Coffee GB

Coffee GB is a Gameboy Color emulator written in Java 8. It's meant to be a development exercise. More info can be found in the blog post. First I implemented all the Gameboy CPU opcodes. It’s not exactly the Z80, but it’s pretty close. As a reference, I’ve used the GameBoy CPU Manual - later on I discovered that it has a few typos and is not specific enough for some of the operations. After implementing the opcodes and memory (modelled by an int[] array) I was eager to check whether it’s possible to run some code on it. I had neither the cartridge nor the GPU emulation yet, so even the simplest game wouldn’t be an option. However, when the original Gameboy starts, it executes a simple 256-bytes program, a kind of firmware displaying the Nintendo logo and self-testing the system. That was exactly the thing I was looking for - after just 3 days I had an application running the Gameboy code!