doc0856 - Instruction Set Nomenclature Status Register...

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Unformatted text preview: 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 8-bit Instruction Set 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. 0856I–AVR–07/10 I/O Registers 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 64K bytes data space, and constant data fetch on MCUs with more than 64K bytes program space. RAMPD Register concatenated with the Z-register enabling direct addressing of the whole data space on MCUs with more than 64K bytes data space. EIND Register concatenated with the Z-register enabling indirect jump and call to the whole program space on MCUs with more than 64K words (128K bytes) program space. 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 2 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set 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: Not all addressing modes are present in all devices. Refer to the device spesific instruction summary. Register Direct, Single Register Rd Figure 1. Direct Single Register Addressing The operand is contained in register d (Rd). Register Direct, Two Registers Rd and Rr Figure 2. Direct Register Addressing, Two Registers Operands are contained in register r (Rr) and d (Rd). The result is stored in register d (Rd). 3 0856I–AVR–07/10 I/O Direct Figure 3. I/O Direct Addressing Operand address is contained in 6 bits of the instruction word. n is the destination or source register address. Note: 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 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. 4 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set Data Indirect with Displacement Figure 5. Data Indirect with Displacement Data Space 0x0000 15 0 Y OR Z - REGISTER 15 10 OP 65 Rr/Rd 0 q RAMEND Operand address is the result of the Y- or Z-register contents added to the address contained in 6 bits of the instruction word. Rd/Rr specify the destination or source register. Data Indirect Figure 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. 5 0856I–AVR–07/10 Data Indirect with Pre-decrement Figure 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. Data Indirect with Post-increment Figure 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. 6 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set Program Memory Constant Addressing using the LPM, ELPM, and SPM Instructions Figure 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. Program Memory with Post-increment using the LPM Z+ and ELPM Z+ Instruction Figure 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. 7 0856I–AVR–07/10 Direct Program Addressing, JMP and CALL Figure 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. Indirect Program Addressing, IJMP and ICALL Figure 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 Zregister). 8 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set Relative Program Addressing, RJMP and RCALL Figure 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. 9 0856I–AVR–07/10 Conditional Branch Summary Test Boolean Rd > Rr Z•(N ⊕ V) = 0 Rd Complementary Boolean BRLT(1) Rd ≤ Rr Z+(N ⊕ V) = 1 (N ⊕ V) = 0 BRGE Rd < Rr Rd = Rr Z=1 BREQ Rd ≠ Rr Rr Rd ≤ Rr Z+(N ⊕ V) = 1 Rd < Rr (N ⊕ V) = 1 Rd > Rr C+Z=0 Rd Mnemonic Mnemonic Comment BRGE* Signed (N ⊕ V) = 1 BRLT Signed Z=0 BRNE Signed Rd > Rr Z•(N ⊕ V) = 0 BRLT* Signed BRLT Rd ≥ Rr (N ⊕ V) = 0 BRGE Signed BRLO(1) Rd ≤ Rr C+Z=1 BRSH* Unsigned BRGE (1) Rr C=0 BRSH/BRCC Rd < Rr C=1 BRLO/BRCS Unsigned Rd = Rr Z=1 BREQ Rd ≠ Rr Z=0 BRNE Unsigned Rd ≤ Rr C+Z=1 BRSH(1) Rd > Rr C+Z=0 BRLO* Unsigned 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 1. Interchange Rd and Rr in the operation before the test, i.e., CP Rd,Rr → CP Rr,Rd AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set Complete Instruction Set Summary Instruction Set Summary Mnemonics Operands Description Operation Flags #Clocks Z,C,N,V,S,H #Clocks XMEGA 1 Arithmetic and Logic Instructions ADD Rd, Rr ADC ADIW(1) SUB ← Add without Carry Rd Rd, Rr Add with Carry Rd ← Rd + Rr + C Z,C,N,V,S,H 1 Rd, K Add Immediate to Word Rd ← Rd + 1:Rd + K Z,C,N,V,S 2 Rd, Rr Subtract without Carry Rd ← Rd - Rr Z,C,N,V,S,H 1 SUBI Rd, K Subtract Immediate Rd ← Rd - K Z,C,N,V,S,H 1 SBC Rd, Rr Subtract with Carry Rd ← Rd - Rr - C Z,C,N,V,S,H 1 Rd, K Subtract Immediate with Carry Rd ← Rd - K - C Z,C,N,V,S,H 1 Rd, K Subtract Immediate from Word Rd + 1:Rd ← Rd + 1:Rd - K Z,C,N,V,S 2 SBCI SBIW (1) Rd + Rr AND Rd, Rr Logical AND Rd ← Rd • Rr Z,N,V,S 1 ANDI Rd, K Logical AND with Immediate Rd ← Rd • K Z,N,V,S 1 OR Rd, Rr Logical OR Rd ← Rd v Rr Z,N,V,S 1 ORI 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 Rd,Rr Multiply Signed R1:R0 ← Rd x Rr (SS) Z,C 2 (1) MULS FMULS(1) FMULSU (1) DES Multiply Signed with Unsigned R1:R0 ← Rd x Rr (SU) Z,C 2 Rd,Rr FMUL(1) Rd,Rr Fractional Multiply Unsigned R1:R0 ← Rd x Rr<<1 (UU) Z,C 2 Rd,Rr Fractional Multiply Signed R1:R0 ← Rd x Rr<<1 (SS) Z,C 2 Rd,Rr Fractional Multiply Signed with Unsigned R1:R0 ← Rd x Rr<<1 (SU) Z,C 2 K MULSU (1) Data Encryption if (H = 0) then R15:R0 else if (H = 1) then R15:R0 ← ← Encrypt(R15:R0, K) Decrypt(R15:R0, K) PC ← PC + k + 1 None 2 Indirect Jump to (Z) PC(15:0) PC(21:16) ← ← Z, 0 None 2 Extended Indirect Jump to (Z) PC(15:0) PC(21:16) ← ← Z, EIND None 2 PC ← k None 3 1/2 Branch Instructions RJMP IJMP k (1) EIJMP(1) JMP(1) k Relative Jump Jump 11 0856I–AVR–07/10 Mnemonics Operands Description RCALL k Relative Call Subroutine Flags Operation #Clocks #Clocks XMEGA PC ← PC + k + 1 None 3 / 4(3)(5) 2 / 3(3) ICALL(1) Indirect Call to (Z) PC(15:0) PC(21:16) ← ← Z, 0 None 3 / 4(3) 2 / 3(3) EICALL(1) Extended Indirect Call to (Z) 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 CALL(1) 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 if (Rr(b) = 0) PC ← SBRS Rr, b Skip if Bit in Register Set if (Rr(b) = 1) PC ← SBIC A, b Skip if Bit in I/O Register Cleared if (I/O(A,b) = 0) PC Rd - Rr Z,C,N,V,S,H 1 Rd - Rr - C Z,C,N,V,S,H 1 Rd - K Z,C,N,V,S,H 1 PC + 2 or 3 None 1/2/3 PC + 2 or 3 None 1/2/3 ← PC + 2 or 3 None 1/2/3 2/3/4 2/3/4 SBIS A, b Skip if Bit in I/O Register Set If (I/O(A,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 Rd ← Rr None 1 Rd+1:Rd ← Rr+1:Rr None 1 Data Transfer Instructions MOV Rd, Rr Copy Register Rd, Rr Copy Register Pair LDI Rd, K Load Immediate Rd ← K None 1 LDS(1) Rd, k Load Direct from data space Rd ← (k) None 1(5)/2(3) 2(3)(4) Rd ← None (5) (3) 1(3)(4) MOVW LD 12 (2) (1) Rd, X Load Indirect (X) 12 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set Flags #Clocks #Clocks XMEGA (X) X+1 None 2(3) 1(3)(4) ← ← X-1 (X) None 2(3)/3(5) 2(3)(4) Rd ← (Y) ← (Y) None 1(5)/2(3) 1(3)(4) Load Indirect and Post-Increment Rd Y ← ← (Y) Y+1 None 2(3) 1(3)(4) Rd, -Y Load Indirect and Pre-Decrement Y Rd ← ← Y-1 (Y) None 2(3)/3(5) 2(3)(4) LDD(1) Rd, Y+q Load Indirect with Displacement Rd ← (Y + q) None 2(3) 2(3)(4) LD(2) Rd, Z Load Indirect Rd ← (Z) None 1(5)/2(3) 1(3)(4) LD(2) Rd, Z+ Load Indirect and Post-Increment Rd Z ← ← (Z), Z+1 None 2(3) 1(3)(4) 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(3) ST(2) X, Rr Store Indirect (X) ← Rr None 1(5)/2(3) 1(3) Mnemonics Operands Description Operation LD(2) Rd, X+ Load Indirect and Post-Increment Rd X ← ← LD(2) Rd, -X Load Indirect and Pre-Decrement X ← X - 1, Rd ← (X) LD(2) Rd, Y Load Indirect LD(2) Rd, Y+ LD(2) X+, Rr Store Indirect and Post-Increment (X) X ← ← Rr, X+1 None 1 /2 ST(2) -X, Rr Store Indirect and Pre-Decrement X (X) ← ← X - 1, Rr None 2(3) ST(2) Y, Rr Store Indirect (Y) ← Rr None 1(5)/2(3) ST (2) (5) Y+, Rr Store Indirect and Post-Increment (Y) Y ← ← Rr, Y+1 None 1 /2 ST(2) -Y, Rr Store Indirect and Pre-Decrement Y (Y) ← ← Y - 1, Rr None Y+q, Rr Store Indirect with Displacement (Y + q) ← Rr None 2(3) (5) ST (2) (5) 1(3) 2(3) 2(3) STD(1) (3) (3) 1(3) 1(3) 2(3) 2(3) 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) (Z + q) ← None (3) 2(3) ST (2) (1) STD Store Indirect with Displacement 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 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 ELPM(1) 2 1(3) Z+q,Rr LPM(1)(2) Rr (3) 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 Pop Register from Stack SPM(1) I/O(A) ← Rr None 1 STACK ← Rr None 2 1(3) Rd ← STACK None 2 2(3) 13 0856I–AVR–07/10 Mnemonics Operands Description Operation Flags #Clocks XCH Z, Rd Exchange (Z) Rd ← ← Rd, (Z) None LAS Z, Rd Load and Set (Z) Rd 1 ← ← Rd v (Z) (Z) None LAC Z, Rd Load and Clear 1 (Z) Rd ← ← ($FF – Rd) • (Z) (Z) None LAT Z, Rd Load and Toggle 1 (Z) Rd ← ← Rd ⊕ (Z) (Z) None 1 Rd(n+1) Rd(0) C ← ← ← Rd(n), 0, Rd(7) Z,C,N,V,H 1 Rd(n) Rd(7) C ← ← ← Rd(n+1), 0, Rd(0) Z,C,N,V 1 Rd(0) Rd(n+1) C ← ← ← C, Rd(n), Rd(7) Z,C,N,V,H #Clocks XMEGA 1 Bit and Bit-test Instructions LSL Rd Logical Shift Left LSR Rd Logical Shift Right ROL Rd Rotate Left Through Carry ROR Rd Rotate Right Through Carry Rd(7) Rd(n) C ← ← ← C, Rd(n+1), 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 A, b Set Bit in I/O Register I/O(A, b) ← 1 None 1(5)2 1 I/O(A, b) ← 0 None (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 1 /2 T ← Rr(b) T 1 Rd(b) ← T None 1 C ← 1 C 1 SEC Set Carry 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 MCU Control Instructions BREAK(1) 14 Break (See specific descr. for BREAK) AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set Mnemonics Operands Description Operation Flags #Clocks NOP No Operation None 1 SLEEP Sleep (see specific descr. for Sleep) None 1 WDR Watchdog Reset (see specific descr. for WDR) None #Clocks XMEGA 1 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. 