Converting your GameShark gameboy codes to MESS format

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kelvSYC
Posts: 1121
Joined: Thu Sep 27, 2001 1:00 am
Location: Calgary, AB, Canada

Converting your GameShark gameboy codes to MESS format

Post by kelvSYC »

Wow. After all this time, this is the very first MESS cheat post. Cower in fear!

OK. Let's get down to business:

Converting Game Boy Game Shark codes to MESS Format
Requirements: MESS v.61 or MESS built upon the v.61 source from CVS.

Generally, Game Boy Game Shark codes are very easy to convert to MESS format. Of course, this is only a temporary measure - future versions of the MESS cheat engine will automatically convert cheat codes for you through the MESS UI. But right now, this will have to do.

Game Boy Game Shark Codes are very easy to change to the address/value pairs needed for the MESS cheat engine, because the address and value is right in front of your nose, and not encrypted in some gobbledy-gook like Game Sharks for other systems.

Also required is the CRC of your rom, which can easily be found using a conventional utility. The best way to get the CRC is right from a rom-audit utility. This is important since games that are similar may use different codes, in a similar vein to the parent/clone relationship in MAME. For example, Pocket Monsters Blue is different than that of its American equivalent, Pok?mon Blue.

Anatomy of a Game Shark code
A Game Shark code is made up of eight hex digits. The first two is insignificant when MESS is concerned. Often times, Game Shark cheat finders will put 01 or 91 there.

The next two hex digits comprise the value (Game Sharks can only poke one byte at a time). The last four digits comprise the address, in byte-swapped format (I hope I'm using the right terminology). That is, if the last four digits is 1234, the address is 3412.

When a Game Shark code is used, it changes the value to the address to whatever the value is, in a similar fashion to the 00000000 cheat type in the MESS cheat engine.

Anatomy of a MESS code
A MESS cheat code is similar to that of MAME (ie. with colon-separated fields), but between the game name (ie. the name of the system) and the cheat type, you must put the CRC of the game. A CRC of 00000000 means that it will appear in all games of that system.

The Actual Conversion
Now that you've taken apart the Game Shark code and the MESS cheat code, it's time to put them together.

The first field (remember, codes for the new cheat engine START with a colon) is the system name. For the Game Boy, it would be "gameboy" for the original Game Boy, "supergb" for the Super Game Boy, and "gbcolor" for the Game Boy Color (MESS does not support the Game Boy Advance). It is generally recommended to make codes for all three systems in one go. After all, it's just one cart spanning three systems, right?

The second field is the CRC.

The third field is the cheat type. Game Sharks are only capable of the MESS equivalent of 00000000, and sometimes they tell you to "turn the Game Shark on and off quickly", indicating a one-shot cheat (the equivalent of 00000001).

The fourth field is the address. Put that in.

The fifth field is the value. Put that in.

The sixth field is the name. Make it up.

The seventh field (optional) is a comment. If necessary, make it up.

You now have a complete cheat. For non-Mac versions of MESS, place your gameboy cheats into "cheat/gameboy.dat", your sugergb cheats into "cheat/supergb.dat", and your gbcolor cheats into "cheat/gbcolor.dat" and reload the cheat database. For Mac versions of MESS, throw them all in "Misc Support Files/cheat.dat" (A quick fix is in the works so that cheat files are segregated by system, like other versions of MESS. When that fix comes, place the cheats in their system .dat files inside the Cheats folder).

And thus you have converted a Game Shark code to a MESS code.
kelvSYC's Guide to the Cheat Engine - http://members.shaw.ca/kelvsyc/cheatguide.html

The New Move List Cheat Collection - http://mamecheat.co.uk/forums/viewtopic.php?p=6469

Underscore Command - What better game is there?
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