6502: Playing Chess on the VS Code db65xx Debugging Extension

I like trying out new programs on things I build and doing so on my VS Code db65xx debugging extension is no exception. I found a fun little chess program by Oscar Toledo that was easy to port to cc65 and needed only a few I/O modifications to get running on db65xx.

It doesn’t play a great game of chess but with the debugging support of db65xx it might be interesting to see if I can boost its playing strength.

Playing chess on db65xx

Here are the moves for the game above (note moves are entered in long algebraic notation, for example, e2e4 for the first move):

1. e4      Nc6
2. Bc4     Nb4
3. Qh5     Nxc2+
4. Kd1     Nf6
5. Qxf7++

Not a very great chess engine, but hey, the code and data fit in only 256 bytes (along with some zero-page usage).


├ôscar Toledo, the program’s author gave me permission to post the ported version. You can find it in my db65xx example projects repository.