15 0856I–AVR–07/10 ADC – Add with Carry 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) Syntax: Program Counter: ADC Rd,Rr (i) Operands: 0 ≤ d ≤ 31, 0 ≤ r ≤ 31 PC ← PC + 1 16-bit Opcode: 0001 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 16 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set ADD – Add without Carry Description: Adds two registers without the C Flag and places the result in the destination register Rd. Operation: Rd ← Rd + Rr (i) Syntax: Program Counter: ADD Rd,Rr (i) Operands: 0 ≤ d ≤ 31, 0 ≤ r ≤ 31 PC ← PC + 1 16-bit Opcode: 0000 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 17 0856I–AVR–07/10 ADIW – Add Immediate to Word 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) Syntax: Operands: Program Counter: ADIW Rd+1:Rd,K (i) d ∈ {24,26,28,30}, 0 ≤ K ≤ 63 PC ← PC + 1 16-bit Opcode: 1001 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 18 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set AND – Logical AND 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) Syntax: Program Counter: AND Rd,Rr (i) Operands: 0 ≤ d ≤ 31, 0 ≤ r ≤ 31 PC ← PC + 1 16-bit Opcode: 0010 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 19 0856I–AVR–07/10 ANDI – Logical AND with Immediate 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) Syntax: Program Counter: ANDI Rd,K (i) Operands: 16 ≤ d ≤ 31, 0 ≤ K ≤ 255 PC ← PC + 1 16-bit Opcode: 0111 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: 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 20 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set ASR – Arithmetic Shift Right 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 C Syntax: Operands: Program Counter: ASR Rd (i) 0 ≤ d ≤ 31 PC ← PC + 1 16-bit Opcode: 1001 010d dddd 0101 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 21 0856I–AVR–07/10 BCLR – Bit Clear in SREG Description: Clears a single Flag in SREG. Operation: SREG(s) ← 0 (i) Syntax: Program Counter: BCLR s (i) Operands: 0≤s≤7 PC ← PC + 1 16-bit Opcode: 1001 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 22 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set BLD – Bit Load from the T Flag in SREG to a Bit in Register Description: Copies the T Flag in the SREG (Status Register) to bit b in register Rd. Operation: Rd(b) ← T (i) Syntax: Program Counter: BLD Rd,b (i) Operands: 0 ≤ d ≤ 31, 0 ≤ b ≤ 7 PC ← PC + 1 16 bit Opcode: 1111 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 23 0856I–AVR–07/10 BRBC – Branch if Bit in SREG is Cleared 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) Syntax: Program Counter: BRBC s,k (i) Operands: 0 ≤ s ≤ 7, -64 ≤ k ≤ +63 PC ← PC + k + 1 PC ← PC + 1, if condition is false 16-bit Opcode: 1111 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 24 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set BRBS – Branch if Bit in SREG is Set 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) Syntax: Program Counter: BRBS s,k (i) Operands: 0 ≤ s ≤ 7, -64 ≤ k ≤ +63 PC ← PC + k + 1 PC ← PC + 1, if condition is false 16-bit Opcode: 1111 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 ; Branch destination (do nothing) Words: 1 (2 bytes) Cycles: 1 if condition is false 2 if condition is true 25 0856I–AVR–07/10 BRCC – Branch if Carry Cleared 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) Syntax: Program Counter: BRCC k (i) Operands: -64 ≤ k ≤ +63 PC ← PC + k + 1 PC ← PC + 1, if condition is false 16-bit Opcode: 1111 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 26 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set BRCS – Branch if Carry Set 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) Syntax: Program Counter: BRCS k (i) Operands: -64 ≤ k ≤ +63 PC ← PC + k + 1 PC ← PC + 1, if condition is false 16-bit Opcode: 1111 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 ; Branch destination (do nothing) Words: 1 (2 bytes) Cycles: 1 if condition is false 2 if condition is true 27 0856I–AVR–07/10 BREAK – Break 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. Syntax: Program Counter: BREAK (i) Operands: None PC ← PC + 1 16-bit Opcode: 1001 0101 1001 1000 Status Register (SREG) and Boolean Formula: I T H S V N Z C – – – – – – – – Words: 1 (2 bytes) Cycles: 1 28 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set BREQ – Branch if Equal 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: If Rd = Rr (Z = 1) then PC ← PC + k + 1, else PC ← PC + 1 (i) Syntax: Program Counter: BREQ k (i) Operands: -64 ≤ k ≤ +63 PC ← PC + k + 1 PC ← PC + 1, if condition is false 16-bit Opcode: 1111 00kk kkkk k001 Status Register (SREG) and Boolean Formula: I T H S V N Z C – – – – – – – – Example: cp r1,r0 breq equal ; Compare registers r1 and r0 ; Branch if registers equal ... equal: nop ; Branch destination (do nothing) Words: 1 (2 bytes) Cycles: 1 if condition is false 2 if condition is true 29 0856I–AVR–07/10 BRGE – Branch if Greater or Equal (Signed) 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: If Rd ≥ Rr (N ⊕ V = 0) then PC ← PC + k + 1, else PC ← PC + 1 (i) Syntax: Program Counter: BRGE k (i) Operands: -64 ≤ k ≤ +63 PC ← PC + k + 1 PC ← PC + 1, if condition is false 16-bit Opcode: 1111 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 30 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set BRHC – Branch if Half Carry Flag is Cleared 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) Syntax: Program Counter: BRHC k (i) Operands: -64 ≤ k ≤ +63 PC ← PC + k + 1 PC ← PC + 1, if condition is false 16-bit Opcode: 1111 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 ; Branch destination (do nothing) Words: 1 (2 bytes) Cycles: 1 if condition is false 2 if condition is true 31 0856I–AVR–07/10 BRHS – Branch if Half Carry Flag is Set 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) Syntax: Program Counter: BRHS k (i) Operands: -64 ≤ k ≤ +63 PC ← PC + k + 1 PC ← PC + 1, if condition is false 16-bit Opcode: 1111 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 32 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set BRID – Branch if Global Interrupt is Disabled 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: If I = 0 then PC ← PC + k + 1, else PC ← PC + 1 (i) Syntax: Program Counter: BRID k (i) Operands: -64 ≤ k ≤ +63 PC ← PC + k + 1 PC ← PC + 1, if condition is false 16-bit Opcode: 1111 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 ; Branch destination (do nothing) Words: 1 (2 bytes) Cycles: 1 if condition is false 2 if condition is true 33 0856I–AVR–07/10 BRIE – Branch if Global Interrupt is Enabled 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: If I = 1 then PC ← PC + k + 1, else PC ← PC + 1 (i) Syntax: Program Counter: BRIE k (i) Operands: -64 ≤ k ≤ +63 PC ← PC + k + 1 PC ← PC + 1, if condition is false 16-bit Opcode: 1111 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 34 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set BRLO – Branch if Lower (Unsigned) 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) Syntax: Program Counter: BRLO k (i) Operands: -64 ≤ k ≤ +63 PC ← PC + k + 1 PC ← PC + 1, if condition is false 16-bit Opcode: 1111 00kk kkkk k000 Status Register (SREG) and Boolean Formula: I T H S V N Z C – – – – – – – – Example: eor loop: r19,r19 ; Clear r19 inc r19 ; Increase r19 ... cpi r19,$10 ; Compare r19 with $10 brlo loop ; 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 35 0856I–AVR–07/10 BRLT – Branch if Less Than (Signed) 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) Syntax: Program Counter: BRLT k (i) Operands: -64 ≤ k ≤ +63 PC ← PC + k + 1 PC ← PC + 1, if condition is false 16-bit Opcode: 1111 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 36 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set BRMI – Branch if Minus 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: If N = 