mirror of
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1537 lines
37 KiB
Markdown
1537 lines
37 KiB
Markdown
# Bugs and Glitches
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These are known bugs and glitches in the original Pokémon Crystal game: code that clearly does not work as intended, or that only works in limited circumstances but has the possibility to fail or crash.
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## Contents
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- [Thick Club and Light Ball can decrease damage done with boosted (Special) Attack](#thick-club-and-light-ball-can-decrease-damage-done-with-boosted-special-attack)
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- [Metal Powder can increase damage taken with boosted (Special) Defense](#metal-powder-can-increase-damage-taken-with-boosted-special-defense)
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- [Belly Drum sharply boosts Attack even with under 50% HP](#belly-drum-sharply-boosts-attack-even-with-under-50-hp)
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- [Confusion damage is affected by type-boosting items and Explosion/Self-Destruct doubling](#confusion-damage-is-affected-by-type-boosting-items-and-explosionself-destruct-doubling)
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- [Moves that lower Defense can do so after breaking a Substitute](#moves-that-lower-defense-can-do-so-after-breaking-a-substitute)
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- [Counter and Mirror Coat still work if the opponent uses an item](#counter-and-mirror-coat-still-work-if-the-opponent-uses-an-item)
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- [A Disabled but PP Up–enhanced move may not trigger Struggle](#a-disabled-but-pp-upenhanced-move-may-not-trigger-struggle)
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- [A Pokémon that fainted from Pursuit will have its old status condition when revived](#a-pokémon-that-fainted-from-pursuit-will-have-its-old-status-condition-when-revived)
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- [Lock-On and Mind Reader don't always bypass Fly and Dig](#lock-on-and-mind-reader-dont-always-bypass-fly-and-dig)
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- [Beat Up can desynchronize link battles](#beat-up-can-desynchronize-link-battles)
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- [Present damage is incorrect in link battles](#present-damage-is-incorrect-in-link-battles)
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- ["Smart" AI encourages Mean Look if its own Pokémon is badly poisoned](#smart-ai-encourages-mean-look-if-its-own-pokémon-is-badly-poisoned)
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- [AI makes a false assumption about `CheckTypeMatchup`](#ai-makes-a-false-assumption-about-checktypematchup)
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- [NPC use of Full Heal or Full Restore does not cure Nightmare status](#npc-use-of-full-heal-or-full-restore-does-not-cure-nightmare-status)
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- [HP bar animation is slow for high HP](#hp-bar-animation-is-slow-for-high-hp)
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- [HP bar animation off-by-one error for low HP](#hp-bar-animation-off-by-one-error-for-low-hp)
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- [Experience underflow for level 1 Pokémon with Medium-Slow growth rate](#experience-underflow-for-level-1-pokémon-with-medium-slow-growth-rate)
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- [Five-digit experience gain is printed incorrectly](#five-digit-experience-gain-is-printed-incorrectly)
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- [BRN/PSN/PAR do not affect catch rate](#brnpsnpar-do-not-affect-catch-rate)
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- [Moon Ball does not boost catch rate](#moon-ball-does-not-boost-catch-rate)
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- [Love Ball boosts catch rate for the wrong gender](#love-ball-boosts-catch-rate-for-the-wrong-gender)
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- [Fast Ball only boosts catch rate for three Pokémon](#fast-ball-only-boosts-catch-rate-for-three-pokémon)
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- [Dragon Scale, not Dragon Fang, boosts Dragon-type moves](#dragon-scale-not-dragon-fang-boosts-dragon-type-moves)
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- [Daisy's grooming doesn't always increase happiness](#daisys-grooming-doesnt-always-increase-happiness)
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- [Magikarp in Lake of Rage are shorter, not longer](#magikarp-in-lake-of-rage-are-shorter-not-longer)
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- [Magikarp length limits have a unit conversion error](#magikarp-length-limits-have-a-unit-conversion-error)
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- [Magikarp lengths can be miscalculated](#magikarp-lengths-can-be-miscalculated)
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- [Battle transitions fail to account for the enemy's level](#battle-transitions-fail-to-account-for-the-enemys-level)
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- [A "HOF Master!" title for 200-Time Famers is defined but inaccessible](#a-hof-master-title-for-200-time-famers-is-defined-but-inaccessible)
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- [Slot machine payout sound effects cut each other off](#slot-machine-payout-sound-effects-cut-each-other-off)
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- [Team Rocket battle music is not used for Executives or Scientists](#team-rocket-battle-music-is-not-used-for-executives-or-scientists)
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- [No bump noise if standing on tile `$3E`](#no-bump-noise-if-standing-on-tile-3e)
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- [Playing Entei's Pokédex cry can distort Raikou's and Suicune's](#playing-enteis-pokédex-cry-can-distort-raikous-and-suicunes)
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- [In-battle “`…`” ellipsis is too high](#in-battle--ellipsis-is-too-high)
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- [Two tiles in the `port` tileset are drawn incorrectly](#two-tiles-in-the-port-tileset-are-drawn-incorrectly)
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- [`LoadMetatiles` wraps around past 128 blocks](#loadmetatiles-wraps-around-past-128-blocks)
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- [Surfing directly across a map connection does not load the new map](#surfing-directly-across-a-map-connection-does-not-load-the-new-map)
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- [`Function6ec1` does not correctly limit object movement](#function6ec1-does-not-correctly-limit-object-movement)
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- [`CheckOwnMon` only checks the first five letters of OT names](#checkownmon-only-checks-the-first-five-letters-of-ot-names)
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- [Catching a Transformed Pokémon always catches a Ditto](#catching-a-transformed-pokémon-always-catches-a-ditto)
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- [Using a Park Ball in normal battles has a corrupt animation](#using-a-park-ball-in-normal-battles-has-a-corrupt-animation)
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- [`HELD_CATCH_CHANCE` has no effect](#held_catch_chance-has-no-effect)
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- [Only the first three `EvosAttacks` evolution entries can have Stone compatibility reported correctly](#only-the-first-three-evosattacks-evolution-entries-can-have-stone-compatibility-reported-correctly)
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- [`EVOLVE_STAT` can break Stone compatibility reporting](#evolve_stat-can-break-stone-compatibility-reporting)
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- [`ScriptCall` can overflow `wScriptStack` and crash](#scriptcall-can-overflow-wscriptstack-and-crash)
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- [`LoadSpriteGFX` does not limit the capacity of `UsedSprites`](#loadspritegfx-does-not-limit-the-capacity-of-usedsprites)
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- [`ChooseWildEncounter` doesn't really validate the wild Pokémon species](#choosewildencounter-doesnt-really-validate-the-wild-pokémon-species)
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- [`TryObjectEvent` arbitrary code execution](#tryobjectevent-arbitrary-code-execution)
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- [`CheckBugContestContestantFlag` can read beyond its data table](#checkbugcontestcontestantflag-can-read-beyond-its-data-table)
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- [`ClearWRAM` only clears WRAM bank 1](#clearwram-only-clears-wram-bank-1)
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## Thick Club and Light Ball can decrease damage done with boosted (Special) Attack
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*Fixing this bug will break compatibility with standard Pokémon Crystal for link battles.*
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([Video](https://www.youtube.com/watch?v=rGqu3d3pdok&t=450))
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This is a bug with `SpeciesItemBoost` in [engine/battle/effect_commands.asm](/engine/battle/effect_commands.asm):
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```asm
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; Double the stat
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sla l
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rl h
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ret
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```
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**Fix:**
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```asm
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; Double the stat
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sla l
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rl h
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ld a, HIGH(MAX_STAT_VALUE)
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cp h
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jr c, .cap
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ld a, LOW(MAX_STAT_VALUE)
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cp l
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ret nc
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.cap
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ld h, HIGH(MAX_STAT_VALUE)
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ld l, LOW(MAX_STAT_VALUE)
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ret
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```
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## Metal Powder can increase damage taken with boosted (Special) Defense
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*Fixing this bug will break compatibility with standard Pokémon Crystal for link battles.*
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([Video](https://www.youtube.com/watch?v=rGqu3d3pdok&t=450))
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This is a bug with `DittoMetalPowder` in [engine/battle/effect_commands.asm](/engine/battle/effect_commands.asm):
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```asm
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ld a, c
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srl a
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add c
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ld c, a
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ret nc
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srl b
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ld a, b
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and a
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jr nz, .done
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inc b
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.done
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scf
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rr c
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ret
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```
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**Fix:**
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```asm
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ld a, c
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srl a
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add c
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ld c, a
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ret nc
