W65C816

An emulator for Western Design Center's W65C816S, a 16-bit derivative of the WDC W65C02S, which is itself a derivative of the MOS 6502.

I'm developing this as there doesn't appear to be any existing standalone '816 cores in Rust, and certainly not at the level of emulation I'm doing (though we can go deeper!). For other programming languages, 816 cores seem pretty sparse, and as far as I know, none provide a bus-accurate cycle-accurate emulator with all signals.

Warning

This emulator is very WIP and is not complete. Less than 60 instructions are missing, but quite a few addressing modes are missing. Correct instruction behavior has not been verified for many instructions.

The external API is finalized, and you are free to base code off of this with the expectation that it will work at some point in the future.

Current plans:

• continue adding instructions
• continue adding addressing modes
• ensure ABORT is implemented for all instructions
  • ensure ABORT is implemented correctly (check with a real '816)
• tests, tests, and more tests
  • ideally generate tests from a real '816.

I am not providing a table showing currently implemented instructions due to the effort involved. You'll either have to open src/instructions.rs and look at the table there or just run some code and see if it panics. Not a great solution, I know. At some point all of the instructions will be implemented so this won't be a problem.