1 then PC ← PC + k + 1, else PC ← PC + 1 (i) Syntax: Program Counter: BRMI k (i) Operands: -64 ≤ k ≤ +63 PC ← PC + k + 1 PC ← PC + 1, if condition is false 16-bit Opcode: 1111 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 ; Branch destination (do nothing) Words: 1 (2 bytes) Cycles: 1 if condition is false 2 if condition is true 37 0856I–AVR–07/10 BRNE – Branch if Not Equal 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) Syntax: Program Counter: BRNE k (i) Operands: -64 ≤ k ≤ +63 PC ← PC + k + 1 PC ← PC + 1, if condition is false 16-bit Opcode: 1111 01kk kkkk k001 Status Register (SREG) and Boolean Formula: I T H S V N Z C – – – – – – – – Example: eor r27,r27 ; Clear r27 inc r27 ; Increase r27 cpi r27,5 ; Compare r27 to 5 brne loop: 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 38 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set BRPL – Branch if Plus 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: If N = 0 then PC ← PC + k + 1, else PC ← PC + 1 (i) Syntax: Program Counter: BRPL k (i) Operands: -64 ≤ k ≤ +63 PC ← PC + k + 1 PC ← PC + 1, if condition is false 16-bit Opcode: 1111 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 ; Branch destination (do nothing) Words: 1 (2 bytes) Cycles: 1 if condition is false 2 if condition is true 39 0856I–AVR–07/10 BRSH – Branch if Same or Higher (Unsigned) 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: If Rd ≥Rr (C = 0) then PC ← PC + k + 1, else PC ← PC + 1 (i) Syntax: Program Counter: BRSH k (i) Operands: -64 ≤ k ≤ +63 PC ← PC + k + 1 PC ← PC + 1, if condition is false 16-bit Opcode: 1111 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 40 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set BRTC – Branch if the T Flag is Cleared 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) Syntax: Program Counter: BRTC k (i) Operands: -64 ≤ k ≤ +63 PC ← PC + k + 1 PC ← PC + 1, if condition is false 16-bit Opcode: 1111 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 ; Branch destination (do nothing) Words: 1 (2 bytes) Cycles: 1 if condition is false 2 if condition is true 41 0856I–AVR–07/10 BRTS – Branch if the T Flag is Set 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: If T = 1 then PC ← PC + k + 1, else PC ← PC + 1 (i) Syntax: Program Counter: BRTS k (i) Operands: -64 ≤ k ≤ +63 PC ← PC + k + 1 PC ← PC + 1, if condition is false 16-bit Opcode: 1111 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 42 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set BRVC – Branch if Overflow Cleared 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 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 ; Branch destination (do nothing) Words: 1 (2 bytes) Cycles: 1 if condition is false 2 if condition is true 43 0856I–AVR–07/10 BRVS – Branch if Overflow Set 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) Syntax: Program Counter: BRVS k (i) Operands: -64 ≤ k ≤ +63 PC ← PC + k + 1 PC ← PC + 1, if condition is false 16-bit Opcode: 1111 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 44 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set BSET – Bit Set in SREG Description: Sets a single Flag or bit in SREG. Operation: SREG(s) ← 1 (i) Syntax: Program Counter: BSET s (i) Operands: 0≤s≤7 PC ← PC + 1 16-bit Opcode: 1001 0100 0sss 1000 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 45 0856I–AVR–07/10 BST – Bit Store from Bit in Register to T Flag in SREG Description: Stores bit b from Rd to the T Flag in SREG (Status Register). Operation: T ← Rd(b) (i) Syntax: Program Counter: BST Rd,b (i) Operands: 0 ≤ d ≤ 31, 0 ≤ b ≤ 7 PC ← PC + 1 16-bit Opcode: 1111 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 46 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set CALL – Long Call to a Subroutine 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, 128K bytes Program memory maximum. Devices with 22 bits PC, 8M bytes Program memory maximum. Syntax: Operands: Program Counter Stack: (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 010k kkkk 111k kkkk kkkk kkkk kkkk 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 nop ; Continue (do nothing) ... check: cpi breq r16,$42 ; Check if r16 has a special value error ; Branch if equal ret ; Return from subroutine ... error: rjmp Words : Cycles : Cycles XMEGA: error ; 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 47 0856I–AVR–07/10 CBI – Clear Bit in I/O Register Description: Clears 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) ← 0 (i) Syntax: Program Counter: CBI A,b (i) Operands: 0 ≤ A ≤ 31, 0 ≤ b ≤ 7 PC ← PC + 1 16-bit Opcode: 1001 1000 AAAA Abbb Status Register (SREG) and Boolean Formula: I T H S V N Z C – – – – – – – – Example: cbi $12,7 ; Clear bit 7 in Port D Words : Cycles : Cycles XMEGA: Cycles Reduced Core tinyAVR: 48 1 (2 bytes) 2 1 1 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set CBR – Clear Bits in Register Description: Clears the specified bits in register Rd. Performs the logical AND between the contents of register Rd and the complement of the constant mask K. The result will be placed in register Rd. Operation: Rd ← Rd • ($FF - K) (i) Syntax: Operands: Program Counter: CBR Rd,K (i) 16 ≤ d ≤ 31, 0 ≤ K ≤ 255 PC ← PC + 1 16-bit Opcode: (see ANDI with K complemented) 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 49 0856I–AVR–07/10 CLC – Clear Carry Flag Description: Clears the Carry Flag (C) in SREG (Status Register). Operation: C←0 (i) Syntax: Program Counter: CLC (i) Operands: None PC ← PC + 1 16-bit Opcode: 1001 0100 1000 1000 Status Register (SREG) and Boolean Formula: I H S V N Z C – C: T – – – – – – 0 0 Carry Flag cleared Example: add r0,r0 clc ; Add r0 to itself ; Clear Carry Flag Words: 1 (2 bytes) Cycles: 1 50 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set CLH – Clear Half Carry Flag Description: Clears the Half Carry Flag (H) in SREG (Status Register). Operation: H←0 (i) Syntax: Program Counter: CLH (i) Operands: None PC ← PC + 1 16-bit Opcode: 1001 0100 1101 1000 Status Register (SREG) and Boolean Formula: I H S V N Z C – H: T – 0 – – – – – 0 Half Carry Flag cleared Example: clh ; Clear the Half Carry Flag Words: 1 (2 bytes) Cycles: 1 51 0856I–AVR–07/10 CLI – Clear Global Interrupt Flag 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) Syntax: Program Counter: CLI (i) Operands: None PC ← PC + 1 16-bit Opcode: 1001 0100 1111 1000 Status Register (SREG) and Boolean Formula: I H S V N Z C 0 I: T – – – – – – – 0 Global Interrupt Flag cleared Example: in temp, SREG ; Store SREG value (temp must be defined by user) cli ; Disable interrupts during timed sequence sbi EECR, EEMWE ; Start EEPROM write sbi EECR, EEWE out SREG, temp ; Restore SREG value (I-Flag) Words: 1 (2 bytes) Cycles: 1 52 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set CLN – Clear Negative Flag Description: Clears the Negative Flag (N) in SREG (Status Register). Operation: N←0 (i) Syntax: Program Counter: CLN (i) Operands: None PC ← PC + 1 16-bit Opcode: 1001 0100 1010 1000 Status Register (SREG) and Boolean Formula: I H S V N Z C – N: T – – – – 0 – – 0 Negative Flag cleared Example: add cln r2,r3 ; Add r3 to r2 ; Clear Negative Flag Words: 1 (2 bytes) Cycles: 1 53 0856I–AVR–07/10 CLR – Clear Register Description: Clears a register. This instruction performs an Exclusive OR between a register and itself. This will clear all bits in the register. Operation: Rd ← Rd ⊕ Rd (i) Syntax: Program Counter: CLR Rd (i) Operands: 0 ≤ d ≤ 31 PC ← PC + 1 16-bit Opcode: (see EOR Rd,Rd) 0010 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: clr loop: r18 ; clear r18 inc r18 ; increase r18 r18,$50 ; Compare r18 to $50 ... cpi brne loop Words: 1 (2 bytes) Cycles: 1 54 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set CLS – Clear Signed Flag Description: Clears the Signed Flag (S) in SREG (Status Register). Operation: S←0 (i) Syntax: Program Counter: CLS (i) Operands: None PC ← PC + 1 16-bit Opcode: 1001 0100 1100 1000 Status Register (SREG) and Boolean Formula: I H S V N Z C – S: T – – 0 – – – – 0 Signed Flag cleared Example: add cls r2,r3 ; Add r3 to r2 ; Clear Signed Flag Words: 1 (2 bytes) Cycles: 1 55 0856I–AVR–07/10 CLT – Clear T Flag Description: Clears the T Flag in SREG (Status Register). Operation: T←0 (i) Syntax: Program Counter: CLT (i) Operands: None PC ← PC + 1 16-bit Opcode: 1001 0100 1110 1000 Status Register (SREG) and Boolean Formula: I H S V N Z C – T: T 0 – – – – – – 0 T Flag cleared Example: clt ; Clear T Flag Words: 1 (2 bytes) Cycles: 1 56 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set CLV – Clear Overflow Flag Description: Clears the Overflow Flag (V) in SREG (Status Register). Operation: V←0 (i) Syntax: Program Counter: