The Logical Next Step: A Gameboy Emulator in Rust

Note: This blog is currently a work in progress! Thank you for your patience.

After getting my Chip-8 emulator written in Zig, I asked myself… what’s the next step? Chip-8 is often seen as the first step in learning emulation, despite not being a true “emulator”, but the second step is less well-defined. A little research lead me to two standard choices:

1. NES emulation - The classic, the OG, what many think of when they think “8-bit”.
2. Gameboy emulation - The ultimate 8-bit console and probably the last.

Thinking it over, the choice was purely personal for me. I grew up with a Gameboy by my side, playing “Pokémon Red Version” and “The Legend of Zelda: Link’s Awakening” as much as I reasonably could. There were NES games that I played, but nowhere near as much as the Gameboy. Jumping up to 16-bit consoles, such as the SNES, is a bit more of a complexity jump, so the Gameboy was the logical and reasonable choice.

Weapon of Choice

I have little self control. I am interested in language design. I had never used Rust. Oops… I decided to learn Rust.

A couple of evenings picking over Rustlings and I felt like I was as ready to roll as I would ever be. The language is notably more complex than Zig, but the LSP and compiler are generally super helpful, so it’s a fair trade in my opinion. Time to write a Gameboy emulator. HELL YEAH, BROTHER!!!

Resources?

Except, wait a second… Where do you start with a Gameboy emulator? The short answer: the PanDocs. The long answer is a little more complex and unsatisfying for a noob:

You see, the Chip-8 is an onboarding point, so the resources are very beginner friendly. The default resources spend more time answering simple questions or explaining context in a granular way. As for the Gameboy, the resources assume you have a higher depth and breadth of knowledge as to basic operations and behaviors.