Re: crc32() optimization

Eric W. Biederman
2002-11-10T23:25:54Z

"Joakim Tjernlund" <Joakim.Tjernlund@lumentis.se> writes:

> > In message <001301c28909$743f1f40$0200a8c0@telia.com> you wrote:
> > > I could not wait until tomorrow, so I did it now instead.
> > > The result was worse. The best I got was 7% improvement.
> > > I tried 16, 8, 6 and 4 as unrolling steps.
> >
> > Makes no sense to me. Should be at least as efficient as your
> > original code (marginally better).
>
> I don't understand this either.
> Anyone?

You might try it with 6. But a lot depends on what gcc can do with
it and gcc may not be like all of those potential entry points..

Running gcc -S and checking to see the difference in the generated
assembly might be instructive.

Eric