[Ffmpeg-devel] PATCH Blackfin optimized byte swapping mechanism

[Michael Niedermayer]

Hi

On Mon, Apr 23, 2007 at 01:12:47PM -0400, Marc Hoffman wrote:
> Michael Niedermayer writes:
>  > Hi
>  > 
>  > On Tue, Apr 17, 2007 at 08:49:40AM -0400, Marc Hoffman wrote:
>  > > Michael Niedermayer writes:
>  > >  > Hi
>  > >  > 
>  > >  > On Tue, Apr 17, 2007 at 07:40:47AM -0400, Marc Hoffman wrote:
>  > >  > Content-Description: message body text
>  > >  > > 
>  > >  > >  > Low level bswap primitive for the Blackfin Architecture.
>  > >  > > 
>  > >  > > sorry mangled patch wrong encoding last time.
>  > >  > 
>  > >  > what advantage do these functions have over the default?
>  > >  > are they faster? if so you should provide some benchmarks
>  > > 
>  > > Sorry about the top post please forgive me
>  > > 
>  > > The current 32bit byte swap routine produces this code sequence
>  > > 
>  > > So I guess this is about 300% improvement in performance for this function.
>  > 
>  > guess is good, hard benchmark is better, its just 5min work to write a
>  > loop of bswap and do a time myprog
>  > also dont forget to set proper -mcpu / -march and -O3 with gcc
> 
> correction ~200%. Is the patch acceptable now?

not as long as it duplicates the c bswap16 and 64 functions

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

In a rich man's house there is no place to spit but his face.
-- Diogenes of Sinope
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