On 22/02/14 1:29 PM, Luca Barbato wrote: > On 22/02/14 06:53, James Almer wrote: >> These are the missing instruction sets introduced with Haswell/Piledriver >> CPUs. >> >> Last two patches are based on x264 detection code. > > The set doesn't look bad at all but I'm wondering about it's usage: > >> James Almer (3): >> x86: add missing XOP checks and macros >> x86: add detection for FMA3 instruction set > > Which is the relationship between FMA3 and FMA4 ? >
It's what happens when Intel and AMD don't talk to each other to coordinate stuff. Short story summary here: https://en.wikipedia.org/wiki/FMA_instruction_set Both sets do the same in essence. The only difference is that one uses three operands while the other uses four (Technically, FMA4 is the most flexible, but it's only supported by AMD). AMD added FMA4 starting with Bulldozer, then added FMA3 as well to Piledriver for compatibility reasons once Intel revealed they would use that starting with Haswell. >> x86: add detection for Bit Manipulation Instruction sets > > Is BMI a subset of AVX2? No, they are independent and work on general registers. AMD added BMI1 starting with Piledriver, which doesn't support AVX2, whereas Intel added both BMI1 and BMI2 starting with Haswell. > > lu > _______________________________________________ > libav-devel mailing list > [email protected] > https://lists.libav.org/mailman/listinfo/libav-devel > _______________________________________________ libav-devel mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-devel
