[FFmpeg-devel] Nasm/yasm support and x264 asm

Jason Garrett-Glaser darkshikari
Tue Jul 29 06:41:10 CEST 2008

> 1. discuss/agree on where to put the code (x264 + lavc, x264, lavc, new lib)

This is a significant issue; it may not be easy to share the code
directly both for practicality reasons and because the code will need
to be modified significantly.  On the other hand, there's still
improvements going into the asm all the time (especially from holger,
one of our SOC students), so copy-pasting the asm would make it more
difficult to maintain.

ffmpeg would probably want to adopt x264's "nasm-based" syntax--that
is, its combinations of macros for doing the following:

1.  Automatic abstraction between 32-bit and 64-bit
2.  Automatic abstraction between MMX and SSE
3.  Automatic handling of macros that permute their arguments
4.  Automatic handling of stack offsets, required for 1)

Without these, it would likely be a nightmare to try to port the asm;
at the very least it would require a complete and total split of the
code into 32-bit and 64-bit versions, and sometimes MMX and SSE
versions, which would be a great way to create yet another "big ball
of mud" in dsputil.

Dark Shikari

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