User's Manual

THE 80286 INSTRUCTION SET
PUSHF-Push Flags Register onto the Stack
Opcode Instruction Clocks Description
9C PUSHF 3 Push flag~ register
FLAGS MODIFIED
None
FLAGS UNDEFINED
None
OPERATION
The stack pointer SP is decremented by 2, and the 80286 flags register is copied to the new top of
stack, which
is pointed to by SS:SP. The flags, from the top bit (15) to the bottom bit (0), are as
follows: undefined, nested task,
I/O privilege level (2 bits), overflow, direction, interrupts enabled,
trap, sign, zero, undefined, auxiliary carry, undefined, parity, undefined, and carry.
PROTECTED MODE EXCEPTIONS
#SS(O) if the new value of SP is outside the stack segment limit.
REAL ADDRESS MODE EXCEPTIONS
None; the 80286 will shut down if SP= I due-to lack of stack space.
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