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Status Register (SREG): SREG: Status register C: Carry flag in status register Z: Zero flag in status register N: Negative flag in status register V: Twos complement overflow indicator S: N Å V, For signed tests H: Half Carry flag in the status register T: Transfer bit used by BLD and BST instructions I: Global interrupt enable/disable flag |
X,Y,Z: Indirect address register (X=R27:R26, Y=R29:R28 and Z=R31:R30) P: I/O port address q: Displacement for direct addressing (6 bit) I/O Registers RAMPX, RAMPY, RAMPZ: Registers concatenated with the X, Y and Z registers enabling indirect addressing of the whole SRAM area on MCUs with more than 64K bytes SRAM. |
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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 literal or byte data (8 bit) k: Constant address data for program counter b: Bit in the register file or I/O register (3 bit) s: Bit in the status register (3 bit) |
Stack: STACK:Stack for return address and pushed registers SP: Stack Pointer to STACK Flags: Û: Flag affected by instruction 0: Flag cleared by instruction 1: Flag set by instruction -: Flag not affected by instruction |
| Mnemonics | Operands | Description | Operation | Flags | Clocks |
|---|---|---|---|---|---|
| ADD | Rd, Rr | Add without Carry | Rd Rd + Rr | Z,C,N,V,H | 1 |
| ADC | Rd, Rr | Add with Carry | Rd Rd + Rr + C | Z,C,N,V,H | 1 |
| ADIW | Rd, K | Add Immediate to Word | Rd+1:Rd Rd+1:Rd + K | Z,C,N,V | 2 |
| SUB | Rd, Rr | Subtract without Carry | Rd Rd - Rr | Z,C,N,V,H | 1 |
| SUBI | Rd, K | Subtract Immediate | Rd Rd - K | Z,C,N,V,H | 1 |
| SBC | Rd, Rr | Subtract with Carry | Rd Rd - Rr - C | Z,C,N,V,H | 1 |
| SBCI | Rd, K | Subtract Immediate with Carry | Rd Rd - K - C | Z,C,N,V,H | 1 |
| SBIW | Rd, K | Subtract Immediate from Word | Rd+1:Rd Rd+1:Rd - K | Z,C,N,V | 2 |
| AND | Rd, Rr | Logical AND | Rd Rd · Rr | Z,N,V | 1 |
| ANDI | Rd, K | Logical AND with Immediate | Rd Rd · K | Z,N,V | 1 |
| OR | Rd, Rr | Logical OR | Rd Rd v Rr | Z,N,V | 1 |
| ORI | Rd, K | Logical OR with Immediate | Rd Rd v K | Z,N,V | 1 |
| EOR | Rd, Rr | Exclusive OR | Rd Rd Rr | Z,N,V | 1 |
| COM | Rd | One's Complement | Rd $FF - Rd | Z,C,N,V | 1 |
| NEG | Rd | Two's Complement | Rd $00 - Rd | Z,C,N,V,H | 1 |
| SBR | Rd,K | Set Bit(s) in Register | Rd Rd v K | Z,N,V | 1 |
| CBR | Rd,K | Clear Bit(s) in Register | Rd Rd · ($FFh - K) | Z,N,V | 1 |
| INC | Rd | Increment | Rd Rd + 1 | Z,N,V | 1 |
| DEC | Rd | Decrement | Rd Rd - 1 | Z,N,V | 1 |
| TST | Rd | Test for Zero or Minus | Rd Rd · Rd | Z,N,V | 1 |
| CLR | Rd | Clear Register | Rd Rd Rd | Z,N,V | 1 |
| SER | Rd | Set Register | Rd $FF | None | 1 |
| CP | Rd,Rr | Compare | Rd - Rr | Z,C,N,V,H | 1 |
| CPC | Rd,Rr | Compare with Carry | Rd - Rr - C | Z,C,N,V,H | 1 |
| CPI | Rd,K | Compare with Immediate | Rd - K | Z,C,N,V,H | 1 |
| Mnemonics | Operands | Description | Operation | Flags | Clocks |
|---|---|---|---|---|---|
| RJMP | k | Relative Jump | PC PC + k + 1 | None | 2 |
| IJMP | Indirect Jump to (Z) | PC Z | None | 2 | |
| JMP | k | Jump | PC k | None | 3 |
| RCALL | k | Relative Call Subroutine | PC PC + k + 1 | None | 3 |
| ICALL | Indirect Call to (Z) | PC Z | None | 3 | |
| CALL | k | Call Subroutine | PC k | None | 4 |
| RET | Subroutine Return | PC STACK | None | 4 | |
| RETI | Interrupt Return | PC STACK | I | 4 | |
| CPSE | Rd,Rr | Compare, Skip if Equal | if (Rd = Rr) PC PC + 2 or 3 | None | 1 / 2 / 3 |
| SBRC | Rr, b | Skip if Bit in Register Cleared | if (Rr(b)=0) PC PC + 2 or 3 | None | 1 / 2 / 3 |
| SBRS | Rr, b | Skip if Bit in Register Set | if (Rr(b)=1) PC PC + 2 or 3 | None | 1 / 2 / 3 |
| SBIC | P, b | Skip if Bit in I/O Register Cleared | if(I/O(P,b)=0) PC PC + 2 or 3 | None | 1 / 2 / 3 |
