[FFmpeg-devel] [PATCH] Add check for Athlon64 and similar AMD processors with slow SSE2.

Justin Ruggles justin.ruggles
Fri Feb 4 01:02:07 CET 2011

On 02/03/2011 01:47 AM, Dominik 'Rathann' Mierzejewski wrote:

> On Thursday, 03 February 2011 at 00:47, Justin Ruggles wrote:
>> On 02/02/2011 06:40 PM, M?ns Rullg?rd wrote:
> [...]
>>> Why does this code only affect AMD processors?  I guess it has
>>> something to do with those magic bit checks before it...
>> That is a guess on my part.  I don't know much about cpuid.  I assume we
>> wouldn't check for 3DNow on a non-AMD processor, but that may be an
>> incorrect assumption.  x264 also checks the AMD vendor string in their
>> equivalent of this whole section, but FFmpeg does not.
> There are others, for example VIA C3 and IDT Winchip 2 (now VIA). I'm not
> sure if they're worth worrying about, as they're probably too slow and
> too scarce to matter.

Yes, but I don't think any of them support SSE2.  Still, I can add an
AMD vendor string check around this part in case some company other than
AMD decides to make an x86 CPU with SSE2 and use the 0x80000001 ext level.


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