emms.h 1.81 KB
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/*
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifndef AVUTIL_X86_EMMS_H
#define AVUTIL_X86_EMMS_H

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#include "config.h"
#include "libavutil/attributes.h"
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#include "libavutil/cpu.h"
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void avpriv_emms_yasm(void);

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#if HAVE_MMX_INLINE
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#   define emms_c emms_c
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/**
 * Empty mmx state.
 * this must be called between any dsp function and float/double code.
 * for example sin(); dsp->idct_put(); emms_c(); cos()
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 * Note, *alloc() and *free() also use float code in some libc implementations
 * thus this also applies to them or any function using them.
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 */
static av_always_inline void emms_c(void)
{
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/* Some inlined functions may also use mmx instructions regardless of
 * runtime cpuflags. With that in mind, we unconditionally empty the
 * mmx state if the target cpu chosen at configure time supports it.
 */
#if !defined(__MMX__)
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    if(av_get_cpu_flags() & AV_CPU_FLAG_MMX)
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#endif
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        __asm__ volatile ("emms" ::: "memory");
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}
#elif HAVE_MMX && HAVE_MM_EMPTY
#   include <mmintrin.h>
#   define emms_c _mm_empty
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#elif HAVE_MMX_EXTERNAL
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#   define emms_c avpriv_emms_yasm
#endif /* HAVE_MMX_INLINE */

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#endif /* AVUTIL_X86_EMMS_H */