diff --git a/asm/dungeon_map_access.s b/asm/dungeon_map_access.s
index b5af22572..738ac1a2b 100644
--- a/asm/dungeon_map_access.s
+++ b/asm/dungeon_map_access.s
@@ -5,431 +5,6 @@
 
   	.text
 
-	thumb_func_start sub_8049BB0
-sub_8049BB0:
-	push {r4-r7,lr}
-	mov r7, r10
-	mov r6, r9
-	mov r5, r8
-	push {r5-r7}
-	sub sp, 0x44
-	mov r10, r0
-	str r1, [sp, 0x40]
-	movs r0, 0
-	str r0, [sp]
-	str r0, [sp, 0x4]
-	str r0, [sp, 0x8]
-	str r0, [sp, 0xC]
-	adds r0, r1, 0
-	adds r0, 0x1
-	mov r9, r0
-	mov r0, r10
-	mov r1, r9
-	bl GetTile
-	ldrh r1, [r0]
-	movs r4, 0x3
-	adds r0, r4, 0
-	ands r0, r1
-	add r6, sp, 0x18
-	str r0, [sp, 0x18]
-	mov r5, r10
-	adds r5, 0x1
-	adds r0, r5, 0
-	mov r1, r9
-	bl GetTile
-	ldrh r1, [r0]
-	adds r0, r4, 0
-	ands r0, r1
-	str r0, [r6, 0x4]
-	adds r0, r5, 0
-	ldr r1, [sp, 0x40]
-	bl GetTile
-	ldrh r1, [r0]
-	adds r0, r4, 0
-	ands r0, r1
-	str r0, [r6, 0x8]
-	ldr r0, [sp, 0x40]
-	subs r0, 0x1
-	mov r8, r0
-	adds r0, r5, 0
-	mov r1, r8
-	bl GetTile
-	ldrh r1, [r0]
-	adds r0, r4, 0
-	ands r0, r1
-	str r0, [r6, 0xC]
-	mov r0, r10
-	mov r1, r8
-	bl GetTile
-	ldrh r1, [r0]
-	adds r0, r4, 0
-	ands r0, r1
-	str r0, [r6, 0x10]
-	subs r5, 0x2
-	adds r0, r5, 0
-	mov r1, r8
-	bl GetTile
-	ldrh r1, [r0]
-	adds r0, r4, 0
-	ands r0, r1
-	str r0, [r6, 0x14]
-	adds r0, r5, 0
-	ldr r1, [sp, 0x40]
-	bl GetTile
-	ldrh r1, [r0]
-	adds r0, r4, 0
-	ands r0, r1
-	str r0, [r6, 0x18]
-	adds r0, r5, 0
-	mov r1, r9
-	bl GetTile
-	ldrh r0, [r0]
-	ands r4, r0
-	str r4, [r6, 0x1C]
-	ldr r1, [sp, 0x18]
-	cmp r1, 0x1
-	bne _08049C6A
-	ldr r0, [sp]
-	orrs r0, r1
-	str r0, [sp]
-_08049C6A:
-	ldr r0, [r6, 0x8]
-	cmp r0, 0x1
-	bne _08049C78
-	ldr r0, [sp]
-	movs r1, 0x4
-	orrs r0, r1
-	str r0, [sp]
-_08049C78:
-	ldr r0, [r6, 0x10]
-	cmp r0, 0x1
-	bne _08049C86
-	ldr r0, [sp]
-	movs r1, 0x10
-	orrs r0, r1
-	str r0, [sp]
-_08049C86:
-	ldr r0, [r6, 0x18]
-	cmp r0, 0x1
-	bne _08049C94
-	ldr r0, [sp]
-	movs r1, 0x40
-	orrs r0, r1
-	str r0, [sp]
-_08049C94:
-	ldr r2, [sp, 0x18]
-	cmp r2, 0
-	beq _08049CAE
-	ldr r0, [r6, 0x4]
-	cmp r0, 0x1
-	bne _08049CAE
-	ldr r0, [r6, 0x8]
-	cmp r0, 0
-	beq _08049CC8
-	ldr r0, [sp]
-	movs r1, 0x2
-	orrs r0, r1
-	str r0, [sp]
-_08049CAE:
-	ldr r0, [r6, 0x8]
-	cmp r0, 0
-	beq _08049CC8
-	ldr r0, [r6, 0xC]
-	cmp r0, 0x1
-	bne _08049CC8
-	ldr r0, [r6, 0x10]
-	cmp r0, 0
-	beq _08049CE2
-	ldr r0, [sp]
-	movs r1, 0x8
-	orrs r0, r1
-	str r0, [sp]
-_08049CC8:
-	ldr r0, [r6, 0x10]
-	cmp r0, 0
-	beq _08049CE2
-	ldr r0, [r6, 0x14]
-	cmp r0, 0x1
-	bne _08049CE2
