mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2024-12-02 03:06:28 +02:00
5b85ca5317
We currently mostly do not empty the MMX state in our MMX
DSP functions; instead we only do so before code that might
be using x87 code. This is a violation of the System V i386 ABI
(and maybe of other ABIs, too):
"The CPU shall be in x87 mode upon entry to a function. Therefore,
every function that uses the MMX registers is required to issue an
emms or femms instruction after using MMX registers, before returning
or calling another function." (See 2.2.1 in [1])
This patch does not intend to change all these functions to abide
by the ABI; it only does so for ff_pixelutils_sad_8x8_mmxext, as this
function can by called by external users, because it is exported
via the pixelutils API. Without this, the following fragment will
assert (on x86/x64):
uint8_t src1[8 * 8], src2[8 * 8];
av_pixelutils_sad_fn fn = av_pixelutils_get_sad_fn(3, 3, 0, NULL);
fn(src1, 8, src2, 8);
av_assert0_fpu();
[1]: https://raw.githubusercontent.com/wiki/hjl-tools/x86-psABI/intel386-psABI-1.1.pdf
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
|
||
|---|---|---|
| .. | ||
| asm.h | ||
| bswap.h | ||
| cpu.c | ||
| cpu.h | ||
| cpuid.asm | ||
| emms.asm | ||
| fixed_dsp_init.c | ||
| fixed_dsp.asm | ||
| float_dsp_init.c | ||
| float_dsp.asm | ||
| imgutils_init.c | ||
| imgutils.asm | ||
| intmath.h | ||
| intreadwrite.h | ||
| lls_init.c | ||
| lls.asm | ||
| Makefile | ||
| pixelutils_init.c | ||
| pixelutils.asm | ||
| pixelutils.h | ||
| timer.h | ||
| tx_float_init.c | ||
| tx_float.asm | ||
| w64xmmtest.h | ||
| x86inc.asm | ||
| x86util.asm | ||