The game program/ROM essentially tells the system how the game is played. Since these ROM chips contain the game, sometimes we use the terms 'game program' and 'ROM' interchangeably. In a video game system, the data for the game is encoded in a number of Read-Only Memory (ROM) chips, on a circuit board, which we call the cartridge. James' answer to this question goes into some detail about the more 'modern' approach to this problem.

I believe more modern devices follow a similar principle, but are far more advanced. Source: Game hacker since 1999, founder of įor the purposes of this, I'm assuming we're talking about the 'classic' GameShark/GameGenie devices, which sit between the cartridge and the hardware. There is plenty more info we could dive into, but that should give you a good basis for understanding. (how many lines it executes is up to the enhancer and often is an option in the codetype itself!) IF the comparison returns true, then the CodeHander will execute the next line in the code. With Conditionals, the CodeHander reads the value at the code's address and compares it to the value in the code. (changing whatever was there, like setting your health to 100!)Ĭonditionals (typical options are >, <, =, !=) With RAM Write, the CodeHandler will take the value and place it at the address. RAM Writes (typical options are 8bit, 16bit, or 32bit)

The value the codetype will use at the specified address.The address in ram that the CodeType will use.The CodeType (this is USUALLY the first byte of the code- the first 2 Hex Characters).

Now a code itself is separated into THREE parts: (other enhancers - like Gecko OS for Wii - don't need master codes because the enhancer itself has a handful of SDK-based hooks that it can 'find' in the game while it loads.) Structure of codes If you are familiar with GameShark's ' Master Code', that is what sets the hook. Once the Code Handler is finished executing, it returns the flow of programming back to the point of hijacking. What the hook actually does is redirect the flow of programming to the Code Handler the enhancer left behind. (because SDKs are used, this makes finding hooks that work in all games for a system much easier) Specific locations in a game's programming that get executed roughly every frame (like reading the controller data) are where 'hooks' will be placed. In doing so, it leaves behind a Code Handler in the system RAM and ' hooks' the game's programming. When GameShark (and other game enhancer products/homebrew) gets loaded by the console, the enhancer is what launches the actual game.

Gba emulator mac works with gameshark