## ALP Programming Guide and Reference

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### Description

The POPF and POPFD instructions pop the word or doubleword on the top of the stack and store the value in the FLAGS register. If the operand-size attribute of the instruction is 16 bits, then a word is popped and the value is stored in the FLAGS register. If the operand-size attribute is 32 bits, then a doubleword is popped and the value is stored in the EFLAGS register.

When the IOPL is less than 3 in virtual-8086 mode, the POPF instruction causes a general protection exception. When the IOPL is equal to 3 while running in virtual-8086 mode, POPF pops a word into the FLAGS register.

Refer to the Intel documentation for information about the FLAGS and EFLAGS registers. Note that bits 16 and 17 of the EFLAGS register, called the VM and RF flags, respectively, are not affected by the POPF or POPFD instruction.

The I/O privilege level is altered only when running at privilege level 0. The interrupt flag is altered only when running at a level at least as privileged as the I/O privilege level. (Real-address mode is equivalent to privilege level 0.) If a POPF instruction is run with insufficient privilege, an exception does not occur, but the privileged bits do not change.