x86 Instruction Set Reference

LAHF - Load Status Flags into AH Register

Opcode Mnemonic Description
9F LAHF Load: AH = EFLAGS(SF:ZF:0:AF:0:PF:1:CF).
Description

Moves the low byte of the EFLAGS register (which includes status flags SF, ZF, AF, PF, and CF) to the AH register. Reserved bits 1, 3, and 5 of the EFLAGS register are set in the AH register as shown in the "Operation" section below.
Operation 
AH = EFLAGS(SF:ZF:0:AF:0:PF:1:CF);
Flags affected

None (that is, the state of the flags in the EFLAGS register is not affected).

Exceptions
None.