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srl b
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ld a, b
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and a
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jr nz, .done
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inc b
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.done
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scf
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rr c
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ld a, HIGH(MAX_STAT_VALUE)
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cp b
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jr c, .cap
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ld a, LOW(MAX_STAT_VALUE)
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cp c
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ret nc
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.cap
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ld b, HIGH(MAX_STAT_VALUE)
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ld c, LOW(MAX_STAT_VALUE)
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ret
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```
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## Belly Drum sharply boosts Attack even with under 50% HP
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*Fixing this bug will break compatibility with standard Pokémon Crystal for link battles.*
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([Video](https://www.youtube.com/watch?v=zuCLMikWo4Y))
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This is a bug with `BattleCommand_BellyDrum` in [engine/battle/move_effects/belly_drum.asm](/engine/battle/move_effects/belly_drum.asm):
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```asm
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BattleCommand_BellyDrum: ; 37c1a
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; bellydrum
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; This command is buggy because it raises the user's attack
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; before checking that it has enough HP to use the move.
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; Swap the order of these two blocks to fix.
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call BattleCommand_AttackUp2
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ld a, [wAttackMissed]
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and a
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jr nz, .failed
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callfar GetHalfMaxHP
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callfar CheckUserHasEnoughHP
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jr nc, .failed
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```
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**Fix:**
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```asm
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BattleCommand_BellyDrum: ; 37c1a
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; bellydrum
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callfar GetHalfMaxHP
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callfar CheckUserHasEnoughHP
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jr nc, .failed
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call BattleCommand_AttackUp2
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ld a, [wAttackMissed]
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and a
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jr nz, .failed
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```
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## Confusion damage is affected by type-boosting items and Explosion/Self-Destruct doubling
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*Fixing this bug will break compatibility with standard Pokémon Crystal for link battles.*
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([Video](https://twitter.com/crystal_rby/status/874626362287562752))
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*To do:* Identify specific code causing this bug and fix it.
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## Moves that lower Defense can do so after breaking a Substitute
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*Fixing this bug will break compatibility with standard Pokémon Crystal for link battles.*
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([Video](https://www.youtube.com/watch?v=OGwKPRJLaaI))
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This bug affects Acid, Iron Tail, and Rock Smash.
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This is a bug with `DefenseDownHit` in [data/moves/effects.asm](/data/moves/effects.asm):
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```asm
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DefenseDownHit:
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checkobedience
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usedmovetext
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doturn
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critical
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damagestats
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damagecalc
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stab
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damagevariation
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checkhit
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effectchance
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hittarget
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failuretext
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checkfaint
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criticaltext
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supereffectivetext
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checkdestinybond
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buildopponentrage
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effectchance ; bug: duplicate effectchance shouldn't be here
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defensedown
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statdownmessage
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endmove
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```
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**Fix:** Delete the second `effectchance`.
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## Counter and Mirror Coat still work if the opponent uses an item
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*Fixing this bug will break compatibility with standard Pokémon Crystal for link battles.*
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([Video](https://www.youtube.com/watch?v=uRYyzKRatFk))
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*To do:* Identify specific code causing this bug and fix it.
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## A Disabled but PP Up–enhanced move may not trigger Struggle
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*Fixing this bug will break compatibility with standard Pokémon Crystal for link battles.*
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([Video](https://www.youtube.com/watch?v=1v9x4SgMggs))
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This is a bug with `CheckPlayerHasUsableMoves` in [engine/battle/core.asm](/engine/battle/core.asm):
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```asm
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.done
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; Bug: this will result in a move with PP Up confusing the game.
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and a ; should be "and PP_MASK"
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ret nz
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.force_struggle
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ld hl, BattleText_MonHasNoMovesLeft
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call StdBattleTextBox
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ld c, 60
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call DelayFrames
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xor a
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ret
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```
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**Fix:** Change `and a` to `and PP_MASK`.
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## A Pokémon that fainted from Pursuit will have its old status condition when revived
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*Fixing this bug will break compatibility with standard Pokémon Crystal for link battles.*
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([Video](https://www.youtube.com/watch?v=tiRvw-Nb2ME))
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*To do:* Identify specific code causing this bug and fix it.
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## Lock-On and Mind Reader don't always bypass Fly and Dig
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*Fixing this bug will break compatibility with standard Pokémon Crystal for link battles.*
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This bug affects Attract, Curse, Foresight, Mean Look, Mimic, Nightmare, Spider Web, Transform, and stat-lowering effects of moves like String Shot or Bubble during the semi-invulnerable turn of Fly or Dig.
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This is a bug with `CheckHiddenOpponent` in [engine/battle/effect_commands.asm](/engine/battle/effect_commands.asm):
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```asm
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CheckHiddenOpponent: ; 37daa
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; BUG: This routine should account for Lock-On and Mind Reader.
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ld a, BATTLE_VARS_SUBSTATUS3_OPP
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call GetBattleVar
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and 1 << SUBSTATUS_FLYING | 1 << SUBSTATUS_UNDERGROUND
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ret
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```
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*To do:* Fix this bug.
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## Beat Up can desynchronize link battles
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*Fixing this bug will break compatibility with standard Pokémon Crystal for link battles.*
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([Video](https://www.youtube.com/watch?v=202-iAsrIa8))
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This is a bug with `BattleCommand_BeatUp` in [engine/battle/move_effects/beat_up.asm](/engine/battle/move_effects/beat_up.asm):
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```asm
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.got_mon
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ld a, [wd002]
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ld hl, wPartyMonNicknames
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call GetNick
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ld a, MON_HP
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call GetBeatupMonLocation
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ld a, [hli]
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or [hl]
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jp z, .beatup_fail ; fainted
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ld a, [wd002]
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ld c, a
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ld a, [wCurBattleMon]
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; BUG: this can desynchronize link battles
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; Change "cp [hl]" to "cp c" to fix
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cp [hl]
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ld hl, wBattleMonStatus
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jr z, .active_mon
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ld a, MON_STATUS
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call GetBeatupMonLocation
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.active_mon
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ld a, [hl]
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and a
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jp nz, .beatup_fail
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```
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**Fix:** Change `cp [hl]` to `cp c`.
