24 files changed, 53 insertions, 113 deletions

diff --git a/src/field_player_avatar.c b/src/field_player_avatar.c
index b1291f0ce..66f176d39 100644
--- a/src/field_player_avatar.c
+++ b/src/field_player_avatar.c
@@ -2125,7 +2125,7 @@ void sub_808D194(void)
     sub_808D1FC(CreateTask(sub_808D1FC, 0));
 }
 
-bool8 sub_808D1B4(void)
+bool32 sub_808D1B4(void)
 {
     return FuncIsActiveTask(sub_808D1FC);
 }
@@ -2135,7 +2135,7 @@ void sub_808D1C8(void)
     sub_808D094(CreateTask(sub_808D094, 0));
 }
 
-bool8 sub_808D1E8(void)
+bool32 sub_808D1E8(void)
 {
     return FuncIsActiveTask(sub_808D094);
 }
diff --git a/src/field_screen_effect.c b/src/field_screen_effect.c
index 3e4965667..b6dcf212c 100644
--- a/src/field_screen_effect.c
+++ b/src/field_screen_effect.c
@@ -32,16 +32,7 @@
 #include "constants/rgb.h"
 #include "trainer_hill.h"
 #include "event_obj_lock.h"
-
-extern void sub_80B6B68(void);
-extern void sub_80B6E4C(u8, u8);
-extern void sub_80B75D8(u8);
-extern void sub_80B7A74(u8);
-extern void sub_808C0A8(u8);
-extern u8 GetMapPairFadeToType(u8, u8);
-extern u8 GetMapPairFadeFromType(u8, u8);
-extern bool32 sub_808D1B4(void);
-extern bool32 sub_808D1E8(void);
+#include "fldeff.h"
 
 extern const u16 gUnknown_82EC7CC[];
 
diff --git a/src/field_specials.c b/src/field_specials.c
index 629dd8015..85bc41723 100644
--- a/src/field_specials.c
+++ b/src/field_specials.c
@@ -81,8 +81,6 @@ extern const u16 gEventObjectPalette17[];
 extern const u16 gEventObjectPalette33[];
 extern const u16 gEventObjectPalette34[];
 
-extern void BlendPalettes(u32, u8, u16);
-extern void FieldInitRegionMap(MainCallback callback);
 
 void UpdateMovedLilycoveFanClubMembers(void);
 void sub_813BF60(void);
diff --git a/src/frontier_util.c b/src/frontier_util.c
index 6fcbd4ffb..8c190f522 100644
--- a/src/frontier_util.c
+++ b/src/frontier_util.c
@@ -35,8 +35,7 @@
 #include "constants/moves.h"
 #include "constants/items.h"
 #include "constants/event_objects.h"
-
-extern u8 gSelectedOrderFromParty[];
+#include "party_menu.h"
 
 struct FrontierBrainMon
 {
@@ -48,8 +47,6 @@ struct FrontierBrainMon
     u16 moves[4];
 };
 
-extern void sub_81B8558(void);
-
 // This file's functions.
 static void sub_81A17A0(void);
 static void sub_81A1830(void);
diff --git a/src/hall_of_fame.c b/src/hall_of_fame.c
index 3f217b782..48e4f8bec 100644
--- a/src/hall_of_fame.c
+++ b/src/hall_of_fame.c
@@ -66,8 +66,6 @@ extern struct MusicPlayerInfo gMPlayInfo_BGM;
 
 #define HALL_OF_FAME_MAX_TEAMS 50
 
-extern void ReturnFromHallOfFamePC(void);
-
 // this file's functions
 static void ClearVramOamPltt_LoadHofPal(void);
 static void sub_8174F70(void);
diff --git a/src/hof_pc.c b/src/hof_pc.c
index 2cea5540a..d76f04372 100644
--- a/src/hof_pc.c
+++ b/src/hof_pc.c
@@ -7,10 +7,6 @@
 #include "script_menu.h"
 #include "task.h"
 
