Scott Dattalo wrote:

> 5  -  0101
> 7  -  0111
> 4  -  0100

> It can be seen that for stage 0 (the lsb) that x & y need to be added,
> stage 1 only y, stage 2 x & y & z, and on stage 3 nothing.

  Rats!
--
  Cheers,
        Paul B.