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## Present damage is incorrect in link battles
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*Fixing this bug will break compatibility with standard Pokémon Crystal for link battles.*
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([Video](https://www.youtube.com/watch?v=XJaQoKtrEuw))
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This bug existed for all battles in Gold and Silver, and was only fixed for single-player battles in Crystal to preserve link compatibility.
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This is a bug with `BattleCommand_Present` in [engine/battle/move_effects/present.asm](/engine/battle/move_effects/present.asm):
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```asm
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BattleCommand_Present: ; 37874
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; present
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ld a, [wLinkMode]
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cp LINK_COLOSSEUM
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jr z, .colosseum_skippush
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push bc
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push de
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.colosseum_skippush
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call BattleCommand_Stab
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ld a, [wLinkMode]
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cp LINK_COLOSSEUM
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jr z, .colosseum_skippop
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pop de
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pop bc
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.colosseum_skippop
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```
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**Fix:**
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```asm
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BattleCommand_Present: ; 37874
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; present
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push bc
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push de
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call BattleCommand_Stab
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pop de
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pop bc
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```
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## "Smart" AI encourages Mean Look if its own Pokémon is badly poisoned
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([Video](https://www.youtube.com/watch?v=cygMO-zHTls))
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This is a bug with `AI_Smart_MeanLook` in [engine/battle/ai/scoring.asm](/engine/battle/ai/scoring.asm):
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```asm
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; 80% chance to greatly encourage this move if the enemy is badly poisoned (buggy).
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; Should check wPlayerSubStatus5 instead.
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ld a, [wEnemySubStatus5]
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bit SUBSTATUS_TOXIC, a
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jr nz, .asm_38e26
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```
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**Fix:** Change `wEnemySubStatus5` to `wPlayerSubStatus5`.
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## AI makes a false assumption about `CheckTypeMatchup`
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In [engine/battle/effect_commands.asm](/engine/battle/effect_commands.asm):
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```asm
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BattleCheckTypeMatchup: ; 347c8
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ld hl, wEnemyMonType1
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ld a, [hBattleTurn]
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and a
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jr z, CheckTypeMatchup
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ld hl, wBattleMonType1
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CheckTypeMatchup: ; 347d3
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; There is an incorrect assumption about this function made in the AI related code: when
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; the AI calls CheckTypeMatchup (not BattleCheckTypeMatchup), it assumes that placing the
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; offensive type in a will make this function do the right thing. Since a is overwritten,
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; this assumption is incorrect. A simple fix would be to load the move type for the
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; current move into a in BattleCheckTypeMatchup, before falling through, which is
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; consistent with how the rest of the code assumes this code works like.
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push hl
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push de
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push bc
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ld a, BATTLE_VARS_MOVE_TYPE
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call GetBattleVar
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ld d, a
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```
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*To do:* Fix this bug.
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|
||
|
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## NPC use of Full Heal or Full Restore does not cure Nightmare status
|
||
|
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([Video](https://www.youtube.com/watch?v=rGqu3d3pdok&t=322))
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|
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This is a bug with `AI_HealStatus` in [engine/battle/ai/items.asm](/engine/battle/ai/items.asm):
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|
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```asm
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AI_HealStatus: ; 384e0
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ld a, [wCurOTMon]
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ld hl, wOTPartyMon1Status
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ld bc, PARTYMON_STRUCT_LENGTH
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call AddNTimes
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xor a
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ld [hl], a
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ld [wEnemyMonStatus], a
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; Bug: this should reset SUBSTATUS_NIGHTMARE too
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; Uncomment the lines below to fix
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; ld hl, wEnemySubStatus1
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; res SUBSTATUS_NIGHTMARE, [hl]
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ld hl, wEnemySubStatus5
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res SUBSTATUS_TOXIC, [hl]
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ret
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; 384f7
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```
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**Fix:** Uncomment `ld hl, wEnemySubStatus1` and `res SUBSTATUS_NIGHTMARE, [hl]`.
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## HP bar animation is slow for high HP
|
||
|
||
([Video](https://www.youtube.com/watch?v=SE-BfsFgZVM))
|
||
|
||
This is a bug with `LongAnim_UpdateVariables` in [engine/battle/anim_hp_bar.asm](/engine/battle/anim_hp_bar.asm):
|
||
|
||
```asm
|
||
; This routine is buggy. The result from ComputeHPBarPixels is stored
|
||
; in e. However, the pop de opcode deletes this result before it is even
|
||
; used. The game then proceeds as though it never deleted that output.
|
||
; To fix, uncomment the line below.
|
||
call ComputeHPBarPixels
|
||
; ld a, e
|
||
pop bc
|
||
pop de
|
||
pop hl
|
||
ld a, e ; Comment or delete this line to fix the above bug.
|
||
ld hl, wCurHPBarPixels
|
||
cp [hl]
|
||
jr z, .loop
|
||
ld [hl], a
|
||
and a
|
||
ret
|
||
```
|
||
|
||
**Fix:** Move `ld a, e` to right after `call ComputeHPBarPixels`.
|
||
|
||
|
||
## HP bar animation off-by-one error for low HP
|
||
|
||
([Video](https://www.youtube.com/watch?v=9KyNVIZxJvI))
|
||
|
||
This is a bug with `ShortHPBar_CalcPixelFrame` in [engine/battle/anim_hp_bar.asm](/engine/battle/anim_hp_bar.asm):
|
||
|
||
```asm
|
||
ld b, 0
|
||
; This routine is buggy. If [wCurHPAnimMaxHP] * [wCurHPBarPixels] is
|
||
; divisible by HP_BAR_LENGTH_PX, the loop runs one extra time.
|
||
; To fix, uncomment the line below.
|
||
.loop
|
||
ld a, l
|
||
sub HP_BAR_LENGTH_PX
|
||
ld l, a
|
||
ld a, h
|
||
sbc $0
|
||
ld h, a
|
||
; jr z, .done
|
||
jr c, .done
|
||
inc b
|
||
jr .loop
|
||
```
|
||
|
||
**Fix:** Uncomment `jr z, .done`.
|
||
|
||
|
||
## Experience underflow for level 1 Pokémon with Medium-Slow growth rate
|
||
|
||
([Video](https://www.youtube.com/watch?v=SXH8u0plHrE))
|
||
|
||
This can bring Pokémon straight from level 1 to 100 by gaining just a few experience points.
