[FFmpeg-devel] [PATCHES] lpc_mmx: merge some asm blocks and add xmm registers to clobber list

[Michael Niedermayer]

On Sat, Oct 30, 2010 at 05:46:58PM -0200, Ramiro Polla wrote:
> $subj, split in 2 patches

>  lpc_mmx.c |   19 ++++++++++---------
>  1 file changed, 10 insertions(+), 9 deletions(-)
> 267c781586fd0713785433848de9168783185e60  0007-lpc_mmx-merge-some-asm-blocks.patch
> From 33992c433a04fe7d9228aafcf86b9d1cd42032cf Mon Sep 17 00:00:00 2001
> From: Ramiro Polla <ramiro.polla at gmail.com>
> Date: Sat, 30 Oct 2010 17:34:14 -0200
> Subject: [PATCH 7/9] lpc_mmx: merge some asm blocks
> 
> These blocks depended on the compiler keeping xmm registers untouched between
> them.
> ---
>  libavcodec/x86/lpc_mmx.c |   19 ++++++++++---------
>  1 files changed, 10 insertions(+), 9 deletions(-)
> 
> diff --git a/libavcodec/x86/lpc_mmx.c b/libavcodec/x86/lpc_mmx.c
> index 2ef5fa6..d7f188e 100644
> --- a/libavcodec/x86/lpc_mmx.c
> +++ b/libavcodec/x86/lpc_mmx.c
> @@ -29,16 +29,15 @@ static void apply_welch_window_sse2(const int32_t *data, int len, double *w_data
>      x86_reg i = -n2*sizeof(int32_t);
>      x86_reg j =  n2*sizeof(int32_t);
>      __asm__ volatile(
> -        "movsd   %0,     %%xmm7                \n\t"
> +        "movsd   %4,     %%xmm7                \n\t"
>          "movapd  "MANGLE(ff_pd_1)", %%xmm6     \n\t"
>          "movapd  "MANGLE(ff_pd_2)", %%xmm5     \n\t"
>          "movlhps %%xmm7, %%xmm7                \n\t"
>          "subpd   %%xmm5, %%xmm7                \n\t"
>          "addsd   %%xmm6, %%xmm7                \n\t"
> -        ::"m"(c)
> -    );
> +        "bt      $1,     %5                    \n\t"

most likely test is faster at least on some cpus

anyway, iam ik with whatever is fastest

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

Incandescent light bulbs waste a lot of energy as heat so the EU forbids them.
Their replacement, compact fluorescent lamps, much more expensive, dont fit in
many old lamps, flicker, contain toxic mercury, produce a fraction of the light
that is claimed and in a unnatural spectrum rendering colors different than
in natural light. Ah and we now need to turn the heaters up more in winter to
compensate the lower wasted heat. Who wins? Not the environment, thats for sure
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