SAHF             Store Register AH into Flags        Flags: O D I T S Z A P C
                                                                    * * * * *
          Logic:    Flag-reg bits   .     AH bits
                      S Z A P C     .    7 6 4 2 0

    SAHF copies bits 7, 6, 4, 2, and 0 from the AH register into the Flags
    register, replacing the previous values of the Sign, Zero, Auxiliary
    Carry, Parity, and the Carry flags.

  --------------------------------------------------------------------------
   Operands                  Clocks   Transfers  Bytes   Example
   no operands                 4          -        1     SAHF
  --------------------------------------------------------------------------

       Notes:         The Overflow, Direction, Interrupt, and Trap flags
                      are not changed by this instruction.

                      This instruction is primarily used to provide upward
                      compatibility between the 8080/8085 family and the
                      8086 family.