|
||
|
||
This is a bug with `CalcExpAtLevel` in [engine/pokemon/experience.asm](/engine/pokemon/experience.asm):
|
||
|
||
```asm
|
||
CalcExpAtLevel: ; 50e47
|
||
; (a/b)*n**3 + c*n**2 + d*n - e
|
||
ld a, [wBaseGrowthRate]
|
||
add a
|
||
add a
|
||
ld c, a
|
||
ld b, 0
|
||
ld hl, GrowthRates
|
||
add hl, bc
|
||
```
|
||
|
||
**Fix:**
|
||
|
||
```asm
|
||
CalcExpAtLevel: ; 50e47
|
||
; (a/b)*n**3 + c*n**2 + d*n - e
|
||
ld a, d
|
||
cp 1
|
||
jr nz, .UseExpFormula
|
||
; Pokémon have 0 experience at level 1
|
||
xor a
|
||
ld hl, hProduct
|
||
ld [hli], a
|
||
ld [hli], a
|
||
ld [hli], a
|
||
ld [hl], a
|
||
ret
|
||
|
||
.UseExpFormula
|
||
ld a, [wBaseGrowthRate]
|
||
add a
|
||
add a
|
||
ld c, a
|
||
ld b, 0
|
||
ld hl, GrowthRates
|
||
add hl, bc
|
||
```
|
||
|
||
|
||
## Five-digit experience gain is printed incorrectly
|
||
|
||
([Video](https://www.youtube.com/watch?v=o54VjpAEoO8))
|
||
|
||
This is a bug with `Text_ABoostedStringBuffer2ExpPoints` and `Text_StringBuffer2ExpPoints` in [data/text/common_2.asm](/data/text/common_2.asm):
|
||
|
||
```asm
|
||
Text_ABoostedStringBuffer2ExpPoints::
|
||
text_start
|
||
line "a boosted"
|
||
cont "@"
|
||
deciram wStringBuffer2, 2, 4
|
||
text " EXP. Points!"
|
||
prompt
|
||
|
||
Text_StringBuffer2ExpPoints::
|
||
text_start
|
||
line "@"
|
||
deciram wStringBuffer2, 2, 4
|
||
text " EXP. Points!"
|
||
prompt
|
||
```
|
||
|
||
**Fix:** Change both `deciram wStringBuffer2, 2, 4` to `deciram wStringBuffer2, 2, 5`.
|
||
|
||
|
||
## BRN/PSN/PAR do not affect catch rate
|
||
|
||
This is a bug with `PokeBallEffect` in [engine/items/item_effects.asm](/engine/items/item_effects.asm):
|
||
|
||
```asm
|
||
; This routine is buggy. It was intended that SLP and FRZ provide a higher
|
||
; catch rate than BRN/PSN/PAR, which in turn provide a higher catch rate than
|
||
; no status effect at all. But instead, it makes BRN/PSN/PAR provide no
|
||
; benefit.
|
||
; Uncomment the line below to fix this.
|
||
ld b, a
|
||
ld a, [wEnemyMonStatus]
|
||
and 1 << FRZ | SLP
|
||
ld c, 10
|
||
jr nz, .addstatus
|
||
; ld a, [wEnemyMonStatus]
|
||
and a
|
||
ld c, 5
|
||
jr nz, .addstatus
|
||
ld c, 0
|
||
.addstatus
|
||
ld a, b
|
||
add c
|
||
jr nc, .max_1
|
||
ld a, $ff
|
||
.max_1
|
||
```
|
||
|
||
**Fix:** Uncomment `ld a, [wEnemyMonStatus]`.
|
||
|
||
|
||
## Moon Ball does not boost catch rate
|
||
|
||
This is a bug with `MoonBallMultiplier` in [items/item_effects.asm](/items/item_effects.asm):
|
||
|
||
```asm
|
||
MoonBallMultiplier:
|
||
; This function is buggy.
|
||
; Intent: multiply catch rate by 4 if mon evolves with moon stone
|
||
; Reality: no boost
|
||
|
||
...
|
||
|
||
; Moon Stone's constant from Pokémon Red is used.
|
||
; No Pokémon evolve with Burn Heal,
|
||
; so Moon Balls always have a catch rate of 1×.
|
||
push bc
|
||
ld a, BANK(EvosAttacks)
|
||
call GetFarByte
|
||
cp MOON_STONE_RED ; BURN_HEAL
|
||
pop bc
|
||
ret nz
|
||
```
|
||
|
||
**Fix:** Change `MOON_STONE_RED` to `MOON_STONE`.
|
||
|
||
|
||
## Love Ball boosts catch rate for the wrong gender
|
||
|
||
This is a bug with `LoveBallMultiplier` in [items/item_effects.asm](/items/item_effects.asm):
|
||
|
||
```asm
|
||
LoveBallMultiplier:
|
||
; This function is buggy.
|
||
; Intent: multiply catch rate by 8 if mons are of same species, different sex
|
||
; Reality: multiply catch rate by 8 if mons are of same species, same sex
|
||
|
||
...
|
||
|
||
ld a, d
|
||
pop de
|
||
cp d
|
||
pop bc
|
||
ret nz ; for the intended effect, this should be "ret z"
|
||
```
|
||
|
||
**Fix:** Change `ret nz` to `ret z`.
|
||
|
||
|
||
## Fast Ball only boosts catch rate for three Pokémon
|
||
|
||
This is a bug with `FastBallMultiplier` in [items/item_effects.asm](/items/item_effects.asm):
|
||
|
||
```asm
|
||
FastBallMultiplier:
|
||
; This function is buggy.
|
||
; Intent: multiply catch rate by 4 if enemy mon is in one of the three
|
||
; FleeMons tables.
|
||
; Reality: multiply catch rate by 4 if enemy mon is one of the first three in
|
||
; the first FleeMons table.
|
||
|
||
...
|
||
|
||
inc hl
|
||
cp -1
|
||
jr z, .next
|
||
cp c
|
||
jr nz, .next ; for the intended effect, this should be "jr nz, .loop"
|
||
sla b
|
||
jr c, .max
|
||
```
|
||
|
||
**Fix:** Change `jr nz, .next` to `jr nz, .loop`.
|
||
|
||
|
||
## Dragon Scale, not Dragon Fang, boosts Dragon-type moves
|
||
|
||
*Fixing this bug will break compatibility with standard Pokémon Crystal for link battles.*
|
||
|
||
This is a bug with `ItemAttributes` in [data/items/attributes.asm](/data/items/attributes.asm):
|
||
|
||
```asm
|
||
; DRAGON_FANG
|
||
item_attribute 100, 0, 0, CANT_SELECT, ITEM, ITEMMENU_NOUSE, ITEMMENU_NOUSE
|
||
|
||
...
|
||
|
||
; DRAGON_SCALE
|
||
item_attribute 2100, HELD_DRAGON_BOOST, 10, CANT_SELECT, ITEM, ITEMMENU_NOUSE, ITEMMENU_NOUSE
|
||
```
|
||
|
||
**Fix:** Move `HELD_DRAGON_BOOST` to the `DRAGON_FANG` attributes and `0` to `DRAGON_SCALE`.
|
||
|
||
|
||
## Daisy's grooming doesn't always increase happiness
|
||
|
||
This is a bug with `HaircutOrGrooming` in [engine/events/specials_2.asm](/engine/events/specials_2.asm):
|
||
|
||
```asm
|
||
; Bug: Subtracting $ff from $ff fails to set c.
|
||
; This can result in overflow into the next data array.
|
||
; In the case of getting a grooming from Daisy, we bleed
|
||
; into CopyPokemonName_Buffer1_Buffer3, which passes
|
||
; $d0 to ChangeHappiness and returns $73 to the script.
|
||
; The end result is that there is a 0.4% chance your
|
||
; Pokemon's happiness will not change at all.
|
||
.loop
|
||
sub [hl]
|
||
jr c, .ok
|
||
inc hl
|
||
inc hl
|
||
inc hl
|
||
jr .loop
|
||
|
||
.ok
|
||
inc hl
|
||
ld a, [hli]
|
||
ld [wScriptVar], a
|
||
ld c, [hl]
|
||
call ChangeHappiness
|
||
ret
|
||
|
||
...
