Back during the X Developers' Conference
last month, one of the sessions was on GL shaders for Shader Model 3/4. This talk led by Ian Romanick called for advanced assembly shader extensions for Mesa, which would greatly benefit some middle-ware projects like Wine and Cedega with Mesa's current state and not having a bolstered GLSL implementation. None of the current OpenGL extensions are suitable for this due to some of the extensions being designed for use on specific hardware, rather than being ideal for use across all Mesa drivers/hardware, and other extensions not satisfying the needs Ian and other developers want. Long story short, Ian has written a new OpenGL extension as a result: GL_MESA_gpu_program3.
The specification for the GL_MESA_gpu_program3 extension is currently considered "alpha" by Ian and has not yet been implemented within any Mesa drivers. Currently the specification is being reviewed by Mesa developers, then Wine developers, and after that we may see such support actually implemented. The announcement of the initial version of GL_MESA_gpu_program3 can be found on the Mesa development list
while the initial version of this spec can be found at FreeDesktop.org
This will surely benefit many Wine gamers running newer graphics hardware capable of Shader Model 3/4 once implemented with the Mesa drivers.