diff --git a/asm/pokedex_area_screen.s b/asm/pokedex_area_screen.s
index b599b365c..9bf70a379 100644
--- a/asm/pokedex_area_screen.s
+++ b/asm/pokedex_area_screen.s
@@ -362,7 +362,7 @@ sub_813CD04: @ 813CD04
 	adds r1, r3, 0
 	bl get_mapheader_by_bank_and_number
 	ldrb r0, [r0, 0x14]
-	bl sub_8123F9C
+	bl CorrectSpecialMapSecId
 	ldr r2, [r4]
 	movs r1, 0x88
 	lsls r1, 1
@@ -653,7 +653,7 @@ _0813CF5A:
 	adds r0, r4, 0
 	adds r1, r6, 0
 	str r3, [sp]
-	bl sub_8123E9C
+	bl GetRegionMapSectionIdAt
 	ldr r3, [sp]
 	ldr r2, [r3]
 	mov r7, r9
@@ -1338,11 +1338,11 @@ _0813D4F8:
 	bl sub_8122D88
 	movs r0, 0x1
 	movs r1, 0x1
-	bl sub_8124288
+	bl CreateRegionMapPlayerIcon
 	movs r1, 0x8
 	negs r1, r1
 	movs r0, 0
-	bl sub_8123824
+	bl PokedexAreaScreen_UpdateRegionMapVariablesAndVideoRegs
 	b _0813D584
 	.pool
 _0813D520:
diff --git a/asm/pokenav.s b/asm/pokenav.s
index b242118aa..3ef99338e 100755
--- a/asm/pokenav.s
+++ b/asm/pokenav.s
@@ -10991,7 +10991,7 @@ _081CC784:
 	bne _081CC7AC
 	movs r0, 0x4
 	movs r1, 0x9
-	bl sub_8124288
+	bl CreateRegionMapPlayerIcon
 	movs r0, 0x5
 	movs r1, 0xA
 	bl CreateRegionMapCursor
diff --git a/asm/region_map.s b/asm/region_map.s
index f7b8bb1a8..d8ab93984 100644
--- a/asm/region_map.s
+++ b/asm/region_map.s
@@ -5,94 +5,6 @@
 
