CHIP-8 Interpreter

CHIP-8 is an interpreted programming language originally used on the COSMAC VIP and Telmac 1800 microcomputers in the 1970s.

This is a CHIP-8 interpreter written in D with SDL3 for the frontend (graphics, input and audio).

Download for Windows.

Unzip, and from a terminal in the unzipped directory, run:

chip8-interpreter.exe path/to/game.ch8

You can find various sites holding CHIP-8 programs available for download.
Make sure to get CHIP-8 games, and not SCHIP or XO-CHIP ones!

Example sources:

• https://johnearnest.github.io/chip8Archive/
• https://github.com/kripod/chip8-roms/tree/master/game

This project uses a conventional key mapping from the original CHIP-8 keypad to the modern keyboard.

A lot of games don't specify their controls. Test each key if you're unsure!

Also:

• ESC: Quit.
• I, O, P: Toggle quirks.

This interpreter passes the CHIP-8 tests in Timendus' test suite.

There exist CHIP-8 interpreter variants which operate slightly differently to the original. The default settings in this project fit the quirks on the original COSMAC VIP (see test 5).

The I, O and P keys toggle some of these quirks.

• I: I-Increment. The save and load opcodes (Fx55, Fx65) increment the index (I) register. Affects MEMORY in test 5.
• O: SetVxToVy. Store the value of Vy into Vx at the beginning of shift opcodes (8xy6, 8xye). Affects SHIFTING in test 5.
• P: SpriteInterrupt. Wait for an interrupt before drawing a sprite. An interrupt occurs once a frame, which means you are limited to one sprite-draw per frame. Affects DISPLAY WAIT in test 5.

Toggling I or O off might break programs expecting COSMAC VIP execution. Toggling P off might cause unintended execution speeds.

Currently, I have only provided a direct download for a Windows executable. If you want to build the interpreter from the code for another platform, or for any other reason:

• Clone this repository.
• Download a D compiler. This provides the DUB package manager.
  The pinned compiler is DMD v2.113.0. Other versions are most likely fine.
• Download the pinned SDL3 DLL (v3.4.16) and place it in the repository root. Other versions are most likely fine.
  This is required to use the SDL bindings, bindbc-sdl.

Build the project with dub build.

• D
• SDL3

• Cowgod's CHIP-8 Technical Reference
• Tvil's Guide to making a CHIP-8 emulator
• Laurence Scotford's Chip-8 on the COSMAC VIP: Drawing Sprites
• corax89's chip8-test-rom
• Timendus' CHIP-8 test suite
• Phobos documentation
• bindbc-sdl documentation
• SDL Wiki

• Pausing.
• Tick speed adjustments in-app.
• Colour schemes / customisation.
• A menu which encompasses the above points.
• App loads into a menu for selecting ROMs. Also enter this menu from the pause menu (or they are the same thing).

This project is licensed under the MIT license. See LICENSE.