CLV (i) Operands: None PC ← PC + 1 16-bit Opcode: 1001 0100 1011 1000 Status Register (SREG) and Boolean Formula: I H S V N Z C – V: T – – – 0 – – – 0 Overflow Flag cleared Example: add clv r2,r3 ; Add r3 to r2 ; Clear Overflow Flag Words: 1 (2 bytes) Cycles: 1 57 0856I–AVR–07/10 CLZ – Clear Zero Flag Description: Clears the Zero Flag (Z) in SREG (Status Register). Operation: Z←0 (i) Syntax: Program Counter: CLZ (i) Operands: None PC ← PC + 1 16-bit Opcode: 1001 0100 1001 1000 Status Register (SREG) and Boolean Formula: I H S V N Z C – Z: T – – – – – 0 – 0 Zero Flag cleared Example: add clz r2,r3 ; Add r3 to r2 ; Clear zero Words: 1 (2 bytes) Cycles: 1 58 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set COM – One’s Complement Description: This instruction performs a One’s Complement of register Rd. Operation: Rd ← $FF - Rd (i) Syntax: Program Counter: COM Rd (i) Operands: 0 ≤ d ≤ 31 PC ← PC + 1 16-bit Opcode: 1001 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 ; Branch destination (do nothing) Words: 1 (2 bytes) Cycles: 1 59 0856I–AVR–07/10 CP – Compare 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 Syntax: Program Counter: CP Rd,Rr (i) Operands: 0 ≤ d ≤ 31, 0 ≤ r ≤ 31 PC ← PC + 1 16-bit Opcode: 0001 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 60 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set 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 Syntax: Program Counter: CPC Rd,Rr (i) Operands: 0 ≤ d ≤ 31, 0 ≤ r ≤ 31 PC ← PC + 1 16-bit Opcode: 0000 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 ; Branch destination (do nothing) 61 0856I–AVR–07/10 Words: 1 (2 bytes) Cycles: 1 62 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set CPI – Compare with Immediate 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: Program Counter: CPI Rd,K (i) Operands: 16 ≤ d ≤ 31, 0≤ K ≤ 255 PC ← PC + 1 16-bit Opcode: 0011 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 63 0856I–AVR–07/10 CPSE – Compare Skip if Equal 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) Syntax: Program Counter: CPSE Rd,Rr (i) Operands: 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 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 64 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set DEC – Decrement 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) Syntax: Program Counter: DEC Rd (i) Operands: 0 ≤ d ≤ 31 PC ← PC + 1 16-bit Opcode: 1001 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: ldi r17,$10 ; Load constant in r17 add r1,r2 ; Add r2 to r1 dec loop: r17 ; Decrement r17 brne loop ; Branch if r17<>0 nop ; Continue (do nothing) Words: 1 (2 bytes) Cycles: 1 65 0856I–AVR–07/10 DES – Data Encryption Standard 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 R8-R15, 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) If H = 0 then If H = 1 then Syntax: Operands: Program Counter: DES K (i) Encrypt round (R7-R0, R15-R8, K) Decrypt round (R7-R0, R15-R8, 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. 66 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set EICALL – Extended Indirect Call to Subroutine 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 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) 67 0856I–AVR–07/10 EIJMP – Extended Indirect Jump 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: Program Counter: Stack: See Operation None Not Affected 16-bit Opcode: 1001 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 ; Set up EIND and Z-pointer ; Jump to $051000 Words: 1 (2 bytes) Cycles: 2 68 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set ELPM – Extended Load Program Memory 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: R0 ← (RAMPZ:Z) Rd ← (RAMPZ:Z) Rd ← (RAMPZ:Z) Operands: Program Counter: ELPM ELPM Rd, Z ELPM Rd, Z+ (i) (ii) (iii) (RAMPZ:Z) ← (RAMPZ:Z) + 1 RAMPZ:Z: Unchanged, R0 implied destination register RAMPZ:Z: Unchanged RAMPZ:Z: Post incremented Syntax: (i) (ii) (iii) Comment: None, R0 implied 0 ≤ d ≤ 31 0 ≤ d ≤ 31 PC ← PC + 1 PC ← PC + 1 PC ← PC + 1 16 bit Opcode: (i) 1001 0101 1101 1000 (ii) 1001 000d dddd 0110 (iii) 1001 000d dddd 0111 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 69 0856I–AVR–07/10 ... Words: 1 (2 bytes) Cycles: 3 70 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set EOR – Exclusive OR 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) Syntax: Program Counter: EOR Rd,Rr (i) Operands: 0 ≤ d ≤ 31, 0 ≤ r ≤ 31 PC ← PC + 1 16-bit Opcode: 0010 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 71 0856I–AVR–07/10 FMUL – Fractional Multiply Unsigned Description: This instruction performs 8-bit × 8-bit → 16-bit unsigned multiplication and shifts the result one bit left. Rd Rr × Multiplicand R1 Multiplier 8 Product High Æ R0 Product Low 8 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 0011 0ddd 1rrr 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. 72 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set 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 73 0856I–AVR–07/10 FMULS – Fractional Multiply Signed Description: This instruction performs 8-bit × 8-bit → 16-bit signed multiplication and shifts the result one bit left. Rd Rr × Multiplicand R1 8 Product High → Multiplier R0 Product Low 8 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 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 74 ; 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 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set Words: 1 (2 bytes) Cycles: 2 75 0856I–AVR–07/10 FMULSU – Fractional Multiply Signed with Unsigned Description: This instruction performs 8-bit × 8-bit → 16-bit signed multiplication and shifts the result one bit left. Rd Rr × Multiplicand R1 8 Product High → Multiplier R0 Product Low 8 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) R1:R0 ← Rd × Rr (signed (1.15) ← signed (1.7) × unsigned (1.7)) Syntax: Operands: Program Counter: (i) FMULSU Rd,Rr 16 ≤ d ≤ 23, 16≤ r ≤ 23 PC ← PC + 1 16-bit Opcode: 0000 0011 1ddd 1rrr 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. 76 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set 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 77 0856I–AVR–07/10 ICALL – Indirect Call to Subroutine 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: PC(15:0) ← Z(15:0) Devices with 16 bits PC, 128K bytes Program memory maximum. PC(15:0) ← Z(15:0) Devices with 22 bits PC, 8M bytes Program memory maximum. PC(21:16) ← 0 (i) (ii) 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 0101 0000 1001 Status Register (SREG) and Boolean Formula: I T H S V N Z C – – – – – – – – Example: mov icall Words : Cycles : Cycles XMEGA: 78 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 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set IJMP – Indirect Jump 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 (128K bytes) section of Program memory. This instruction is not available in all devices. Refer to the device specific instruction set summary. Operation: PC ← Z(15:0) Devices with 16 bits PC, 128K bytes Program memory maximum. PC(15:0) ← Z(15:0) Devices with 22 bits PC, 8M bytes Program memory maximum. PC(21:16) ← 0 (i) (ii) Syntax: (i),(ii) Operands: IJMP Program Counter: Stack: See Operation None Not Affected 16-bit Opcode: 1001 0100 0000 1001 Status Register (SREG) and Boolean Formula: I T H S V N Z C – – – – – – – – Example: mov ijmp r30,r0 ; Set offset to jump table ; Jump to routine pointed to by r31:r30 Words: 1 (2 bytes) Cycles: 2 79 0856I–AVR–07/10 IN - Load an I/O Location to Register 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) Syntax: Program Counter: IN Rd,A (i) Operands: 0 ≤ d ≤ 31, 0 ≤ A ≤ 63 PC ← PC + 1 16-bit Opcode: 1011 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 80 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set INC – Increment 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) Syntax: Program Counter: INC Rd (i) Operands: 0 ≤ d ≤ 31 PC ← PC + 1 16-bit Opcode: 1001 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: clr r22 ; clear r22 inc r22 ; increment r22 cpi r22,$4F ; Compare r22 to $4f brne loop: loop ; Branch if not equal ... nop ; Continue (do nothing) 81 0856I–AVR–07/10 Words: 1 (2 bytes) Cycles: 1 82 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set JMP – Jump Description: Jump to an address within the entire 4M (words) Program memory. See also RJMP. This instruction is not available in all devices. Refer to the device specific instruction set summary. Operation: (i) PC ← k Syntax: Operands: Program Counter: Stack: (i) JMP k 0 ≤ k < 4M PC ← k Unchanged 32-bit Opcode: 1001 010k kkkk 110k kkkk kkkk kkkk kkkk Status Register (SREG) and Boolean Formula: I T H S V N Z C – – – – – – – – Example: mov r1,r0 ; Copy r0 to r1 jmp farplc ; Unconditional jump ... farplc: nop ; Jump destination (do nothing) Words: 2 (4 bytes) Cycles: 3 83 0856I–AVR–07/10 LAC – Load And Clear Description: Operation: (i) (Z) ← Rd • ($FF – (Z)) Syntax: (i) Operands: Program Counter: LAC Z,Rd 0 ≤ d ≤ 31 PC ← PC + 1 16-bit Opcode: 1001 001r rrrr 0110 Words: 1 (2 bytes) Cycles: 1 84 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set LAS – Load And Set Description: Operation: (i) (Z) ← Rd v (Z), Rd ← (Z) Syntax: (i) Operands: Program Counter: LAS Z,Rd 0 ≤ d ≤ 31 PC ← PC + 1 16-bit Opcode: 1001 001r rrrr 0101 Words: 1 (2 bytes) Cycles: 1 85 0856I–AVR–07/10 LAT – Load And Toggle Description: Operation: (i) (Z) ← Rd ⊕ (Z), Rd ← (Z) Syntax: (i) Operands: Program Counter: LAT Z,Rd 0 ≤ d ≤ 31 PC ← PC + 1 16-bit Opcode: 1001 001r rrrr 0111 Words: 1 (2 bytes) Cycles: 1 86 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set LD – Load Indirect from Data Space to Register using Index X 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 64K bytes. To access another data segment in devices with more than 64K bytes 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 pre-decremented. 