|
||
|
||
INCLUDE "data/events/happiness_probabilities.asm"
|
||
|
||
CopyPokemonName_Buffer1_Buffer3: ; 746e
|
||
ld hl, wStringBuffer1
|
||
ld de, wStringBuffer3
|
||
ld bc, MON_NAME_LENGTH
|
||
jp CopyBytes
|
||
```
|
||
|
||
In [data/events/happiness_probabilities.asm](/data/events/happiness_probabilities.asm):
|
||
|
||
```asm
|
||
HappinessData_DaisysGrooming: ; 746b
|
||
db $ff, 2, HAPPINESS_GROOMING ; 99.6% chance
|
||
```
|
||
|
||
**Fix:**
|
||
|
||
```asm
|
||
HappinessData_DaisysGrooming: ; 746b
|
||
db $80, 2, HAPPINESS_GROOMING ; 50% chance
|
||
db $ff, 2, HAPPINESS_GROOMING ; 50% chance
|
||
```
|
||
|
||
|
||
## Magikarp in Lake of Rage are shorter, not longer
|
||
|
||
This is a bug with `LoadEnemyMon.CheckMagikarpArea` in [engine/battle/core.asm](/engine/battle/core.asm):
|
||
|
||
```asm
|
||
.CheckMagikarpArea:
|
||
; The "jr z" checks are supposed to be "jr nz".
|
||
|
||
; Instead, all maps in GROUP_LAKE_OF_RAGE (Mahogany area)
|
||
; and Routes 20 and 44 are treated as Lake of Rage.
|
||
|
||
; This also means Lake of Rage Magikarp can be smaller than ones
|
||
; caught elsewhere rather than the other way around.
|
||
|
||
; Intended behavior enforces a minimum size at Lake of Rage.
|
||
; The real behavior prevents a minimum size in the Lake of Rage area.
|
||
|
||
; Moreover, due to the check not being translated to feet+inches, all Magikarp
|
||
; smaller than 4'0" may be caught by the filter, a lot more than intended.
|
||
ld a, [wMapGroup]
|
||
cp GROUP_LAKE_OF_RAGE
|
||
jr z, .Happiness
|
||
ld a, [wMapNumber]
|
||
cp MAP_LAKE_OF_RAGE
|
||
jr z, .Happiness
|
||
```
|
||
|
||
**Fix:** Change both `jr z, .Happiness` to `jr nz, .Happiness`.
|
||
|
||
|
||
## Magikarp length limits have a unit conversion error
|
||
|
||
This is a bug with `LoadEnemyMon.CheckMagikarpArea` in [engine/battle/core.asm](/engine/battle/core.asm):
|
||
|
||
```asm
|
||
; Get Magikarp's length
|
||
ld de, wEnemyMonDVs
|
||
ld bc, wPlayerID
|
||
callfar CalcMagikarpLength
|
||
|
||
; No reason to keep going if length > 1536 mm (i.e. if HIGH(length) > 6 feet)
|
||
ld a, [wMagikarpLength]
|
||
cp HIGH(1536) ; should be "cp 5", since 1536 mm = 5'0", but HIGH(1536) = 6
|
||
jr nz, .CheckMagikarpArea
|
||
|
||
; 5% chance of skipping both size checks
|
||
call Random
|
||
cp 5 percent
|
||
jr c, .CheckMagikarpArea
|
||
; Try again if length >= 1616 mm (i.e. if LOW(length) >= 3 inches)
|
||
ld a, [wMagikarpLength + 1]
|
||
cp LOW(1616) ; should be "cp 3", since 1616 mm = 5'3", but LOW(1616) = 80
|
||
jr nc, .GenerateDVs
|
||
|
||
; 20% chance of skipping this check
|
||
call Random
|
||
cp 20 percent - 1
|
||
jr c, .CheckMagikarpArea
|
||
; Try again if length >= 1600 mm (i.e. if LOW(length) >= 2 inches)
|
||
ld a, [wMagikarpLength + 1]
|
||
cp LOW(1600) ; should be "cp 2", since 1600 mm = 5'2", but LOW(1600) = 64
|
||
jr nc, .GenerateDVs
|
||
```
|
||
|
||
**Fix:** Change the three `cp` instructions to use their commented values.
|
||
|
||
|
||
## Magikarp lengths can be miscalculated
|
||
|
||
This is a bug with `CalcMagikarpLength.BCLessThanDE` in [engine/events/magikarp.asm](/engine/events/magikarp.asm):
|
||
|
||
```asm
|
||
.BCLessThanDE: ; fbc9a
|
||
; Intention: Return bc < de.
|
||
; Reality: Return b < d.
|
||
ld a, b
|
||
cp d
|
||
ret c
|
||
ret nc ; whoops
|
||
ld a, c
|
||
cp e
|
||
ret
|
||
; fbca1
|
||
```
|
||
|
||
**Fix:** Delete `ret nc`.
|
||
|
||
|
||
## Battle transitions fail to account for the enemy's level
|
||
|
||
([Video](https://www.youtube.com/watch?v=eij_1060SMc))
|
||
|
||
This is a bug with `StartTrainerBattle_DetermineWhichAnimation` in [engine/battle/battle_transition.asm](/engine/battle/battle_transition.asm):
|
||
|
||
```asm
|
||
StartTrainerBattle_DetermineWhichAnimation: ; 8c365 (23:4365)
|
||
; The screen flashes a different number of times depending on the level of
|
||
; your lead Pokemon relative to the opponent's.
|
||
; BUG: wBattleMonLevel and wEnemyMonLevel are not set at this point, so whatever
|
||
; values happen to be there will determine the animation.
|
||
ld de, 0
|
||
ld a, [wBattleMonLevel]
|
||
add 3
|
||
ld hl, wEnemyMonLevel
|
||
cp [hl]
|
||
jr nc, .okay
|
||
set 0, e
|
||
.okay
|
||
ld a, [wEnvironment]
|
||
cp CAVE
|
||
jr z, .okay2
|
||
cp ENVIRONMENT_5
|
||
jr z, .okay2
|
||
cp DUNGEON
|
||
jr z, .okay2
|
||
set 1, e
|
||
.okay2
|
||
ld hl, .StartingPoints
|
||
add hl, de
|
||
ld a, [hl]
|
||
ld [wJumptableIndex], a
|
||
ret
|
||
; 8c38f (23:438f)
|
||
|
||
.StartingPoints: ; 8c38f
|
||
db 1, 9
|
||
db 16, 24
|
||
; 8c393
|
||
```
|
||
|
||
*To do:* Fix this bug.