| SBIS | P, b | Skip if Bit in I/O Register Set | If(I/O(P,b)=1) PC PC + 2 or 3 | None | 1 / 2 / 3 |
| BRBS | s, k | Branch if Status Flag Set | if (SREG(s) = 1) then PC PC+k + 1 | None | 1 / 2 |
| BRBC | s, k | Branch if Status Flag Cleared | if (SREG(s) = 0) then PC PC+k + 1 | None | 1 / 2 |
| BREQ | k | Branch if Equal | if (Z = 1) then PC PC + k + 1 | None | 1 / 2 |
| BRNE | k | Branch if Not Equal | if (Z = 0) then PC PC + k + 1 | None | 1 / 2 |
| BRCS | k | Branch if Carry Set | if (C = 1) then PC PC + k + 1 | None | 1 / 2 |
| BRCC | 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 |
| Mnemonics | Operands | Description | Operation | Flags | Clocks |
|---|---|---|---|---|---|
| MOV | Rd, Rr | Copy Register | Rd Rr | None | 1 |
| LDI | Rd, K | Load Immediate | Rd K | None | 1 |
| LDS | Rd, k | Load Direct from SRAM | Rd (k) | None | 3 |
| LD | Rd, X | Load Indirect | Rd (X) | None | 2 |
| LD | Rd, X+ | Load Indirect and Post-Increment | Rd (X), X X + 1 | None | 2 |
| LD | Rd, -X | Load Indirect and Pre-Decrement | X X - 1, Rd (X) | None | 2 |
| LD | Rd, Y | Load Indirect | Rd (Y) | None | 2 |
| LD | Rd, Y+ | Load Indirect and Post-Increment | Rd (Y), Y Y + 1 | None | 2 |
| LD | Rd, -Y | Load Indirect and Pre-Decrement | Y Y - 1, Rd (Y) | None | 2 |
| LDD | Rd,Y+q | Load Indirect with Displacement | Rd (Y + q) | None | 2 |
| LD | Rd, Z | Load Indirect | Rd (Z) | None | 2 |
| LD | Rd, Z+ | Load Indirect and Post-Increment | Rd (Z), Z Z+1 | None | 2 |
| LD | Rd, -Z | Load Indirect and Pre-Decrement | Z Z - 1, Rd (Z) | None | 2 |
| LDD | Rd, Z+q | Load Indirect with Displacement | Rd (Z + q) | None | 2 |
| STS | k, Rr | Store Direct to SRAM | Rd (k) | None | 3 |
| ST | X, Rr | Store Indirect | (X) Rr | None | 2 |
| ST | X+, Rr | Store Indirect and Post-Increment | (X) Rr, X X + 1 | None | 2 |
| ST | -X, Rr | Store Indirect and Pre-Decrement | X X - 1, (X) Rr | None | 2 |
| ST | Y, Rr | Store Indirect | (Y) Rr | None | 2 |
| ST | Y+, Rr | Store Indirect and Post-Increment | (Y) Rr, Y Y + 1 | None | 2 |
| ST | -Y, Rr | Store Indirect and Pre-Decrement | Y Y - 1, (Y) Rr | None | 2 |
| STD | Y+q,Rr | Store Indirect with Displacement | (Y + q) Rr | None | 2 |
| ST | Z, Rr | Store Indirect | (Z) Rr | None | 2 |
| ST | Z+, Rr | Store Indirect and Post-Increment | (Z) Rr, Z Z + 1 | None | 2 |
| ST | -Z, Rr | Store Indirect and Pre-Decrement | Z Z - 1, (Z) Rr | None | 2 |
| STD | Z+q,Rr | Store Indirect with Displacement | (Z + q) Rr | None | 2 |
| LPM | Load Program Memory | R0 (Z) | None | 3 | |
| IN | Rd, P | In Port | Rd P | None | 1 |
| OUT | P, Rr | Out Port | P Rr | None | 1 |
| PUSH | Rr | Push Register on Stack | STACK Rr | None | 2 |
| POP | Rd | Pop Register from Stack | Rd STACK | None | 2 |
| Mnemonics | Operands | Description | Operation | Flags | #Clock Note |
|---|---|---|---|---|---|
| LSL | Rd | Logical Shift Left | Rd(n+1) Rd(n),Rd(0) 0,C Rd(7) | Z,C,N,V,H | 1 |
| LSR | Rd | Logical Shift Right | Rd(n) Rd(n+1),Rd(7) 0,C Rd(0) | Z,C,N,V | 1 |
| ROL | Rd | Rotate Left Through Carry | Rd(0) C,Rd(n+1) Rd(n),C Rd(7) | Z,C,N,V,H | 1 |
| ROR | Rd | Rotate Right Through Carry | Rd(7) C,Rd(n) Rd(n+1),C Rd(0) | Z,C,N,V | 1 |
| ASR | Rd | Arithmetic Shift Right | Rd(n) Rd(n+1), n=0..6 | Z,C,N,V | 1 |
| SWAP | Rd | Swap Nibbles | Rd(3..0) Rd(7..4) | None | 1 |
| BSET | s | Flag Set | SREG(s) 1 | SREG(s) | 1 |
| BCLR | s | Flag Clear | SREG(s) 0 | SREG(s) | 1 |
| SBI | P, b | Set Bit in I/O Register | I/O(P, b) 1 | None | 2 |
| CBI | P, b | Clear Bit in I/O Register | I/O(P, b) 0 | None | 2 |
| BST | Rr, b | Bit Store from Register to T | T Rr(b) | T | 1 |
| BLD | Rd, b | Bit load from T to Register | 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 | |
| NOP | No Operation | None | 1 | ||
| SLEEP | Sleep | (see specific descr. for Sleep) | None | 1 | |
| WDR | Watchdog | Reset (see specific descr. for WDR) | None | 1 |