-extern void Overworld_PlaySpecialMapMusic(void);
-extern bool16 ScrSpecial_CreatePCMenu(void);
-extern void ScriptMenu_DisplayPCStartupPrompt(void);
-
 static void ReshowPCMenuAfterHallOfFamePC(void);
 static void Task_WaitForPaletteFade(u8);
 
diff --git a/src/ice.c b/src/ice.c
index 34ad572e8..fa1913b96 100644
--- a/src/ice.c
+++ b/src/ice.c
@@ -21,30 +21,29 @@ struct HailStruct {
 };
 
 static void sub_810B6C4(struct Sprite *);
-extern void sub_810B848(struct Sprite *);
-extern void AnimIcePunchSwirlingParticle(struct Sprite *);
-extern void AnimIceBeamParticle(struct Sprite *);
-extern void AnimIceEffectParticle(struct Sprite *);
-extern void AnimFlickerIceEffectParticle(struct Sprite *);
-extern void AnimSwirlingSnowball_Step1(struct Sprite *);
-extern void AnimSwirlingSnowball_Step2(struct Sprite *);
-extern void AnimSwirlingSnowball_Step3(struct Sprite *);
-extern void AnimSwirlingSnowball_End(struct Sprite *);
-extern void AnimMoveParticleBeyondTarget(struct Sprite *);
-extern void AnimWiggleParticleTowardsTarget(struct Sprite *);
-extern void AnimWaveFromCenterOfTarget(struct Sprite *);
-extern void InitSwirlingFogAnim(struct Sprite *);
-extern void AnimSwirlingFogAnim(struct Sprite *);
-extern void AnimThrowMistBall(struct Sprite *);
-extern void InitPoisonGasCloudAnim(struct Sprite *);
-extern void MovePoisonGasCloud(struct Sprite *);
-extern void AnimHailBegin(struct Sprite *);
-extern void AnimHailContinue(struct Sprite *);
-extern void sub_80A8EE4(struct Sprite *);
-extern void InitIceBallAnim(struct Sprite *);
-extern void AnimThrowIceBall(struct Sprite *);
-extern void InitIceBallParticle(struct Sprite *);
-extern void AnimIceBallParticle(struct Sprite *);
+void sub_810B848(struct Sprite *);
+void AnimIcePunchSwirlingParticle(struct Sprite *);
+void AnimIceBeamParticle(struct Sprite *);
+void AnimIceEffectParticle(struct Sprite *);
+void AnimFlickerIceEffectParticle(struct Sprite *);
+void AnimSwirlingSnowball_Step1(struct Sprite *);
+void AnimSwirlingSnowball_Step2(struct Sprite *);
+void AnimSwirlingSnowball_Step3(struct Sprite *);
+void AnimSwirlingSnowball_End(struct Sprite *);
+void AnimMoveParticleBeyondTarget(struct Sprite *);
+void AnimWiggleParticleTowardsTarget(struct Sprite *);
+void AnimWaveFromCenterOfTarget(struct Sprite *);
+void InitSwirlingFogAnim(struct Sprite *);
+void AnimSwirlingFogAnim(struct Sprite *);
+void AnimThrowMistBall(struct Sprite *);
+void InitPoisonGasCloudAnim(struct Sprite *);
+void MovePoisonGasCloud(struct Sprite *);
+void AnimHailBegin(struct Sprite *);
+void AnimHailContinue(struct Sprite *);
+void InitIceBallAnim(struct Sprite *);
+void AnimThrowIceBall(struct Sprite *);
+void InitIceBallParticle(struct Sprite *);
+void AnimIceBallParticle(struct Sprite *);
 void AnimTask_Haze2(u8);
 void AnimTask_OverlayFogTiles(u8);
 void AnimTask_Hail2(u8);
diff --git a/src/item_menu.c b/src/item_menu.c
index b3d341c2e..877444575 100755
--- a/src/item_menu.c
+++ b/src/item_menu.c
@@ -140,7 +140,6 @@ void unknown_ItemMenu_Confirm2(u8 taskId);
 void unknown_item_menu_type(u8 taskId);
 void item_menu_type_2(u8 taskId);
 void display_sell_item_ask_str(u8 taskId);
-void unknown_ItemMenu_Confirm(u8 taskId);
 void display_deposit_item_ask_str(u8 taskId);
 void item_menu_type_b(u8 taskId);
 void BagMenuActuallyToss(u8 taskId);
diff --git a/src/item_use.c b/src/item_use.c
index 16fb22d94..f9d81bfc0 100755
--- a/src/item_use.c
+++ b/src/item_use.c
@@ -8,13 +8,15 @@
 #include "coins.h"
 #include "data2.h"
 #include "event_data.h"
-#include "fieldmap.h"
 #include "event_object_movement.h"
+#include "fieldmap.h"
+#include "field_effect.h"
 #include "field_player_avatar.h"
 #include "field_screen_effect.h"
 #include "field_weather.h"
 #include "item.h"
 #include "item_menu.h"
+#include "item_use.h"
 #include "mail.h"
 #include "main.h"
 #include "menu.h"
@@ -39,29 +41,13 @@
 #include "constants/vars.h"
 #include "event_obj_lock.h"
 