 	.text
 
-	thumb_func_start sub_81243B0
-sub_81243B0: @ 81243B0
-	push {lr}
-	ldr r3, =gRegionMap
-	ldr r0, [r3]
-	ldr r2, [r0, 0x20]
-	cmp r2, 0
-	beq _081243CE
-	adds r2, 0x3E
-	ldrb r0, [r2]
-	movs r1, 0x4
-	orrs r0, r1
-	strb r0, [r2]
-	ldr r0, [r3]
-	ldr r1, [r0, 0x20]
-	ldr r0, =SpriteCallbackDummy
-	str r0, [r1, 0x1C]
-_081243CE:
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end sub_81243B0
-
-	thumb_func_start sub_81243DC
-sub_81243DC: @ 81243DC
-	push {lr}
-	ldr r0, =gRegionMap
-	ldr r3, [r0]
-	ldr r1, [r3, 0x20]
-	cmp r1, 0
-	beq _08124452
-	adds r0, r3, 0
-	adds r0, 0x78
-	ldrb r0, [r0]
-	cmp r0, 0x1
-	bne _0812441C
-	adds r0, r3, 0
-	adds r0, 0x74
-	ldrh r0, [r0]
-	lsls r0, 4
-	subs r0, 0x30
-	strh r0, [r1, 0x20]
-	ldr r1, [r3, 0x20]
-	adds r0, r3, 0
-	adds r0, 0x76
-	ldrh r0, [r0]
-	lsls r0, 4
-	subs r0, 0x42
-	strh r0, [r1, 0x22]
-	ldr r1, [r3, 0x20]
-	ldr r0, =sub_812445C
-	b _08124444
-	.pool
-_0812441C:
-	adds r0, r3, 0
-	adds r0, 0x74
-	ldrh r0, [r0]
-	lsls r0, 3
-	adds r0, 0x4
-	movs r2, 0
-	strh r0, [r1, 0x20]
-	ldr r1, [r3, 0x20]
-	adds r0, r3, 0
-	adds r0, 0x76
-	ldrh r0, [r0]
-	lsls r0, 3
-	adds r0, 0x4
-	strh r0, [r1, 0x22]
-	ldr r0, [r3, 0x20]
-	strh r2, [r0, 0x24]
-	ldr r0, [r3, 0x20]
-	strh r2, [r0, 0x26]
-	ldr r1, [r3, 0x20]
-	ldr r0, =sub_81244EC
-_08124444:
-	str r0, [r1, 0x1C]
-	adds r1, 0x3E
-	ldrb r2, [r1]
-	movs r0, 0x5
-	negs r0, r0
-	ands r0, r2
-	strb r0, [r1]
-_08124452:
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end sub_81243DC
-
 	thumb_func_start sub_812445C
 sub_812445C: @ 812445C
 	push {r4,lr}
@@ -521,7 +433,7 @@ _0812479C:
 	bl CreateRegionMapCursor
 	movs r0, 0x1
 	movs r1, 0x1
-	bl sub_8124288
+	bl CreateRegionMapPlayerIcon
 	ldr r0, [r4]
 	ldrh r1, [r0, 0x8]
 	strh r1, [r0, 0x6]
diff --git a/include/region_map.h b/include/region_map.h
index 272ffd5b5..bcd94ea9d 100644
--- a/include/region_map.h
+++ b/include/region_map.h
@@ -225,7 +225,7 @@ enum {
 struct RegionMap {
     /*0x000*/ u16 mapSecId;
     /*0x002*/ u8 iconDrawType;
-    /*0x003*/ u8 unk_003;
+    /*0x003*/ u8 posWithinMapSec;
     /*0x004*/ u8 mapSecName[0x14];
     /*0x018*/ u8 (*inputCallback)(void);
     /*0x01c*/ struct Sprite *cursorSprite;
@@ -303,9 +303,10 @@ bool8 sub_8122DB0(void);
 void UpdateRegionMapVideoRegs(void);
 void InitRegionMap(struct RegionMap *regionMap, u8 argument);
 u8 sub_81230AC(void);
+bool8 sub_8123514(void);
 void FreeRegionMapIconResources(void);
-u16 sub_8123E9C(u16 x, u16 y);
-void sub_8124288(u16 x, u16 y);
+u16 GetRegionMapSectionIdAt(u16 x, u16 y);
+void CreateRegionMapPlayerIcon(u16 x, u16 y);
 void CreateRegionMapCursor(u16 tileTag, u16 paletteTag);
 bool32 sub_8124668(u16 mapSecId);
 void GetMapName(u8 *, u16, u16);
diff --git a/src/field_region_map.c b/src/field_region_map.c
index 6c483c6b6..776ca6934 100644
--- a/src/field_region_map.c
+++ b/src/field_region_map.c
@@ -23,15 +23,15 @@ static EWRAM_DATA struct {
     u32 filler_004;
     struct RegionMap regionMap;
     u16 state;
-} *gUnknown_0203BCD0 = NULL;
+} *sFieldRegionMapHandler = NULL;
 
 // Static ROM declarations
 
-static void sub_81701C4(void);
-static void sub_8170260(void);
-static void sub_8170274(void);
-static void sub_8170290(void);
-static void sub_8170428(void);
+static void MCB2_InitRegionMapRegisters(void);
+static void VBCB_FieldUpdateRegionMap(void);
+static void MCB2_FieldUpdateRegionMap(void);
+static void FieldUpdateRegionMap(void);
+static void PrintRegionMapSecName(void);
 
 // .rodata
 
@@ -68,13 +68,13 @@ static const struct WindowTemplate gUnknown_085E5070[] = {
 void sub_817018C(MainCallback callback)
 {
     SetVBlankCallback(NULL);
-    gUnknown_0203BCD0 = malloc(sizeof(*gUnknown_0203BCD0));
-    gUnknown_0203BCD0->state = 0;
-    gUnknown_0203BCD0->callback = callback;
-    SetMainCallback2(sub_81701C4);
+    sFieldRegionMapHandler = malloc(sizeof(*sFieldRegionMapHandler));
+    sFieldRegionMapHandler->state = 0;
+    sFieldRegionMapHandler->callback = callback;
+    SetMainCallback2(MCB2_InitRegionMapRegisters);
 }
 
