The emulator requires Python 3.10 or later. The assembly written in this repository requires dasm because it's the easiest one I could find to install on my laptop when I started this project.

• The uv Python package manager
• Python 3.10 or later
• dasm if you want to compile the assembly code contained in the repository

The dasm settings are pretty straightforward. The output needs to be written raw (-f3) which is why we need to change the default format (-f1) which adds a two-byte origin in little-endian order (as per the documentation). We set the origin manually in code, so this extra information isn't really needed. For more information, check out the dasm documentation.

$ dasm hello_world.asm -f3 -ohello_world.out

The bus is built, but I need to clean it up a bit and document how you attach things to it. For now, you can create custom BusObjects and attach them to the main bus. There are also two pre-created BusObjects: RAM (BusRam) and ROM (BusRom). Also, you can attach the same object to the bus at a different location by setting the mirror option to True when attaching it to the bus.

All of the undocumented/illegal opcodes have been implemented except for the unstable ones (ANE, LXA, SHA, SHX, SHY, TAS). These will likely stay unimplented due to the complexity of even trying to simulated some of the potential issues they cause. Testing for undocumented/illegal opcodes will have to wait until I have the ability to either find a very accurate emulator to test my results against or building an actual MOS6502 testbed.

The project uses pytest to run through all of the tests in the tests directory. This is currently the sole external dependency of the project, and can be installed uv sync.

To run all of the tests, simply run pytest at the root of the repository.