-	ldr r0, [r6, 0x18]
-	cmp r0, 0
-	beq _08049CFA
-	ldr r0, [sp]
-	movs r1, 0x20
-	orrs r0, r1
-	str r0, [sp]
-_08049CE2:
-	ldr r0, [r6, 0x18]
-	cmp r0, 0
-	beq _08049CFA
-	ldr r0, [r6, 0x1C]
-	cmp r0, 0x1
-	bne _08049CFA
-	cmp r2, 0
-	beq _08049CFA
-	ldr r0, [sp]
-	movs r1, 0x80
-	orrs r0, r1
-	str r0, [sp]
-_08049CFA:
-	add r4, sp, 0x38
-	movs r7, 0x1
-	adds r2, r4, 0
-	adds r1, r6, 0
-	movs r5, 0
-	movs r3, 0x7
-_08049D06:
-	ldr r0, [r1]
-	subs r0, 0x1
-	cmp r0, 0x1
-	bhi _08049D12
-	strb r7, [r2]
-	b _08049D14
-_08049D12:
-	strb r5, [r2]
-_08049D14:
-	adds r2, 0x1
-	adds r1, 0x4
-	subs r3, 0x1
-	cmp r3, 0
-	bge _08049D06
-	ldrb r0, [r4]
-	cmp r0, 0
-	beq _08049D2C
-	ldr r0, [sp, 0x4]
-	movs r1, 0x1
-	orrs r0, r1
-	str r0, [sp, 0x4]
-_08049D2C:
-	ldrb r0, [r4, 0x2]
-	cmp r0, 0
-	beq _08049D3A
-	ldr r0, [sp, 0x4]
-	movs r1, 0x4
-	orrs r0, r1
-	str r0, [sp, 0x4]
-_08049D3A:
-	ldrb r0, [r4, 0x4]
-	cmp r0, 0
-	beq _08049D48
-	ldr r0, [sp, 0x4]
-	movs r1, 0x10
-	orrs r0, r1
-	str r0, [sp, 0x4]
-_08049D48:
-	ldrb r0, [r4, 0x6]
-	cmp r0, 0
-	beq _08049D56
-	ldr r0, [sp, 0x4]
-	movs r1, 0x40
-	orrs r0, r1
-	str r0, [sp, 0x4]
-_08049D56:
-	ldr r2, [sp, 0x18]
-	cmp r2, 0
-	beq _08049D70
-	ldrb r0, [r4, 0x1]
-	cmp r0, 0
-	beq _08049D70
-	ldr r0, [r6, 0x8]
-	cmp r0, 0
-	beq _08049D8A
-	ldr r0, [sp, 0x4]
-	movs r1, 0x2
-	orrs r0, r1
-	str r0, [sp, 0x4]
-_08049D70:
-	ldr r0, [r6, 0x8]
-	cmp r0, 0
-	beq _08049D8A
-	ldrb r0, [r4, 0x3]
-	cmp r0, 0
-	beq _08049D8A
-	ldr r0, [r6, 0x10]
-	cmp r0, 0
-	beq _08049DA4
-	ldr r0, [sp, 0x4]
-	movs r1, 0x8
-	orrs r0, r1
-	str r0, [sp, 0x4]
-_08049D8A:
-	ldr r0, [r6, 0x10]
-	cmp r0, 0
-	beq _08049DA4
-	ldrb r0, [r4, 0x5]
-	cmp r0, 0
-	beq _08049DA4
-	ldr r0, [r6, 0x18]
-	cmp r0, 0
-	beq _08049DBC
-	ldr r0, [sp, 0x4]
-	movs r1, 0x20
-	orrs r0, r1
-	str r0, [sp, 0x4]
-_08049DA4:
-	ldr r0, [r6, 0x18]
-	cmp r0, 0
-	beq _08049DBC
-	ldrb r0, [r4, 0x7]
-	cmp r0, 0
-	beq _08049DBC
-	cmp r2, 0
-	beq _08049DC8
-	ldr r0, [sp, 0x4]
-	movs r1, 0x80
-	orrs r0, r1
-	str r0, [sp, 0x4]
-_08049DBC:
-	cmp r2, 0
-	beq _08049DC8
-	ldr r0, [sp, 0x8]
-	movs r1, 0x1
-	orrs r0, r1
-	str r0, [sp, 0x8]
-_08049DC8:
-	ldr r0, [r6, 0x8]
-	cmp r0, 0
-	beq _08049DD6
-	ldr r0, [sp, 0x8]
-	movs r1, 0x4
-	orrs r0, r1
-	str r0, [sp, 0x8]
-_08049DD6:
-	ldr r0, [r6, 0x10]
-	cmp r0, 0
-	beq _08049DE4
-	ldr r0, [sp, 0x8]
-	movs r1, 0x10
-	orrs r0, r1
-	str r0, [sp, 0x8]
-_08049DE4:
-	ldr r0, [r6, 0x18]
-	cmp r0, 0
-	beq _08049DF2
-	ldr r0, [sp, 0x8]
-	movs r1, 0x40
-	orrs r0, r1
-	str r0, [sp, 0x8]
