Displaying 2 results from an estimated 2 matches for "frsqrte".
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vrsqrte
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...
2003 Oct 12
1
Altivec-enabled libvorbis...
...into registers, etc).
Overall, some .ogg files seem to spend a lot of time in
vorbis_lsp_to_curve()...I assume this .ogg is from an older version of
the vorbis spec, and such files tend to eat more CPU (although there are
some wins here by inlining the the lookup table functions and using the
frsqrte opcode instead of the invsqrt lookup table...memory access is a
huge bottleneck on the Mac, so recalculating things is frequently faster
than using a lookup table)...these files lean towards the 30% speedup
side of the field. Other .oggs (newer version?) seem to skip this
function altogether an...