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80386 Programmer's Reference Manual -- Opcode PUSHF

PUSHF/PUSHFD -- Push Flags Register onto the Stack

Opcode	Instruction	Clocks	Description	Example
9C	pushf	4	Push FLAGS	`pushf`
9C	pushfl	4	Push EFLAGS	`pushfl`

Operation




IF OperandSize = 32
THEN push(EFLAGS);
ELSE push(FLAGS);
FI;

Description

PUSHF decrements the stack pointer by 2 and copies the FLAGS register to the new top of stack; PUSHFD decrements the stack pointer by 4, and the 80386 EFLAGS register is copied to the new top of stack which is pointed to by SS:eSP. Refer to Chapter 2 and Chapter 4 for information on the EFLAGS register.

Flags Affected

None

Protected Mode Exceptions

#SS(0) if the new value of eSP is outside the stack segment boundaries

Real Address Mode Exceptions

None; the 80386 shuts down due to a lack of stack space

Virtual 8086 Mode Exceptions

#GP(0) fault if IOPL is less than 3, to permit emulation

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