Same here, got my Atari 400 (with the membrane keyboard) and wrote so many games, then later utility programs, machine code routines, and not long after macro a

Same here, got my Atari 400 (with the membrane keyboard) and wrote so many games, then later utility programs, machine code routines, and not long after macro assembler. In no time, we were exposed to FFI (calling machine code routines) and internals (like BASIC program/token storage to make a line renumbering utility), and all the hardware interface memory locations. Learning how software copy-protection worked and defeating it was a great reverse-engineering/debugging passtime. We were always reading about new tricks and sharing with each other who had the same machines. Getting a copy of the "De Re Atari" document was the holy grail where we felt like we had access to know everything, and we mostly did. I even tried as a kid to make a multitasking 'game' which failed because I didn't know enough about interrupt handlers, but I was close--it worked, briefly.