Can anyone point me to some documentation on making your own Game Genie codes? I've been searching the net for hours, but the only sites I've found were either dead, or the Game Genie Creators Club. None of the links on their site work either...

Thanks
- Tim

I found a site, gscentral.com that has some documents, but I haven't read them yet. Hopefully you guys can supply me with more.

There are some ROM address to GG code converters here on the site.

But it can be tricky to come up with a code that does exactly what you want it to do, generally you'll need to look at the game's code (which requires some familiarity with 6502 assembly).

I find it pretty amazing that Codemasters actually wrote such a huge book with all those codes. They must've had some good way of creating codes that I don't know about.

if like datel's action reply, then they had a cheat finder module, which you played so long i game and when something happened like dying (for finding life cheat, which was easiest) then press reset and it'll list a load of codes - hopefully a couple and you look for value you want, but sometimes it was trial and error, and then did't work (i guess it monitored memory, and listed recently changed memory locations)

Action Replay seems to modify RAM. At least I think so, just from looking at a list of codes.

Game Genie modifies ROM (only up to 3 bytes). So you need to know where it loads a certain value from, instead of where it saves it.

Using NESten's cheat finder to find where it stores a certain value, and the debugger to see when/where it loads that value might be one way to make a GG code.

Thanks for the input guys, although I actually want to create my own codes, for the fun of it! I like playing around in Hex, and I am fairly familiar with the 6502 (Read Rodnay Zaks: Programming the 6502) but I am active duty military, and I'm in Iraq. I don't have time to write entire games or demos right now, but I have time to play around in Hex and have some fun!

Later!

Well, I found a bunch of documents about making Game Genie codes at http://www.angelfire.com/games2/codehut/ They are all very well written and easy to understand. Unfortunately, when it actually comes to changing the HEX addresses to GG codes, they use a utility to do it. I'm glad this utility exists, and I downloaded it, but I would prefer to know how it's done before I resort to using a program to do it. Any ideas? Please don't tell me I'm going to have to reverse the PC utility myself and try to translate the algorithm from x86 assembly to english :)

Thanks
- Tim

Yeah, those are some interesting docs. I might have to put those on the site.

Maybe there's another doc I haven't seen, but this is the only one about GG encoding that I know of:
http://nesdev.parodius.com/nesgg.txt

One thing to keep in mind is that GG codes work on the actual address in the ROM. So while the NES sees everything at $8000-$FFFF, the equivalent GG addresses are at $0000-$7FFF.

You might also want to try http://www.dragoneyestudios.net
They have a custom build of FCEU which has a great debugger included. Also, in their "documents" section there are a couple of tutorials on how to use it.