Parity Checking in CPUs (was: Byte sizes...

Dwight K. Elvey dwight.elvey at
Tue Mar 15 18:04:27 CST 2005

>From: "Eric Smith" <eric at>
>river wrote:
>> Yes, the 8080/8085/8086 series chips did parity checking. The PSW had a
>> flag for odd/even parity. Naturally, the Z80, being a superset of the 8080,
>> also had this ability.
>In that regard, the Z80 is not a proper superset of the 8080.  The
>parity flag is usurped to act as an overflow flag after arithmetic
>operations.  It is still partity after moves and logical operations.

 Giving it some thought, the only compute application
for parity that I can think of would be reverse bit
swapping. This is generally done on an address though
and might not be all that useful on a byte value.
( FFT's often need this function ).

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