Creating Codes?

[originaljoker00]

I downloaded this program along with ePSXe because someone told me that you could create codebreaker codes for your games to use on your regular playstation. Can anyone explain how to do this to me or point me in the right direction. For instance, I'm playing FFVII and want to set my parties maximum HP to a number other than 9999 how would I go about doing that. Any help would be appreciated.

[Satori]

[pec]chu, the [pec]cheat hacking unit, is a feature of the [pec] plugin only, so you will need to use the ePSXe if you want to hunt down new addresses with it. However, you may not need to.

If you have codes already, as you hint, and only want to modify them, you probably will not need to use [pec]chu. The Final Fantasy games in particular are heavily documented in that regard -- you can find lists of known addresses on many websites, as well as umpteen hundred complete codes. Changing an existing GameShark code, or using the address lists to create your own new code, will be very easy once you understand the code syntax.

A GameShark style code can be simply a statement: "set the value at address x to value y." Or it can stipulate conditions, using an "if, then" structure; i.e. "if the value at address a equals b, then set the value at address x to y." A common code is to find the address that registers the state of an input trigger (a button press) and link that to such a code, so that pressing a button sets a value in the game. From your nick, I assume that you may know this -- it being referred to as a "joker." And it gets more elabourate as your hacking skills advance -- the code format is a simple programming language of sorts.

PSX GameShark codes have the following structure:

NNXXXXXX YYYY

NN is the code command, XXXXXX is the memory address, and YYYY is the code value. It's all hexadecimal.

You have a lot of options for how to shuffle numbers around with GS codes. There is even a command to optimize long codes that effect many addresses so they can be entered faster on a real GS unit. Here are the available code types:

80-XXXXXX YYYY - 16-Bit Constant Write
30-XXXXXX 00YY - 8-Bit Constant Write
10-XXXXXX YYYY - 16-Bit Increment Once
11-XXXXXX YYYY - 16-Bit Decrement Once
20-XXXXXX 00YY - 8-Bit Increment Once
21-XXXXXX 00YY - 8-Bit Decrement Once
50-00AABB CCCC - Serial Repeater
C0-XXXXXX YYYY - 16-Bit Master Code
C1-XXXXXX YYYY - Activate Codes On Delay
C2-XXXXXX YYYY - Copy Bytes Code part 1
80-ZZZZZZ 0000 - Copy Bytes Code part 2
D0-XXXXXX YYYY - 16-Bit If Equal To
D1-XXXXXX YYYY - 16-Bit If Not Equal To
D2-XXXXXX YYYY - 16-Bit If Less Than
D3-XXXXXX YYYY - 16-Bit If Greater Than
D4-000000 YYYY - 16-Bit Universal Joker
D5-000000 YYYY - 16-Bit All Codes On
D6-000000 YYYY - 16-Bit All Codes Off
E0-XXXXXX 00YY - 8-Bit If Equal To
E1-XXXXXX 00YY - 8-Bit If Not Equal To
E2-XXXXXX 00YY - 8-Bit If Less Than
E3-XXXXXX 00YY - 8-Bit If Greater Than

The difference between 8 and 16 bit codes is that an 8bit code only affects a two digit (hex) value. Many PSX games use 16bit slots for everything, but some cramp lots of registers together in 8bit slots. RPG games commonly do this with stat lists. You'll have to use 8bit codes for those things.

The D* and E* codes are the "if statements" and the rest are mostly "thens."

The C* codes are a little weird, but you will figure them out if you ever need them.

The 50 code (serial repeater) is the one that allows you to modify many addresses with a short code, as it is used to fill ranges of memory addresses with the same value.

Use the chart to interpret some of the codes you currently have. Once you are able to "read" existing codes, it will be a cinch to start making your own. And then, if you ever run into a situation where you need to find an address yourself, you can fire up [pec]chu and start hunting.


*edit:

Here is a very useful document on the subject, going way beyond what I said. It might be scary-looking if you are new to the subject, but don't sweat it. It's really not so complicated.