Sample code is provided in the src folder, with one file corresponding to each chapter.
The code is based on Ben Eater's code, and can be assembled with the same kind of command:
vasm6502-oldstyle -Fbin -dotdir <filename>
I'm using local labels, but hopefully it's clear enough how they work - if not, refer to the vasm documentation.
The LCD control code is Ben's and won't be discussed here.