-_08049DF2:
-	cmp r2, 0
-	beq _08049E0A
-	ldr r0, [r6, 0x4]
-	cmp r0, 0
-	beq _08049E0A
-	ldr r0, [r6, 0x8]
-	cmp r0, 0
-	beq _08049E24
-	ldr r0, [sp, 0x8]
-	movs r1, 0x2
-	orrs r0, r1
-	str r0, [sp, 0x8]
-_08049E0A:
-	ldr r0, [r6, 0x8]
-	cmp r0, 0
-	beq _08049E24
-	ldr r0, [r6, 0xC]
-	cmp r0, 0
-	beq _08049E24
-	ldr r0, [r6, 0x10]
-	cmp r0, 0
-	beq _08049E3E
-	ldr r0, [sp, 0x8]
-	movs r1, 0x8
-	orrs r0, r1
-	str r0, [sp, 0x8]
-_08049E24:
-	ldr r0, [r6, 0x10]
-	cmp r0, 0
-	beq _08049E3E
-	ldr r0, [r6, 0x14]
-	cmp r0, 0
-	beq _08049E3E
-	ldr r0, [r6, 0x18]
-	cmp r0, 0
-	beq _08049E56
-	ldr r0, [sp, 0x8]
-	movs r1, 0x20
-	orrs r0, r1
-	str r0, [sp, 0x8]
-_08049E3E:
-	ldr r0, [r6, 0x18]
-	cmp r0, 0
-	beq _08049E56
-	ldr r0, [r6, 0x1C]
-	cmp r0, 0
-	beq _08049E56
-	cmp r2, 0
-	beq _08049E56
-	ldr r0, [sp, 0x8]
-	movs r1, 0x80
-	orrs r0, r1
-	str r0, [sp, 0x8]
-_08049E56:
-	movs r0, 0xFF
-	str r0, [sp, 0xC]
-	mov r0, r10
-	cmp r0, 0x1
-	bgt _08049E64
-	movs r0, 0x1F
-	str r0, [sp, 0xC]
-_08049E64:
-	ldr r0, [sp, 0x40]
-	cmp r0, 0x1
-	bgt _08049E74
-	ldr r0, [sp, 0xC]
-	movs r1, 0x39
-	negs r1, r1
-	ands r0, r1
-	str r0, [sp, 0xC]
-_08049E74:
-	mov r0, r10
-	cmp r0, 0x35
-	ble _08049E84
-	ldr r0, [sp, 0xC]
-	movs r1, 0xF
-	negs r1, r1
-	ands r0, r1
-	str r0, [sp, 0xC]
-_08049E84:
-	ldr r0, [sp, 0x40]
-	cmp r0, 0x1D
-	ble _08049E94
-	ldr r0, [sp, 0xC]
-	movs r1, 0x84
-	negs r1, r1
-	ands r0, r1
-	str r0, [sp, 0xC]
-_08049E94:
-	mov r0, r10
-	ldr r1, [sp, 0x40]
-	bl GetTileSafe
-	ldr r1, [sp]
-	strb r1, [r0, 0xA]
-	mov r0, r10
-	ldr r1, [sp, 0x40]
-	bl GetTileSafe
-	ldr r1, [sp, 0x4]
-	strb r1, [r0, 0xB]
-	mov r0, r10
-	ldr r1, [sp, 0x40]
-	bl GetTileSafe
-	ldr r1, [sp, 0x8]
-	strb r1, [r0, 0xC]
-	mov r0, r10
-	ldr r1, [sp, 0x40]
-	bl GetTileSafe
-	ldr r1, [sp, 0xC]
-	strb r1, [r0, 0xD]
-	add sp, 0x44
-	pop {r3-r5}
-	mov r8, r3
-	mov r9, r4
-	mov r10, r5
-	pop {r4-r7}
-	pop {r0}
-	bx r0
-	thumb_func_end sub_8049BB0
-
 	thumb_func_start sub_8049ED4
 sub_8049ED4:
 	push {r4-r7,lr}
diff --git a/src/dungeon_map_access.c b/src/dungeon_map_access.c
index 1a1911f75..da9ec46f9 100644
--- a/src/dungeon_map_access.c
+++ b/src/dungeon_map_access.c
@@ -57,7 +57,7 @@ void sub_80495E4(void)
 {
   s32 YCoord;
   s32 XCoord;
-  
+
   for(YCoord = 0; YCoord < DUNGEON_MAX_SIZE_Y; YCoord++)
   {
     for(XCoord = 0; XCoord < DUNGEON_MAX_SIZE_X; XCoord++)
@@ -75,7 +75,7 @@ void LoadDungeonTilesetAssets(void)
   OpenedFile *file;
   OpenedFile *file_1;
   u8 fileName [12];
-  
+
