8051 Instruction Set Summary Rn Data Register R7-R0 of the currently selected Register Bank 8-bit internal data location’s address This could be an internal Data RAM location (0-127) or a SFR [i.e I/O port, control register, status register, etc (128-255)] @Ri 8-bit Internal Data RAM location (0-255) addressed indirectly through register R1 or R0 #data 8-bit constant included in instruction #data16 16-bit constant included in instruction addr16 16-bit destination address Used by LCALL and LJMP A branch can be anywhere within the 64k byte Program Memory address space addr11 11-bit destination address Used by ACALL and AJMP The branch will be within the same 2k byte page of Program Memory as the first byte of the following instruction rel Signed (two’s component) 8-bit offset byte Used by SJMP and all conditional jumps Range is –128 to +127 bytes relative to first byte of the following instruction bit Direct Addressed bit in Internal Data RAM or Special Function Register Instruction Flag OV X X X X X Instruction Flag OV C AC C AC ADD X X CLR C O ADDC X X CPL C X SUBB X X ANL C,bit X MUL O ANL C,/bit X DIV O ORL C,bit X DA X ORL C,/bit X RRC X MOV C,bit X RLC X CJNE X SETB C Note that operations on SFR byte address 206 or bit addresses 209-215 (i.e the PSW or bits in the PSW) will also affect flag settings Mnemonic Description Byte A,Rn Add register to accumulator Description Byte Cycle Mnemonic Description Byte CPL A Complement accumulator 1 CJNE A,#data,rel Compare immediate to A and jump if not equal RL A Rotate accumulator left 1 CJNE Rn,#data,rel Compare immed to reg and jump if not equal RLC A Rotate accumulator left through carry 1 CJNE @Rn,#data,rel Compare immed to ind and jump if not equal RR A Rotate accumulator right 1 DJNZ Rn,rel Decrement register and jump in not zero 2 RRC A Rotate accumulator right through carry 1 DJNZ direct,rel Decrement direct byte and jump in not zero Swap nibbles within the accumulator 1 NOP No operation 1 SWAP A Logic operations Cycle Data transfer ANL A,Rn AND register to accumulator 1 MOV A,Rn Move register to accumulator ANL A,direct AND direct byte to accumulator MOV A,direct*) Move direct byte to accumulator ANL A,@Ri AND indirect RAM to accumulator 1 MOV A,@Ri Move indirect RAM to accumulator 1 ANL A,#data AND immediate data to accumulator MOV A,#data Move immediate data to accumulator ANL direct,A AND accumulator to direct byte MOV Rn,A Move accumulator to register 1 ANL direct,#data AND immediate data to direct byte MOV Rn,direct Move direct byte to register 2 ORL A,Rn OR register to accumulator 1 MOV Rn,#data Move immediate data to register ORL A,direct OR direct byte to accumulator MOV direct,A Move accumulator to direct byte ORL A,@Ri OR indirect RAM to accumulator 1 MOV direct,Rn Move register to direct byte 2 ORL A,#data OR immediate data to accumulator MOV direct,direct Move direct byte to direct byte ORL direct,A OR accumulator to