The POPF instruction is intended for use when the operand-size attribute is 16; the POPFD instruction is intended for use when the operand-size attribute is 32. Some assemblers may force the operand size to 16 for POPF and to 32 for POPFD. POPF/POPFD -- Pop Stack into FLAGS or EFLAGS Register. Opcode Instruction Clocks Description 9D POPF 5 Pop top of stack FLAGS 9D POPFD 5 Pop top of Documentation Home > IA-32 Assembly Language Reference Manual > Chapter 2 Instruction-Set Mapping > Flag Instructions > Pop Stack into Flag (popf). The POPF instruction is intended for use when the operand-size attribute is 16 and the POPFD instruction for when the operand-size attribute is 32. Some assemblers may force the operand size to 16 when POPF is used and to 32 when POPFD is used. The POPF instruction is intended for use when the operand-size attribute is 16 and the POPFD instruction for when the operand-size attribute is 32. Some assemblers may force the operand size to 16 when POPF is used and to 32 when POPFD is used. 13. Jan. 201811. Marz 2016