I don't have a great single resource unfortunately. I'd like to put up a web page about it at some point.

This is the github repo that contains everything: https://github.com/jes/scamp-cpu/ - some of the stuff under "doc/" might be what you're after (but some of it is just incoherent ramblings).

I have some blog posts here: https://incoherency.co.uk/blog/tags/cpu.html

And there is a video here, but it's not really very informative: https://www.youtube.com/watch?v=4sBB0iD6XvI