[FFmpeg-devel] the future of fastmemcpy.h
Sat May 26 20:33:18 CEST 2007
> > > > Also in long term we could try asking fastmemcpy authors for LGPL
> > > > licensing. Big part of it was written by Michael anyway (agpcopy).
> > >
> > > you have my agreement for LGPL-ing the parts of fastmemcpy i wrote
> > > but IIRC part of the fastmemcpy code came from the linux kernel though
> > > maybe i remember that wrong its a long time ago ...
> > The file consists largely of two functions, memcpy_pic() and
> > mem2agpcpy(). The first was added by Arpi in r5505, the second by you
> > in r4682. Arpi, did you write that function yourself or where did it
> > come from? And if it's completely your code, do you agree to LGPL it?
> >From initial checkin: http://svn.mplayerhq.hu/mplayer/trunk/
> This part of code was taken by from Linux-2.4.3 and slightly modified
> for MMX2 instruction set. I have done it since linux uses page aligned
> blocks but mplayer uses weakly ordered data and original sources can not
> speedup their. Only using prefetch and movntq together have effect!
> If you have questions please contact with me: Nick Kurshev: nickols_k at mail.ru.
> Changes in revisions:
> 369, 371 oneliners (arpi)
> 377 P3 fix, asm changes (arpi)
> 410 SSE support (nick)
> 478 3dnow support (from kernel 2.4.2) (pontscho)
> 479, 514 minor changes (pontscho)
> 568 sse fix (arpi)
> 582 new sse code (atmos)
> 645 optimized sse for athlon (atmos)
> 686 minor change (arpi)
> 699 creating aclib.c (nick)
at this point the interetsing code has been moved to aclib*.c
fastmemcpy.h is only the declarations and 2 simple trivial
wrapper to handle pic types (array of 3 pointer pairs) instead
of single copies.
aclib is problematic, due to kernel code, as it's GPL and
nobody knows who was the original author...
anyway i bet (almost) nothing left from original kernel
version as Nick, Atmos and Michael rewrote these functions
> 801 minor change (pontscho)
> 1132 minor change (alex)
> 4682,4709 agpcopy (michael)
> 5505 memcpy_picture() (arpi)
> 12651 include change (diego)
> 12664 reversing the above (diego)
> 13788 reversing the above (diego)
> 15070 negative stride fix in memcpy_picture() (henry)
> 17096 cosmetic in memcpy_picture (rathann)
> 22018 warning fix (gpoirier)
> 22021 inttypes.h (diego)
> Based on this review, what should happen with the optimized picture copy
> Alex Beregszaszi
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