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authorVitor Sessak <vitor1001@gmail.com>2011-04-23 19:24:31 +0200
committerReinhard Tartler <siretart@tauware.de>2011-04-26 18:18:22 +0200
commit13dfce3d44f99a2d7df71aba8ae003d58db726f7 (patch)
treed0997a169ba8e4e7c97dcfc36b60f74e2295b087 /libavutil/mem.c
parent33cbfa6fa37d9aea235ce7d3c389d8eec279205f (diff)
Increase alignment of av_malloc() as needed by AVX ASM.
Signed-off-by: Reinhard Tartler <siretart@tauware.de>
Diffstat (limited to 'libavutil/mem.c')
-rw-r--r--libavutil/mem.c16
1 files changed, 7 insertions, 9 deletions
diff --git a/libavutil/mem.c b/libavutil/mem.c
index 2aef9b0a1b..27bb30b8ef 100644
--- a/libavutil/mem.c
+++ b/libavutil/mem.c
@@ -69,21 +69,21 @@ void *av_malloc(size_t size)
#endif
/* let's disallow possible ambiguous cases */
- if(size > (INT_MAX-16) )
+ if(size > (INT_MAX-32) )
return NULL;
#if CONFIG_MEMALIGN_HACK
- ptr = malloc(size+16);
+ ptr = malloc(size+32);
if(!ptr)
return ptr;
- diff= ((-(long)ptr - 1)&15) + 1;
+ diff= ((-(long)ptr - 1)&31) + 1;
ptr = (char*)ptr + diff;
((char*)ptr)[-1]= diff;
#elif HAVE_POSIX_MEMALIGN
- if (posix_memalign(&ptr,16,size))
+ if (posix_memalign(&ptr,32,size))
ptr = NULL;
#elif HAVE_MEMALIGN
- ptr = memalign(16,size);
+ ptr = memalign(32,size);
/* Why 64?
Indeed, we should align it:
on 4 for 386
@@ -93,10 +93,8 @@ void *av_malloc(size_t size)
Because L1 and L2 caches are aligned on those values.
But I don't want to code such logic here!
*/
- /* Why 16?
- Because some CPUs need alignment, for example SSE2 on P4, & most RISC CPUs
- it will just trigger an exception and the unaligned load will be done in the
- exception handler or it will just segfault (SSE2 on P4).
+ /* Why 32?
+ For AVX ASM. SSE / NEON needs only 16.
Why not larger? Because I did not see a difference in benchmarks ...
*/
/* benchmarks with P3