[x264-devel] Wrong instruction

[Loren Merritt]

On Tue, 23 Oct 2007, SIEGERSTEIN wrote:
> On Tue, 23 Oct 2007, Guillaume Poirier wrote:
>> On Tue, 23 Oct 2007, SIEGERSTEIN wrote:
>>
>>> Hi! I found, that x264 encoder convert with wrong instruction:
>>> Program received signal SIGFPE, Arithmetic exception.

A wrong instruction would be SIGILL, not SIGFPE.

My guess: transcode managed to enable floating-point exceptions, such 
that division by zero becomes a crash rather than infinity.
The crash is near a division, and the denominator can be zero with some 
settings, but the result of that computation won't be used in the cases 
where it is zero, so inf or NaN don't matter.

>> MMXExt is supported by your CPU. Your problem must be elsewhere.
>
> Where you see MMXEXT suport in my processor ?!?
> I see only SSE, SSE2, SSE3(pni) and MMX instructions.
>
> MMXEXT is exclusive to AMD processors.

SSE is Intel's name for MMXEXT. Or if you prefer, MMXEXT is AMD's name for 
a subset of SSE. In any case, x264 doesn't have any AMD-specific code. 
3DNow detection is there only because we can detect it, not because it's 
used.

--Loren Merritt