[TOTW #2] Basic Jokering Tutorial

**-LeetGamer-** · 09-24-2010, 04:38 PM

Tutorial: How to joker a code
Credit: -LeetGamer-

I recomend that you read the intire guide before trying anything. If you have any questions read over the guide one more time before PM-ing me or posting a reply, most likely I said something that will clear it up for you in this guide.

Before reading this guide I am expecting that you know:

- Exact Value Searching
- Unknown Value Searching
- Text Searching
- Single Level DMA
- How to write a basic subroutine such as this:

Code:

Lui t0 $XXXX
Lui t1 $XXXX
Addiu t1 t1 $XXXX
Sw t1 $XXXX(t0)
Jr ra

Some of those are not NEEDED to know for this tutorial but they will help.

First of all you need to know what a joker is: A joker is a code that does something when you press a button. Now when learning this

it might take you a few tries, it took me like two months :P but hopefuly this guide will help you!

Basic Information:

Spoiler

You will be learning some MIPS commands:

Lui
Addi
Bne
Beq
Nop
Lw
Sw
Jr
J

You can learn them here:

Spoiler

You will also need to know some basic registers, think of registers as a box that can hold a value for you, here is the list:

zero
t0
t1
t2
t3
t4
t5
t6
t7
t8
t9
ra

Now the zero register will always hold the value 0, this can not be changed. The temporary registers (t0 - t9) will hold a value that

we want them to, until we put a value into them there value is 0. The return address register (ra) is going to hold a memory address,

this memory address is the address below are hook, which calls are subroutine, I will be going over this later.

So all a joker really is is this:

- Get current value from controller address
- Load a button value into a register
- Check if they equal, if not go to the end of the subroutine, if they do continue on here:
- Activate a code, or turn a code off, or what ever you want to do really
- End the subroutine

Doesn't seem so hard right? Well it's not really. Now if this is your first jokering tutorial you might not know what a controller

address is, well a controller address is a memory address in games that functions use to see what button you are pressing. In most

games there will be one controller address for all buttons, but in some games such as the Star Wars Battlefront series there are a

memory address for each button. Now let's say that you are using a game with only one controller address, it's value can be a few

different things, and each value represents a button. In most games with one controller address the button values are these:

Select button = 0x00000001
Start button = 0x00000008
Up D-Pad button = 0x00000010
Right D-Pad button = 0x00000020
Down D-Pad button = 0x00000040
Left D-Pad button = 0x00000080
Left trigger = 0x00000100
Right trigger = 0x00000200
Triangle button = 0x00001000
Circle button = 0x00002000
Cross button = 0x00004000
Square button = 0x00008000

Now how do you find your controller address? Simple:

Games with one controller address and the normal button values:

Spoiler

Games with one controller address but not normal button values:

Spoiler

Games with a controller address for each button:

Spoiler

Now in some games if you set the value to 0x200 or what ever the value is for the R button you might not get the result of normally

pressing the R button. This doesn't mean that that address is not your controller address. All a controller address has to do is have a value change when you stop/start pressing a button.

Now we are going to start writing are subroutine, earlyer I said:

- Get current value from controller address
- Load a button value into a register
- Check if they equal, if not go to the end of the subroutine, if they do continue on here:
- Activate a code, or turn a code off, or what ever you want to do really
- End the subroutine

Well here is ONE way of doing that in MIPS:

Lui t0 $XXXX // Upper controller address in true addressing
Lw t0 $XXXX(t0) // Lowe controller address
// t0 now holds the current value in the controller address
Addi t1 zero $XXXX // Button value that you want to use to turn your code on
// t1 Now holds are button value
Bne t0 t1 ${Address of the "JR RA" line}
Nop
// This is saying: if we are not pressing the button jump to the jr ra line.
// All you have to do is copy the address that the jr ra is on and paste it after the $
// I leave this at 0 before until I finish my subroutine
// Now we are going to make a code activate
Lui t2 $XXXX // Upper code address in true addressing
Lui t3 $XXXX // Upper code value
Addi t3 t3 $XXXX // Lower code value
Sw t3 $XXXX(t2) // Lower code address
// Now are code will activate
Jr ra
// This is going to goto the address in the ra register, which is right after our subroutine call (aka our hook)
// Just think of this as ending the subroutine

Make sure to check the MIPS explinations that I posted above. Here is an example for Medal of Honor Heroes (ULUS-10141)

Code:

#Exit Game Joker
;TheEliteOne aka -LeetGamer-
;Press Left to exit the game.
0x00339D78 0x0A2A21AC
0x002886B0 0x3C0808d4
0x002886B4 0x850842B0
0x002886B8 0x34090080
0x002886BC 0x15280003
0x002886C4 0x0E324Add
0x002886CC 0x03E00008

That is a code to exit to the home menu, it is a good example of a joker.

So in this tutorial we have gone over how to make a "joker" and that joker will turn on one code when we press a button. Now we can add as many codes in there as we want, example:

Spoiler

If you want an example of another type of joker besides a simple one button turn code on type reply to this thread and I will let you know how.

Subroutine Calls and Our Hook:

Spoiler

Well that is it for this tutorial, if you need any help please PM me or reply to this thread.

-Leet