Reduced Core tinyAVR.
2. Updated sections for Reduced Core tinyAVR compatibility:
Section 37., “CBI – Clear Bit in I/O Register” on page 47
Section 70., “LD – Load Indirect from Data Space to Register using Index X” on page 83
Section 71., “LD (LDD) – Load Indirect from Data Space to Register using Index Y” on page 85
Section 72., “LD (LDD) – Load Indirect From Data Space to Register using Index Z” on page 87
Section 91., “RCALL – Relative Call to Subroutine” on page 108
Section 99., “SBI – Set Bit in I/O Register” on page 116
Section 118., “ST – Store Indirect From Register to Data Space using Index X” on page 136
Section 119., “ST (STD) – Store Indirect From Register to Data Space using Index Y” on page 138
Section 120., “ST (STD) – Store Indirect From Register to Data Space using Index Z” on page 140
3. Added sections for Reduced Core tinyAVR compatibility:
Section 75., “LDS (16-bit) – Load Direct from Data Space” on page 91
Section 122., “STS (16-bit) – Store Direct to Data Space” on page 143
150
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129.4 Rev.0856G – 07/2008
1. Inserted “Datasheet Revision History”.
2. Updated “Cycles XMEGA” for ST, by removing (iv).
3. Updated “SPM #2” opcodes.
129.5 Rev.0856F – 05/2008
1. This revision is based on the AVR Instruction Set 0856E-AVR-11/05.
Changes done compared to AVR Instruction Set 0856E-AVR-11/05:
-Updated “Complete Instruction Set Summary” with DES and SPM #2.
-Updated AVR Instruction Set with XMEGA Clock cycles and Instruction Description.
Instruction Set Manual
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151
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© 2014 Atmel Corporation. / Rev.: Atmel-0856J-AVR-Instruction-Set-Manual_07/2014.
Atmel®, Atmel logo and combinations thereof, AVR®, Enabling Unlimited Possibilities®, tinyAVR®, XMEGA®, and others are registered trademarks or trademarks of
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