xref: /third_party/ffmpeg/libavutil/x86/emms.h (revision cabdff1a)
1/*
2 * This file is part of FFmpeg.
3 *
4 * FFmpeg is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * FFmpeg is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with FFmpeg; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19#ifndef AVUTIL_X86_EMMS_H
20#define AVUTIL_X86_EMMS_H
21
22#include "config.h"
23#include "libavutil/attributes.h"
24
25void avpriv_emms_asm(void);
26
27#if HAVE_MMX_INLINE
28#ifndef __MMX__
29#include "libavutil/cpu.h"
30#endif
31
32#   define emms_c emms_c
33/**
34 * Empty mmx state.
35 * this must be called between any dsp function and float/double code.
36 * for example sin(); dsp->idct_put(); emms_c(); cos()
37 * Note, *alloc() and *free() also use float code in some libc implementations
38 * thus this also applies to them or any function using them.
39 */
40static av_always_inline void emms_c(void)
41{
42/* Some inlined functions may also use mmx instructions regardless of
43 * runtime cpuflags. With that in mind, we unconditionally empty the
44 * mmx state if the target cpu chosen at configure time supports it.
45 */
46#if !defined(__MMX__)
47    if(av_get_cpu_flags() & AV_CPU_FLAG_MMX)
48#endif
49        __asm__ volatile ("emms" ::: "memory");
50}
51#elif HAVE_MMX && HAVE_MM_EMPTY
52#   include <mmintrin.h>
53#   define emms_c _mm_empty
54#elif HAVE_MMX_EXTERNAL
55#   define emms_c avpriv_emms_asm
56#endif /* HAVE_MMX_INLINE */
57
58#endif /* AVUTIL_X86_EMMS_H */
59