It's been a while since there's been a challenge. And since there's
been a bunch talk about RS232 stuff, I thought it might be appropriate
if we had a really fast parity generator for those software bit-banging
UARTs.

So here's the challenge:
Given the variable X, write a routine that computes the odd-parity
of X.

Here's a routine that's slow/looped:

        CLRF    parity
LOOP:
        CLRC
        RRF     X,F             ;Get LSB and put it in the carry
        SKPNC                   ;If LSB (i.e. C) is set
          INCF  parity,F        ;then count it
        MOVF    X,F
        SKPZ
          GOTO    LOOP

The least significant bit of 'parity' contains the parity of X.

The best I could do executes in 7 cycles and trashes X.

Scott