emul8

Terminal CHIP8 emulator. This is the first project I have written in Rust, and I started it as a learning exercise. It is far from finished.

Repository structure

• decoder - A CHIP8 instruction decoder library.
• instruction_emulator - A CHIP8 instruction emulator library.
• c8d - A command line utility for disasembling CHIP8 instructions.
• src - The sources of the CHIP8 emulator.

Building

cargo build [--release]

Running

cargo run [--release] -- path/to/rom [--trace path/to/log/file]
# Or
emul8 path/ro/rom [--trace path/to/log/file]

If --trace is used, each step of the instruction emulator is logeed. Sample output:

00200: a24c LD I, [0x24c]
V0 = 0x00 V1 = 0x00 V2 = 0x00 V3 = 0x00 V4 = 0x00 V5 = 0x00 V6 = 0x00 V7 = 0x00
V8 = 0x00 V9 = 0x00 Va = 0x00 Vb = 0x00 Vc = 0x00 Vd = 0x00 Ve = 0x00 VF = 0x00
PC = 0x000200 SP = 0x00
 I = 0x000000
DT = 0x00 ST = 0x00
00202: 6530 LD V5, 0x30
V0 = 0x00 V1 = 0x00 V2 = 0x00 V3 = 0x00 V4 = 0x00 V5 = 0x00 V6 = 0x00 V7 = 0x00
V8 = 0x00 V9 = 0x00 Va = 0x00 Vb = 0x00 Vc = 0x00 Vd = 0x00 Ve = 0x00 VF = 0x00
PC = 0x000202 SP = 0x00
 I = 0x00024c
DT = 0x00 ST = 0x00

This currenlty uses cursive with the crossterm backend, simply because it works both in Windows and Linux. I'm thinking about ditching the terminal emulator idea and switching to SDL2 sometime (or maybe keeping both).

Missing functionalities

I've mostly tested this against basic ROMs, it is not ready to attempt to run an actual game.

Resources

• Cowgod's Chip-8 Technical Reference
• Some excellent articles by Craig Thomas
• Octo
• The good people at r/emudev