This is marvelous. Thank you! I have copies of the two Motorola manuals, and they are comprehensive and quite useful. The OP is tremendously helpful as well be

This is marvelous. Thank you! I have copies of the two Motorola manuals, and they are comprehensive and quite useful. The OP is tremendously helpful as well because it's a bit higher level. Now I can flip between the manual for opcodes and the tutorial for assembler names and contextual understanding. I'm excited to dig into this thread as well. There's a lot here that looks fascinating. Particularly the microcode exploration, the reference on the sound chip, and the interrupt handling. Not to mention timing information. I haven't gotten much further in my experimentation than rudimentary execution of a few opcodes, and have mostly been floundering around trying to make the code and project feel ergonomic. I'm discovering (and expected) that there is quite a lot of stuff you want to set up early on in a project like this. Mainly debugging and other sundry tooling. I'm away from my laptop, but I'll try to post the code somewhere tomorrow.