d-dorazio / chip8

A rust chip8 interpreter

Chip8 interpreter in Rust

$ cargo run --release -- --help
$ cargo run --release games/PONG

Virtual Key mappings

The original CHIP-8 had 16 virtual keys had the layout on the left, which has been mapped (by default) to the keyboard layout on the right:

 1 2 3 C                                   1 2 3 4
 4 5 6 D    This is emulated with these    Q W E R
 7 8 9 E    keyboard keys -->              A S D F
 A 0 B F                                   Z X C V

To play PONG use Q and 1 to move the bar on the left up and down and 4 and R for bar on the right.

Notes

The flickering is caused by how the interpreter draws sprites onto the screen. In particular, it performs a bitwise xor between the vram and the sprite to draw. This ends up in flickering when drawing a sprite over an existing sprite (1 ^ 1 = 0).

Resources

• https://en.wikipedia.org/wiki/CHIP-8
• http://mattmik.com/files/chip8/mastering/chip8.html
• http://devernay.free.fr/hacks/chip8/C8TECH10.HTM