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Instruction Set Summary
A-8
RET
= Return from CALL:
4-202
Within segment
1 1 0 0 0 0 1 1
Within seg adding immed. to SP
1 1 0 0 0 0 1 0
data-low
data-high
Intersegment
1 1 0 0 1 0 1 1
Intersegment adding immed. to SP
1 1 0 0 1 0 1 0
data-low
data-high
ROL
= Rotate left
4-205
Register/Memory by 1
1 1 0 1 0 0 0 w
mod 000 r/m
Register/Memory by CL
1 1 0 1 0 0 1 w
mod 000 r/m
Register/Memory by Count*
1 1 0 0 0 0 0 w
mod 000 r/m
data-8
ROR
= Rotate right
4-207
Register/Memory by 1
1 1 0 1 0 0 0 w
mod 001 r/m
Register/Memory by CL
1 1 0 1 0 0 1 w
mod 001 r/m
Register/Memory by Count*
1 1 0 0 0 0 0 w
mod 001 r/m
data-8
SAHF
= Store AH in flags
1 0 0 1 1 1 1 0
4-209
SAL/SHL
= Shift arithmetic left/shift left
4-211
Register/Memory by 1
1 1 0 1 0 0 0 w
mod 100 r/m
Register/Memory by CL
1 1 0 1 0 0 1 w
mod 100 r/m
Register/Memory by Count*
1 1 0 0 0 0 0 w
mod 100 r/m
data-8
SAR
= Shift arithmetic right
4-214
Register/Memory by 1
1 1 0 1 0 0 0 w
mod 111 r/m
Register/Memory by CL
1 1 0 1 0 0 1 w
mod 111 r/m
Register/Memory by Count*
1 1 0 0 0 0 0 w
mod 111 r/m
data-8
SBB
= Subtract with borrow:
4-216
Reg/memory and register to either
0 0 0 1 1 0 d w
mod reg r/m
Immediate from register/memory
1 0 0 0 0 0 s w
mod 011 r/m
data-8/data-low
data-high if sw=01
(sw
≠
10)
Immediate from accumulator
0 0 0 1 1 1 0 w
data-8/data-low
data-high if w=1
SCAS/SCASB/SCASW
= Scan string
for byte/word
SHR
= Shift right
1 0 1 0 1 1 1 w
4-219
4-225
Register/Memory by 1
1 1 0 1 0 0 0 w
mod 101r/m
Register/Memory by CL
1 1 0 1 0 0 1 w
mod 101 r/m
Register/Memory by Count*
1 1 0 0 0 0 0 w
mod 101 r/m
data-8
SS
= SS segment register override prefix
0 0 1 1 0 1 1 0
2-2
STC
= Set carry flag
1 1 1 1 1 0 0 1
4-228
T able A-2
Instruc tion S et S ummary by Mnemonic
Instruction
Opcode
For
More
Info.,
See
Page
Notes:
* Indicates instructions not available in 8086 or 8088 systems.
**Indicates instructions that are not supported with the necessary pinout.
***The external LOCK pin is only available on some members of the Am186 and Am188 family of microcontrollers. However, LOCK internal
logic is still in effect on parts without the LOCK pin.