[FFmpeg-devel] [PATCH] change some | to + in h264_cabac

Michael Niedermayer michaelni
Thu Mar 25 13:09:56 CET 2010


On Thu, Mar 25, 2010 at 03:35:08AM -0400, Alexander Strange wrote:
> 6 insns less on x86-64, since gcc doesn't know the range of get_cabac_noinline's return value and can't change or to lea (well, I'm not sure it can do that in the first place).

> No speed change.

:(


>  h264_cabac.c |   16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
> 9ec22d9c32e88dc95c4b6c241a7793e8925c45b3  0004-cabac-Use-instead-of-in-some-places.patch
> From bf53d404b2ca048450177689cb3d418f286f5ce4 Mon Sep 17 00:00:00 2001
> From: Alexander Strange <astrange at ithinksw.com>
> Date: Wed, 24 Mar 2010 16:28:42 -0400
> Subject: [PATCH 4/4] cabac: Use + instead of | in some places.
> 
> 6 insns less on x86-64.

ok


[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Awnsering whenever a program halts or runs forever is
On a turing machine, in general impossible (turings halting problem).
On any real computer, always possible as a real computer has a finite number
of states N, and will either halt in less than N cycles or never halt.
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