[Ffmpeg-devel] PATCH Blackfin optimized byte swapping mechanism

Marc Hoffman mmh
Tue Apr 24 03:01:51 CEST 2007


Michael Niedermayer writes:
 > 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
 > 

No problem how do I solve that considering thats the strategy everyone
else used?

Thanks
Marc




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