NASM 2.05 based x86 Instruction Reference[ch306]

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