Documentation of the 6502/6510/8500/8502 instruction set from a Commodore 64 emulator. I don't know where this originally came from, though the addresses of the authors are in the document itself.
Or, Why my emulator doesn't work quite the way it should.
Lots of stuff about lots of stuff. All in PostScript, though.
I haven't a clue who originally authored this text.
I don't know the origin of this document either.