|
||
|
||
|
||
## A "HOF Master!" title for 200-Time Famers is defined but inaccessible
|
||
|
||
([Video](https://www.youtube.com/watch?v=iHkWubvxmSg))
|
||
|
||
This is a bug with `_HallOfFamePC.DisplayMonAndStrings` in [engine/events/halloffame.asm](/engine/events/halloffame.asm):
|
||
|
||
```asm
|
||
ld a, [wHallOfFameTempWinCount]
|
||
cp HOF_MASTER_COUNT + 1 ; should be HOF_MASTER_COUNT
|
||
jr c, .print_num_hof
|
||
ld de, .HOFMaster
|
||
hlcoord 1, 2
|
||
call PlaceString
|
||
hlcoord 13, 2
|
||
jr .finish
|
||
```
|
||
|
||
**Fix:** Change `HOF_MASTER_COUNT + 1` to `HOF_MASTER_COUNT`.
|
||
|
||
|
||
## Slot machine payout sound effects cut each other off
|
||
|
||
([Video](https://www.youtube.com/watch?v=ojq3xqfRF6I))
|
||
|
||
This is a bug with `Slots_PayoutAnim` in [engine/games/slot_machine.asm](/engine/games/slot_machine.asm):
|
||
|
||
```asm
|
||
.okay
|
||
ld [hl], e
|
||
dec hl
|
||
ld [hl], d
|
||
ld a, [wSlotsDelay]
|
||
and $7
|
||
ret z ; ret nz would be more appropriate
|
||
ld de, SFX_GET_COIN_FROM_SLOTS
|
||
call PlaySFX
|
||
ret
|
||
```
|
||
|
||
**Fix:** Change `ret z` to `ret nz`.
|
||
|
||
|
||
## Team Rocket battle music is not used for Executives or Scientists
|
||
|
||
This is a bug with `PlayBattleMusic` in [engine/battle/start_battle.asm](/engine/battle/start_battle.asm):
|
||
|
||
```asm
|
||
; They should have included EXECUTIVEM, EXECUTIVEF, and SCIENTIST too...
|
||
ld de, MUSIC_ROCKET_BATTLE
|
||
cp GRUNTM
|
||
jr z, .done
|
||
cp GRUNTF
|
||
jr z, .done
|
||
```
|
||
|
||
**Fix:**
|
||
|
||
```asm
|
||
ld de, MUSIC_ROCKET_BATTLE
|
||
cp GRUNTM
|
||
jr z, .done
|
||
cp GRUNTF
|
||
jr z, .done
|
||
cp EXECUTIVEM
|
||
jr z, .done
|
||
cp EXECUTIVEF
|
||
jr z, .done
|
||
cp SCIENTIST
|
||
jr z, .done
|
||
```
|
||
|
||
|
||
## No bump noise if standing on tile `$3E`
|
||
|
||
This is a bug with `DoPlayerMovement.CheckWarp` in [engine/overworld/player_movement.asm](/engine/overworld/player_movement.asm):
|
||
|
||
```asm
|
||
; Bug: Since no case is made for STANDING here, it will check
|
||
; [.edgewarps + $ff]. This resolves to $3e at $8035a.
|
||
; This causes wd041 to be nonzero when standing on tile $3e,
|
||
; making bumps silent.
|
||
|
||
ld a, [wWalkingDirection]
|
||
; cp STANDING
|
||
; jr z, .not_warp
|
||
ld e, a
|
||
ld d, 0
|
||
ld hl, .EdgeWarps
|
||
add hl, de
|
||
ld a, [wPlayerStandingTile]
|
||
cp [hl]
|
||
jr nz, .not_warp
|
||
|
||
ld a, 1
|
||
ld [wd041], a
|
||
ld a, [wWalkingDirection]
|
||
; This is in the wrong place.
|
||
cp STANDING
|
||
jr z, .not_warp
|
||
```
|
||
|
||
**Fix:**
|
||
|
||
```asm
|
||
ld a, [wWalkingDirection]
|
||
cp STANDING
|
||
jr z, .not_warp
|
||
ld e, a
|
||
ld d, 0
|
||
ld hl, .EdgeWarps
|
||
add hl, de
|
||
ld a, [wPlayerStandingTile]
|
||
cp [hl]
|
||
jr nz, .not_warp
|
||
|
||
ld a, 1
|
||
ld [wd041], a
|
||
ld a, [wWalkingDirection]
|
||
```
|
||
|
||
|
||
## Playing Entei's Pokédex cry can distort Raikou's and Suicune's
|
||
|
||
([Video](https://www.youtube.com/watch?v=z305e4sIO24))
|
||
|
||
The exact cause is unknown, but a workaround exists for `DexEntryScreen_MenuActionJumptable.Cry` in [engine/pokedex/pokedex.asm](/engine/pokedex/pokedex.asm):
|
||
|
||
```asm
|
||
.Cry: ; 40340
|
||
call Pokedex_GetSelectedMon
|
||
ld a, [wd265]
|
||
call GetCryIndex
|
||
ld e, c
|
||
ld d, b
|
||
call PlayCry
|
||
ret
|
||
```
|
||
|
||
**Workaround:**
|
||
|
||
```asm
|
||
.Cry: ; 40340
|
||
ld a, [CurPartySpecies]
|
||
call PlayMonCry
|
||
ret
|
||
```
|
||
|
||
|
||
## In-battle “`…`” ellipsis is too high
|
||
|
||
This is a mistake with the “`…`” tile in [gfx/battle/hp_exp_bar_border.png](/gfx/battle/hp_exp_bar_border.png):
|
||
|
||
|
||
|
||
**Fix:** Lower the ellipsis by two pixels:
|
||
|
||
|
||
|
||
|
||
## Two tiles in the `port` tileset are drawn incorrectly
|
||
|
||
This is a mistake with the left-hand warp carpet corner tiles in [gfx/tilesets/port.png](/gfx/tilesets/port.png):
|
||
|
||
|
||
|
||
**Fix:** Adjust them to match the right-hand corner tiles:
|
||
|
||
|
||
|
||
|
||
## `LoadMetatiles` wraps around past 128 blocks
|
||
|
||
This bug prevents you from using blocksets with more than 128 blocks.
|
||
|
||
In [home/map.asm](/home/map.asm):
|
||
|
||
```asm
|
||
; Set hl to the address of the current metatile data ([wTilesetBlocksAddress] + (a) tiles).
|
||
; This is buggy; it wraps around past 128 blocks.
|
||
; To fix, uncomment the line below.
|
||
add a ; Comment or delete this line to fix the above bug.
|
||
ld l, a
|
||
ld h, 0
|
||
; add hl, hl
|
||
add hl, hl
|
||
add hl, hl
|
||
add hl, hl
|
||
ld a, [wTilesetBlocksAddress]
|
||
add l
|
||
ld l, a
|
||
ld a, [wTilesetBlocksAddress + 1]
|
||
adc h
|
||
ld h, a
|
||
```
|
||
|
||
**Fix:** Delete `add a` and uncomment `add hl, hl`.
|
||
|
||
|
||
## Surfing directly across a map connection does not load the new map
|
||
|
||
([Video](https://www.youtube.com/watch?v=XFOWvMNG-zw))
|
||
|
||
*To do:* Identify specific code causing this bug and fix it.
|
||
|
||
|
||
## `Function6ec1` does not correctly limit object movement
|
||
|
||
This bug is why the Lapras in [maps/UnionCaveB2F.asm](/maps/UnionCaveB2F.asm), which uses `SPRITEMOVEDATA_SWIM_WANDER`, is not restricted by its `1, 1` movement radius.