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 64K bytes data space or more than 64K bytes 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: Operation: Comment: (i) (ii) (iii) Rd ← (X) Rd ← (X) X←X-1 X←X+1 Rd ← (X) X: Unchanged X: Post incremented X: Pre decremented Syntax: (i) (ii) (iii) 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 87 0856I–AVR–07/10 16-bit Opcode: (i) 1001 000d dddd 1100 (ii) 1001 000d dddd 1101 (iii) 1001 000d dddd 1110 Status Register (SREG) and Boolean Formula: I H S V N Z C – 88 T – – – – – – – AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set 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 1 clock cycle, and loading from the program memory takes 2 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 1 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 2 clock cycles, and loading from the program memory takes 3 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 1 clock cycle to execute. 89 0856I–AVR–07/10 LD (LDD) – Load Indirect from Data Space to Register using Index Y 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 64K bytes. To access another data segment in devices with more than 64K bytes 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 pre-decremented. 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 64K bytes data space or more than 64K bytes 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) 90 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: (i) (ii) (iii) (iv) 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 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set 16-bit Opcode: (i) 1000 000d dddd 1000 (ii) 1001 000d dddd 1001 (iii) 1001 000d dddd 1010 (iv) 10q0 qq0d dddd 1qqq 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 1 clock cycle, and loading from the program memory takes 2 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 1 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 2 clock cycles, and loading from the program memory takes 3 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 1 clock cycle to execute. 91 0856I–AVR–07/10 LD (LDD) – Load Indirect From Data Space to Register using Index Z 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 64K bytes. To access another data segment in devices with more than 64K bytes 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 pre-decremented. 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 64K bytes data space or more than 64K bytes 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) 92 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: (i) (ii) (iii) (iv) 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 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set 16-bit Opcode: (i) 1000 000d dddd 0000 (ii) 1001 000d dddd 0001 (iii) 1001 000d dddd 0010 (iv) 10q0 qq0d dddd 0qqq 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. $64 Words: 1 (2 bytes) Cycles: (i) 1(2) (ii) 2 (iii) 3(2) Cycles XMEGA: (i) 1(1) (ii) 1(1) (iii) 2(1) (iv) 2(1) Notes: 1. IF the LD instruction is accessing internal SRAM, one extra cycle is inserted. 2. LD instruction can load data from program memory since the flash is memory mapped. Loading data from the data memory takes 1 clock cycle, and loading from the program memory takes 2 clock cycles. But if an interrupt occur (before the last clock cycle) no additional clock cycles is necessary when loading from the program memory. Hence, the instruction takes only 1 clock cycle to execute. LD instruction with pre-decrement can load data from program memory since the flash is memory mapped. Loading data from the data memory takes 2 clock cycles, and loading from the program memory takes 3 clock cycles. But if an interrupt occur (before the last clock cycle) no additional clock cycles is necessary when loading from the program memory. Hence, the instruction takes only 1 clock cycle to execute. 93 0856I–AVR–07/10 LDI – Load Immediate Description: Loads an 8 bit constant directly to register 16 to 31. Operation: Rd ← K (i) Syntax: Program Counter: LDI Rd,K (i) Operands: 16 ≤ d ≤ 31, 0 ≤ K ≤ 255 PC ← PC + 1 16-bit Opcode: 1110 KKKK dddd KKKK Status Register (SREG) and Boolean Formula: I T H S V N Z C – – – – – – – – Example: clr r31 ldi r30,$F0 lpm ; Clear Z high byte ; Set Z low byte to $F0 ; Load constant from Program ; memory pointed to by Z Words: 1 (2 bytes) Cycles: 1 94 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set LDS – Load Direct from Data Space Description: Loads one byte from the data space to a register. For parts with SRAM, the data space consists of the Register File, I/O memory and internal SRAM (and external SRAM if applicable). For parts without SRAM, the data space consists of the register file only. The EEPROM has a separate address space. A 16-bit address must be supplied. Memory access is limited to the current data segment of 64K bytes. The LDS instruction uses the RAMPD Register to access memory above 64K bytes. To access another data segment in devices with more than 64K bytes data space, the RAMPD in register in the I/O area has to be changed. This instruction is not available in all devices. Refer to the device specific instruction set summary. Operation: Rd ← (k) (i) Syntax: Program Counter: LDS Rd,k (i) Operands: 0 ≤ d ≤ 31, 0 ≤ k ≤ 65535 PC ← PC + 2 32-bit Opcode: 1001 000d dddd 0000 kkkk kkkk kkkk kkkk Status Register (SREG) and Boolean Formula: I T H S V N Z C – – – – – – – – Example: lds r2,$FF00 ; Load r2 with the contents of data space location $FF00 add r2,r1 ; add r1 to r2 sts $FF00,r2 ; Write back Words: 2 (4 bytes) Cycles: Cycles XMEGA: 2 2 If the LDS instruction is accessing internal SRAM, one extra cycle is inserted. 95 0856I–AVR–07/10 LDS (16-bit) – Load Direct from Data Space 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) Syntax: Program Counter: LDS Rd,k (i) Operands: 16 ≤ d ≤ 31, 0 ≤ k ≤ 127 PC ← PC + 1 16-bit Opcode: 1010 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: 96 Registers r0..r15 are remapped to r16..r31. AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set LPM – Load Program Memory 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 64K bytes (32K words) of Program memory. The Z-pointer 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+ Operation: 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+ (i) (ii) (iii) Comment: R0 ← (Z) Rd ← (Z) Rd ← (Z) (i) (ii) (iii) None, R0 implied 0 ≤ d ≤ 31 0 ≤ d ≤ 31 PC ← PC + 1 PC ← PC + 1 PC ← PC + 1 16-bit Opcode: (i) 1001 0101 1100 1000 (ii) 1001 000d dddd 0100 (iii) 1001 000d dddd 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 ... 