microprocessor

                                                                      The Flags register 

•          S-sign flag

–        The sign flag is set if bit D7 of the accumulator is set after an arithmetic or logic operation.

•          Z-zero flag

–        Set if the result of the ALU operation is 0. Otherwise is reset. This flag is affected by operations on the accumulator as well as other registers. (DCR B).

•          AC-Auxiliary Carry

–        This flag is set when a carry is generated from bit D3 and passed to D4 . This flag is used only internally for BCD operations. (Section 10.5 describes BCD addition including the DAA instruction).

•          P-Parity flag

–        After an ALU operation if the result has an even # of 1’s the p-flag is set. Otherwise it is cleared. So, the flag can be used to indicate even parity.

•          CY-carry flag

Discussed earlier