[FFmpeg-devel] [PATCH] EA TGQ video fixes

Vitor Sessak vitor1001
Thu Apr 16 20:40:56 CEST 2009

Reimar D?ffinger wrote:
> On Thu, Apr 16, 2009 at 07:46:38PM +0200, Vitor Sessak wrote:
>> Reimar D?ffinger wrote:
>>>>> -    DCTELEM block[6][64];
>>>>> +    DECLARE_ALIGNED_8(DCTELEM, block[6][64]);
>>>>>      mode = bytestream_get_byte((const uint8_t**)bs);
>>>>>      if (mode>buf_end-*bs) {
>>> Moving it into the context instead should be more reliable.
>> Why?
> Because you are declaring a stack variable as aligned which only works
> up to the value that the stack is already aligned usually which in the
> past on e.g. Windows usually meant it wouldn't be aligned.
> The situation should be better now but I doubt it is flawless and I also
> don't really see a point in keeping the variable on the stack anyway.

Ugh... Makes me wonder two things:

1- Why nobody thought of the possibility of mixing ASM+C when writing 
the C99 spec?
2- Why the heck GCC implement __attribute__ (aligned) without making it 
work properly (or warning when it don't)?

Anyway, thanks for reminding me why I never learned ASM properly...


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