-static void sub_81701C4(void)
+static void MCB2_InitRegionMapRegisters(void)
 {
     SetGpuReg(REG_OFFSET_DISPCNT, 0);
     SetGpuReg(REG_OFFSET_BG0HOFS, 0);
@@ -93,37 +93,37 @@ static void sub_81701C4(void)
     DeactivateAllTextPrinters();
     sub_809882C(0, 0x27, 0xd0);
     clear_scheduled_bg_copies_to_vram();
-    SetMainCallback2(sub_8170274);
-    SetVBlankCallback(sub_8170260);
+    SetMainCallback2(MCB2_FieldUpdateRegionMap);
+    SetVBlankCallback(VBCB_FieldUpdateRegionMap);
 }
 
-static void sub_8170260(void)
+static void VBCB_FieldUpdateRegionMap(void)
 {
     LoadOam();
     ProcessSpriteCopyRequests();
     TransferPlttBuffer();
 }
 
-static void sub_8170274(void)
+static void MCB2_FieldUpdateRegionMap(void)
 {
-    sub_8170290();
+    FieldUpdateRegionMap();
     AnimateSprites();
     BuildOamBuffer();
     UpdatePaletteFade();
     do_scheduled_bg_tilemap_copies_to_vram();
 }
 
-void sub_8170290(void)
+static void FieldUpdateRegionMap(void)
 {
     u8 offset;
 
-    switch (gUnknown_0203BCD0->state)
+    switch (sFieldRegionMapHandler->state)
     {
         case 0:
-            InitRegionMap(&gUnknown_0203BCD0->regionMap, 0);
-            sub_8124288(0, 0);
+            InitRegionMap(&sFieldRegionMapHandler->regionMap, 0);
+            CreateRegionMapPlayerIcon(0, 0);
             CreateRegionMapCursor(1, 1);
-            gUnknown_0203BCD0->state ++;
+            sFieldRegionMapHandler->state ++;
             break;
         case 1:
             SetWindowBorderStyle(1, 0, 0x27, 0xd);
@@ -131,47 +131,47 @@ void sub_8170290(void)
             PrintTextOnWindow(1, 1, gText_Hoenn, offset, 1, 0, NULL);
             schedule_bg_copy_tilemap_to_vram(0);
             SetWindowBorderStyle(0, 0, 0x27, 0xd);
-            sub_8170428();
+            PrintRegionMapSecName();
             BeginNormalPaletteFade(-1, 0, 16, 0, 0);
-            gUnknown_0203BCD0->state ++;
+            sFieldRegionMapHandler->state ++;
             break;
         case 2:
             SetGpuRegBits(REG_OFFSET_DISPCNT, DISPCNT_OBJ_1D_MAP | DISPCNT_OBJ_ON);
             ShowBg(0);
             ShowBg(2);
-            gUnknown_0203BCD0->state ++;
+            sFieldRegionMapHandler->state ++;
             break;
         case 3:
             if (!gPaletteFade.active)
             {
-                gUnknown_0203BCD0->state ++;
+                sFieldRegionMapHandler->state ++;
             }
             break;
         case 4:
             switch (sub_81230AC())
             {
                 case INPUT_EVENT_MOVE_END:
-                    sub_8170428();
+                    PrintRegionMapSecName();
                     break;
                 case INPUT_EVENT_A_BUTTON:
                 case INPUT_EVENT_B_BUTTON:
-                    gUnknown_0203BCD0->state ++;
+                    sFieldRegionMapHandler->state ++;
                     break;
             }
             break;
         case 5:
             BeginNormalPaletteFade(-1, 0, 0, 16, 0);
-            gUnknown_0203BCD0->state ++;
+            sFieldRegionMapHandler->state ++;
             break;
         case 6:
             if (!gPaletteFade.active)
             {
                 FreeRegionMapIconResources();
-                SetMainCallback2(gUnknown_0203BCD0->callback);
-                if (gUnknown_0203BCD0 != NULL)
+                SetMainCallback2(sFieldRegionMapHandler->callback);
+                if (sFieldRegionMapHandler != NULL)
                 {
-                    free(gUnknown_0203BCD0);
-                    gUnknown_0203BCD0 = NULL;
+                    free(sFieldRegionMapHandler);
+                    sFieldRegionMapHandler = NULL;
                 }
                 FreeAllWindowBuffers();
             }
@@ -179,12 +179,12 @@ void sub_8170290(void)
     }
 }
 
