From HacDC Wiki
Some links to get us started:
git repository for work so far is at git://git.cluephone.com/atari8/spaceinvaders/
- documentation of the atari 800
get and install cc65, etc.
* description of the various tools included in the package
Set up your info file:
jason started with the example info file from the cc65 website http://www.cc65.org/doc/da65-4.html#ss4.7
** notes about setting up your info file tell the DA what is code, what is a bytetable, what is a list of addresses tell the DA about the labels you are aware of
iterative process of creating this info file as you learn more about the program
eventually naming functions, etc.
disassemble your ROM
da65 --start-addr 0xa000 Space\ Invaders.rom --comments 3
re-assemble your ROM
first time, this should be from the base output from the disassembly subsequent assemblies will include changes that you made to the ASM in your quest for information