ffmpeg/libavutil/emms.h
Andreas Rheinhardt ac46514327 avutil/emms: Add ff_assert[01]_fpu()
These will be used to mark and check parts of the code
where the floating point state is supposed to be not
clobbered. They are an improvement on the (deprecated)
av_assert0_fpu() because of proper file and line number
information; they also reset the floating point state
if the assert is actually triggered.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2026-03-02 11:55:30 +01:00

102 lines
2.7 KiB
C

/*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* 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.
*
* FFmpeg is distributed in the hope that it will be useful,
* 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
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef AVUTIL_EMMS_H
#define AVUTIL_EMMS_H
#include <stdint.h>
#include <stdlib.h>
#include "config.h"
#include "libavutil/attributes.h"
#include "libavutil/log.h"
#if ARCH_X86
void avpriv_emms_asm(void);
#if HAVE_MMX_INLINE
#ifndef __MMX__
#include "libavutil/cpu.h"
#endif
# define emms_c emms_c
/**
* Empty mmx state.
* this must be called between any dsp function and float/double code.
* for example sin(); dsp->idct_put(); emms_c(); cos()
* Note, *alloc() and *free() also use float code in some libc implementations
* thus this also applies to them or any function using them.
*/
static av_always_inline void emms_c(void)
{
/* 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__)
if(av_get_cpu_flags() & AV_CPU_FLAG_MMX)
#endif
__asm__ volatile ("emms" ::: "memory");
}
static inline void ff_assert0_fpu(const char *file, int line_number)
{
uint16_t state[14];
__asm__ volatile (
"fstenv %0 \n\t"
: "+m" (state)
:
: "memory"
);
if ((state[4] & 3) != 3) {
emms_c();
av_log(NULL, AV_LOG_PANIC,
"Invalid floating point state assertion "
"triggered at line %u in file %s\n",
line_number, file);
abort();
}
}
#define ff_assert0_fpu() ff_assert0_fpu(__FILE__, __LINE__)
#elif HAVE_MMX && HAVE_MM_EMPTY
# include <mmintrin.h>
# define emms_c _mm_empty
#elif HAVE_MMX_EXTERNAL
# define emms_c avpriv_emms_asm
#endif /* HAVE_MMX_INLINE */
#endif /* ARCH_X86 */
#ifndef emms_c
# define emms_c() do {} while(0)
#endif
#ifndef ff_assert0_fpu
#define ff_assert0_fpu() ((void)0)
#endif
#if defined(ASSERT_LEVEL) && ASSERT_LEVEL >= 1
#define ff_assert1_fpu() ff_assert0_fpu()
#else
#define ff_assert1_fpu() ((void)0)
#endif
#endif /* AVUTIL_EMMS_H */