[FFmpeg-devel] H.264 CABAC Decoder on IBM Cell

Loren Merritt lorenm
Thu May 7 21:20:19 CEST 2009

On Thu, 7 May 2009, Jason Garrett-Glaser wrote:
> I'm going to blame the fact that the primary core of the Cell (stupidly)
> doesn't have a barrel shift unit, resulting in variable shifts, such as
> those in renormalization, being implemented in microcode (and
> correspondingly being extraordinarily slow).
> But that's just a guess.  It needs to be profiled.

Those shifts could all be multiplies if that's faster. But a quick google
says that PPU sucks at integer multiplies too, just not quite as much as
c->range could be LUTed, but c->low would take quite a big LUT.

--Loren Merritt

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