Le lauantaina 27. toukokuuta 2023, 23.35.14 EEST Martin Storsjö a écrit : > > NEON detection could be added here, though I've yet to see an Armv8 > > implementation without AdvSIMD. > > I guess we could, but as it's part of the require baseline for armv8-a I > don't think there's much need for it?
I mean that if you have 95% of the code needed, you might as well add the last 5%. I don't think it's used by much anything. > If configured with --disable-neon we > don't return that cpuflag though. > > > FWIW, DotProd is exposed as HWCAP_ASIMDDP and I8MM is exposed via > > HWCAP2_I8MM, using trapped ID registers is not (yet) necessary. > > Ah, I see. I guess using those would be more straightforward. > > OTOH, HWCAP_CPUID is available much earlier than HWCAP_ASIMDDP or > HWCAP2_I8MM (I do some amount of cross building with a fairly old > sysroot). If the sysroot shares the not-too-old kernel of the host, then ID registers will work anyway. The age of the userspace toolchain affects availability of HWCAP constant definitions, not that of ID registers, which is a purely in- kernel feature. > I'll think about it, whether it's worth complicating things to > try both approaches, or if we should just go with the plain HWCAPs here. I don't really mind either way. -- 雷米‧德尼-库尔蒙 http://www.remlab.net/ _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
