[FFmpeg-devel] [PATCH] update doc/optimization.txt

Alex Converse alex.converse
Mon Sep 20 23:13:56 CEST 2010

On Mon, Sep 20, 2010 at 10:20 AM, Michael Niedermayer <michaelni at gmx.at> wrote:
> I dont mind at all if code is changed to yasm if it is faster or if it is
> neccessary and the only known clean way to solve a bug.
> i dont even mind if code is yasm instead of asm() to begin with
> but changing the code just because someone decided to make a usefull change
> on top of the yasm code instead of in inline, i really dont like this and i
> wouldnt like the other way around either, rewriting yasm to inline for no
> good reason
> thats just besides that it totally fucks up svn blame and even git blame

Besides the bugs Ronald mentioned, we were using split asm sections
and counted on them preserving values between the sections which is
undefined behavior. In addition in some cases GCC was unrolling C
loops around the asm sections which also sucked a ton. Both of these
situations are possible to fix with inline asm (yasm loops and
manually stacking variables things) but these mistakes are much harder
to make in yasm in the first place.

tl;dr: +1 for yasm

Alex Converse

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