|
||
|
||
In [engine/overworld/npc_movement.asm](/engine/overworld/npc_movement.asm):
|
||
|
||
```asm
|
||
ld hl, OBJECT_FLAGS1
|
||
add hl, bc
|
||
bit 4, [hl] ; lost, uncomment next line to fix
|
||
; jr nz, .resume
|
||
```
|
||
|
||
**Fix:** Uncomment `jr nz, .resume`.
|
||
|
||
|
||
## `CheckOwnMon` only checks the first five letters of OT names
|
||
|
||
([Video](https://www.youtube.com/watch?v=GVTTmReM4nQ))
|
||
|
||
This bug can allow you to talk to Eusine in Celadon City and encounter Ho-Oh with only traded legendary beasts.
|
||
|
||
In [engine/pokemon/search.asm](/engine/pokemon/search.asm):
|
||
|
||
```asm
|
||
; check OT
|
||
; This only checks five characters, which is fine for the Japanese version,
|
||
; but in the English version the player name is 7 characters, so this is wrong.
|
||
|
||
ld hl, wPlayerName
|
||
|
||
rept NAME_LENGTH_JAPANESE + -2 ; should be PLAYER_NAME_LENGTH + -2
|
||
ld a, [de]
|
||
cp [hl]
|
||
jr nz, .notfound
|
||
cp "@"
|
||
jr z, .found ; reached end of string
|
||
inc hl
|
||
inc de
|
||
endr
|
||
|
||
ld a, [de]
|
||
cp [hl]
|
||
jr z, .found
|
||
```
|
||
|
||
**Fix:** Change `rept NAME_LENGTH_JAPANESE + -2` to `rept PLAYER_NAME_LENGTH + -2`.
|
||
|
||
|
||
## Catching a Transformed Pokémon always catches a Ditto
|
||
|
||
This bug can affect Mew or Pokémon other than Ditto that used Transform via Mirror Move or Sketch.
|
||
|
||
This is a bug with `PokeBallEffect` in [engine/items/item_effects.asm](/engine/items/item_effects.asm):
|
||
|
||
```asm
|
||
ld hl, wEnemySubStatus5
|
||
ld a, [hl]
|
||
push af
|
||
set SUBSTATUS_TRANSFORMED, [hl]
|
||
|
||
; This code is buggy. Any wild Pokémon that has Transformed will be
|
||
; caught as a Ditto, even if it was something else like Mew.
|
||
; To fix, do not set [wTempEnemyMonSpecies] to DITTO.
|
||
bit SUBSTATUS_TRANSFORMED, a
|
||
jr nz, .ditto
|
||
jr .not_ditto
|
||
|
||
.ditto
|
||
ld a, DITTO
|
||
ld [wTempEnemyMonSpecies], a
|
||
jr .load_data
|
||
|
||
.not_ditto
|
||
set SUBSTATUS_TRANSFORMED, [hl]
|
||
ld hl, wEnemyBackupDVs
|
||
ld a, [wEnemyMonDVs]
|
||
ld [hli], a
|
||
ld a, [wEnemyMonDVs + 1]
|
||
ld [hl], a
|
||
|
||
.load_data
|
||
ld a, [wTempEnemyMonSpecies]
|
||
ld [wCurPartySpecies], a
|
||
ld a, [wEnemyMonLevel]
|
||
ld [wCurPartyLevel], a
|
||
farcall LoadEnemyMon
|
||
|
||
pop af
|
||
ld [wEnemySubStatus5], a
|
||
```
|
||
|
||
**Fix:**
|
||
|
||
```asm
|
||
ld hl, wEnemySubStatus5
|
||
ld a, [hl]
|
||
push af
|
||
set SUBSTATUS_TRANSFORMED, [hl]
|
||
|
||
bit SUBSTATUS_TRANSFORMED, a
|
||
jr nz, .load_data
|
||
|
||
ld hl, wEnemyBackupDVs
|
||
ld a, [wEnemyMonDVs]
|
||
ld [hli], a
|
||
ld a, [wEnemyMonDVs + 1]
|
||
ld [hl], a
|
||
|
||
.load_data
|
||
ld a, [wTempEnemyMonSpecies]
|
||
ld [wCurPartySpecies], a
|
||
ld a, [wEnemyMonLevel]
|
||
ld [wCurPartyLevel], a
|
||
farcall LoadEnemyMon
|
||
|
||
pop af
|
||
ld [wEnemySubStatus5], a
|
||
```
|
||
|
||
|
||
## Using a Park Ball in normal battles has a corrupt animation
|
||
|
||
([Video](https://www.youtube.com/watch?v=v1ErZdLCIyU))
|
||
|
||
This is a bug with `PokeBallEffect` in [engine/items/item_effects.asm](/engine/items/item_effects.asm):
|
||
|
||
```asm
|
||
.room_in_party
|
||
xor a
|
||
ld [wWildMon], a
|
||
ld a, [wCurItem]
|
||
cp PARK_BALL
|
||
call nz, ReturnToBattle_UseBall
|
||
```
|
||
|
||
**Fix:**
|
||
|
||
```asm
|
||
.room_in_party
|
||
xor a
|
||
ld [wWildMon], a
|
||
ld a, [wBattleType]
|
||
cp BATTLETYPE_CONTEST
|
||
call nz, ReturnToBattle_UseBall
|
||
```
|
||
|
||
|
||
## `HELD_CATCH_CHANCE` has no effect
|
||
|
||
This is a bug with `PokeBallEffect` in [engine/items/item_effects.asm](/engine/items/item_effects.asm):
|
||
|
||
```asm
|
||
; BUG: farcall overwrites a, and GetItemHeldEffect takes b anyway.
|
||
; This is probably the reason the HELD_CATCH_CHANCE effect is never used.
|
||
; Uncomment the line below to fix.
|
||
ld d, a
|
||
push de
|
||
ld a, [wBattleMonItem]
|
||
; ld b, a
|
||
farcall GetItemHeldEffect
|
||
ld a, b
|
||
cp HELD_CATCH_CHANCE
|
||
pop de
|
||
ld a, d
|
||
jr nz, .max_2
|
||
add c
|
||
jr nc, .max_2
|
||
ld a, $ff
|
||
.max_2
|
||
```
|
||
|
||
**Fix:** Uncomment `ld b, a`.
|
||
|
||
|
||
## Only the first three `EvosAttacks` evolution entries can have Stone compatibility reported correctly
|
||
|
||
This is a bug with `PlacePartyMonEvoStoneCompatibility.DetermineCompatibility` in [engine/pokemon/party_menu.asm](/engine/pokemon/party_menu.asm):
|
||
|
||
```asm
|
||
.DetermineCompatibility: ; 50268
|
||
ld de, wStringBuffer1
|
||
ld a, BANK(EvosAttacksPointers)
|
||
ld bc, 2
|
||
call FarCopyBytes
|
||
ld hl, wStringBuffer1
|
||
ld a, [hli]
|
||
ld h, [hl]
|
||
ld l, a
|
||
ld de, wStringBuffer1
|
||
ld a, BANK(EvosAttacks)
