On Thu, Jan 14, 2016 at 5:02 AM, Henrik Gramner <hen...@gramner.com> wrote: > Use the x86inc syntax for FMA instructions (basically FMA4 syntax that > gets assembled as FMA3) since normal FMA3 opcodes are horrible to > read, nobody ever remembers the ordering of operands.
1. It is very easy to remember: take fmadd231pd x, y, z for instance. This means 2*3 + 1, so x = y*z+x. How the macro is more readable is beyond me; especially with some side cases that are undocumented, see below. 2. If anything, the macro is harder, since it is not Intel supported, I can't look it up at https://www-ssl.intel.com/content/dam/www/public/us/en/documents/manuals/64-ia-32-architectures-software-developer-instruction-set-reference-manual-325383.pdf. 3. The macro does not seem to take care of the mov's (if any), still requiring explicit thought on the part of the programmer. 4. The macro lacks documentation. In particular, it is not a thorough fma4 emulation in the spirit of https://gist.github.com/rygorous/22180ced9c7a00bd68dd. Or put in other words, IMO not good. > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