direct byte MOV direct,@Ri Move indirect RAM to direct byte 2 ORL direct,#data OR immediate data to direct byte MOV direct,#data Move immediate data to direct byte XRL A,Rn Exclusive OR register to accumulator 1 MOV @Ri,A Move accumulator to indirect RAM 1 XRL A,direct Exclusive OR direct byte to accumulator MOV @Ri,direct Move direct byte to indirect RAM 2 XRL A,@Ri Exclusive OR indirect RAM to accumulator 1 MOV @Ri,#data Move immediate data to indirect RAM XRL A,#data Exclusive OR immediate data to accumulator MOV DPTR,#data16 Load data pointer with a 16-bit constant XRL direct,A Exclusive OR accumulator to direct byte MOVC A,@A+DPTR Move code byte relative to DPTR to accumulator XRL direct,#data Exclusive OR immediate data to direct byte MOVC A,@A+PC Move code byte relative to PC to accumulator MOVX A,@Ri Move external RAM (8-bit addr.) to A CLR C Clear carry flag 1 MOVX A,@DPTR Move external RAM (16-bit addr.) to A CLR bit Clear direct bit MOVX @Ri,A Move A to external RAM (8-bit addr.) SETB C Set carry flag 1 MOVX @DPTR,A Move A to external RAM (16-bit addr.) SETB bit Set direct bit PUSH direct Push direct byte onto stack 2 CPL C Complement carry flag 1 POP direct Pop direct byte from stack 2 bit Complement direct bit XCH A,Rn Exchange register to accumulator 1 Cycle Arithmetic operations ADD Mnemonic Boolean variable manipulation ADD A,direct Add direct byte to accumulator CPL ADD A,@Ri Add indirect RAM to accumulator 1 ANL C,bit AND direct bit to carry flag 2 XCH A,direct Exchange direct byte to accumulator ADD A,#data Add immediate data to accumulator ANL C,/bit AND complement of direct bit to carry 2 XCH A,@Ri Exchange indirect RAM to accumulator 1 C,bit OR direct bit to carry flag 2 XCHD A,@Ri Exchange low-order nibble indir RAM with A 1 *) MOV A,ACC is not a valid instruction ADDC A,Rn Add register to accumulator with carry flag 1 ORL ADDC A,direct Add direct byte to A with carry flag ORL C,/bit OR complement of direct bit to carry 2 ADDC A,@Ri Add indirect RAM to A with carry flag 1 MOV C,bit Move direct bit to carry flag ADDC A,#data Add immediate data to A with carry flag MOV bit,C Move carry flag to direct bit 2 A,#data,@ Subtract register to accumulator with borrow 1 Program and machine control jne A,#data,@ (jump if A ! = data) cjne SUBB A,Rn SUBB A,direct Subtract direct byte to A with carry borrow ACALL addr11 Absolute subroutine call 2 SUBB A,@Ri Subtract indirect RAM to A with carry borrow 1 LCALL addr16 Long subroutine call je A, #data,@ (jump if A == data) add jz A,#low(−data) @ SUBB A,#data Subtract immediate data to A with carry borrow RET Return from subroutine INC A Increment accumulator 1 RETI Return from interrupt ja, jnbe A,#data,@ (jump if A > data) add jc A,#low(−data−1) or cjne @ ne: jnc A,#(data+1),ne @ INC Rn Increment register 1 AJMP addr11 Absolute jump 2 INC direct Increment direct byte LJMP addr16 Long jump jae, jnb A,#data,@ (jump if A >= data) add jc A,#low(−data) @ or cjne ne: jnc A,#(data),ne @ INC @Ri Increment indirect RAM 1 SJMP rel Short jump (relative address) 2 A Decrement accumulator 1 JMP Jump indirect relative to the DPTR jb, jnae A,#data,@ (jump if A < data) add jnc A,#low,(−data) @ or DEC cjne ne: jc A,#(data),ne @ DEC Rn Decrement register 1 JZ rel Jump if accumulator is zero 2 DEC direct Decrement direct byte JNZ rel Jump if accumulator is not zero 2 jbe, jna A,#data,@ (jump if A [B hi]:[A lo] JB bit,rel Jump if bit is set @A+DPTR DIV AB Divide A by B -> A=result, B=remainder JNB bit,rel Jump if bit is not set DA A Decimal adjust accumulator 1 JBC bit,rel Jump if direct bit is set and clear bit CLR A Clear accumulator 1 CJNE A,direct,rel Compare direct byte to A and jump if not equal This paper was created by Štěpán Matějka alias Mates for anybody who needs it Mates, Prague – Czech Republic 1998,2002 switch A #data (no A modification) cjne ne: jc jnc or cjne jmp ne: A,#(data),ne @ A,#(data+1),ne @ A,#data,ne is_below is_above ; execute code if A==data ; jump if Adata or exec code Enjoy It! Mates 8051 Instruction Set Table 2c NOP AJMP 0A8 16 2c 17 2c 0101 1c 1c LJMP A16 RR A INC A INC A8 INC @R0 18 2c 19 1c 20 1c 21 1c @R1 1c 0111 R0 1c 1000 R1 1001 R2 1c 1c INC @R1 INC R0 22 1c 23 1c 24 1c 1010 R3 1011 R4 1100 R5 1101 R6 1110 R7 1111 10 1c 11 1c 12 1c 13 1c 14 1c 15 1c INC R1 INC R2 INC R3 INC R4 INC R5 INC R6 INC R7 25 1c 26 1c 27 1c 28 1c 29 1c 30 1c 31 1c RRC A DEC A DEC A8 DEC @R0 DEC @R1 DEC R0 DEC R1 DEC R2 DEC R3 DEC R4 DEC R5 DEC R6 DEC R7 35 1c 36 1c 37 1c 38 1c 39 1c 40 1c 41 1c 42 1c 43 1c 44 1c 45 1c 46 1c 47 1c RET RL A ADD A,#D ADD A,A8 50 2c 51 1c 52 1c 53 1c 54 1c 55 1c 56 1c 57 1c 58 1c 59 1c 60 1c 61 1c 62 1c 63 1c 70 1c 71 1c 72 1c 73 1c 74 1c 75 1c 76 1c 77 1c 78 1c 79 1c ORL A,R0 ORL A,R1 ORL A,R2 ORL A,R3 ORL A,R4 ORL A,R5 ORL A,R6 ORL A,R7 88 1c 89 1c 90 1c 91 1c ANL A,R0 ANL A,R1 ANL A,R2 ANL A,R3 ANL A,R4 ANL A,R5 ANL A,R6 ANL A,R7 32 2c 33 2c JB BIT,AR AJMP 1A8 48 2c 49 2c RETI RLC A 34 2c ADD A,R0 ADD A,R1 ADD A,R2 ADD A,R3 ADD A,R4 ADD A,R5 ADD A,R6 ADD A,R7 ADDC A,#D ADDC A,A8 64 2c 65 2c 66 1c 67 1c 68 1c 69 1c JC AR AJMP 2A8 ORL A8,A ORL A8,#D ORL A,#D ORL A,A8 80 2c 81 2c 82 1c 83 1c 84 1c 85 1c ACALL A8 ANL A8,A ANL A8,#D ANL A,#D ANL A,A8 JNC AR 0110 1c JBC BIT,AR ACALL A8 LCALL A16 JNB BIT,AR ACALL A8 0100 86 1c 87 1c 92 1c 93 1c 94 1c 95 1c 96 2c 97 2c 98 1c 99 1c 100 1c 101 1c 102 1c 103 1c 104 1c 105 1c 106 1c 107 1c 108 1c 109 1c 110 1c 111 1c JZ AR AJMP 3A8 XRL A8,A XRL A8,#D XRL A,#D XRL A,A8 XRL A,R0 XRL A,R1 XRL A,R2 XRL A,R3 XRL A,R4 XRL A,R5 XRL A,R6 XRL A,R7 112 2c 113 2c 114 2c 115 2c 116 1c 117 2c 118 1c 119 1c 120 1c 121 1c 122 1c 123 2c 124 1c 125 1c 126 1c 127 1c JNZ AR ACALL A8 ORL C,BIT MOV A,#D MOV A8,#D MOV R0,#D MOV R1,#D MOV R2,#D MOV R3,#D MOV R4,#D MOV R5,#D MOV R6,#D MOV R7,#D 128 2c 129 2c 130 2c 131 2c 132 4c 133 2c 134 2c 135 2c 136 2c 