Twilight_guy said:
So... its a hex editor with very specific functionality that is pre-programmed? Huh.
Yeah, Game Genie was basically a 6 line (I think that's how many codes you could use) Hex editor that would "freeze" values as defined.
Each code was 8 characters - the last 6 characters of the code were a memory offset, and the first two were the Hex value of that offset. (so, 0-255 for the values)
So, if you wanted infinite lives, you would put in the offset that stored the "lives remaining" variable, and then the value to lock it at. You could come up with your own codes by trying to guess at memory offsets around other codes (randomly or hoping to be near other counters in memory).
Not that anyone cares, but an example from the FF3 codes:
D35C-78E5 Start Terra with Blizzard equipped
F75C-78E5 Start Terra with Enhancer equipped
9A58-7675 Start Terra with Mithril shield equipped
9258-7675 Start Terra with Gold shield equipped
5C-78E5 = Terra's (starting loadout) weapon slot
58-7675 = Terra's (starting loadout) offhand slot
D3 = item code for the Blizzard weapon
9A = item code for the Mithril shield
The fun thing is some games only had one item list, so you could do things like put D3 in the wrong item slot and wear swords on your feet. (I think FF had separate lists for each slot though)