From 7ec2354c38978b918dc079b611393becb6c80bf7 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Martin=20Storsj=C3=B6?= Date: Fri, 26 Jan 2024 14:55:49 +0200 Subject: [PATCH] x86: Remove inline MMX assembly that clobbers the FPU state MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit These inline implementations of AV_COPY64, AV_SWAP64 and AV_ZERO64 are known to clobber the FPU state - which has to be restored with the 'emms' instruction afterwards. This was known and signaled with the FF_COPY_SWAP_ZERO_USES_MMX define, which calling code seems to have been supposed to check, in order to call emms_c() after using them. See 0b1972d4096df5879038f0af776f87f41e90ebd4, 29c4c0886d143790fcbeddbe40a23dfc6f56345c and df215e575850e41b19aeb1fd99e53372a6b3d537 for history on earlier fixes in the same area. However, new code can use these AV_*64() macros without knowing about the need to call emms_c(). Just get rid of these dangerous inline assembly snippets; this doesn't make any difference for 64 bit architectures anyway. Signed-off-by: Martin Storsjö --- libavcodec/dca_core.c | 16 ---------------- libavutil/x86/intreadwrite.h | 36 ------------------------------------ 2 files changed, 52 deletions(-) diff --git a/libavcodec/dca_core.c b/libavcodec/dca_core.c index 60508fabb9..5dd727fc72 100644 --- a/libavcodec/dca_core.c +++ b/libavcodec/dca_core.c @@ -770,10 +770,6 @@ static void erase_adpcm_history(DCACoreDecoder *s) for (ch = 0; ch < DCA_CHANNELS; ch++) for (band = 0; band < DCA_SUBBANDS; band++) AV_ZERO128(s->subband_samples[ch][band] - DCA_ADPCM_COEFFS); - -#ifdef FF_COPY_SWAP_ZERO_USES_MMX - emms_c(); -#endif } static int alloc_sample_buffer(DCACoreDecoder *s) @@ -837,10 +833,6 @@ static int parse_frame_data(DCACoreDecoder *s, enum HeaderType header, int xch_b } } -#ifdef FF_COPY_SWAP_ZERO_USES_MMX - emms_c(); -#endif - return 0; } @@ -1283,10 +1275,6 @@ static void erase_x96_adpcm_history(DCACoreDecoder *s) for (ch = 0; ch < DCA_CHANNELS; ch++) for (band = 0; band < DCA_SUBBANDS_X96; band++) AV_ZERO128(s->x96_subband_samples[ch][band] - DCA_ADPCM_COEFFS); - -#ifdef FF_COPY_SWAP_ZERO_USES_MMX - emms_c(); -#endif } static int alloc_x96_sample_buffer(DCACoreDecoder *s) @@ -1516,10 +1504,6 @@ static int parse_x96_frame_data(DCACoreDecoder *s, int exss, int xch_base) } } -#ifdef FF_COPY_SWAP_ZERO_USES_MMX - emms_c(); -#endif - return 0; } diff --git a/libavutil/x86/intreadwrite.h b/libavutil/x86/intreadwrite.h index 40f375b013..5e57d6a8cd 100644 --- a/libavutil/x86/intreadwrite.h +++ b/libavutil/x86/intreadwrite.h @@ -27,42 +27,6 @@ #if HAVE_MMX -#if !HAVE_FAST_64BIT && defined(__MMX__) - -#define FF_COPY_SWAP_ZERO_USES_MMX - -#define AV_COPY64 AV_COPY64 -static av_always_inline void AV_COPY64(void *d, const void *s) -{ - __asm__("movq %1, %%mm0 \n\t" - "movq %%mm0, %0 \n\t" - : "=m"(*(uint64_t*)d) - : "m" (*(const uint64_t*)s) - : "mm0"); -} - -#define AV_SWAP64 AV_SWAP64 -static av_always_inline void AV_SWAP64(void *a, void *b) -{ - __asm__("movq %1, %%mm0 \n\t" - "movq %0, %%mm1 \n\t" - "movq %%mm0, %0 \n\t" - "movq %%mm1, %1 \n\t" - : "+m"(*(uint64_t*)a), "+m"(*(uint64_t*)b) - ::"mm0", "mm1"); -} - -#define AV_ZERO64 AV_ZERO64 -static av_always_inline void AV_ZERO64(void *d) -{ - __asm__("pxor %%mm0, %%mm0 \n\t" - "movq %%mm0, %0 \n\t" - : "=m"(*(uint64_t*)d) - :: "mm0"); -} - -#endif /* !HAVE_FAST_64BIT && defined(__MMX__) */ - #ifdef __SSE__ #define AV_COPY128 AV_COPY128