137 2c 138 2c 139 2c 140 2c 141 2c 142 2c 143 2c SJMP AR AJMP 4A8 ANL C,BIT DIV AB MOV A8,A8 MOV A8,R0 MOV A8,R1 MOV A8,R2 MOV A8,R3 MOV A8,R4 MOV A8,R5 MOV A8,R6 MOV A8,R7 144 2c 145 2c 146 2c 147 2c 148 1c 149 1c 150 1c 151 1c 152 1c 153 1c 154 1c 155 1c 156 1c 157 1c 158 1c 159 1c ACALL A8 MOV BIT,C SUBB A,#D SUBB A,A8 208 2c 161 2c 162 1c 163 2c 164 4c 165 ORL C,BIT AJMP 5A8 MOV C,BIT INC DPTR MUL AB 166 2c 167 2c 168 2c 169 2c 170 2c 171 2c 172 2c 173 2c 174 2c 175 2c MOV R0,A8 MOV R1,A8 MOV R2,A8 MOV R3,A8 MOV R4,A8 MOV R5,A8 MOV R6,A8 MOV R7,A8 176 2c 177 2c 178 1c 179 1c 180 2c 181 2c 182 2c 183 2c 184 2c 185 2c 186 2c 187 2c 188 2c 189 2c 190 2c 191 2c ANL C,BIT ACALL A8 CPL BIT CPL C 192 2c 193 2c 194 1c 195 1c 196 1c 197 1c 198 1c 199 1c 200 1c 201 1c 202 1c 203 1c 204 1c 205 1c 206 1c 207 1c PUSH A8 AJMP 6A8 CLR BIT CLR C SWAP A XCH A,A8 XCH A,R0 XCH A,R1 XCH A,R2 XCH A,R3 XCH A,R4 XCH A,R5 XCH A,R6 XCH A,R7 208 2c 209 2c 210 1c 211 1c 212 1c 213 2c 214 1c 215 1c 216 2c 217 2c 218 2c 219 2c 220 2c 221 2c 222 2c 223 2c POP A8 ACALL A8 SETB BIT SETB C DA A 224 2c 225 2c 226 2c 227 2c 228 1c 229 1c 230 1c 231 1c 232 1c 233 1c 234 1c 235 1c 236 1c 237 1c 238 1c 239 1c AJMP 7A8 CLR A MOV A,A8 MOV A,R0 MOV A,R1 MOV A,R2 MOV A,R3 MOV A,R4 MOV A,R5 MOV A,R6 MOV A,R7 240 2c 241 2c 242 2c 243 2c 244 1c 245 1c 246 1c 247 1c 248 1c 249 1c 250 1c 251 1c 252 1c 253 1c 254 1c 255 1c ACALL A8 A8 address bits A16 address 16 bits CPL A AR relative address bits BIT bit's address MOV A8,A D data bits D16 data 16 bits MOV R0,A MOV R1,A MOV R2,A MOV R3,A MOV R4,A MOV R5,A MOV R6,A MOV R7,A INC 2c 0011 DEC 0010 ORL ADDC ADD 1c 0001 ANL A B C D E F @R0 A B C D E F 0000 MOV MOV DJNZ XCH CJNE MOV SUBB MOV MOV XRL Mates (c) 1995, 2002 8051 Instruction Set Table 2c NOP AJMP 0A8 16 2c 17 2c 0101 1c 1c LJMP A16 RR A INC A INC A8 INC @R0 18 2c 19 1c 20 1c 21 1c @R1 1c 0111 R0 1000 R1 1c 1001 R2 1c 1c INC @R1 INC R0 22 1c 23 1c 24 1c 1010 R3 1011 R4 1100 R5 1101 R6 1110 R7 1111 10 1c 11 1c 12 1c 13 1c 14 1c 15 1c INC R1 INC R2 INC R3 INC R4 INC R5 INC R6 INC R7 25 1c 26 1c 27 1c 28 1c 29 1c 30 1c 31 1c RRC A DEC A DEC A8 DEC @R0 DEC @R1 DEC R0 DEC R1 DEC R2 DEC R3 DEC R4 DEC R5 DEC R6 DEC R7 35 1c 36 1c 37 1c 38 1c 39 1c 40 1c 41 1c 42 1c 43 1c 44 1c 45 1c 46 1c 47 1c RET RL A ADD A,#D ADD A,A8 50 2c 51 1c 52 1c 53 1c 54 1c 55 1c 56 1c 57 1c 58 1c 59 1c 60 1c 61 1c 62 1c 63 1c 70 1c 71 1c 72 1c 73 1c 74 1c 75 1c 76 1c 77 1c 78 1c 79 1c ORL A,R0 ORL A,R1 ORL A,R2 ORL A,R3 ORL A,R4 ORL A,R5 ORL A,R6 ORL A,R7 88 1c 89 1c 90 1c 91 1c ANL A,R0 ANL A,R1 ANL A,R2 ANL A,R3 ANL A,R4 ANL A,R5 ANL A,R6 ANL A,R7 32 2c 33 2c JB BIT,AR AJMP 1A8 48 2c 49 2c RETI RLC A 34 2c ADD A,R0 ADD A,R1 ADD A,R2 ADD A,R3 ADD A,R4 ADD A,R5 ADD A,R6 ADD A,R7 ADDC A,#D ADDC A,A8 64 2c 65 2c 66 1c 67 1c 68 1c 69 1c JC AR AJMP 2A8 ORL A8,A ORL A8,#D ORL A,#D ORL A,A8 80 2c 81 2c 82 1c 83 1c 84 1c 85 1c ACALL A8 ANL A8,A ANL A8,#D