Re: [PATCH] zlib: Optimize inffast even more

[Joakim Tjernlund]

roel kluin <roel.kluin@xxxxxxxxx> wrote on 12/11/2009 00:46:41:
>
> On Mon, Nov 9, 2009 at 11:22 AM, Joakim Tjernlund
> <Joakim.Tjernlund@xxxxxxxxxxxx> wrote:
> > This improves zlib: Optimize inffast when copying direct from output
> > and gives another 3-4% improvement for my MPC8321 target.
> > Does not need CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS,
> > uses get_unaligned() but only in one place.
> > The copy loop just above this one can also use this
> > optimization, but I havn't done so as I have not tested if it
> > is a win there too.
> >
> > Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@xxxxxxxxxxxx>
> > ---
>
>
> > @@ -240,52 +243,49 @@ void inflate_fast(z_streamp strm, unsigned start)
> >                 }
> >                 else {
> >                     from = out - dist;          /* copy direct from output */
> > -#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
> >                     /* minimum length is three */
> >                    if (dist > 2 ) {
> > -                       unsigned short *sout = (unsigned short *)(out - OFF);
> > -                       unsigned short *sfrom = (unsigned short *)(from - OFF);
> > -                       unsigned long loops = len >> 1;
> > +                       unsigned short *sout;
> > +                       unsigned short *sfrom;
> > +                       unsigned long loops;
> >
> > +                       /* Align out addr, only sfrom might be unaligned */
> > +                       if (!((long)(out - 1 + OFF)) & 1) {
>
> I think this is wrong
>
> did you mean
>
> if (!((long)(out - 1 + OFF) & 1))

Yes, will fix and send out a new patch with
cleanups and fixes for CPUs that cannot do unaligned
accesses. Thanks

      Jocke

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