On Sat, 2009-11-28 at 20:18 +0000, Andrew Church wrote: > (Replying one message too deep because I accidentally deleted Francesco's > message before replying to that...) > > >Francesco> `mmxext' is deep jargon (mostly found on linux field AFAIK) > >Francesco> for some MMX extended instructions that aren't explicitly > >Francesco> advertised; I can't recall the exact details but those were > >Francesco> added together with the first round of SSE or something like > >Francesco> that. > I'm afraid you're missing something. (: MMXEXT (like 3DNow!) is an > AMD-specific extension that was added in some old AMD CPUs back before > AMD and Intel settled on a common SIMD instruction set. The MMXEXT > instructions have since been superseded by SSE in both AMD and Intel CPUs, > so Intel never added support for them.
Yes, my bad :) Actually I knew that, but my memory served me badly this time. I was also confident that since SSE superde MMXEXT, an Intel CPU supporting the SSE should be able to support the MMXEXT acceleration; however, I'm not so sure right now. :| Lastly, I'd rather expect SIGILL in that scenario, and not SIGSEGV. However, there still a potential bug in our (= transcode) code because not all modules follows the --accel setting. libmpeg2 for sure doesn't. I'll add that as bug. Bests, -- Francesco Romani // Ikitt http://fromani.exit1.org ::: transcode homepage http://tcforge.berlios.de ::: transcode experimental forge
