How to hack/mod arcade games/roms?

Joined
Sep 3, 2011
Messages
315
Reaction score
15
Location
Florida
I've tried searching google but nothing of use is coming up.
I am fairly good with C+ but I am not totally sure how video games were/are even made?
Anyone have any experience or know of where I could find any information?
 
Arcade game info is mainly written in hex code that the onboard processors interpret and use to display the game info in the form of audio and video. You have to use a program like WinHex or something similar to view and change the code. That's how I moded MK1's Turbo Ninja's projectiles...








It's really not that hard once you learn how to do it and how to read and interpret the code so you know what to change. Does that answer your question?


:)
 
Rom hacks fall into two broad catagories: data hacks, and code hacks.

Of data hacks, graphics hacks are most common. However, text hacks and sound hacks would also fall into the same catagory, and level/map/maze data type hacks. These are generally easier to accomplish.

Code hacks, of course, actually involve modifying the code executing in the game. No matter what language was used in the development of a game, all you have is the actual machine language. So the first step is to determine which processor was used, and get familiar with it's architecture and opcodes (instruction set). Then find a memory map of the game, if possible. Then start up MAME from the command line using the "-debug" option. Read up on use of the debugger in MAME. A good example is described in detail here: http://www.paladingrp.com/brianb/rom_hacks/ikari.html
 
Excellent overview by Darren!

"mame -debug" is so incredibly useful for figuring out what is going on in memory when a game is running. Is fun and useful to look at the mame memory map for a game, figure out where video RAM is, and watch it while the game is running. I've used this before to figure out which ram chips are bad in games, etc. by writing values into memory in Mame until I figure out which locations are messed up.
 
Back
Top Bottom