Kjetil's Information Center: A Blog About My Projects

lazyboNES Emulator FDS Support

The lazyboNES emulator has been updated to support the Famicom Disk System. This is needed to be able to run Super Mario Bros 2, only released in Japan on disk format. The graphics in SMB2 is similarly structured to SMB1 so only a few changes were needed on that part to be able to support it in lazyboNES.

The changes are incorporated in version 0.5 and has also been pushed to the GitHub repository. This update also contains the unannounced version 0.4 changes which is mostly increased compatibilities with the CPU emulation. Also some compile time defines have been removed and presented as command line options, notably the ability to switch on and off the SDL2 or console graphics.

The lazyboNES emulator is still heavily tied to Super Mario Bros on the NES and SMB2 is the only FDS-based game that has been tested. A hack was implemented in the PPU code to delay the NMI by two scanlines in order to fix a problem where part of the status bar in SMB2 was getting scrolled. SMB1 still works with this hack, but it might break other games.

Here is a screenshot for reference:

lazyboNES running Super Mario Bros 2

A YouTube demo video has also been uploaded.

Topic: Open Source, by Kjetil @ 17/04-2023, Article Link