-extern void unknown_ItemMenu_Confirm(u8 taskId);
-extern void sub_81C5B14(u8 taskId);
-extern void ItemUseOutOfBattle_TMHM(u8 a);
-extern void ItemUseOutOfBattle_EvolutionStone(u8 b);
-extern bool8 IsPlayerFacingSurfableFishableWater(void);
-extern bool8 sub_81221AC(void);
 extern u8 Route102_EventScript_274482[];
 extern u8 Route102_EventScript_2744C0[];
 extern u8 BattleFrontier_OutsideEast_EventScript_242CFC[];
-extern int sub_80247BC(void);
-extern struct MapHeader* mapconnection_get_mapheader(struct MapConnection *connection);
-extern void SetUpItemUseCallback(u8 taskId);
-extern void ItemUseCB_Medicine(u8, TaskFunc);
-extern void bag_menu_yes_no(u8, u8, const struct YesNoFuncTable*);
-extern void sub_81C5924(void);
-extern void sub_81C59BC(void);
-extern void sub_81AB9A8(u8);
-extern void StartEscapeRopeFieldEffect(void);
-extern u8* sub_806CF78(u16);
-extern void sub_81B89F0(void);
-extern u8 GetItemEffectType(u16);
-extern struct MapConnection *sub_8088A8C(s16, s16);
 
+extern s32 sub_80247BC(void);
+
+void SetUpItemUseCallback(u8 taskId);
 void MapPostLoadHook_UseItem(void);
 void sub_80AF6D4(void);
 void Task_CallItemUseOnFieldCallback(u8 taskId);
@@ -404,12 +390,12 @@ bool8 sub_80FD6D4(const struct MapEvents *events, s16 x, s16 y)
 
 bool8 sub_80FD730(struct MapConnection *connection, int x, int y)
 {
-    struct MapHeader *mapHeader;
+    
     u16 localX, localY;
     u32 localOffset;
     s32 localLength;
 
-    mapHeader = mapconnection_get_mapheader(connection);
+    struct MapHeader const *const mapHeader = mapconnection_get_mapheader(connection);
 
     switch (connection->direction)
     {
diff --git a/src/link.c b/src/link.c
index 72ac3e878..05da4e458 100644
--- a/src/link.c
+++ b/src/link.c
@@ -1893,7 +1893,7 @@ u32 GetLinkRecvQueueLength(void)
     return gLink.recvQueue.count;
 }
 
-bool8 sub_800B504(void)
+bool32 sub_800B504(void)
 {
     if (GetLinkRecvQueueLength() > 2)
     {
diff --git a/src/link_rfu.c b/src/link_rfu.c
index 8da6b166a..d80ff2ae9 100644
--- a/src/link_rfu.c
+++ b/src/link_rfu.c
@@ -17,9 +17,9 @@
 #include "text.h"
 #include "constants/species.h"
 #include "save.h"
+#include "rom_8011DC0.h"
 
 extern u16 gHeldKeyCodeToSend;
-extern void nullsub_89(u8 taskId);
 
 struct UnkRfuStruct_1 gUnknown_03004140;
 struct UnkRfuStruct_2 gUnknown_03005000;
diff --git a/src/load_save.c b/src/load_save.c
index 0d19c6dae..a0d2568d3 100644
--- a/src/load_save.c
+++ b/src/load_save.c
@@ -11,10 +11,10 @@
 #include "trainer_hill.h"
 #include "gba/flash_internal.h"
 #include "decoration_inventory.h"
+#include "agb_flash.h"
 
 static void ApplyNewEncryptionKeyToAllEncryptedData(u32 encryptionKey);
 
-extern bool16 IdentifyFlash(void);
 extern void ApplyNewEncryptionKeyToBerryPowder(u32 key);
 
 #define SAVEBLOCK_MOVE_RANGE    128
diff --git a/src/main.c b/src/main.c
index 61c5e3386..aa42c5958 100644
--- a/src/main.c
+++ b/src/main.c
@@ -24,9 +24,6 @@
 #include "main.h"
 #include "trainer_hill.h"
 
