For anyone who wants non-paper versions of stuff like this (focused on Amiga and 8-bit Commodore computers, but there's also a bunch of more generic stuff, and 6502/68000 material): http://www.bombjack.org/commodore/
Also, the M68k programming manuals should still be downloadable from FreeScale (what used to be Motorola's semiconductor division). At least they were when I looked for the last a year ago or so. They are wonderfully clear and detailed.
For sure! I really got my programming feet wet writing programs in Z80 assembly for my TI-83 graphing calculator as a middle schooler. A few years later I dabbled a bit in 68k when I got a TI-89.
Also, the M68k programming manuals should still be downloadable from FreeScale (what used to be Motorola's semiconductor division). At least they were when I looked for the last a year ago or so. They are wonderfully clear and detailed.