Displaying 1 result from an estimated 1 matches for "_fast_sqrt".
2000 Nov 26
5
Another good optimization (for PPC only, though)
Using the PPC frsqrte and fres instructions, I got the percentage time take in the smoothing code in _vp_compute_mask() down from 13.64% to 1.88% of the running time.
In my local copy of Vorbis I have a fast_math.[hc] in vorbis/lib and have a _fast_sqrt() inline in fast_math.h. If anyone else wants to try it out, it follows.
I can currently encode my test file (the first 15 seconds of Supervixen by Garbage) in about 11.1 seconds. Faster than real time, at least :)
-tim
#if defined(__ppc__)
// Vanilla PPC code, but since PPC has a reciprocal...