Description
Decrements the stack pointer by 4 (if the current operand-size attribute is 32) and pushes the entire contents of the EFLAGS register onto the stack, or decrements the stack pointer by 2 (if the operand-size attribute is 16) and pushes the lower 16 bits of the EFLAGS register (that is, the FLAGS register) onto the stack. (These instructions reverse the operation of the POPF/POPFD instructions.) When copying the entire EFLAGS register to the stack, the VM and RF flags (bits 16 and 17) are not copied; instead, the values for these flags are cleared in the EFLAGS image stored on the stack. See the section titled "EFLAGS Register" in Chapter 3 of the IA-32 Intel(R) Architecture Software Developer's Manual, Volume 1, for information about the EFLAGS registers.