Here's a simple patch that gives about a 50% (on my box) speed boost to glReadPixels performance in 24-bit. I measured using the benchmark built into progs/demos/readpix. The interesting thing is that the core MMX & SSE2 routines can be used for other cards as well. For example, it looks like MGA, Unichrome, and others can use the same code for 24-bit.
Before persuing this too far, I'd like to look at ways to make the *compiled* code from spantmp.h be more device-independent. That would make it easier to generate a bunch of these generic routines and just plug them in.
Here's an updated version of the patch. I think this one includes all the code. ;) In addition, this patch adds support for the Unichrome driver. It is still called r200_readpixels-*.patch.
r200_readpixels-02.tar.bz2
Description: BZip2 compressed data
