[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.

From: Jonathan Morton
      jonathan.morton at movial.com

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