ANL A,#D ANL A,A8 JNC AR 0110 1c JBC BIT,AR ACALL A8 LCALL A16 JNB BIT,AR ACALL A8 0100 86 1c 87 1c 92 1c 93 1c 94 1c 95 1c 96 2c 97 2c 98 1c 99 1c 100 1c 101 1c 102 1c 103 1c 104 1c 105 1c 106 1c 107 1c 108 1c 109 1c 110 1c 111 1c JZ AR AJMP 3A8 XRL A8,A XRL A8,#D XRL A,#D XRL A,A8 XRL A,R0 XRL A,R1 XRL A,R2 XRL A,R3 XRL A,R4 XRL A,R5 XRL A,R6 XRL A,R7 112 2c 113 2c 114 2c 115 2c 116 1c 117 2c 118 1c 119 1c 120 1c 121 1c 122 1c 123 2c 124 1c 125 1c 126 1c 127 1c JNZ AR ACALL A8 ORL C,BIT MOV A,#D MOV A8,#D MOV R0,#D MOV R1,#D MOV R2,#D MOV R3,#D MOV R4,#D MOV R5,#D MOV R6,#D MOV R7,#D 128 2c 129 2c 130 2c 131 2c 132 4c 133 2c 134 2c 135 2c 136 2c 137 2c 138 2c 139 2c 140 2c 141 2c 142 2c 143 2c SJMP AR AJMP 4A8 ANL C,BIT DIV AB MOV A8,A8 MOV A8,R0 MOV A8,R1 MOV A8,R2 MOV A8,R3 MOV A8,R4 MOV A8,R5 MOV A8,R6 MOV A8,R7 144 2c 145 2c 146 2c 147 2c 148 1c 149 1c 150 1c 151 1c 152 1c 153 1c 154 1c 155 1c 156 1c 157 1c 158 1c 159 1c ACALL A8 MOV BIT,C SUBB A,#D SUBB A,A8 208 2c 161 2c 162 1c 163 2c 164 4c 165 ORL C,BIT AJMP 5A8 MOV C,BIT INC DPTR MUL AB 166 2c 167 2c 168 2c 169 2c 170 2c 171 2c 172 2c 173 2c 174 2c 175 2c MOV R0,A8 MOV R1,A8 MOV R2,A8 MOV R3,A8 MOV R4,A8 MOV R5,A8 MOV R6,A8 MOV R7,A8 176 2c 177 2c 178 1c 179 1c 180 2c 181 2c 182 2c 183 2c 184 2c 185 2c 186 2c 187 2c 188 2c 189 2c 190 2c 191 2c ANL C,BIT ACALL A8 CPL BIT CPL C 192 2c 193 2c 194 1c 195 1c 196 1c 197 1c 198 1c 199 1c 200 1c 201 1c 202 1c 203 1c 204 1c 205 1c 206 1c 207 1c PUSH A8 AJMP 6A8 CLR BIT CLR C SWAP A XCH A,A8 XCH A,R0 XCH A,R1 XCH A,R2 XCH A,R3 XCH A,R4 XCH A,R5 XCH A,R6 XCH A,R7 208 2c 209 2c 210 1c 211 1c 212 1c 213 2c 214 1c 215 1c 216 2c 217 2c 218 2c 219 2c 220 2c 221 2c 222 2c 223 2c POP A8 ACALL A8 SETB BIT SETB C DA A 224 2c 225 2c 226 2c 227 2c 228 1c 229 1c 230 1c 231 1c 232 1c 233 1c 234 1c 235 1c 236 1c 237 1c 238 1c 239 1c AJMP 7A8 CLR A MOV A,A8 MOV A,R0 MOV A,R1 MOV A,R2 MOV A,R3 MOV A,R4 MOV A,R5 MOV A,R6 MOV A,R7 240 2c 241 2c 242 2c 243 2c 244 1c 245 1c 246 1c 247 1c 248 1c 249 1c 250 1c 251 1c 252 1c 253 1c 254 1c 255 1c ACALL A8 A8 address bits A16 address 16 bits CPL A AR relative address bits BIT bit's address MOV A8,A D data bits D16 data 16 bits MOV R0,A MOV R1,A MOV R2,A MOV R3,A MOV R4,A MOV R5,A MOV R6,A MOV R7,A Code Cycles Bytes INSTRUCTION INC 2c 0011 DEC 0010 ORL ADDC ADD 1c 0001 ANL A B C D E F @R0 A B C D E F 0000 MOV MOV DJNZ XCH CJNE MOV SUBB MOV MOV XRL Mates (c) 1995, 2002 .. .8051 Instruction Set Table 2c NOP AJMP 0A8 16 2c 17 2c 0101 1c 1c LJMP A16 RR A INC A INC A8 INC @R0... C D E F @R0 A B C D E F 0000 MOV MOV DJNZ XCH CJNE MOV SUBB MOV MOV XRL Mates (c) 1995, 2002 8051 Instruction Set Table 2c NOP AJMP 0A8 16 2c 17 2c 0101 1c 1c LJMP A16 RR A INC A INC A8 INC @R0... bits MOV R0,A MOV R1,A MOV R2,A MOV R3,A MOV R4,A MOV R5,A MOV R6,A MOV R7,A Code Cycles Bytes INSTRUCTION INC 2c 0011 DEC 0010 ORL ADDC ADD 1c 0001 ANL A B C D E F @R0 A B C D E F 0000 MOV MOV