On Thu, Jun 6, 2024, 05:53 Rémi Denis-Courmont <r...@remlab.net> wrote:
> > > Le 6 juin 2024 10:43:05 GMT+03:00, Sean McGovern <gsean...@gmail.com> a > écrit : > >Hi, > > > >Attached inline is a _non-working_ implementation of flac_wasted32 for > >VSX developed on a POWER9 in little-endian mode but probably just as > >usable on POWER{8,10}. > > > >I'm not sure why probably one of the simplest DSP functions in lavc > >does not work for me, I imagine this is probably something endian > >related even though IBM's documentation for vec_sl()[1] does not > >suggest any. > > Mixing up bytes and elements in the iterator. But you should be able to > track this down with gdb or good ol' printf(). > > >Here's my code: > > > >#define VSX_STRIDE 16 > > > >void ff_flac_wasted32_vsx(int32_t *decoded, int wasted, int len) > >{ > > register vec_s32 vec1; > > register vec_u32 vec2 = { wasted, wasted, wasted, wasted }; > > There should be an instruction to splat a scalar to a vector. Better yet > use vector-scalar shift, if VSX has it. > In the POWER ISA, vec_splat() only accepts an immediate, so I think this is the only way to do it in flac_wasted32. > > register vec_s32 shifted; > > > > for (int i = 0; i < len; i += VSX_STRIDE) { > > vec1 = vec_vsx_ld(i, decoded); > > shifted = vec_sl(vec1, vec2); > > vec_vsx_st(shifted, i, decoded); > > } > >} > > > >Anyone with experience with AltiVec or VSX see something obvious I am > missing? > > > >-- Sean McGovern > > > >[1] > https://www.ibm.com/docs/en/xl-c-and-cpp-linux/16.1.1?topic=functions-vec-sl > >_______________________________________________ > >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". > > > _______________________________________________ > 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". > _______________________________________________ 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".