-extern void sub_800B9B8(void);
-extern u8 gUnknown_03002748;
-
 static void VBlankIntr(void);
 static void HBlankIntr(void);
 static void VCountIntr(void);
@@ -313,8 +310,6 @@ void SetSerialCallback(IntrCallback callback)
     gMain.serialCallback = callback;
 }
 
-extern void CopyBufferedValuesToGpuRegs(void);
-
 static void VBlankIntr(void)
 {
     if (gWirelessCommType != 0)
diff --git a/src/match_call.c b/src/match_call.c
index e7e91969f..ce1573164 100644
--- a/src/match_call.c
+++ b/src/match_call.c
@@ -111,8 +111,6 @@ static void PopulateSpeciesFromTrainerParty(int, u8 *);
 static void PopulateBattleFrontierFacilityName(int, u8 *);
 static void PopulateBattleFrontierStreak(int, u8 *);
 
-extern void sub_81973A4(void);
-
 #define TEXT_ID(topic, id) (((topic) << 8) | ((id) & 0xFF))
 
 static const struct MatchCallTrainerTextInfo sMatchCallTrainers[] =
diff --git a/src/menu.c b/src/menu.c
index ae589dff4..e82a6355c 100644
--- a/src/menu.c
+++ b/src/menu.c
@@ -122,20 +122,18 @@ const struct MoveMenuInfoIcon gMoveMenuInfoIcons[] =
     {  8,  8, 0xAF },       // Unused (Small dark pokeball)
 };
 
+
 // Forward declarations
-extern void sub_81973A4(void);
-extern void DrawStandardFrame(u8, u8, u8, u8, u8, u8);
-extern void DrawDialogueFrame(u8, u8, u8, u8, u8, u8);
-extern void sub_81977BC(u8, u8, u8, u8, u8, u8);
-extern void sub_8197804(u8, u8, u8, u8, u8, u8);
-extern void sub_8197BB4(u8, u8, u8, u8, u8, u8);
-extern void sub_8197E30(u8, u8, u8, u8, u8, u8);
-extern void DrawWindowBorder(u8, u8, u8, u8, u8, u8);
-extern void sub_81980A8(u8, u8, u8, u8, u8, u8);
-extern u8 Menu_MoveCursor(s8);
-extern u8 sub_8199134(s8, s8);
-extern void sub_8198C78(void);
-extern void task_free_buf_after_copying_tile_data_to_vram(u8 taskId);
+void DrawStandardFrame(u8, u8, u8, u8, u8, u8);
+void DrawDialogueFrame(u8, u8, u8, u8, u8, u8);
+void sub_81977BC(u8, u8, u8, u8, u8, u8);
+void sub_8197804(u8, u8, u8, u8, u8, u8);
+void sub_8197BB4(u8, u8, u8, u8, u8, u8);
+void sub_8197E30(u8, u8, u8, u8, u8, u8);
+void DrawWindowBorder(u8, u8, u8, u8, u8, u8);
+void sub_81980A8(u8, u8, u8, u8, u8, u8);
+void task_free_buf_after_copying_tile_data_to_vram(u8 taskId);
+void sub_8198C78(void);
 
 void InitStandardTextBoxWindows(void)
 {
diff --git a/src/menu_helpers.c b/src/menu_helpers.c
index 846c23b6b..1f9979eca 100644
--- a/src/menu_helpers.c
+++ b/src/menu_helpers.c
@@ -18,8 +18,6 @@
 #include "constants/items.h"
 #include "constants/maps.h"
 
-extern bool32 sub_800B504(void);
-
 // this file's functions
 static void Task_ContinueTaskAfterMessagePrints(u8 taskId);
 static void Task_CallYesOrNoCallback(u8 taskId);
diff --git a/src/mystery_event_script.c b/src/mystery_event_script.c
index 4196bb34c..dba914b51 100644
--- a/src/mystery_event_script.c
+++ b/src/mystery_event_script.c
@@ -17,8 +17,6 @@
 #include "mystery_event_msg.h"
 #include "pokemon_storage_system.h"
 