-static void sub_8170428(void)
+static void PrintRegionMapSecName(void)
 {
-    if (gUnknown_0203BCD0->regionMap.iconDrawType != 0)
+    if (sFieldRegionMapHandler->regionMap.iconDrawType != MAPSECTYPE_NONE)
     {
         FillWindowPixelBuffer(0, 0x11);
-        PrintTextOnWindow(0, 1, gUnknown_0203BCD0->regionMap.mapSecName, 0, 1, 0, NULL);
+        PrintTextOnWindow(0, 1, sFieldRegionMapHandler->regionMap.mapSecName, 0, 1, 0, NULL);
         schedule_bg_copy_tilemap_to_vram(0);
     }
     else
diff --git a/src/region_map.c b/src/region_map.c
index 241cb1b15..78bcfb563 100644
--- a/src/region_map.c
+++ b/src/region_map.c
@@ -45,20 +45,20 @@ static u8 MoveRegionMapCursor_Full(void);
 static u8 ProcessRegionMapInput_Zoomed(void);
 static u8 MoveRegionMapCursor_Zoomed(void);
 static void CalcZoomScrollParams(s16 scrollX, s16 scrollY, s16 c, s16 d, u16 e, u16 f, u8 rotation);
-u16 GetRegionMapSectionIdAt(u16 x, u16 y);
-static void sub_812378C(s16 x, s16 y);
-static void sub_81238AC(void);
-static void sub_8123C00(void);
+static u16 GetRegionMapSectionIdAt_Internal(u16 x, u16 y);
+static void RegionMap_SetBG2XAndBG2Y(s16 x, s16 y);
+static void RegionMap_InitializeStateBasedOnPlayerLocation(void);
+static void RegionMap_InitializeStateBasedOnSSTidalLocation(void);
 static u8 get_flagnr_blue_points(u16 mapSecId);
-u16 sub_8123EB4(u16 mapSecId);
-static u16 sub_8123F04(void);
-static void sub_8123F30(u16 *x, u16 *y);
-static bool32 sub_8123F74(u8 mapSecId);
-static void sub_8123FB0(void);
-static bool8 sub_8124038(u16 y);
-static void sub_8124238(void);
-void sub_81243B0(void);
-void sub_81243DC(void);
+static u16 CorrectSpecialMapSecId_Internal(u16 mapSecId);
+static u16 RegionMap_GetTerraCaveMapSecId(void);
+static void RegionMap_GetMarineCaveCoords(u16 *x, u16 *y);
+static bool32 RegionMap_IsPlayerInCave(u8 mapSecId);
+static void RegionMap_GetPositionOfCursorWithinMapSection(void);
+static bool8 RegionMap_IsMapSecIdInNextRow(u16 y);
+static void FreeRegionMapCursorSprite(void);
+static void HideRegionMapPlayerIcon(void);
+static void UnhideRegionMapPlayerIcon(void);
 void sub_812445C(struct Sprite *sprite);
 void sub_81244EC(struct Sprite *sprite);
 
