[MPlayer-dev-eng] [PATCH] Add NEON optimizations to some critical audio functions.

[Reimar Döffinger]

On 25.10.2013, at 21:58, Reimar Döffinger <Reimar.Doeffinger at gmx.de> wrote:

> One big issue is that lrintf is ridiculously slow on most (all?)
> ARM Linux distributions, which makes the format conversion take
> more time than the audio decoding.
> It uses intrinsics because I was too lazy to learn the inline asm
> syntax and for these trivial cases gcc doesn't seem to be able to
> mess it up.

And there I once again underestimated how ridiculously bad gcc is.
Already for the ad_ffmpeg.c code gcc spills the registers it loaded directly onto the stack, just to load them _into the same registers_ again two instructions later.
Not surprisingly, this one actually makes things slower (the af_format one I had checked that everything works and gives a good speedup).
Any volunteers to teach me how to do it in inline asm?