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 #include "libavutil/cpu.h"
25
26 void avpriv_emms_asm(void);
27
28 #if HAVE_MMX_INLINE
29 # define emms_c emms_c
30 /**
31 * Empty mmx state.
32 * this must be called between any dsp function and float/double code.
33 * for example sin(); dsp->idct_put(); emms_c(); cos()
34 * Note, *alloc() and *free() also use float code in some libc implementations
35 * thus this also applies to them or any function using them.
36 */
emms_c(void)37 static av_always_inline void emms_c(void)
38 {
39 /* Some inlined functions may also use mmx instructions regardless of
40 * runtime cpuflags. With that in mind, we unconditionally empty the
41 * mmx state if the target cpu chosen at configure time supports it.
42 */
43 #if !defined(__MMX__)
44 if(av_get_cpu_flags() & AV_CPU_FLAG_MMX)
45 #endif
46 __asm__ volatile ("emms" ::: "memory");
47 }
48 #elif HAVE_MMX && HAVE_MM_EMPTY
49 # include <mmintrin.h>
50 # define emms_c _mm_empty
51 #elif HAVE_MMX_EXTERNAL
52 # define emms_c avpriv_emms_asm
53 #endif /* HAVE_MMX_INLINE */
54
55 #endif /* AVUTIL_X86_EMMS_H */
56