NASM 2.05 based x86 Instruction Reference[ch270]
A.5.246 POPFx: Pop Flags Register POPF ; 9D [8086] POPFW ; o16 9D [8086] POPFD ; o32 9D [386] - POPFW pops a word from the stack and stores it in the bottom 16 bits of the flags register (or the whole flags register, on processors below a 386). - POPFD pops a doubleword and stores it in the entire flags register. POPF is an alias mnemonic for either POPFW or POPFD, depending on the current BITS setting. See also PUSHF (section A.5.265).