SNES hacking


SuperFX GSU chip

My SNES interests mostly lie in the SuperFX chip. It's best known for being used by Star Fox to render 3D graphics. It was also used by Super Mario World 2 to do improved/fancy 2D graphics.

Many are under the mistaken impression that the SuperFX is a dedicated 3D processor. In reality, it is a simple general purpose RISC processor with an extremely orthogonal instruction set. It lacks even a jump instruction (you load the PC directly, of course).

star fox

Given that the SuperFX a general purpose CPU, this means that Star Fox actually contains a software 3D renderer.

I tried my hand at reverse engineering the code for this, but it proved very difficult. The furthest I got was finding the matrix math routines (i.e., the mult operations) and nop'ing a few.

All I really have to show for it are some slightly messed up ROMs. Feel free to play with my NOP'd Star Fox roms. Try the training stage.