|
||
ld bc, 10
|
||
call FarCopyBytes
|
||
```
|
||
|
||
**Fix:** Change `ld bc, 10` to `ld bc, wStringBuffer2 - wStringBuffer1` to support up to six Stone entries.
|
||
|
||
|
||
## `EVOLVE_STAT` can break Stone compatibility reporting
|
||
|
||
This is a bug with `PlacePartyMonEvoStoneCompatibility.DetermineCompatibility` in [engine/pokemon/party_menu.asm](/engine/pokemon/party_menu.asm):
|
||
|
||
```asm
|
||
.loop2
|
||
ld a, [hli]
|
||
and a
|
||
jr z, .nope
|
||
inc hl
|
||
inc hl
|
||
cp EVOLVE_ITEM
|
||
jr nz, .loop2
|
||
```
|
||
|
||
**Fix:**
|
||
|
||
```asm
|
||
.loop2
|
||
ld a, [hli]
|
||
and a
|
||
jr z, .nope
|
||
cp EVOLVE_STAT
|
||
jr nz, .not_four_bytes
|
||
inc hl
|
||
.not_four_bytes
|
||
inc hl
|
||
inc hl
|
||
cp EVOLVE_ITEM
|
||
jr nz, .loop2
|
||
```
|
||
|
||
|
||
## `ScriptCall` can overflow `wScriptStack` and crash
|
||
|
||
In [engine/overworld/scripting.asm](/engine/overworld/scripting.asm):
|
||
|
||
```asm
|
||
ScriptCall:
|
||
; Bug: The script stack has a capacity of 5 scripts, yet there is
|
||
; nothing to stop you from pushing a sixth script. The high part
|
||
; of the script address can then be overwritten by modifications
|
||
; to wScriptDelay, causing the script to return to the rst/interrupt
|
||
; space.
|
||
|
||
push de
|
||
ld hl, wScriptStackSize
|
||
ld e, [hl]
|
||
inc [hl]
|
||
ld d, $0
|
||
ld hl, wScriptStack
|
||
add hl, de
|
||
add hl, de
|
||
add hl, de
|
||
pop de
|
||
ld a, [wScriptBank]
|
||
ld [hli], a
|
||
ld a, [wScriptPos]
|
||
ld [hli], a
|
||
ld a, [wScriptPos + 1]
|
||
ld [hl], a
|
||
ld a, b
|
||
ld [wScriptBank], a
|
||
ld a, e
|
||
ld [wScriptPos], a
|
||
ld a, d
|
||
ld [wScriptPos + 1], a
|
||
ret
|
||
```
|
||
|
||
*To do:* Fix this bug.
|
||
|
||
|
||
## `LoadSpriteGFX` does not limit the capacity of `UsedSprites`
|
||
|
||
In [engine/overworld/overworld.asm](/engine/overworld/overworld.asm):
|
||
|
||
```asm
|
||
LoadSpriteGFX: ; 14306
|
||
; Bug: b is not preserved, so it's useless as a next count.
|
||
; Uncomment the lines below to fix.
|
||
|
||
ld hl, wUsedSprites
|
||
ld b, SPRITE_GFX_LIST_CAPACITY
|
||
.loop
|
||
ld a, [hli]
|
||
and a
|
||
jr z, .done
|
||
push hl
|
||
call .LoadSprite
|
||
pop hl
|
||
ld [hli], a
|
||
dec b
|
||
jr nz, .loop
|
||
|
||
.done
|
||
ret
|
||
|
||
.LoadSprite:
|
||
; push bc
|
||
call GetSprite
|
||
; pop bc
|
||
ld a, l
|
||
ret
|
||
; 1431e
|
||
```
|
||
|
||
**Fix:** Uncomment `push bc` and `pop bc`.
|
||
|
||
|
||
## `ChooseWildEncounter` doesn't really validate the wild Pokémon species
|
||
|
||
In [engine/overworld/wildmons.asm](/engine/overworld/wildmons.asm):
|
||
|
||
```asm
|
||
ChooseWildEncounter: ; 2a14f
|
||
...
|
||
ld a, b
|
||
ld [wCurPartyLevel], a
|
||
ld b, [hl]
|
||
; ld a, b
|
||
call ValidateTempWildMonSpecies
|
||
jr c, .nowildbattle
|
||
|
||
ld a, b ; This is in the wrong place.
|
||
cp UNOWN
|
||
jr nz, .done
|
||
|
||
...
|
||
|
||
ValidateTempWildMonSpecies: ; 2a4a0
|
||
; Due to a development oversight, this function is called with the wild Pokemon's level, not its species, in a.
|
||
```
|
||
|
||
**Fix:**
|
||
|
||
```asm
|
||
ld a, b
|
||
ld [wCurPartyLevel], a
|
||
ld b, [hl]
|
||
ld a, b
|
||
call ValidateTempWildMonSpecies
|
||
jr c, .nowildbattle
|
||
|
||
cp UNOWN
|
||
jr nz, .done
|
||
```
|
||
|
||
## `TryObjectEvent` arbitrary code execution
|
||
|
||
In [engine/overworld/events.asm](/engine/overworld/events.asm):
|
||
|
||
```asm
|
||
; Bug: If IsInArray returns nc, data at bc will be executed as code.
|
||
push bc
|
||
ld de, 3
|
||
ld hl, .pointers
|
||
call IsInArray
|
||
jr nc, .nope_bugged
|
||
pop bc
|
||
|
||
inc hl
|
||
ld a, [hli]
|
||
ld h, [hl]
|
||
ld l, a
|
||
jp hl
|
||
|
||
.nope_bugged
|
||
; pop bc
|
||
xor a
|
||
ret
|
||
```
|
||
|
||
**Fix:** Uncomment `pop bc`.
|
||
|
||
|
||
## `CheckBugContestContestantFlag` can read beyond its data table
|
||
|
||
In [engine/events/bug_contest/contest_2.asm](/engine/events/bug_contest/contest_2.asm):
|
||
|
||
```asm
|
||
CheckBugContestContestantFlag: ; 139ed
|
||
; Checks the flag of the Bug Catching Contestant whose index is loaded in a.
|
||
|
||
; Bug: If a >= NUM_BUG_CONTESTANTS when this is called,
|
||
; it will read beyond the table.
|
||
|
||
ld hl, BugCatchingContestantEventFlagTable
|
||
ld e, a
|
||
ld d, 0
|
||
add hl, de
|
||
add hl, de
|
||
ld e, [hl]
|
||
inc hl
|
||
ld d, [hl]
|
||
ld b, CHECK_FLAG
|
||
call EventFlagAction
|
||
ret
|
||
; 139fe
|
||
|
||
INCLUDE "data/events/bug_contest_flags.asm"
|
||
```
|
||
|
||
However, `a < NUM_BUG_CONTESTANTS` should always be true, so in practice this is not a problem.
|
||
|
||
|
||
## `ClearWRAM` only clears WRAM bank 1
|
||
|
||
In [home/init.asm](/home/init.asm):
|
||
|
||
```asm
|
||
ClearWRAM:: ; 25a
|
||
; Wipe swappable WRAM banks (1-7)
|
||
; Assumes CGB or AGB
|
||
|
||
ld a, 1
|
||
.bank_loop
|
||
push af
|
||
ld [rSVBK], a
|
||
xor a
|
||
ld hl, WRAM1_Begin
|
||
ld bc, WRAM1_End - WRAM1_Begin
|
||
call ByteFill
|
||
pop af
|
||
inc a
|
||
cp 8
|
||
jr nc, .bank_loop ; Should be jr c
|
||
ret
|
||
; 270
|
||
```
|
||
|
||
**Fix:** Change `jr nc, .bank_loop` to `jr c, .bank_loop`.
|