User's Manual

THE 80286 INSTRUCTION SET
PUSH-Push a Word onto the Stack
Opcode
Instruction Clocks Description
06
PUSH ES
3
Push ES
OE PUSH CS
3
Push CS
16 PUSH SS
3
Push SS
1E
PUSH DS
3
Push DS
50+ rw PUSH rw
3
Push word register
FF
/6
PUSH mw
5
Push memory word
68
dw PUSH dw
3
Push immediate word
6A
db PUSH db 3
Push immediate sign-extended byte
FLAGS MODIFIED
None
FLAGS UNDEFINED
None
OPERATION
The stack pointer SP is decremented by 2, and the operand is placed on the new top of stack, which is
pointed to by SS:SP.
The
80286 PUSH SP instruction pushes the value of SP as it existed before the instruction. This differs
from the
8086, which pushes the new (decremented by 2) value.
PROTECTED MODE EXCEPTIONS
#SS(O) if the new value of SP is outside the stack segment limit.
#GP(O) for an illegal memory operand effective address in the CS, DS, or ES segments; #SS(O) for an
illegal address
in the SS segment.
REAL ADDRESS MODE EXCEPTIONS
None; the 80286 will shut down if SP = I-due to lack of stack space.
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