   sprintf(fileName,gUnknown_80F6A04,gUnknown_8108EC0[gDungeon->tileset]); // b%02dfon
   file = OpenFileAndGetFileDataPtr(fileName,&gDungeonFileArchive);
   DecompressATGlobalFile((u32 *)0x06008000,0,file);
@@ -142,7 +142,7 @@ void sub_8049884(void)
 {
   s32 XCoord;
   s32 YCoord;
-  
+
   for(YCoord = 0; YCoord < DUNGEON_MAX_SIZE_Y; YCoord++)
   {
     for(XCoord = 0; XCoord < DUNGEON_MAX_SIZE_X; XCoord++) {
@@ -165,7 +165,7 @@ void sub_80498A8(int x,int y)
   u16 sp_0x20; // sp 0x20
   int r4;
   s32 r7; // r7
-  
+
   if (x < 0) {
     return;
   }
@@ -325,7 +325,7 @@ void sub_8049B8C(void)
 {
   s32 XCoord;
   s32 YCoord;
-  
+
   for(YCoord = 0; YCoord < DUNGEON_MAX_SIZE_Y; YCoord++)
   {
     for(XCoord = 0; XCoord < DUNGEON_MAX_SIZE_X; XCoord++) {
@@ -333,3 +333,103 @@ void sub_8049B8C(void)
     }
   }
 }
+
+void sub_8049BB0(s32 x, s32 y)
+{
+    s32 terrainFlags;
+    s32 i;
+    s32 flags[6];
+    s32 var_4C[8];
+    bool8 var_2C[8];
+
+    flags[0] = 0;
+    flags[1] = 0;
+    flags[2] = 0;
+    flags[3] = 0;
+
+    terrainFlags = GetTile(x,   y+1)->terrainType & (TERRAIN_TYPE_NORMAL | TERRAIN_TYPE_SECONDARY);
+    var_4C[0] = terrainFlags;
+    var_4C[1] = GetTile(x+1, y+1)->terrainType & (TERRAIN_TYPE_NORMAL | TERRAIN_TYPE_SECONDARY);
+    var_4C[2] = GetTile(x+1, y)->terrainType & (TERRAIN_TYPE_NORMAL | TERRAIN_TYPE_SECONDARY);
+    var_4C[3] = GetTile(x+1, y-1)->terrainType & (TERRAIN_TYPE_NORMAL | TERRAIN_TYPE_SECONDARY);
+    var_4C[4] = GetTile(x,   y-1)->terrainType & (TERRAIN_TYPE_NORMAL | TERRAIN_TYPE_SECONDARY);
+    var_4C[5] = GetTile(x-1, y-1)->terrainType & (TERRAIN_TYPE_NORMAL | TERRAIN_TYPE_SECONDARY);
+    var_4C[6] = GetTile(x-1, y)->terrainType & (TERRAIN_TYPE_NORMAL | TERRAIN_TYPE_SECONDARY);
+    var_4C[7] = GetTile(x-1, y+1)->terrainType & (TERRAIN_TYPE_NORMAL | TERRAIN_TYPE_SECONDARY);
+
+    if (var_4C[0] == TERRAIN_TYPE_NORMAL)
+        flags[CROSSABLE_TERRAIN_REGULAR] |= 1;
+    if (var_4C[2] == TERRAIN_TYPE_NORMAL)
+        flags[CROSSABLE_TERRAIN_REGULAR] |= 4;
+    if (var_4C[4] == TERRAIN_TYPE_NORMAL)
+        flags[CROSSABLE_TERRAIN_REGULAR] |= 0x10;
+    if (var_4C[6] == TERRAIN_TYPE_NORMAL)
+        flags[CROSSABLE_TERRAIN_REGULAR] |= 0x40;
+
+    if (var_4C[0] != 0 && var_4C[1] == TERRAIN_TYPE_NORMAL && var_4C[2] != 0)
+        flags[CROSSABLE_TERRAIN_REGULAR] |= 2;
+    if (var_4C[2] != 0 && var_4C[3] == TERRAIN_TYPE_NORMAL && var_4C[4] != 0)
+        flags[CROSSABLE_TERRAIN_REGULAR] |= 8;
+    if (var_4C[4] != 0 && var_4C[5] == TERRAIN_TYPE_NORMAL && var_4C[6] != 0)
