through MapGridGetMetatileIdAt

asm/field_camera.s

@@ -528,7 +528,7 @@ sub_805A948: @ 805A948
 	mov r8, r1
 	adds r0, r6, 0
 	adds r1, r7, 0
-	bl sub_8058E48
+	bl MapGridGetMetatileIdAt
 	lsls r0, 16
 	lsrs r4, r0, 16
 	movs r0, 0x80

asm/field_door.s

@@ -337,7 +337,7 @@ sub_805B158: @ 805B158
 	adds r6, r2, 0
 	adds r0, r5, 0
 	adds r1, r6, 0
-	bl sub_8058E48
+	bl MapGridGetMetatileIdAt
 	adds r1, r0, 0
 	lsls r1, 16
 	lsrs r1, 16
@@ -392,7 +392,7 @@ sub_805B1B8: @ 805B1B8
 	adds r6, r2, 0
 	adds r0, r5, 0
 	adds r1, r6, 0
-	bl sub_8058E48
+	bl MapGridGetMetatileIdAt
 	adds r1, r0, 0
 	lsls r1, 16
 	lsrs r1, 16
@@ -439,7 +439,7 @@ sub_805B210: @ 805B210
 	adds r6, r2, 0
 	adds r0, r5, 0
 	adds r1, r6, 0
-	bl sub_8058E48
+	bl MapGridGetMetatileIdAt
 	adds r1, r0, 0
 	lsls r1, 16
 	lsrs r1, 16
@@ -643,7 +643,7 @@ sub_805B388: @ 805B388
 	adds r4, r0, 0
 	adds r0, r1, 0
 	adds r1, r2, 0
-	bl sub_8058E48
+	bl MapGridGetMetatileIdAt
 	adds r1, r0, 0
 	lsls r1, 16
 	lsrs r1, 16

asm/field_map_obj.s

@@ -12332,7 +12332,7 @@ npc_block_way: @ 80636AC
 _080636E2:
 	adds r0, r5, 0
 	adds r1, r4, 0
-	bl sub_8058DC4
+	bl MapGridIsImpassableAt
 	lsls r0, 24
 	cmp r0, 0
 	bne _08063724
@@ -12432,7 +12432,7 @@ sub_8063770: @ 8063770
 	lsrs r4, r1, 31
 	adds r0, r6, 0
 	adds r1, r5, 0
-	bl sub_8058DC4
+	bl MapGridIsImpassableAt
 	lsls r0, 24
 	cmp r0, 0
 	bne _080637E8

asm/field_tasks.s

@@ -490,7 +490,7 @@ _0806EB8E:
 	ldrsh r0, [r0, r3]
 	movs r2, 0
 	ldrsh r1, [r4, r2]
-	bl sub_8058E48
+	bl MapGridGetMetatileIdAt
 	ldr r1, _0806EBDC @ =0x0000020a
 	cmp r0, r1
 	bne _0806EBE4
@@ -534,7 +534,7 @@ sub_806EC04: @ 806EC04
 	asrs r4, r1, 16
 	adds r0, r5, 0
 	adds r1, r4, 0
-	bl sub_8058E48
+	bl MapGridGetMetatileIdAt
 	ldr r1, _0806EC38 @ =0x0000022f
 	ldr r2, _0806EC3C @ =0x00000237
 	cmp r0, r1

