Writing a Game Boy Emulator in OCaml

Summary

IntroductionFor the past few months, I have been working on a project called CAMLBOY, a Game Boy emulator written in OCaml that runs in the browser. You can try it out on the following demo page:Demo PageI included several homebrew ROMs in the demo, so please try them out (I recommend Bouncing ball and Rocket Man Demo). You can also play with it in your mobile browser as it runs at 60 FPS on recent smartphones.RepositoryYou can find the repository here:https://github.com/linoscope/CAMLBOYStarForkScreenshotsWhy implement a Game Boy emulator in OCaml?Have you ever felt like the following when learning a new programming language?You can write simple program snippets but you don’t know how to write medium/large scale code.You have studied advanced language features and have a rough understanding of how they work, but you don’t know how to use them in practice.These were exactly my thoughts when I started to study OCaml seriously a few months ago. I understood the basics of the language by reading books and implementing simple algorithms, but the above two “don’t know"s prevented me from feeling like I could really write OCaml. I knew that the only way to get out of this situation was practice, so I started looking for a project to work on.I choose a Game Boy emulator as the project for the following reasons:It has clear specifications, so there is no need to think about what to implement.It is complex enough that it cannot be completed in a few days or weeks.It is not so complex that it can’t be completed in a few months.I have fond childhood memories of playing the Game Boy.I set the following goals for the emulator:Write code with an emphasis on readability and maintainability.Compile to JavaScript using js_of_ocaml and run it in the browser.Achieve playable FPS in the smartphone browser.Implement some benchmarks and compare various compiler backends.Goal of this articleThis article aims to take you through the journey of creating a Game Boy emulator in OCaml.This art...