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https://github.com/varunshenoy/rusty-chip8

A CHIP-8 emulator written in Rust 🦀
https://github.com/varunshenoy/rusty-chip8

chip8 emulator rust

Last synced: 2 months ago
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A CHIP-8 emulator written in Rust 🦀

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README 

        
# A *Rusty* CHIP-8 Emulator



![tetris in chip8](tetris.png)



> CHIP-8 is an interpreted programming language, developed by Joseph Weisbecker. It was initially used on the COSMAC VIP and Telmac 1800 8-bit microcomputers in the mid-1970s. CHIP-8 programs are run on a CHIP-8 virtual machine.



> — [Wikipedia on CHIP-8](https://en.wikipedia.org/wiki/CHIP-8)



I first wanted to build a GBA emulator, since I've grown up on those ([Pokemon ROM hacks](https://tvtropes.org/pmwiki/pmwiki.php/VideoGame/PokemonSweetVersion#:~:text=Pok%C3%A9mon%20Sweet%20Version%20is%20a,Pok%C3%A9mon%20Sweet%202th%2C%20available%20here%20.) made up my childhood), but it seemed like a lot for a first time emulator. Honestly, implementing [every single instruction](https://meganesulli.com/generate-gb-opcodes/) would have taken forever. I'm also new to Rust, so building a CHIP-8 emulator is a good place to start. Overall, this is a fantastic systems project to learn a new language and have something to show at the end of it all.



I primarily tested this emulator on `TETRIS` and `PONG`. Note that it seems like the key debouncer within `minifb` is not the best, so sometimes keys may not be received properly. This is a first time Rust and "building an emulator" project I've done, so expect some quirks. The `TEST` ROM (listed below) was also used in debugging the emulator. 



Some interesting extensions would be to build an interactive debugger (which would involve the user being able to step through opcode instructions and visually look under the hood to examine registers and the stack) and replacing `minifb` with `sdl2` for better abstractions and proper device periphery separation.



### 🎮 Advice for Building a Emulator

Instead of writing the emulator and testing it afterwards (as I did in this project), it is best to initially write a minimal amount of code. First, load a ROM. When the interpreter gets to an unimplemented opcode, crash/panic and print the opcode. At that point, write the code to parse the opcode and make sure it gets appropriately handled. This build-test loop chunks this larger project into much smaller pieces and makes sure every opcode gets the attention it needs.



### 🕹 Resources Used:

- [The Rust Programming Language](https://doc.rust-lang.org/book/)

- [Cowgod's Chip-8 Technical Reference](http://devernay.free.fr/hacks/chip8/C8TECH10.HTM#1.0)

- [Colin Eberhardt's WASM Rust Chip-8 Output](https://colineberhardt.github.io/wasm-rust-chip8/web/) 



    *this one helped me make sure my emulator was reading and parsing bits correctly*

- [Test ROM](https://github.com/corax89/chip8-test-rom)

- [Why learn Rust at all?](https://www.youtube.com/watch?v=4YU_r70yGjQ)