97 0856I–AVR–07/10 Words: 1 (2 bytes) Cycles: 3 98 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set LSL – Logical Shift Left 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 b7 - - - - - - - - - - - - - - - - - - b0 ←0 Syntax: Operands: Program Counter: LSL Rd (i) 0 ≤ d ≤ 31 PC ← PC + 1 16-bit Opcode: (see ADD Rd,Rd) 0000 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 99 0856I–AVR–07/10 LSR – Logical Shift Right 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→ → b7 - - - - - - - - - - - - - - - - - - b0 C Syntax: Program Counter: LSR Rd (i) Operands: 0 ≤ d ≤ 31 PC ← PC + 1 16-bit Opcode: 1001 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: 1 100 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set MOV – Copy Register 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: Rd ← Rr (i) Syntax: Program Counter: MOV Rd,Rr (i) Operands: 0 ≤ d ≤ 31, 0 ≤ r ≤ 31 PC ← PC + 1 16-bit Opcode: 0010 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: 1 101 0856I–AVR–07/10 MOVW – Copy Register Word 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 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 ; Return from subroutine Words: 1 (2 bytes) Cycles: 1 102 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set MUL – Multiply Unsigned Description: This instruction performs 8-bit × 8-bit → 16-bit unsigned multiplication. Rd Rr × Multiplicand R1 8 Product High → Multiplier R0 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: R1:R0 ← Rd × Rr Operands: Program Counter: MUL Rd,Rr (i) (unsigned ← unsigned × unsigned) Syntax: (i) 0 ≤ d ≤ 31, 0 ≤ r ≤ 31 PC ← PC + 1 16-bit Opcode: 1001 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: 2 103 0856I–AVR–07/10 MULS – Multiply Signed Description: This instruction performs 8-bit × 8-bit → 16-bit signed multiplication. Rd Rr × Multiplicand R1 8 Product High → Multiplier R0 Product Low 8 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: R1:R0 ← Rd × Rr Operands: Program Counter: MULS Rd,Rr (i) (signed ← signed × signed) Syntax: (i) 16 ≤ d ≤ 31, 16 ≤ r ≤ 31 PC ← PC + 1 16-bit Opcode: 0000 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: 2 104 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set MULSU – Multiply Signed with Unsigned Description: This instruction performs 8-bit × 8-bit → 16-bit multiplication of a signed and an unsigned number. Rd Rr × Multiplicand R1 8 Product High → Multiplier R0 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: R1:R0 ← Rd × Rr Operands: Program Counter: MULSU Rd,Rr (i) (signed ← signed × unsigned) Syntax: (i) 16 ≤ d ≤ 23, 16 ≤ r ≤ 23 PC ← PC + 1 16-bit Opcode: 0000 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. 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 105 0856I–AVR–07/10 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: 2 106 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set NEG – Two’s Complement Description: Replaces the contents of register Rd with its two’s complement; the value $80 is left unchanged. Operation: Rd ← $00 - Rd (i) Syntax: Program Counter: NEG Rd (i) Operands: 0 ≤ d ≤ 31 PC ← PC + 1 16-bit Opcode: 1001 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 r11,r0 ; Subtract r0 from r11 brpl positive positive: ; Branch if result positive neg ; Take two’s complement of r11 nop r11 ; Branch destination (do nothing) Words: 1 (2 bytes) Cycles: 1 107 0856I–AVR–07/10 NOP – No Operation Description: This instruction performs a single cycle No Operation. Operation: (i) No Syntax: Program Counter: NOP (i) Operands: None PC ← PC + 1 16-bit Opcode: 0000 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 ; Write ones to Port B Words: 1 (2 bytes) Cycles: 1 108 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set OR – Logical OR 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) Syntax: Program Counter: OR Rd,Rr (i) Operands: 0 ≤ d ≤ 31, 0 ≤ r ≤ 31 PC ← PC + 1 16-bit Opcode: 0010 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: 1 109 0856I–AVR–07/10 ORI – Logical OR with Immediate Description: Performs the logical OR between the contents of register Rd and a constant and places the result in the destination register Rd. Operation: Rd ← Rd v K (i) Syntax: Program Counter: ORI Rd,K (i) Operands: 16 ≤ d ≤ 31, 0 ≤ K ≤ 255 PC ← PC + 1 16-bit Opcode: 0110 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: 1 110 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set OUT – Store Register to I/O Location 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) Syntax: Program Counter: OUT A,Rr (i) Operands: 0 ≤ r ≤ 31, 0 ≤ A ≤ 63 PC ← PC + 1 16-bit Opcode: 1011 1AAr rrrr AAAA Status Register (SREG) and Boolean Formula: I T H S V N Z C – – – – – – – – Example: clr r16 ser r17 ; Set r17 out $18,r16 ; Write zeros to Port B nop out ; Clear r16 ; Wait (do nothing) $18,r17 ; Write ones to Port B Words: 1 (2 bytes) Cycles: 1 111 0856I–AVR–07/10 POP – Pop Register from Stack 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: Rd ← STACK (i) Syntax: Operands: Program Counter: Stack: POP Rd (i) 0 ≤ d ≤ 31 PC ← PC + 1 SP ← SP + 1 16-bit Opcode: 1001 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 ; Restore r14 ... ret ; Return from subroutine Words: 1 (2 bytes) Cycles: 2 112 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set PUSH – Push Register on Stack 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) Operands: Program Counter: Stack: 0 ≤ r ≤ 31 PUSH Rr PC ← PC + 1 SP ← SP - 1 16-bit Opcode: 1001 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 1 113 0856I–AVR–07/10 RCALL – Relative Call to Subroutine 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 (8K bytes) this instruction can address the entire memory from every address location. The Stack Pointer uses a post-decrement scheme during RCALL. Operation: PC ← PC + k + 1 PC ← PC + k + 1 Devices with 16 bits PC, 128K bytes Program memory maximum. Devices with 22 bits PC, 8M bytes 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) (i) (ii) 16-bit Opcode: 1101 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 ; Return from subroutine Words : Cycles : 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:4 114 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set RET – Return from Subroutine Description: Returns from subroutine. The return address is loaded from the STACK. The Stack Pointer uses a pre-increment scheme during RET. Operation: PC(15:0) ← STACK Devices with 16 bits PC, 128K bytes Program memory maximum. PC(21:0) ← STACKDevices with 22 bits PC, 8M bytes Program memory maximum. (i) (ii) Syntax: Operands: Program Counter: Stack: (i) RET None See Operation SP←SP + 2, (2bytes,16 bits) (ii) RET None See Operation SP←SP + 3, (3bytes,22 bits) 16-bit Opcode: 1001 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 115 0856I–AVR–07/10 RETI – Return from Interrupt 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: (i) (ii) PC(15:0) ← STACK Devices with 16 bits PC, 128K bytes Program memory maximum. PC(21:0) ← STACKDevices with 22 bits PC, 8M bytes Program memory maximum. 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 0101 0001 1000 Status Register (SREG) and Boolean Formula: I T H S V N Z C 1 – – – – – – – I: 1 The I Flag is set. Example: ... extint: push r0 ; Save r0 on the Stack ... pop r0 reti ; Restore r0 ; Return and enable interrupts Words: 1 (2 bytes) Cycles: 4 devices with 16-bit PC 5 devices with 22-bit PC 116 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set RJMP – Relative Jump Description: Relative jump to an address within PC - 2K +1 and PC + 2K (words). For AVR microcontrollers with Program memory not exceeding 4K words (8K bytes) this instruction can address the entire memory from every address location. See also JMP. Operation: PC ← PC + k + 1 (i) Syntax: Program Counter: Stack RJMP k (i) Operands: -2K ≤ k < 2K PC ← PC + k + 1 Unchanged 16-bit Opcode: 1100 kkkk kkkk kkkk Status Register (SREG) and Boolean Formula: I T H S V N Z C – – – – – – – – Example: cpi ; Branch if r16 <> $42 ok ; Unconditional branch add r16,r17 ; Add r17 to r16 inc ok: ; Compare r16 to $42 error rjmp error: r16,$42 brne r16 ; Increment r16 nop ; Destination for rjmp (do nothing) Words: 1 (2 bytes) Cycles: 2 117 0856I–AVR–07/10 ROL – Rotate Left trough Carry 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 ¨ b7 - - - - - - - - - - - - - - - - - - b0 ←C Syntax: Program Counter: ROL Rd (i) Operands: 0 ≤ d ≤ 31 PC ← PC + 1 16-bit Opcode: (see ADC Rd,Rd) 0001 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 ; Multiply r19:r18 by two rol r19 ; r19:r18 is a signed or unsigned two-byte integer brcs oneenc ; Branch if carry set ... oneenc: nop ; Branch destination (do nothing) Words: 1 (2 bytes) Cycles: 1 118 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set ROR – Rotate Right through Carry 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 multibyte unsigned values by two. The Carry Flag can be used to round the result. Operation: → → C b7 - - - - - - - - - - - - - - - - - - b0 → C Syntax: Program Counter: ROR Rd (i) Operands: 0 ≤ d ≤ 31 PC ← PC + 1 16-bit Opcode: 1001 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 ; Divide r19:r18 by two ror r18 ; r19:r18 is an unsigned two-byte integer brcc zeroenc1 ; Branch if carry cleared asr r17 ; Divide r17:r16 by two ror r16 ; r17:r16 is a signed two-byte integer brcc zeroenc2 ; Branch if carry cleared ... zeroenc1: nop ; Branch destination (do nothing) ... 