@@ -118,7 +118,7 @@ void sub_8122CF8(struct RegionMap *regionMap, struct BgTemplate *template, bool8
 void sub_8122D88(struct RegionMap *regionMap)
 {
     gRegionMap = regionMap;
-    sub_81238AC();
+    RegionMap_InitializeStateBasedOnPlayerLocation();
     gRegionMap->playerIconSpritePosX = gRegionMap->cursorPosX;
     gRegionMap->playerIconSpritePosY = gRegionMap->cursorPosY;
 }
@@ -163,10 +163,10 @@ bool8 sub_8122DB0(void)
             LZ77UnCompWram(gUnknown_0859F650, gRegionMap->cursorLargeImage);
             break;
         case 5:
-            sub_81238AC();
+            RegionMap_InitializeStateBasedOnPlayerLocation();
             gRegionMap->playerIconSpritePosX = gRegionMap->cursorPosX;
             gRegionMap->playerIconSpritePosY = gRegionMap->cursorPosY;
-            gRegionMap->mapSecId = sub_8123EB4(gRegionMap->mapSecId);
+            gRegionMap->mapSecId = CorrectSpecialMapSecId_Internal(gRegionMap->mapSecId);
             gRegionMap->iconDrawType = get_flagnr_blue_points(gRegionMap->mapSecId);
             GetMapName(gRegionMap->mapSecName, gRegionMap->mapSecId, 16);
             break;
@@ -185,7 +185,7 @@ bool8 sub_8122DB0(void)
             }
             break;
         case 7:
-            sub_8123FB0();
+            RegionMap_GetPositionOfCursorWithinMapSection();
             UpdateRegionMapVideoRegs();
             gRegionMap->cursorSprite = NULL;
             gRegionMap->playerIconSprite = NULL;
@@ -302,14 +302,14 @@ static u8 MoveRegionMapCursor_Full(void)
     {
         gRegionMap->cursorPosY --;
     }
-    mapSecId = GetRegionMapSectionIdAt(gRegionMap->cursorPosX, gRegionMap->cursorPosY);
+    mapSecId = GetRegionMapSectionIdAt_Internal(gRegionMap->cursorPosX, gRegionMap->cursorPosY);
     gRegionMap->iconDrawType = get_flagnr_blue_points(mapSecId);
     if (mapSecId != gRegionMap->mapSecId)
     {
         gRegionMap->mapSecId = mapSecId;
         GetMapName(gRegionMap->mapSecName, gRegionMap->mapSecId, 16);
     }
-    sub_8123FB0();
+    RegionMap_GetPositionOfCursorWithinMapSection();
     gRegionMap->inputCallback = ProcessRegionMapInput_Full;
     return INPUT_EVENT_MOVE_END;
 }
@@ -365,7 +365,7 @@ static u8 MoveRegionMapCursor_Zoomed(void)
 
     gRegionMap->scrollY += gRegionMap->zoomedCursorDeltaY;
     gRegionMap->scrollX += gRegionMap->zoomedCursorDeltaX;
-    sub_812378C(gRegionMap->scrollX, gRegionMap->scrollY);
+    RegionMap_SetBG2XAndBG2Y(gRegionMap->scrollX, gRegionMap->scrollY);
     gRegionMap->zoomedCursorMovementFrameCounter ++;
     if (gRegionMap->zoomedCursorMovementFrameCounter == 8)
     {
@@ -375,14 +375,14 @@ static u8 MoveRegionMapCursor_Zoomed(void)
         {
             gRegionMap->zoomedCursorPosX = x;
             gRegionMap->zoomedCursorPosY = y;
-            mapSecId = GetRegionMapSectionIdAt(x, y);
+            mapSecId = GetRegionMapSectionIdAt_Internal(x, y);
             gRegionMap->iconDrawType = get_flagnr_blue_points(mapSecId);
             if (mapSecId != gRegionMap->mapSecId)
             {
                 gRegionMap->mapSecId = mapSecId;
                 GetMapName(gRegionMap->mapSecName, gRegionMap->mapSecId, 16);
             }
-            sub_8123FB0();
+            RegionMap_GetPositionOfCursorWithinMapSection();
         }
         gRegionMap->zoomedCursorMovementFrameCounter = 0;
         gRegionMap->inputCallback = ProcessRegionMapInput_Zoomed;
@@ -422,13 +422,13 @@ void sub_8123418(void)
         gRegionMap->unk_050 = 0x800;
     }
     gRegionMap->unk_06e = 0;
-    sub_8124238();
-    sub_81243B0();
+    FreeRegionMapCursorSprite();
+    HideRegionMapPlayerIcon();
 }
 
