8086 instruction code summary (table)

8086 Instruction code summary

 

8086 Instructions have two forms: assembly language instructions and instruction codes , The assembly language instruction form is processed by the assembler to generate the instruction code form .

Through the form of instruction code, it can help to understand the meaning and usage of assembly language instruction format .

8086 Script format

0B/1B	1B/2B	0B/1B	0B/1B/2B/4B	0B/1B/2B/4B
Instruction prefix	Opcode segment	Addressing mode segment	Offset parameter	Immediate parameter

explain ： The presence or absence of the offset parameter and the immediate parameter is determined by the addressing mode segment ;

 

• Transfer class instructions

MOV Instructions
REG/MEM→/←REG	100010DW	mod reg r/m
IMME→REG/MEM	1000111w	mod 000 r/m	data	data if w=1
IMME→REG	1011wreg	data	data if w=1
MEM→AX	1010000w	addr-low	addr-high
AX→MEM	1010001w	addr-low	addr-high
REG/MEM→ paragraph REG	10001110	mod reg r/m
paragraph REG→REG/MEM	10001100	mod reg r/m
PUSH Instructions
REG/MEM	11111111	mod 110 r/m
REG	01010reg
paragraph REG	000reg110
POP Instructions
REG/MEM	10001111	mod 000 r/m
REG	01011reg
paragraph REG	000reg111
XCHG Instructions
REG/MEM←→REG	1000011w	mod reg r/m
REG←→AX	10010reg
XLAT Instructions	11010111
LEA Instructions	10001101	mod reg r/m
LDS Instructions	11000101	mod reg r/m
LES Instructions	11000100	mod reg r/m
LAHF Instructions	10011111
SAHF Instructions	10011110
PUSHF Instructions	10011100
POPF Instructions	10011101
IN Instructions
Direct addressing	1110010w	port
Indirect addressing	1110110w
OUT Instructions
Direct addressing	1110011w	port
Indirect addressing	1110111w
CBW Instructions	10011000
CWD Instructions	10011001

explain ：d--0/1 Express REG As source / Destination operands ;

w--0/1 Indicates that the operand type is BYTE/WORD;

mod、r/m-- Addressing mode ;

IMME-- Immediate operands , Use... In the field data Express ;

reg-- Universal REG use 3 Bit code , paragraph REG use 2 Bit code ;

 

• Arithmetic instructions

ADD Instructions
REG/MEM+REG→ any	000000dw	mod reg r/m
REG/MEM+=IMME	100000sw	mod 000 r/m	data	data if sw=01
AX+=IMME	0000010w	data	data if w=1
ADC Instructions
REG/MEM+REG→ any	000100dw	mod reg r/m
REG/MEM+=IMME	100000sw	mod 010 r/m	data	data if sw=01
AX+=IMME	0001010w	data	data if w=1
INC Instructions
REG/MEM	1111111w	mod 000 r/m
REG	01000reg
SUB Instructions
REG/MEM-REG→ any	001010dw	mod reg r/m
REG/MEM-=IMME	100000sw	mod reg r/m	data	data if sw=01
AX-=IMME	0010110w	data	data if w=1
SBB Instructions
REG/MEM-REG→ any	000110dw	mod reg r/m
REG/MEM-=IMME	100000sw	mod 011 r/m	data	data if sw=01
AX-=IMME	0001110w	data	data if w=1
DEC Instructions
REG/MEM	11111111w	mod 001 r/m
REG	01001reg
NEG	1111011w	mod 011 r/m
CMP Instructions
REG/MEM-REG	001110dw	mod reg r/m
REG/MEM-IMME	100000sw	mod 111 r/m	data	data if sw=01
AX-IMME	0011110w	data	data if w=1
MUL Instructions	1111011w	mod 100 r/m
IMUL Instructions	1111011w	mod 101 r/m
DIV Instructions	1111011w	mod 110 r/m
IDIV Instructions	1111011w	mod 111 r/m
AAA Instructions	00110111
DAA Instructions	00100111
AAS Instructions	00111111
DAS Instructions	00101111
AAM Instructions	11010100	00001010
AAD Instructions	11010101	00001010

explain ：sw--01 Express 16 Immediately ,11 Express 8 Immediately , When operating, expand to 16 position ;

REG/MEM-REG--MEM It can be subtracted or subtracted ;