119 0856I–AVR–07/10 zeroenc1: nop ; Branch destination (do nothing) Words: 1 (2 bytes) Cycles: 1 120 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set SBC – Subtract with Carry 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) Syntax: Program Counter: SBC Rd,Rr (i) Operands: 0 ≤ d ≤ 31, 0 ≤ r ≤ 31 PC ← PC + 1 16-bit Opcode: 0000 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: 1 121 0856I–AVR–07/10 SBCI – Subtract Immediate with Carry 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) Syntax: Program Counter: SBCI Rd,K (i) Operands: 16 ≤ d ≤ 31, 0 ≤ K ≤ 255 PC ← PC + 1 16-bit Opcode: 0100 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: 1 122 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set SBI – Set Bit in I/O Register 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) Syntax: Program Counter: SBI A,b (i) Operands: 0 ≤ A ≤ 31, 0 ≤ b ≤ 7 PC ← PC + 1 16-bit Opcode: 1001 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:1 123 0856I–AVR–07/10 SBIC – Skip if Bit in I/O Register is Cleared 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) Syntax: Program Counter: SBIC A,b (i) Operands: 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 Status Register (SREG) and Boolean Formula: I T H S V N Z C – – – – – – – – Example: e2wait: 124 ; EEPROM write not finished nop Cycles XMEGA: ; Skip next inst. if EEWE cleared rjmp e2wait Words : Cycles : sbic $1C,1 ; 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 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set SBIS – Skip if Bit in I/O Register is Set 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) Syntax: Program Counter: SBIS A,b (i) Operands: 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 Status Register (SREG) and Boolean Formula: I T H S V N Z C – – – – – – – – Example: waitset: sbis $10,0 ; Skip next inst. if bit 0 in Port D set rjmp waitset ; Bit not set nop ; Continue (do nothing) Words : Cycles : Cycles XMEGA: 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 125 0856I–AVR–07/10 SBIW – Subtract Immediate from Word 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) Syntax: Operands: Program Counter: SBIW Rd+1:Rd,K (i) d ∈ {24,26,28,30}, 0 ≤ K ≤ 63 PC ← PC + 1 16-bit Opcode: 1001 0111 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 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: 2 126 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set SBR – Set Bits in Register 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) Syntax: Program Counter: SBR Rd,K (i) Operands: 16 ≤ d ≤ 31, 0 ≤ K ≤ 255 PC ← PC + 1 16-bit Opcode: 0110 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 $00; cleared otherwise. R (Result) equals Rd after the operation. Example: sbr r16,3 ; Set bits 0 and 1 in r16 sbr r17,$F0 ; Set 4 MSB in r17 Words: 1 (2 bytes) Cycles: 1 127 0856I–AVR–07/10 SBRC – Skip if Bit in Register is Cleared 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) Syntax: Program Counter: SBRC Rr,b (i) Operands: 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 Status Register (SREG) and Boolean Formula: I T H S V N Z C – – – – – – – – Example: sub r0,r1 sbrc r0,7 sub nop r0,r1 ; Subtract r1 from r0 ; Skip if bit 7 in r0 cleared ; Only executed if bit 7 in r0 not cleared ; 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 128 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set SBRS – Skip if Bit in Register is Set 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) Syntax: Program Counter: SBRS Rr,b (i) Operands: 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 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 nop ; Only executed if bit 7 in r0 not set ; 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 129 0856I–AVR–07/10 SEC – Set Carry Flag Description: Sets the Carry Flag (C) in SREG (Status Register). Operation: C←1 (i) Syntax: Program Counter: SEC (i) Operands: None PC ← PC + 1 16-bit Opcode: 1001 0100 0000 1000 Status Register (SREG) and Boolean Formula: I T H S V N Z C – – – – – – – 1 C: 1 Carry Flag set Example: sec adc ; Set Carry Flag r0,r1 ; r0=r0+r1+1 Words: 1 (2 bytes) Cycles: 1 130 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set SEH – Set Half Carry Flag Description: Sets the Half Carry (H) in SREG (Status Register). Operation: H←1 (i) Syntax: Program Counter: SEH (i) Operands: None PC ← PC + 1 16-bit Opcode: 1001 0100 0101 1000 Status Register (SREG) and Boolean Formula: I H S V N Z C – H: T – 1 – – – – – 1 Half Carry Flag set Example: seh ; Set Half Carry Flag Words: 1 (2 bytes) Cycles: 1 131 0856I–AVR–07/10 SEI – Set Global Interrupt Flag 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) Syntax: Program Counter: SEI (i) Operands: None PC ← PC + 1 16-bit Opcode: 1001 0100 0111 1000 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: 1 132 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set SEN – Set Negative Flag Description: Sets the Negative Flag (N) in SREG (Status Register). Operation: N←1 (i) Syntax: Program Counter: SEN (i) Operands: None PC ← PC + 1 16-bit Opcode: 1001 0100 0010 1000 Status Register (SREG) and Boolean Formula: I H S V N Z C – N: T – – – – 1 – – 1 Negative Flag set Example: add sen r2,r19 ; Add r19 to r2 ; Set Negative Flag Words: 1 (2 bytes) Cycles: 1 133 0856I–AVR–07/10 SER – Set all Bits in Register Description: Loads $FF directly to register Rd. Operation: Rd ← $FF (i) Syntax: Program Counter: SER Rd (i) Operands: 16 ≤ d ≤ 31 PC ← PC + 1 16-bit Opcode: 1110 1111 dddd 1111 Status Register (SREG) and Boolean Formula: I T H S V N Z C – – – – – – – – Example: clr r16 ser r17 ; Set r17 out $18,r16 ; Write zeros to Port B nop out ; Clear r16 ; Delay (do nothing) $18,r17 ; Write ones to Port B Words: 1 (2 bytes) Cycles: 1 134 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set SES – Set Signed Flag Description: Sets the Signed Flag (S) in SREG (Status Register). Operation: S←1 (i) Syntax: Program Counter: SES (i) Operands: None PC ← PC + 1 16-bit Opcode: 1001 0100 0100 1000 Status Register (SREG) and Boolean Formula: I H S V N Z C – S: T – – 1 – – – – 1 Signed Flag set Example: add ses r2,r19 ; Add r19 to r2 ; Set Negative Flag Words: 1 (2 bytes) Cycles: 1 135 0856I–AVR–07/10 SET – Set T Flag Description: Sets the T Flag in SREG (Status Register). Operation: T←1 (i) Syntax: Program Counter: SET (i) Operands: None PC ← PC + 1 16-bit Opcode: 1001 0100 0110 1000 Status Register (SREG) and Boolean Formula: I T H S V N Z C – 1 – – – – – – T: 1 T Flag set Example: set ; Set T Flag Words: 1 (2 bytes) Cycles: 1 136 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set SEV – Set Overflow Flag Description: Sets the Overflow Flag (V) in SREG (Status Register). Operation: V←1 (i) Syntax: Program Counter: SEV (i) Operands: None PC ← PC + 1 16-bit Opcode: 1001 0100 0011 1000 Status Register (SREG) and Boolean Formula: I H S V N Z C – V: T – – – 1 – – – 1 Overflow Flag set Example: add sev r2,r19 ; Add r19 to r2 ; Set Overflow Flag Words: 1 (2 bytes) Cycles: 1 137 0856I–AVR–07/10 SEZ – Set Zero Flag Description: Sets the Zero Flag (Z) in SREG (Status Register). Operation: Z←1 (i) Syntax: Program Counter: SEZ (i) Operands: None PC ← PC + 1 16-bit Opcode: 1001 0100 0001 1000 Status Register (SREG) and Boolean Formula: I T H S V N Z C – – – – – – 1 – Z: 1 Zero Flag set Example: add sez r2,r19 ; Add r19 to r2 ; Set Zero Flag Words: 1 (2 bytes) Cycles: 1 138 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set SLEEP 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 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 ; Put MCU in sleep mode Words: 1 (2 bytes) Cycles: 1 139 0856I–AVR–07/10 SPM – Store Program Memory 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: 140 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set ;page erase ldispmcrval, (1<<PGERS) + (1<<SPMEN) calldo_spm ;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 141 0856I–AVR–07/10 ret Words: 1 (2 bytes) Cycles: depends on the operation 142 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set SPM #2– Store Program Memory 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: Z←Z+2 Z←Z+2 Z←Z+2 Operands: Program Counter: None None (i)-(iii) SPM (iv)-(vi) SPM Z+ PC ← PC + 1 PC ← PC + 1 16-bit Opcode: (i)-(iii) 1001 0101 1110 1000 (iv)-(vi) 1001 0101 1111 1000 Status Register (SREG) and Boolean Formula: I T H S V N Z C – – – – – – – – Example: TBD Words: 1 (2 bytes) Cycles: depends on the operation 143 0856I–AVR–07/10 ST – Store Indirect From Register to Data Space using Index X 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 64K bytes. To access another data segment in devices with more than 64K bytes 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 pre-decremented. 