-extern void sub_811EFC0(u8);
-
 extern ScrCmdFunc gMysteryEventScriptCmdTable[];
 extern ScrCmdFunc gMysteryEventScriptCmdTableEnd[];
 
diff --git a/src/option_menu.c b/src/option_menu.c
index 122ba8d8a..caeb3d5da 100644
--- a/src/option_menu.c
+++ b/src/option_menu.c
@@ -13,8 +13,7 @@
 #include "text_window.h"
 #include "international_string_util.h"
 #include "strings.h"
-
-extern void SetPokemonCryStereo(u32 val);
+#include "gba/m4a_internal.h"
 
 // Task data
 enum
diff --git a/src/poison.c b/src/poison.c
index c86ec2cd8..9af981694 100644
--- a/src/poison.c
+++ b/src/poison.c
@@ -3,8 +3,6 @@
 #include "trig.h"
 #include "constants/rgb.h"
 
-extern void sub_80A77C8(struct Sprite *);
-
 void sub_810DBAC(struct Sprite *);
 void sub_810DC2C(struct Sprite *);
 void sub_810DCD0(struct Sprite *);
diff --git a/src/pokeblock_feed.c b/src/pokeblock_feed.c
index b1f182b66..42a71ad52 100644
--- a/src/pokeblock_feed.c
+++ b/src/pokeblock_feed.c
@@ -55,8 +55,6 @@ extern struct MusicPlayerInfo gMPlayInfo_BGM;
 extern const struct CompressedSpriteSheet gMonFrontPicTable[];
 extern const u16 gUnknown_0860F074[];
 
-extern bool8 sub_81221EC(void);
-
 // this file's functions
 static void HandleInitBackgrounds(void);
 static void HandleInitWindows(void);
diff --git a/src/pokemon.c b/src/pokemon.c
index a35033d49..a984abbb9 100644
--- a/src/pokemon.c
+++ b/src/pokemon.c
@@ -10,6 +10,7 @@
 #include "battle_tower.h"
 #include "event_data.h"
 #include "evolution_scene.h"
+#include "field_specials.h"
 #include "item.h"
 #include "link.h"
 #include "main.h"
@@ -72,10 +73,6 @@ extern const struct CompressedSpritePalette gMonPaletteTable[];
 extern const struct CompressedSpritePalette gMonShinyPaletteTable[];
 extern const u8 gTrainerClassNames[][13];
 
-extern u16 get_unknown_box_id(void);
-extern void set_unknown_box_id(u8);
-extern bool8 sub_806F104(void);
-
 // this file's functions
 static u16 CalculateBoxMonChecksum(struct BoxPokemon *boxMon);
 static union PokemonSubstruct *GetSubstruct(struct BoxPokemon *boxMon, u32 personality, u8 substructType);
diff --git a/src/pokemon_size_record.c b/src/pokemon_size_record.c
index b0e14d2b1..98d83d8ce 100644
--- a/src/pokemon_size_record.c
+++ b/src/pokemon_size_record.c
@@ -1,5 +1,6 @@
 #include "global.h"
 #include "event_data.h"
+#include "pokedex.h"
 #include "pokemon.h"
 #include "pokemon_size_record.h"
 #include "string_util.h"
@@ -15,9 +16,6 @@ struct UnknownStruct
     u16 unk4;
 };
 
-extern u16 GetPokedexHeightWeight(u16 dexNo, bool8 height);
-extern u16 SpeciesToNationalPokedexNum(u16 species);
-
 static const struct UnknownStruct sBigMonSizeTable[] =
 {
     {  290,   1,      0 },
diff --git a/src/script_menu.c b/src/script_menu.c
index 7180bfc60..d9dbc770c 100644
--- a/src/script_menu.c
+++ b/src/script_menu.c
@@ -1312,7 +1312,7 @@ static void Task_HandleMultichoiceGridInput(u8 taskId)
 
 #undef tWindowId
 
-bool8 ScrSpecial_CreatePCMenu(void)
+bool16 ScrSpecial_CreatePCMenu(void)
 {
     if (FuncIsActiveTask(Task_HandleMultichoiceInput) == TRUE)
     {
diff --git a/src/water.c b/src/water.c
index d13b1378e..c856b9aa4 100644
--- a/src/water.c
+++ b/src/water.c
@@ -41,7 +41,6 @@ extern void sub_8108BE0(struct Sprite *);
 extern void sub_8108C08(struct Sprite *);
 extern void sub_8108C54(struct Sprite *);
 extern void sub_8108CDC(struct Sprite *);
-extern void sub_80A8EE4(struct Sprite *);
 void sub_810756C(u8);
 void sub_81076F4(u8);
 void sub_8107B84(u8);