-u8 sub_8123514(void)
+bool8 sub_8123514(void)
 {
-    u8 r4;
+    bool8 r4;
 
     if (gRegionMap->unk_06e >= 16)
     {
@@ -445,8 +445,8 @@ u8 sub_8123514(void)
         gRegionMap->zoomed = !gRegionMap->zoomed;
         gRegionMap->inputCallback = (gRegionMap->zoomed == FALSE) ? ProcessRegionMapInput_Full : ProcessRegionMapInput_Zoomed;
         CreateRegionMapCursor(gRegionMap->cursorTileTag, gRegionMap->cursorPaletteTag);
-        sub_81243DC();
-        r4 = 0;
+        UnhideRegionMapPlayerIcon();
+        r4 = FALSE;
     }
     else
     {
@@ -481,7 +481,7 @@ u8 sub_8123514(void)
                 gRegionMap->unk_050 = 0;
             }
         }
-        r4 = 1;
+        r4 = TRUE;
     }
     CalcZoomScrollParams(gRegionMap->scrollX, gRegionMap->scrollY, 0x38, 0x48, gRegionMap->unk_04c >> 8, gRegionMap->unk_04c >> 8, 0);
     return r4;
@@ -510,7 +510,7 @@ static void CalcZoomScrollParams(s16 scrollX, s16 scrollY, s16 c, s16 d, u16 e,
     gRegionMap->needUpdateVideoRegs = TRUE;
 }
 
-static void sub_812378C(s16 x, s16 y)
+static void RegionMap_SetBG2XAndBG2Y(s16 x, s16 y)
 {
     gRegionMap->bg2x = (x << 8) + 0x1c00;
     gRegionMap->bg2y = (y << 8) + 0x2400;
@@ -533,7 +533,7 @@ void UpdateRegionMapVideoRegs(void)
     }
 }
 
-void sub_8123824(s16 x, s16 y)
+void PokedexAreaScreen_UpdateRegionMapVariablesAndVideoRegs(s16 x, s16 y)
 {
     CalcZoomScrollParams(x, y, 0x38, 0x48, 0x100, 0x100, 0);
     UpdateRegionMapVideoRegs();
@@ -544,7 +544,7 @@ void sub_8123824(s16 x, s16 y)
     }
 }
 
-u16 GetRegionMapSectionIdAt(u16 x, u16 y)
+static u16 GetRegionMapSectionIdAt_Internal(u16 x, u16 y)
 {
     if (y < MAPCURSOR_Y_MIN || y > MAPCURSOR_Y_MAX || x < MAPCURSOR_X_MIN || x > MAPCURSOR_X_MAX)
     {
@@ -555,7 +555,7 @@ u16 GetRegionMapSectionIdAt(u16 x, u16 y)
     return gUnknown_085A096C[x + y * MAP_WIDTH];
 }
 
-static void sub_81238AC(void)
+static void RegionMap_InitializeStateBasedOnPlayerLocation(void)
 {
     const struct MapHeader *mapHeader;
     u16 mapWidth;
@@ -571,7 +571,7 @@ static void sub_81238AC(void)
             || gSaveBlock1Ptr->location.mapNum == MAP_ID_SS_TIDAL_LOWER_DECK
             || gSaveBlock1Ptr->location.mapNum == MAP_ID_SS_TIDAL_ROOMS))
     {
-        sub_8123C00();
+        RegionMap_InitializeStateBasedOnSSTidalLocation();
         return;
     }
 
@@ -639,7 +639,7 @@ static void sub_81238AC(void)
                 mapHeader = get_mapheader_by_bank_and_number(r4->mapGroup, r4->mapNum);
                 gRegionMap->mapSecId = mapHeader->regionMapSectionId;
             }
-            if (sub_8123F74(gRegionMap->mapSecId))
+            if (RegionMap_IsPlayerInCave(gRegionMap->mapSecId))
             {
                 gRegionMap->playerIsInCave = TRUE;
             }
@@ -723,14 +723,14 @@ static void sub_81238AC(void)
             }
             break;
         case MAPSEC_UNDERWATER_MARINE_CAVE:
-            sub_8123F30(&gRegionMap->cursorPosX, &gRegionMap->cursorPosY);
+            RegionMap_GetMarineCaveCoords(&gRegionMap->cursorPosX, &gRegionMap->cursorPosY);
             return;
     }
     gRegionMap->cursorPosX = gRegionMapEntries[gRegionMap->mapSecId].x + x + MAPCURSOR_X_MIN;
     gRegionMap->cursorPosY = gRegionMapEntries[gRegionMap->mapSecId].y + y + MAPCURSOR_Y_MIN;
 }
 
