MIPS Assembly programming for the Playstation 1 (PS1/PSX)

The Playstation was Sony's first home console, While inferior in some ways to the more powerful N64, the Playstations huge storage capability, combined with an impressive game library saw the Playstation become the most popular console of the period, catapulting the playstation to the top of the console market.

Cpu 33.87 mhz  R3000 (MIPS I) Ram 2MB Video 1MB VRAM Resolution 256x224 / 320x240 / 640x480

Documentation

Memory Map

Gpu Commands

Screen Memory

Each pixel is represented by one BIG ENDIAN word, in the format %-BBBBBGGGGGRRRRR

Joypad Bits

We want to start the joypad reading routine. First we set up a valid stack pointer, Next we're going to call the bios function at address 0x000000B0 The command is stored in register T1, A1,A2,A3 and A4 contain the parameters We point A0 and A2 to 'Joydata'... once we perform these two bios calls, the JoyData memory will automatically be updated with the data from the joypad

The format of the bits in 'JoyData are shown below:

Endian

The N64 is BIG ENDIAN
the PSX is LITTLE ENDIAN