 

• Logic operation class instruction

NOT Instructions	1111011w	mod 010 r/m
AND Instructions
REG/MEM&REG→ any	001000dw	mod reg r/m
REG/MEM&=IMME	1000000w	mod 100 r/m	data	data if w=1
AX&=IMME	0010010w	data	data if w=1
OR
REG/MEM|REG→ any	000010dw	mod reg r/m
REG/MEM|=IMME	1000000w	mod 001 r/m	data	data if w=1
AX|=IMME	0000110w	data	data if w=1
TEST Instructions
RET/MEM&REG	100010dw	mod reg r/m
REG/MEM&IMME	1111011w	mod 000 r/m	data	data if w=1
AX&IMME	1010110w	data	data if w=1
SHL/SA/ Instructions	110100vw	mod 100 r/m
SHR Instructions	110100vw	mod 101 r/m
SAR Instructions	110100vw	mod 111 r/m
POL Instructions	110100vw	mod 000 r/m
ROR Instructions	110100vw	mod 001 r/m
RCL Instructions	110100vw	mod 010 r/m
RCR Instructions	110100vw	mod 011 r/m

explain ：v--0/1 Represents the number of displacements 1/（CL）.

 

• Control transfer class instruction

JMP Instructions
In segment - Direct short transfer	11101011	disp
In segment - Direct transfer	11101001	disp-low	disp-high
In segment - Indirect transfer	11111111	mod 100 r/m
Inter segment - Direct transfer	11101010	offset-low	offset-high	seg-low seg-high
Inter segment - Indirect transfer	11111111	mod 101 r/m
JO Instructions	01110000	disp
JNO Instructions	01110001	disp
JC Instructions	01110010	disp
JNC Instructions	01110011	disp
JE/JZ Instructions	01110100	disp
JNE/JNZ Instructions	01110101	disp
JS Instructions	01111000	disp
JNS Instructions	01111001	disp
JP/JPE Instructions	01111010	disp
JNP/JPO Instructions	01111011	disp
JA/JNBE Instructions	01110111	disp
JAE/JNB Instructions	01110011	disp
JB/JNAE Instructions	01110010	disp
JBE/JNA Instructions	01110110	disp
JG/JNE Instructions	01111111	disp
JGE/JNL Instructions	01111101	disp
JL/JNGE Instructions	01111100	disp
JLE/JNG Instructions	01111110	disp
JCXZ Instructions	11100011	disp
LOOP Instructions	11100010	disp
LOOPZ/LOOPE Instructions	11100001	disp
LOOPNZ/LOOPN Instructions	11100000	disp
CALL Instructions
In segment - direct	11101000	disp-low	disp-high
In segment - indirect	11111111	mod 010 r/m
Inter segment - direct	10011010	offset-low	offset-high	seg-low set-high
Inter segment - indirect	11111111	mod 011 r/m
RET Instructions
In segment - return	11000011
In segment - Add parameters to return	11000010	data-low	data-high
Inter segment - return	11001011
Inter segment - Add parameters to return	11001010	data-low	data-high
INT Instructions
Routine interrupt	11001101	type
3 Interrupt number	11001100
INTO Instructions	11001110
IRET Instructions	11001111

explain ：JB/JNE-- And JC The same instruction ;

JAE/JNB-- And JNC The same instruction ;

type-- Interrupt type number ;

 

 

• String operation class instruction

REP Instructions	1111011z
MOVS Instructions	1010010w
CMPS Instructions	1010011w
SCAS Instructions	1010111w
LODS Instructions	1010110w
STOS Instructions	1010101w

explain ：REP--z=0 When is REPNE,z=1 When is REP and REPZ,8086 Default REP Corresponding MOVS、STOS,REPZ Corresponding CMPS、SCAS（ Compare the two with 5 Effectiveness of the coordination of instructions ）;

• Processor control class instructions

CLC Instructions	11111000
STC Instructions	11111001
CMC Instructions	11110101
CLI Instructions	11111010
STI Instructions	11111011
CLD Instructions	11111100
STD Instructions	11111101
NOP Instructions	10010000
HLT Instructions	11110100
WAIT Instructions	10011011
ESC Instructions	11011xxx	mod xxx r/m
LOCK Instructions	11110000

explain ：x-- It can be any value （0/1）;