🚀 go-pugleaf

In article <24216@lanl.gov>, jlg@cochiti.lanl.gov (Jim Giles) writes:
> Leading zero count is a 3 clock instruction.  I doubt that could be
> implemented in fewer clocks than the pop count if you did it with a
> table.

I suspect it could. You would only have to do a table-lookup on the first
non-zero byte. You could even use binary search techniques to reduce the
number of compares with zero.

But the question isn't whether you can do these operations in software
anywhere near as fast as they can be done in hardware, but rather whether
they can be done fast enough. That is, how much faster would applications
that make heavy use of these instructions run if you sped them up by a
factor of 10 (which is about what I would have guessed the speed difference
to be)? If you speed up 3% of the program by a factor of 10, it's pretty
much lost in the noise.
-- 
Peter da Silva; Ferranti International Controls Corporation; +1 713 274 5180;
Sugar Land, TX  77487-5012;         `-_-' "Have you hugged your wolf, today?"