[FFmpeg-devel] [PATCH] SPARC VIS simple_idct try#6

[Michael Niedermayer]

Hi

On Wed, Aug 29, 2007 at 01:13:17AM +0200, Balatoni Denes wrote:
> Hi!
> 
> Wednesday 29 August 2007 00:13-kor Michael Niedermayer ezt ?rta:
> > > > Indeed, I didn't take that into account. So if I fix that 25% and the
> > > > clamping part, will you accept the patch?
> > >
> > > Better yet: that would be 4 instructions. How about I gain 4 clocks in
> > > some other way instead - how, let it be my secret. Okay?
> >
> > hmm no but you have to do that secret optimization too now at minimum for
> > it to be considered for svn
> 
> 4 instructions dealing with f46 (fzero and ldd in the macros) can be 
> eliminated, if f60 or f62 is also put to use.
> 
> > ill investigate the register shortage vs. avoidable load/stores vs. latency
> > after (the unlikely) case that you do correct the undisputed
> > suboptimalities
> 
> Argh, I checked what it would involve to fix the 25% overlap. Half of the 
> registers would have to be carefully renamed all over the place.

5min search and replace work ...
or does your editor lack a search and replace function?


> 
> While the suboptimalities are not disputed, whether the benefit from fixing 
> them outweights the cost (in time, and code beuty) is heavily disputed.

dont you think optimality is beautifull?

look at the other idct code in ffmpeg or libmpeg2 they dont do unneeded
things ...

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

It is dangerous to be right in matters on which the established authorities
are wrong. -- Voltaire
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