Hi All,
My new book, Fun Computer Science Projects in Python, that was just released today with No Starch Press, includes a chapter (Chapter 6) on how to write a very simple NES Emulator in Python. To my knowledge, I believe this will be the first book published by a traditional publisher with a chapter on how to write an NES emulator (someone please let me know if that's wrong!).
Is it possible to do in a single chapter? Yes, the chapter includes the entire source code of the emulator and a quite detailed explanation of the code and enough NES knowledge to understand how the NES's CPU and PPU work. I believe it is a great tutorial on writing an NES emulator. We do however build up to it. The prior chapter covers building a CHIP-8 VM and some of the concepts are elucidated in earlier chapters on how to write simple interpreters.
Why did I write the chapter? Well when I got into writing emulators almost a decade ago I was very frustrated by the lack of complete and high quality tutorials on writing NES emulators. There are more online NES emulation tutorials today than there were back then, but I wanted to make something that was extremely clear, complete to just the right level, and in Python so as to be attractive to many of today's intermediate programmers.
Although it is a working emulator capable of playing included open source games and the simplest commercial ones, it leaves you plenty of room to do your own thing, improve compatibility, and still figure out many puzzles. It's an extremely simple emulator—a starting point. It has a complete CPU (which I actually recommend you mostly write on your own in the chapter although my solution is provided), a greatly simplified PPU that only redraws once per frame and lacks scrolling support, only support for the NROM mapper, and no APU. Plus because it's in pure Python it won't even run at full speed on a modern laptop. So you are left with plenty of ways to expand and learn on this foundation: build an APU, add more features to the PPU, implement other mappers, use Cython or some other means to speed up the code, etc.
These forums and the NESDev wiki were instrumental as I was writing my first NES emulator back in the day. I utilized the NESDev Wiki as my main (in fact almost my only) source for the book. Thanks to its extremely liberal license I was able to reuse some figures from the Wiki and other information. Thank you for that. I guess another way you can think of the chapter is as the ultimate tutorial to the NESDev wiki.
Anyway, the book includes a lot of other interesting projects (BASIC interpreter, abstract art program, CHIP-8 VM, etc.) but I think the NES Emulator chapter is the crown jewel. So, thank you again to this great community for all of its support over the years to myself and so many other emulator authors.
You can buy the book on No Starch Press's website (it's technically an Early Access eBook for now but it's the full text of the book basically as it will appear in print later this year):
https://nostarch.com/fun-python-projects
And you can find the full source code to the emulator (and all the other projects in the book) on the book's GitHub repository:
https://github.com/davecom/FunComputerS ... tsInPython
In short, this is the tutorial I wish I had when I was learning NES emulator development. I hope you enjoy it and it helps you improve your understanding of the discipline. I'm happy to answer any questions that folks have.
Best,
David
My new book, Fun Computer Science Projects in Python, that was just released today with No Starch Press, includes a chapter (Chapter 6) on how to write a very simple NES Emulator in Python. To my knowledge, I believe this will be the first book published by a traditional publisher with a chapter on how to write an NES emulator (someone please let me know if that's wrong!).
Is it possible to do in a single chapter? Yes, the chapter includes the entire source code of the emulator and a quite detailed explanation of the code and enough NES knowledge to understand how the NES's CPU and PPU work. I believe it is a great tutorial on writing an NES emulator. We do however build up to it. The prior chapter covers building a CHIP-8 VM and some of the concepts are elucidated in earlier chapters on how to write simple interpreters.
Why did I write the chapter? Well when I got into writing emulators almost a decade ago I was very frustrated by the lack of complete and high quality tutorials on writing NES emulators. There are more online NES emulation tutorials today than there were back then, but I wanted to make something that was extremely clear, complete to just the right level, and in Python so as to be attractive to many of today's intermediate programmers.
Although it is a working emulator capable of playing included open source games and the simplest commercial ones, it leaves you plenty of room to do your own thing, improve compatibility, and still figure out many puzzles. It's an extremely simple emulator—a starting point. It has a complete CPU (which I actually recommend you mostly write on your own in the chapter although my solution is provided), a greatly simplified PPU that only redraws once per frame and lacks scrolling support, only support for the NROM mapper, and no APU. Plus because it's in pure Python it won't even run at full speed on a modern laptop. So you are left with plenty of ways to expand and learn on this foundation: build an APU, add more features to the PPU, implement other mappers, use Cython or some other means to speed up the code, etc.
These forums and the NESDev wiki were instrumental as I was writing my first NES emulator back in the day. I utilized the NESDev Wiki as my main (in fact almost my only) source for the book. Thanks to its extremely liberal license I was able to reuse some figures from the Wiki and other information. Thank you for that. I guess another way you can think of the chapter is as the ultimate tutorial to the NESDev wiki.
Anyway, the book includes a lot of other interesting projects (BASIC interpreter, abstract art program, CHIP-8 VM, etc.) but I think the NES Emulator chapter is the crown jewel. So, thank you again to this great community for all of its support over the years to myself and so many other emulator authors.
You can buy the book on No Starch Press's website (it's technically an Early Access eBook for now but it's the full text of the book basically as it will appear in print later this year):
https://nostarch.com/fun-python-projects
And you can find the full source code to the emulator (and all the other projects in the book) on the book's GitHub repository:
https://github.com/davecom/FunComputerS ... tsInPython
In short, this is the tutorial I wish I had when I was learning NES emulator development. I hope you enjoy it and it helps you improve your understanding of the discipline. I'm happy to answer any questions that folks have.
Best,
David
Statistics: Posted by davecom — Fri Jan 10, 2025 6:08 pm — Replies 0 — Views 69