-static void sub_8123C00(void)
+static void RegionMap_InitializeStateBasedOnSSTidalLocation(void)
 {
     u16 y;
     u16 x;
@@ -829,12 +829,12 @@ static u8 get_flagnr_blue_points(u16 mapSecId)
     }
 }
 
-u16 sub_8123E9C(u16 x, u16 y)
+u16 GetRegionMapSectionIdAt(u16 x, u16 y)
 {
-    return GetRegionMapSectionIdAt(x, y);
+    return GetRegionMapSectionIdAt_Internal(x, y);
 }
 
-u16 sub_8123EB4(u16 mapSecId)
+static u16 CorrectSpecialMapSecId_Internal(u16 mapSecId)
 {
     u32 i;
 
@@ -842,7 +842,7 @@ u16 sub_8123EB4(u16 mapSecId)
     {
         if (gUnknown_085A1B84[i] == mapSecId)
         {
-            return sub_8123F04();
+            return RegionMap_GetTerraCaveMapSecId();
         }
     }
     for (i = 0; gUnknown_085A1B24[i][0] != MAPSEC_NONE; i ++)
@@ -855,7 +855,7 @@ u16 sub_8123EB4(u16 mapSecId)
     return mapSecId;
 }
 
-static u16 sub_8123F04(void)
+static u16 RegionMap_GetTerraCaveMapSecId(void)
 {
     s16 idx;
 
@@ -867,7 +867,7 @@ static u16 sub_8123F04(void)
     return gUnknown_085A1B8A[idx];
 }
 
-static void sub_8123F30(u16 *x, u16 *y)
+static void RegionMap_GetMarineCaveCoords(u16 *x, u16 *y)
 {
     u16 idx;
 
@@ -881,7 +881,7 @@ static void sub_8123F30(u16 *x, u16 *y)
     *y = gUnknown_085A1BAC[idx].y + MAPCURSOR_Y_MIN;
 }
 
-static bool32 sub_8123F74(u8 mapSecId)
+static bool32 RegionMap_IsPlayerInCave(u8 mapSecId)
 {
     int i;
 
@@ -895,20 +895,20 @@ static bool32 sub_8123F74(u8 mapSecId)
     return FALSE;
 }
 
-u16 sub_8123F9C(u16 mapSecId)
+u16 CorrectSpecialMapSecId(u16 mapSecId)
 {
-    return sub_8123EB4(mapSecId);
+    return CorrectSpecialMapSecId_Internal(mapSecId);
 }
 
-static void sub_8123FB0(void)
+static void RegionMap_GetPositionOfCursorWithinMapSection(void)
 {
     u16 x;
     u16 y;
-    u16 unk_003;
+    u16 posWithinMapSec;
 
     if (gRegionMap->mapSecId == MAPSEC_NONE)
     {
-        gRegionMap->unk_003 = 0;
+        gRegionMap->posWithinMapSec = 0;
         return;
     }
     if (!gRegionMap->zoomed)
@@ -921,12 +921,12 @@ static void sub_8123FB0(void)
         x = gRegionMap->zoomedCursorPosX;
         y = gRegionMap->zoomedCursorPosY;
     }
-    unk_003 = 0;
+    posWithinMapSec = 0;
     while (1)
     {
         if (x <= MAPCURSOR_X_MIN)
         {
-            if (sub_8124038(y))
+            if (RegionMap_IsMapSecIdInNextRow(y))
             {
                 y --;
                 x = MAPCURSOR_X_MAX + 1;
@@ -939,26 +939,26 @@ static void sub_8123FB0(void)
         else
         {
             x --;
-            if (GetRegionMapSectionIdAt(x, y) == gRegionMap->mapSecId)
+            if (GetRegionMapSectionIdAt_Internal(x, y) == gRegionMap->mapSecId)
             {
-                unk_003 ++;
+                posWithinMapSec ++;
             }
         }
     }
-    gRegionMap->unk_003 = unk_003;
+    gRegionMap->posWithinMapSec = posWithinMapSec;
 }
 
