See the Game programming page. See my A5200 emulator page for details. This is designed to programming 3D stuff with Allegro as simple as possible. See my PSX programming page. Get them from my PSX Programming Page .
Source is included.
My memory card and file reading examples for mipsgcc will be up soon too. You'll need some PSX dev stuff like Xplorer or AR and psexe etc to use this. My Atari Lynx Demo is on the game programming page.