Quote Originally Posted by artivision View Post
The GLSL compiler compiles to assembly-level (MAD, MUL, TEX, LOG, FRC, LIT, and other assembly-level commands). Then the GPU hardware execute them internally with smaller instructions, atomic operations, possibly micro-instructions (if the GPU has microcode), and others. The compiler doesn't have access to the entire instruction set like you have on a CPU with a software-rasterizer.
If you're saying "the GPU hardware may execute hardware instructions by breaking them down internally to even simpler operations, in the same way that modern x86 CPUs execute x86 instructions by breaking them down to simpler operations" then I guess I agree. That doesn't mean there is an internal instruction set you could potentially program in though.

Quote Originally Posted by artivision View Post
Even if Nvidia gives you access on the entire instruction-set you still can't use it with any compiler or anything else. Thats because GPUs missing various control and execution units that only a CPU has. For a GPU, programs must be pre-controled, and thats a higher level sub-set.
I don't work for NVidia

That said, I think you'll find that both NVidia and AMD GPUs today are more capable than what you are describing. I know that SI is, and I imagine the corresponding NVidia parts aren't too different.