FLAG TRANSFER INSTRUCTIONS

FLAG TRANSFER INSTRUCTIONS

• LAHF Instruction - Load Register AH From Flags

LAHF instruction copies the value of SF, ZF, AF, PF, and CF, into bits of 7, 6, 4, 2, 0 respectively of AH register. This LAHF instruction was provided to make conversion of assembly language programs written for 8080 and 8085 to 8086 easier.

• SAHF instruction - Store AH Register into FLAGS

SAHF instruction transfers the bits 0-7 of AH of SF, ZF, AF, PF, and CF, into the Flag register.

• PUSHF Instruction - Push flag register on the stack

This instruction decrements the SP by 2 and copies the word in flag register to the memory location pointed to by SP.

• POPF Instruction - Pop word from top of stack to flag - register.

This instruction copies a word from the two memory location at the top of the stack to flag register and increments the stack pointer by 2.