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

Reimar Döffinger Reimar.Doeffinger
Tue Sep 21 01:34:12 CEST 2010

On Mon, Sep 20, 2010 at 09:58:53AM -0400, Ronald S. Bultje wrote:
> For the win64 bugfix/"feature", there was a clear advantage.

While that's good enough I doubt there was much of an advantage
besides it obviously being more motivating/rewarding work to you.
While the "obvious" failures may be gone, proper clobber lists
for inline asm are still necessary and some parts like
merging asm block would have been quite independent of how
you write it.

> and I intend for the overall quality of FFmpeg
> (portability, speed, ...) to improve as I change things.

Well, no questions you improve them right now. However
I think Michaels concern is that the chances for future optimization
(e.g. by inlining more MMX/SSE functions, which particularly
for x86_64 often should not be so hard) may have been decreased
quite a bit.
In a similar way my concern is that not even much effort
may have been saved in the long term, since it seems unlikely
we can forever avoid using proper clobber list.
Or to put it differently: How sure are you/we changing to
yasm did more that provide quick results (not that bad
in itself I admit), will it be a net positive in the long term
as well?
Please don't feel like I'm bashing you, I find my quest to
support nasm at least as questionable, I'd just like
you to get a chance to see my line of thought.


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