ASLR

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ASLR (Address space layout randomization) is the name given for a mechanic in Pokémon games such as Pokémon FireRed and LeafGreen, Pokémon Emerald and the Generation IV games.

In Generation III

ASLR will randomize the locations of specific chunks of memory addresses (such as party and stored Pokémon data) to one of 64 possible locations every time the player performs an action such as entering/leaving a building, opening a menu or entering battle.

This offers a form of memory protection, however a cheating device may be used to circumvent the protection, for example a Game Boy Advance GameShark may be used to make a temporary patch of the game's ROM (similar to the Game Genie) which disables the DMA system. Codes to circumvent the system are commonly known as Anti-DMA codes.

In the Pomeg corruption glitch

In Pokémon FireRed and LeafGreen and Pokémon Emerald, the ASLR is abused in the Pomeg corruption glitch to randomly have a chance of setting bit 0 and 2 (+03h) or bit 6 (+40h) to a memory address which the player desires to corrupt, such as setting bit 6 of the most significant byte of DOTS or SEASOR's personality value (with the help of a corruption initiator) to convert it into another Pokémon based on its EVs.

Without the DMA system the player would only be able to create the same corruptions each iteration of the scrolling.

In Pokémon Diamond/Pearl ASE/ACE

When performing ASE/ACE, the ASLR should be accounted for. Currently the Japanese community has made some advancements to avoid it.[1]

References

See also

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