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 64K bytes data space or more than 64K bytes 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: Operation: 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 (i) (ii) (iii) Comment: (X) ← Rr (X) ← Rr X←X-1 (i) (ii) (iii) 0 ≤ r ≤ 31 0 ≤ r ≤ 31 0 ≤ r ≤ 31 PC ← PC + 1 PC ← PC + 1 PC ← PC + 1 16-bit Opcode : (i) 1001 001r rrrr 1100 (ii) 1001 001r rrrr 1101 (iii) 1001 001r rrrr 1110 Status Register (SREG) and Boolean Formula: I T H S V N Z C – – – – – – – – 144 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set 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: 1 (2 bytes) Cycles: Cycles XMEGA: 2 (i) (ii) (iii) Cycles Reduced Core tinyAVR:(i) (ii) (iii) 1 1 2 1 1 2 145 0856I–AVR–07/10 ST (STD) – Store Indirect From Register to Data Space using Index Y 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 64K bytes. To access another data segment in devices with more than 64K bytes 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 pre-decremented. 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 64K bytes data space or more than 64K bytes 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) 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: (i) (ii) (iii) (iv) 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) 001r rrrr 1000 1001 001r rrrr 1001 (iii) 1001 001r rrrr 1010 (iv) 146 1000 (ii) 10q0 qq1r rrrr 1qqq AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set 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 2 147 0856I–AVR–07/10 ST (STD) – Store Indirect From Register to Data Space using Index Z 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 64K bytes. To access another data segment in devices with more than 64K bytes 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 pre-decremented. 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 64K bytes data space or more than 64K bytes 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: Comment: (i) (ii) (iii) (iv) (Z) ←Rr (Z) ← Rr Z←Z-1 (Z+q) ← Rr Z ← Z+1 (Z) ← Rr Z: Unchanged Z: Post incremented Z: Pre decremented Z: Unchanged, q: Displacement Syntax: Operands: Program Counter: (i) (ii) (iii) (iv) 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 + 1 148 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set 16-bit Opcode : (i) 1000 001r rrrr 0000 (ii) 1001 001r rrrr 0001 (iii) 1001 001r rrrr 0010 (iv) 10q0 qq1r rrrr 0qqq 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. $64 Words: 1 (2 bytes) Cycles: Cycles XMEGA: (i) (ii) (iii) (iv) Cycles Reduced Core tinyAVR:(i) (ii) (iii) 2 1 1 2 2 1 1 2 149 0856I–AVR–07/10 STS – Store Direct to Data Space Description: Stores one byte from a Register to the data space. For parts with SRAM, the data space consists of the Register File, I/O memory and internal SRAM (and external SRAM if applicable). For parts without SRAM, the data space consists of the Register File only. The EEPROM has a separate address space. A 16-bit address must be supplied. Memory access is limited to the current data segment of 64K bytes. The STS instruction uses the RAMPD Register to access memory above 64K bytes. To access another data segment in devices with more than 64K bytes data space, the RAMPD in register in the I/O area has to be changed. This instruction is not available in all devices. Refer to the device specific instruction set summary. Operation: (k) ← Rr (i) Syntax: Program Counter: STS k,Rr (i) Operands: 0 ≤ r ≤ 31, 0 ≤ k ≤ 65535 PC ← PC + 2 32-bit Opcode: 1001 001d dddd 0000 kkkk kkkk kkkk kkkk Status Register (SREG) and Boolean Formula: I T H S V N Z C – – – – – – – – Example: lds r2,$FF00 ; Load r2 with the contents of data space location $FF00 add r2,r1 ; add r1 to r2 sts $FF00,r2 ; Write back Words: 2 (4 bytes) Cycles: 2 150 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set STS (16-bit) – Store Direct to Data Space 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) Syntax: Program Counter: STS k,Rr (i) Operands: 16 ≤ r ≤ 31, 0 ≤ k ≤ 127 PC ← PC + 1 16-bit Opcode: 1010 1kkk 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 remaped to r16..r31 151 0856I–AVR–07/10 SUB – Subtract without Carry Description: Subtracts two registers and places the result in the destination register Rd. Operation: Rd ← Rd - Rr (i) Syntax: Program Counter: SUB Rd,Rr (i) Operands: 0 ≤ d ≤ 31, 0 ≤ r ≤ 31 PC ← PC + 1 16-bit Opcode: 0001 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 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 ; Branch destination (do nothing) Words: 1 (2 bytes) Cycles: 1 152 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set SUBI – Subtract Immediate 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) Syntax: Program Counter: SUBI Rd,K (i) Operands: 16 ≤ d ≤ 31, 0 ≤ K ≤ 255 PC ← PC + 1 16-bit Opcode: 0101 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 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: 1 153 0856I–AVR–07/10 SWAP – Swap Nibbles Description: Swaps high and low nibbles in a register. Operation: R(7:4) ← Rd(3:0), R(3:0) ← Rd(7:4) (i) Syntax: Program Counter: SWAP Rd (i) Operands: 0 ≤ d ≤ 31 PC ← PC + 1 16-bit Opcode: 1001 010d dddd 0010 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: 1 154 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set TST – Test for Zero or Minus Description: Tests if a register is zero or negative. Performs a logical AND between a register and itself. The register will remain unchanged. Operation: Rd ← Rd • Rd (i) Syntax: Program Counter: TST Rd (i) Operands: 0 ≤ d ≤ 31 PC ← PC + 1 16-bit Opcode: (see AND Rd, Rd) 0010 00dd dddd dddd 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: 1 155 0856I–AVR–07/10 WDR – Watchdog Reset 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. Syntax: Program Counter: WDR (i) Operands: None PC ← PC + 1 16-bit Opcode: 1001 0101 1010 1000 Status Register and Boolean Formula: I T H S V N Z C – – – – – – – – Example: wdr ; Reset watchdog timer Words: 1 (2 bytes) Cycles: 1 156 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set XCH – Exchange Description: Operation: (i) (Z) ← Rd, Rd ← (Z) Syntax: (i) Operands: Program Counter: XCH Z,Rd 0 ≤ d ≤ 31 PC ← PC + 1 16-bit Opcode: 1001 001r rrrr 0100 Words: 1 (2 bytes) Cycles: 1 157 0856I–AVR–07/10 Datasheet Revision History Please 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. Rev.0856I – 07/10 1. Updated “Complete Instruction Set Summary” on page 11 with new instructions: LAC, LAS, LAT and XCH. “LAC – Load And Clear” on page 84 “LAS – Load And Set” on page 85 “LAT – Load And Toggle” on page 86 “XCH – Exchange” on page 157 2. Updated number of clock cycles column to include Reduced Core tinyAVR. (ATtiny replaced by Reduced Core tinyAVR). Rev.0856H – 04/09 1. Updated “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: “CBI – Clear Bit in I/O Register” on page 48 “LD – Load Indirect from Data Space to Register using Index X” on page 87 “LD (LDD) – Load Indirect from Data Space to Register using Index Y” on page 90 “LD (LDD) – Load Indirect From Data Space to Register using Index Z” on page 92 “RCALL – Relative Call to Subroutine” on page 114 “SBI – Set Bit in I/O Register” on page 123 “ST – Store Indirect From Register to Data Space using Index X” on page 144 “ST (STD) – Store Indirect From Register to Data Space using Index Y” on page 146 “ST (STD) – Store Indirect From Register to Data Space using Index Z” on page 148 3. Added sections for Reduced Core tinyAVR compatibility: “LDS (16-bit) – Load Direct from Data Space” on page 96 “STS (16-bit) – Store Direct to Data Space” on page 151 Rev.0856G – 07/08 1. Inserted “Datasheet Revision History” 2. Updated “Cycles XMEGA” for ST, by removing (iv). 3. Updated “SPM #2” opcodes. 158 AVR Instruction Set 0856I–AVR–07/10 AVR Instruction Set Rev.0856F – 05/08 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. 159 0856I–AVR–07/10 Headquarters International Atmel Corporation 2325 Orchard Parkway San Jose, CA 95131 USA Tel: 1(408) 441-0311 Fax: 1(408) 487-2600 Atmel Asia Unit 1-5 & 16, 19/F BEA Tower, Millennium City 5 418 Kwun Tong Road Kwun Tong, Kowloon Hong Kong Tel: (852) 2245-6100 Fax: (852) 2722-1369 Atmel Europe Le Krebs 8, Rue Jean-Pierre Timbaud BP 309 78054 Saint-Quentin-enYvelines Cedex France Tel: (33) 1-30-60-70-00 Fax: (33) 1-30-60-71-11 Atmel Japan 9F, Tonetsu Shinkawa Bldg. 1-24-8 Shinkawa Chuo-ku, Tokyo 104-0033 Japan Tel: (81) 3-3523-3551 Fax: (81) 3-3523-7581 Technical Support avr@atmel.com Sales Contact www.atmel.com/contacts Product Contact Web Site www.atmel.com Literature Requests www.atmel.com/literature Disclaimer: T he information in this document is provided in connection with Atmel products. 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This document was uploaded on 11/02/2011 for the course ECE 433 at Boise State.

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