[FFmpeg-devel] [PATCH 1/2] x86inc: Extend FMA_INSTR functionality

[James Almer]

On 13/02/14 6:21 PM, Michael Niedermayer wrote:
> On Wed, Feb 12, 2014 at 05:17:07PM -0300, James Almer wrote:
>> On 08/02/14 2:54 AM, James Almer wrote:
>>> Support the cases where the first and last operand of
>>> the XOP instruction are the same.
>>>
>>> Also add vpmacsdql emulation.
>>>
>>> Signed-off-by: James Almer <jamrial at gmail.com>
>>> ---
>>>  libavutil/x86/x86inc.asm | 4 ++++
>>>  1 file changed, 4 insertions(+)
>>
>> Ping for patchset.
> 
> applied
> 
> but iam not sure about the solution to %4==%1, maybe the user
> should explicitly pass a temporary insteda of %2 being used
> but thats more a question for x264-devel

You're right, a fifth parameter is probably the proper way. See 
FMULADD_PS in x86util. It would allow actual non-destructive emulation 
of these XOP instructions if it's ever needed.
It's not for now, but changing it will not hurt and it will probably have 
to be done at some point anyway.

Regards.