+        flags[CROSSABLE_TERRAIN_REGULAR] |= 0x20;
+    if (var_4C[6] != 0 && var_4C[7] == TERRAIN_TYPE_NORMAL && var_4C[0] != 0)
+        flags[CROSSABLE_TERRAIN_REGULAR] |= 0x80;
+
+    for (i = 0; i < 8; i++) {
+        if (var_4C[i] == TERRAIN_TYPE_NORMAL || var_4C[i] == TERRAIN_TYPE_SECONDARY)
+            var_2C[i] = TRUE;
+        else
+            var_2C[i] = FALSE;
+    }
+
+    if (var_2C[0])
+        flags[CROSSABLE_TERRAIN_LIQUID] |= 1;
+    if (var_2C[2])
+        flags[CROSSABLE_TERRAIN_LIQUID] |= 4;
+    if (var_2C[4])
+        flags[CROSSABLE_TERRAIN_LIQUID] |= 0x10;
+    if (var_2C[6])
+        flags[CROSSABLE_TERRAIN_LIQUID] |= 0x40;
+
+    if (var_4C[0] != 0 && var_2C[1] && var_4C[2] != 0)
+        flags[CROSSABLE_TERRAIN_LIQUID] |= 2;
+    if (var_4C[2] != 0 && var_2C[3] && var_4C[4] != 0)
+        flags[CROSSABLE_TERRAIN_LIQUID] |= 8;
+    if (var_4C[4] != 0 && var_2C[5] && var_4C[6] != 0)
+        flags[CROSSABLE_TERRAIN_LIQUID] |= 0x20;
+    if (var_4C[6] != 0 && var_2C[7] && var_4C[0] != 0)
+        flags[CROSSABLE_TERRAIN_LIQUID] |= 0x80;
+
+    if (var_4C[0] != 0)
+        flags[2] |= 1;
+    if (var_4C[2] != 0)
+        flags[2] |= 4;
+    if (var_4C[4] != 0)
+        flags[2] |= 0x10;
+    if (var_4C[6] != 0)
+        flags[2] |= 0x40;
+
+    if (var_4C[0] != 0 && var_4C[1] != 0 && var_4C[2] != 0)
+        flags[CROSSABLE_TERRAIN_CREVICE] |= 2;
+    if (var_4C[2] != 0 && var_4C[3] != 0 && var_4C[4] != 0)
+        flags[CROSSABLE_TERRAIN_CREVICE] |= 8;
+    if (var_4C[4] != 0 && var_4C[5] != 0 && var_4C[6] != 0)
+        flags[CROSSABLE_TERRAIN_CREVICE] |= 0x20;
+    if (var_4C[6] != 0 && var_4C[7] != 0 && var_4C[0] != 0)
+        flags[CROSSABLE_TERRAIN_CREVICE] |= 0x80;
+
+    flags[3] = 0xFF;
+    if (x <= 1)
+        flags[CROSSABLE_TERRAIN_WALL] = 0x1F;
+    if (y <= 1)
+        flags[CROSSABLE_TERRAIN_WALL] &= ~(0x8 | 0x10 | 0x20);
+    if (x > 53)
+        flags[CROSSABLE_TERRAIN_WALL] &= ~(0x2 | 0x4 | 0x8);
+    if (y > 29)
+        flags[CROSSABLE_TERRAIN_WALL] &= ~(0x80 | 0x1 | 0x2);
+
+    GetTileSafe(x, y)->walkableNeighborFlags[CROSSABLE_TERRAIN_REGULAR] = flags[CROSSABLE_TERRAIN_REGULAR];
+    GetTileSafe(x, y)->walkableNeighborFlags[CROSSABLE_TERRAIN_LIQUID] = flags[CROSSABLE_TERRAIN_LIQUID];
+    GetTileSafe(x, y)->walkableNeighborFlags[CROSSABLE_TERRAIN_CREVICE] = flags[CROSSABLE_TERRAIN_CREVICE];
+    GetTileSafe(x, y)->walkableNeighborFlags[CROSSABLE_TERRAIN_WALL] = flags[CROSSABLE_TERRAIN_WALL];
+}