PUSHF/PUSHFD -- Push Flags Register onto the Stack

Opcode  Instruction  Clocks   Description

9C      PUSHF        4        Push FLAGS
9C      PUSHFD       4        Push EFLAGS

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

up: Chapter 17 -- 80386 Instruction Set
prev: PUSHA/PUSHAD Push all General Registers
next: RCL/RCR/ROL/ROR Rotate