8051 Opcodes

List of All Instruction Types

The following table lists the 8051 instructions sorted by the opcode. The instructions can be divided into 5 categories: arithmetic instructions. logic instructions, data transfer instructions, boolean variable manipulation instructions and program and machine control instructions.

OpcodeBytesMnemonicOperands
00 1 NOP  
01 2 AJMP addr11
02 3 LJMP addr16
03 1 RR A
04 1 INC A
05 2 INC direct
06 1 INC @R0
07 1 INC @R1
08 1 INC R0
09 1 INC R1
0A 1 INC R2
0B 1 INC R3
0C 1 INC R4
0D 1 INC R5
0E 1 INC R6
0F 1 INC R7
10 3 JBC bit, offset
11 2 ACALL addr11
12 3 LCALL addr16
13 1 RRC A
14 1 DEC A
15 2 DEC direct
16 1 DEC @R0
17 1 DEC @R1
18 1 DEC R0
19 1 DEC R1
1A 1 DEC R2
1B 1 DEC R3
1C 1 DEC R4
1D 1 DEC R5
1E 1 DEC R6
1F 1 DEC R7
20 3 JB bit, offset
21 2 AJMP addr11
22 1 RET  
23 1 RL A
24 2 ADD A, #immediate
25 2 ADD A, direct
26 1 ADD A, @R0
27 1 ADD A, @R1
28 1 ADD A, R0
29 1 ADD A, R1
2A 1 ADD A, R2
2B 1 ADD A, R3
2C 1 ADD A, R4
2D 1 ADD A, R5
2E 1 ADD A, R6
2F 1 ADD A, R7
30 3 JNB bit, offset
31 2 ACALL addr11
32 1 RETI  
33 1 RLC A
34 2 ADDC A, #immediate
35 2 ADDC A, direct
36 1 ADDC A, @R0
37 1 ADDC A, @R1
38 1 ADDC A, R0
39 1 ADDC A, R1
3A 1 ADDC A, R2
3B 1 ADDC A, R3
3C 1 ADDC A, R4
3D 1 ADDC A, R5
3E 1 ADDC A, R6
3F 1 ADDC A, R7
40 2 JC offset
41 2 AJMP addr11
42 2 ORL direct, A
43 3 ORL direct, #immediate
44 2 ORL A, #immediate
45 2 ORL A, direct
4 6 1 ORL A, @R0
47 1 ORL A, @R1
48 1 ORL A, R0
49 1 ORL A, R1
4A 1 ORL A, R2
4B 1 ORL A, R3
4C 1 ORL A, R4
4D 1 ORL A, R5
4E 1 ORL A, R6
4F 1 ORL A, R7
50 2 JNC offset
51 2 ACALL addr11
52 2 ANL direct, A
53 3 ANL direct, #immediate
54 2 ANL A, #immediate
55 2 ANL A, direct
56 1 ANL A, @R0
57 1 ANL A, @R1
58 1 ANL A, R0
59 1 ANL A, R1
5A 1 ANL A, R2
5B 1 ANL A, R3
5C 1 ANL A, R4
5D 1 ANL A, R5
5E 1 ANL A, R6
5F 1 ANL A, R7
60 2 JZ offset
61 2 AJMP addr11
62 2 XRL direct, A
63 3 XRL direct, #immediate
64 2 XRL A, #immediate
65 2 XRL A, direct
66 1 XRL A, @R0
67 1 XRL A, @R1
68 1 XRL A, R0
69 1 XRL A, R1
6A 1 XRL A, R2
6B 1 XRL A, R3
6C 1 XRL A, R4
6D 1 XRL A, R5
6E 1 XRL A, R6
6F 1 XRL A, R7
70 2 JNZ offset
71 2 ACALL addr11
72 2 ORL C, bit
73 1 JMP @A+DPTR
74 2 MOV A, #immediate
75 3 MOV direct, #immediate
76 2 MOV @R0, #immediate
77 2 MOV @R1, #immediate
78 2 MOV R0, #immediate
79 2 MOV R1, #immediate
7A 2 MOV R2, #immediate
7B 2 MOV R3, #immediate
7C 2 MOV R4, #immediate
7D 2 MOV R5, #immediate
7E 2 MOV R6, #immediate
7F 2 MOV R7, #immediate
 
