Museum of the Game® & International Arcade Museum® Forums
Sorry if this has been covered, I searched a bit and didn't find anything.
I've been working on a few free play with attract mode ROMs and I've ran across a few games that have me stumped. I'm not strong with assembly, but I can usually stumble around enough to make something work. On most games I can find all the switch inputs in RAM and can bumble-screw my way through the hacks using those address. But I've ran across a few games where I just can't find where the programs are checking for inputs from the coin switches. I can see the joysticks, "fire" buttons, and start buttons in RAM... but not the coin switches. Seems to be mainly Universal games, but there's also at least 1 Midway game (Solar Fox) where I can see everything else in RAM, but just not the coin switches.
For example; in Lady Bug I can see the control panel inputs at around $9000, but the coin switches don't show up there, or seemingly anywhere else. With Solar Fox I can see the coin switches in IO Space Memory in MAME's debugger, but again, I'm not strong with assembly and I'm not sure what what checks I should be looking for in the code for that area of memory.
Any one have any tips or tricks for finding where some games are looking for these inputs?
I've been working on a few free play with attract mode ROMs and I've ran across a few games that have me stumped. I'm not strong with assembly, but I can usually stumble around enough to make something work. On most games I can find all the switch inputs in RAM and can bumble-screw my way through the hacks using those address. But I've ran across a few games where I just can't find where the programs are checking for inputs from the coin switches. I can see the joysticks, "fire" buttons, and start buttons in RAM... but not the coin switches. Seems to be mainly Universal games, but there's also at least 1 Midway game (Solar Fox) where I can see everything else in RAM, but just not the coin switches.
For example; in Lady Bug I can see the control panel inputs at around $9000, but the coin switches don't show up there, or seemingly anywhere else. With Solar Fox I can see the coin switches in IO Space Memory in MAME's debugger, but again, I'm not strong with assembly and I'm not sure what what checks I should be looking for in the code for that area of memory.
Any one have any tips or tricks for finding where some games are looking for these inputs?