NASM 2.05 based x86 Instruction Reference[ch152]

A.5.131 LAHF: Load AH from Flags LAHF ; 9F [8086] LAHF sets the AH register according to the contents of the low byte of the flags word. The operation of LAHF is: AH <-- SF:ZF:0:AF:0:PF:1:CF See also SAHF (section A.5.282).