[FFmpeg-devel] [RFC]lavu/x86/pixelutils: Call emms before returning.

Michael Niedermayer michael at niedermayer.cc
Mon Oct 3 00:06:13 EEST 2016

On Sun, Oct 02, 2016 at 10:53:17PM +0200, Carl Eugen Hoyos wrote:
> Hi!
> The functions in libavutil/x86/pixelutils.asm are exported 
> to the library users if I understand the code correctly.
> I suspect it can be expected that the MMX state is reset 
> after returning.
> Fixes the pixelutils fate test with musl on x86-32.
> Please comment, Carl Eugen

>  pixelutils.asm |    5 +++++
>  1 file changed, 5 insertions(+)
> a7b729f55ec6170b1c4b1959a4be7530926368ce  0001-lavu-x86-pixelutils-Call-emms-before-returning.patch
> From f16831e6dc0f36c8f290d927bf51142c64fe8afc Mon Sep 17 00:00:00 2001
> From: Carl Eugen Hoyos <cehoyos at ag.or.at>
> Date: Sun, 2 Oct 2016 22:45:51 +0200
> Subject: [PATCH] lavu/x86/pixelutils: Call emms before returning.
> The functions are exported and the library user can
> expect that the MMX state is reset after returning.
> ---
>  libavutil/x86/pixelutils.asm |    5 +++++
>  1 file changed, 5 insertions(+)

I think the performance impact of this on some CPUs is too large
to call this at a 8x8 and 16x16 granularity


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Breaking DRM is a little like attempting to break through a door even
though the window is wide open and the only thing in the house is a bunch
of things you dont want and which you would get tomorrow for free anyway
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