OpcodeBytesMnemonicOperands
80 2 SJMP offset
81 2 AJMP addr11
82 2 ANL C, bit
83 1 MOVC A, @A+PC
84 1 DIV AB
85 3 MOV direct, direct
86 2 MOV direct, @R0
87 2 MOV direct, @R1
88 2 MOV direct, R0
89 2 MOV direct, R1
8A 2 MOV direct, R2
8B 2 MOV direct, R3
8C 2 MOV direct, R4
8D 2 MOV direct, R5
8E 2 MOV direct, R6
8F 2 MOV direct, R7
90 3 MOV DPTR, #immediate
91 2 ACALL addr11
92 2 MOV bit, C
93 1 MOVC A, @A+DPTR
94 2 SUBB A, #immediate
95 2 SUBB A, direct
96 1 SUBB A, @R0
97 1 SUBB A, @R1
98 1 SUBB A, R0
99 1 SUBB A, R1
9A 1 SUBB A, R2
9B 1 SUBB A, R3
9C 1 SUBB A, R4
9D 1 SUBB A, R5
9E 1 SUBB A, R6
9F 1 SUBB A, R7
A0 2 ORL C, /bit
A1 2 AJMP addr11
A2 2 MOV C, bit
A3 1 INC DPTR
A4 1 MUL AB
A5   undefined  
A6 2 MOV @R0, direct
A7 2 MOV @R1, direct
A8 2 MOV R0, direct
A9 2 MOV R1, direct
AA 2 MOV R2, direct
AB 2 MOV R3, direct
AC 2 MOV R4, direct
AD 2 MOV R5, direct
AE 2 MOV R6, direct
AF 2 MOV R7, direct
B0 2 ANL C, /bit
B1 2 ACALL addr11
B2 2 CPL bit
B3 1 CPL C
B4 3 CJNE A, #immediate, offset
B5 3 CJNE A, direct, offset
B6 3 CJNE @R0, #immediate, offset
B7 3 CJNE @R1, #immediate, offset
B8 3 CJNE R0, #immediate, offset
B9 3 CJNE R1, #immediate, offset
BA 3 CJNE R2, #immediate, offset
BB 3 CJNE R3, #immediate, offset
BC 3 CJNE R4, #immediate, offset
BD 3 CJNE R5, #immediate, offset
BE 3 CJNE R6, #immediate, offset
BF 3 CJNE R7, #immediate, offset
C0 2 PUSH direct
C1 2 AJMP addr11
C2 2 CLR bit
C3 1 CLR C
C4 1 SWAP A
C5 2 XCH A, direct
C6 1 XCH A, @R0
C7 1 XCH A, @R1
C8 1 XCH A, R0
C9 1 XCH A, R1
CA 1 XCH A, R2
CB 1 XCH A, R3
CC 1 XCH A, R4
CD 1 XCH A, R5
CE 1 XCH A, R6
CF 1 XCH A, R7
D0 2 POP direct
D1 2 ACALL addr11
D2 2 SETB bit
D3 1 SETB C
D4 1 DA A
D5 3 DJNZ direct, offset
D6 1 XCHD A, @R0
D7 1 XCHD A, @R1
D8 2 DJNZ R0, offset
D9 2 DJNZ R1, offset
DA 2 DJNZ R2, offset
DB 2 DJNZ R3, offset
DC 2 DJNZ R4, offset
DD 2 DJNZ R5, offset
DE 2 DJNZ R6, offset
DF 2 DJNZ R7, offset
E0 1 MOVX A, @DPTR
E1 2 AJMP addr11
E2 1 MOVX A, @R0
E3 1 MOVX A, @R1
E4 1 CLR A
E5 2 MOV A, direct
E6 1 MOV A, @R0
E7 1 MOV A, @R1
E8 1 MOV A, R0
E9 1 MOV A, R1
EA 1 MOV A, R2
EB 1 MOV A, R3
EC 1 MOV A, R4
ED 1 MOV A, R5
EE 1 MOV A, R6
EF 1 MOV A, R7
F0 1 MOVX @DPTR, A
F1 2 ACALL addr11
F2 1 MOVX @R0, A
F3 1 MOVX @R1, A
F4 1 CPL A
F5 2 MOV direct, A
F6 1 MOV @R0, A
F7 1 MOV @R1, A
F8 1 MOV R0, A
F9 1 MOV R1, A
FA 1 MOV R2, A
FB 1 MOV R3, A
FC 1 MOV R4, A
FD 1 MOV R5, A
FE 1 MOV R6, A
FF 1 MOV R7, A
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