[Pixman] FPU-based implementation of the core pixel pipeline
Jonathan Morton
jonathan.morton at movial.com
Tue Oct 5 06:44:16 PDT 2010
On Tue, 2010-10-05 at 09:38 +0200, Soeren Sandmann wrote:
> How must of a performance improvement is that table really over just
> using regular conversions?
It's substantial on at least PowerPC and ARM using GCC, for differing
reasons. I can't remember whether I saw much of a difference on x86 as
well. Generally, moving things between integer and FP worlds is not
well optimised at the hardware level.
It strikes me that initialising only the channel bit-depths that are
actually used, rather than the whole table, would be a substantial
saving. The largest depth in the predefined-formats table (10) would
consume 4KB, the much more common 8bpc table takes just 1KB.
So when I get some time, I'll have another look at this.
--
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From: Jonathan Morton
jonathan.morton at movial.com
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