-static bool8 sub_8124038(u16 y)
+static bool8 RegionMap_IsMapSecIdInNextRow(u16 y)
 {
     u16 x;
 
     if (y -- == 0)
     {
-        return 0;
+        return FALSE;
     }
     for (x = MAPCURSOR_X_MIN; x <= MAPCURSOR_X_MAX; x ++)
     {
-        if (GetRegionMapSectionIdAt(x, y) == gRegionMap->mapSecId)
+        if (GetRegionMapSectionIdAt_Internal(x, y) == gRegionMap->mapSecId)
         {
             return TRUE;
         }
@@ -966,7 +966,7 @@ static bool8 sub_8124038(u16 y)
     return FALSE;
 }
 
-static void sub_8124088(struct Sprite *sprite)
+static void SpriteCallback_CursorFull(struct Sprite *sprite)
 {
     if (gRegionMap->cursorMovementFrameCounter != 0)
     {
@@ -976,7 +976,7 @@ static void sub_8124088(struct Sprite *sprite)
     }
 }
 
-static void TaskDummy8(struct Sprite *sprite)
+static void SpriteCallback_CursorZoomed(struct Sprite *sprite)
 {
 
 }
@@ -1000,13 +1000,13 @@ void CreateRegionMapCursor(u16 tileTag, u16 paletteTag)
     {
         sheet.data = gRegionMap->cursorSmallImage;
         sheet.size = sizeof(gRegionMap->cursorSmallImage);
-        template.callback = sub_8124088;
+        template.callback = SpriteCallback_CursorFull;
     }
     else
     {
         sheet.data = gRegionMap->cursorLargeImage;
         sheet.size = sizeof(gRegionMap->cursorLargeImage);
-        template.callback = TaskDummy8;
+        template.callback = SpriteCallback_CursorZoomed;
     }
     LoadSpriteSheet(&sheet);
     LoadSpritePalette(&palette);
@@ -1033,7 +1033,7 @@ void CreateRegionMapCursor(u16 tileTag, u16 paletteTag)
     }
 }
 
-static void sub_8124238(void)
+static void FreeRegionMapCursorSprite(void)
 {
     if (gRegionMap->cursorSprite != NULL)
     {
@@ -1053,7 +1053,7 @@ void sub_8124278(void)
     gRegionMap->cursorSprite->data3 = FALSE;
 }
 
-void sub_8124288(u16 tileTag, u16 paletteTag)
+void CreateRegionMapPlayerIcon(u16 tileTag, u16 paletteTag)
 {
     u8 spriteId;
     struct SpriteSheet sheet = {gUnknown_085A084C, 0x80, tileTag};
@@ -1087,3 +1087,35 @@ void sub_8124288(u16 tileTag, u16 paletteTag)
         gRegionMap->playerIconSprite->callback = sub_812445C;
     }
 }
+
+static void HideRegionMapPlayerIcon(void)
+{
+    if (gRegionMap->playerIconSprite != NULL)
+    {
+        gRegionMap->playerIconSprite->invisible = TRUE;
+        gRegionMap->playerIconSprite->callback = SpriteCallbackDummy;
+    }
+}
+
+static void UnhideRegionMapPlayerIcon(void)
+{
+    if (gRegionMap->playerIconSprite != NULL)
+    {
+        if (gRegionMap->zoomed == TRUE)
+        {
+            gRegionMap->playerIconSprite->pos1.x = gRegionMap->playerIconSpritePosX * 16 - 0x30;
+            gRegionMap->playerIconSprite->pos1.y = gRegionMap->playerIconSpritePosY * 16 - 0x42;
+            gRegionMap->playerIconSprite->callback = sub_812445C;
+            gRegionMap->playerIconSprite->invisible = FALSE;
+        }
+        else
+        {
+            gRegionMap->playerIconSprite->pos1.x = gRegionMap->playerIconSpritePosX * 8 + 4;
+            gRegionMap->playerIconSprite->pos1.y = gRegionMap->playerIconSpritePosY * 8 + 4;
+            gRegionMap->playerIconSprite->pos2.x = 0;
+            gRegionMap->playerIconSprite->pos2.y = 0;
+            gRegionMap->playerIconSprite->callback = sub_81244EC;
+            gRegionMap->playerIconSprite->invisible = FALSE;
+        }
+    }
+}