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PP copier glitch: Difference between revisions
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(Created page with "{{incomplete|1=Mechanics for specific corruptions}} The '''PP copier glitch''' is a buffer overflow glitch which occurs in Generation I when the game attempts to draw "PP" on the screen over four times, due to corruption of CD6C (wNumMovesMinusOne). Though this situation is usually impossible, it can occur when: *CD6C is corrupted (e.g. with a specific Brock Through Walls) *The player has a Pokémon with - as the top move...") |
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{{incomplete|1=Mechanics for specific corruptions, more information on what the relevant routine does}}
The '''PP copier glitch''' is a [[buffer overflow]] glitch which occurs in [[bp:Generation I|Generation I]] when the game attempts to draw "PP" on the screen over four times, due to corruption of CD6C (wNumMovesMinusOne). Though this situation is usually impossible, it can occur when:
*CD6C is corrupted (e.g. with a specific [[Brock Through Walls]])
*The player has a Pokémon with [[AttackDex/RB:000|-]] as the top move (e.g. with Ditto and the [[swapping Transform moves glitch]]). This makes the game skip changing CD6C to the usual number of moves.
This glitch appears to write "PP" in unrelated memory addresses, allowing for side effects like the corruption of Pokémon nicknames (which could potentially be used to get an [[unterminated name Pokémon]] and stats, without corrupting the player's name.
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*The player must have a [[Rival's effect]] item such as [[ItemDex/RB:148]]. To do that, a glitch such as [[item duplication glitch]] for a x255 stack and [[dry underflow glitch]] is necessary.
*The Pewter Gym guide must be preserved (the player can skip him with the [[Pewter Gym skip glitch]]).
*The player's PC box should have no 0xFF bytes for the first 5 Pokémon (so Pokémon with 255 as the catch rate by default such as Pidgey and Rattata should be avoided).
*The sixth Pokémon in the PC box must have specific PP for move 3, corresponding with the desired number of PPs to copy on the screen. A [[PP underflow glitch (disambiguation)|PP underflow glitch]] can be used to get a value of 255 (then 254 after one use of the move).
*The player must have the Pokémon with - as the top move.
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*Change boxes to save the game, then reset the game to avoid a freeze.
*Manipulate wCurMapTileset (D367; item 37 quantity) to a value that allows leaving the map with Escape Rope (e.g. 03). Though the animation might be glitched and lag, this can be used to escape the map. If Fly flags were corrupted, attempting to Fly away may be impossible due to the [[unterminated Fly destinations]] glitch.
==Explanation==
[https://github.com/pret/pokered/blob/2954013da1f10e11db4ec96f9586b7c01706ae1a/engine/pokemon/status_screen.asm The relevant subroutines in the Pokémon Red disassembly can be found here].
==YouTube video==
{{YouTube|wthNjgJ0bCk|ChickasaurusGL}}
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