Source: https://blog.rekawek.eu/2017/02/09/coffee-gb/
From 2017, this coder covers why (and how) he created a new GB emulator using Java called Coffee GB.
So why did I spend all this time trying to write it? I treated it as a programming riddle (or a series of riddles), quite similar to those you can find on the Project Euler. It’s a complex, self-contained problem that can be nicely splitted into stages (as I did in the blogpost) and every stage, once completed correctly, gives a rewarding result. Maybe because of these results I got quite addicted to the project itself.
Tomek Rękawek
You can find the source code on GitHub. Important resources mentioned are The Ultimate Game Boy Talk and the Unofficial Game Boy CPU Manual, which may get their own posts in the future. 😊
I’ve tried my own hand at developing a GB emulator (in JavaScript), and this post really does a great job at breaking down the basic principles and the process of iterating until you get something “real.” Seeing the correct Nintendo boot logo is incredibly satisfying!
Andrew
GameBoy.blog 