[x264-devel] x86inc: activate REP_RET automatically

[Zuxy Meng]

2013/1/9 Loren Merritt <git at videolan.org>

> x264 | branch: master | Loren Merritt <pengvado at akuvian.org> | Sun Dec  2
> 15:56:30 2012 +0000| [f6c628650558803ed65cb15c1853113cc589ae4a] |
> committer: Jason Garrett-Glaser
>
> x86inc: activate REP_RET automatically
> Now RET checks whether it immediately follows a branch, so the programmer
> dosen't have to keep track of that condition.
> REP_RET is still needed manually when it's a branch target, but that's
> much rarer.
> The implementation involves lots of spurious labels, but that's ok because
> we strip them.
>
> >
> http://git.videolan.org/gitweb.cgi/x264.git/?a=commit;h=f6c628650558803ed65cb15c1853113cc589ae4a
> ---
>
>  common/x86/cabac-a.asm   |    4 ++--
>  common/x86/dct-a.asm     |    4 ++--
>  common/x86/deblock-a.asm |   28 ++++++++++++++--------------
>  common/x86/mc-a.asm      |   44
> ++++++++++++++++++++++----------------------
>  common/x86/mc-a2.asm     |   46
> +++++++++++++++++++++++-----------------------
>  common/x86/predict-a.asm |   32 ++++++++++++++++----------------
>  common/x86/quant-a.asm   |   16 ++++++++--------
>  common/x86/x86inc.asm    |   36 +++++++++++++++++++++++++++++++-----
>  tools/checkasm-a.asm     |    2 +-
>  9 files changed, 119 insertions(+), 93 deletions(-)
>
>
Do we still need this hack? Phenom prefers "ret $0" over "rep ret" and
Bulldozer and all Intel CPUs seem to require neither.

-- 
Zuxy
Beauty is truth,
While truth is beauty.
PGP KeyID: E8555ED6
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