asm/fieldmap.s

@@ -5,252 +5,6 @@
 
 	.text
 
-	thumb_func_start MapGridGetZCoordAt
-MapGridGetZCoordAt: @ 8058D44
-	push {r4-r7,lr}
-	adds r2, r0, 0
-	adds r7, r1, 0
-	cmp r2, 0
-	blt _08058D74
-	ldr r1, _08058D70 @ =VMap
-	ldr r3, [r1]
-	cmp r2, r3
-	bge _08058D74
-	cmp r7, 0
-	blt _08058D74
-	ldr r0, [r1, 0x4]
-	cmp r7, r0
-	bge _08058D74
-	adds r0, r3, 0
-	muls r0, r7
-	adds r0, r2, r0
-	ldr r1, [r1, 0x8]
-	lsls r0, 1
-	adds r0, r1
-	ldrh r1, [r0]
-	b _08058DA8
-	.align 2, 0
-_08058D70: .4byte VMap
-_08058D74:
-	ldr r0, _08058DB4 @ =gMapHeader
-	ldr r6, [r0]
-	subs r0, r2, 0x7
-	ldrb r5, [r6, 0x18]
-	lsls r1, r5, 3
-	adds r0, r1
-	adds r1, r5, 0
-	bl __modsi3
-	adds r4, r0, 0
-	subs r0, r7, 0x7
-	ldrb r1, [r6, 0x19]
-	lsls r2, r1, 3
-	adds r0, r2
-	bl __modsi3
-	muls r0, r5
-	adds r4, r0
-	ldr r0, [r6, 0x8]
-	lsls r4, 1
-	adds r4, r0
-	ldrh r1, [r4]
-	movs r2, 0xC0
-	lsls r2, 4
-	adds r0, r2, 0
-	orrs r1, r0
-_08058DA8:
-	ldr r0, _08058DB8 @ =0x000003ff
-	cmp r1, r0
-	beq _08058DBC
-	lsrs r0, r1, 12
-	b _08058DBE
-	.align 2, 0
-_08058DB4: .4byte gMapHeader
-_08058DB8: .4byte 0x000003ff
-_08058DBC:
-	movs r0, 0
-_08058DBE:
-	pop {r4-r7}
-	pop {r1}
-	bx r1
-	thumb_func_end MapGridGetZCoordAt
-
-	thumb_func_start sub_8058DC4
-sub_8058DC4: @ 8058DC4
-	push {r4-r7,lr}
-	adds r2, r0, 0
-	adds r7, r1, 0
-	cmp r2, 0
-	blt _08058DF4
-	ldr r1, _08058DF0 @ =VMap
-	ldr r3, [r1]
-	cmp r2, r3
-	bge _08058DF4
-	cmp r7, 0
-	blt _08058DF4
-	ldr r0, [r1, 0x4]
-	cmp r7, r0
-	bge _08058DF4
-	adds r0, r3, 0
-	muls r0, r7
-	adds r0, r2, r0
-	ldr r1, [r1, 0x8]
-	lsls r0, 1
-	adds r0, r1
-	ldrh r1, [r0]
-	b _08058E28
-	.align 2, 0
-_08058DF0: .4byte VMap
-_08058DF4:
-	ldr r0, _08058E38 @ =gMapHeader
-	ldr r6, [r0]
-	subs r0, r2, 0x7
-	ldrb r5, [r6, 0x18]
-	lsls r1, r5, 3
-	adds r0, r1
-	adds r1, r5, 0
-	bl __modsi3
-	adds r4, r0, 0
-	subs r0, r7, 0x7
-	ldrb r1, [r6, 0x19]
-	lsls r2, r1, 3
-	adds r0, r2
-	bl __modsi3
-	muls r0, r5
-	adds r4, r0
-	ldr r0, [r6, 0x8]
-	lsls r4, 1
-	adds r4, r0
-	ldrh r1, [r4]
-	movs r2, 0xC0
-	lsls r2, 4
-	adds r0, r2, 0
-	orrs r1, r0
-_08058E28:
-	ldr r0, _08058E3C @ =0x000003ff
-	cmp r1, r0
-	beq _08058E40
-	movs r0, 0xC0
-	lsls r0, 4
-	ands r1, r0
-	lsrs r0, r1, 10
-	b _08058E42
-	.align 2, 0
-_08058E38: .4byte gMapHeader
-_08058E3C: .4byte 0x000003ff
-_08058E40:
-	movs r0, 0x1
-_08058E42:
-	pop {r4-r7}
-	pop {r1}
-	bx r1
-	thumb_func_end sub_8058DC4
-
-	thumb_func_start sub_8058E48
-sub_8058E48: @ 8058E48
-	push {r4-r7,lr}
-	mov r7, r9
-	mov r6, r8
-	push {r6,r7}
-	mov r8, r0
-	mov r9, r1
-	cmp r0, 0
-	blt _08058E80
-	ldr r1, _08058E7C @ =VMap
-	ldr r2, [r1]
-	cmp r8, r2
-	bge _08058E80
-	mov r0, r9
-	cmp r0, 0
-	blt _08058E80
-	ldr r0, [r1, 0x4]
-	cmp r9, r0
-	bge _08058E80
-	mov r0, r9
-	muls r0, r2
-	add r0, r8
-	ldr r1, [r1, 0x8]
-	lsls r0, 1
-	adds r0, r1
-	ldrh r7, [r0]
-	b _08058EBA
-	.align 2, 0
-_08058E7C: .4byte VMap
-_08058E80:
-	ldr r0, _08058EC8 @ =gMapHeader
-	ldr r6, [r0]
-	mov r0, r8
-	subs r0, 0x7
-	ldrb r5, [r6, 0x18]
-	lsls r1, r5, 3
-	adds r0, r1
-	adds r1, r5, 0
-	bl __modsi3
-	adds r4, r0, 0
-	mov r0, r9
-	subs r0, 0x7
-	ldrb r1, [r6, 0x19]
-	lsls r2, r1, 3
-	adds r0, r2
-	bl __modsi3
-	muls r0, r5
-	adds r4, r0
-	ldr r0, [r6, 0x8]
-	lsls r4, 1
-	adds r4, r0
-	ldrh r1, [r4]
-	movs r2, 0xC0
-	lsls r2, 4
-	adds r0, r2, 0
-	adds r7, r0, 0
-	orrs r7, r1
-_08058EBA:
-	ldr r0, _08058ECC @ =0x000003ff
-	cmp r7, r0
-	beq _08058ED0
-	ands r7, r0
-	adds r0, r7, 0
-	b _08058F0A
-	.align 2, 0
-_08058EC8: .4byte gMapHeader
-_08058ECC: .4byte 0x000003ff
-_08058ED0:
-	ldr r0, _08058F18 @ =gMapHeader
-	ldr r6, [r0]
-	mov r0, r8
-	subs r0, 0x7
-	ldrb r5, [r6, 0x18]
-	lsls r1, r5, 3
-	adds r0, r1
-	adds r1, r5, 0
-	bl __modsi3
-	adds r4, r0, 0
-	mov r0, r9
-	subs r0, 0x7
-	ldrb r1, [r6, 0x19]
-	lsls r2, r1, 3
-	adds r0, r2
-	bl __modsi3
-	muls r0, r5
-	adds r4, r0
-	ldr r0, [r6, 0x8]
-	lsls r4, 1
-	adds r4, r0
-	ldrh r0, [r4]
-	movs r2, 0xC0
-	lsls r2, 4
-	adds r1, r2, 0
-	orrs r0, r1
-	ands r0, r7
-_08058F0A:
-	pop {r3,r4}
-	mov r8, r3
-	mov r9, r4
-	pop {r4-r7}
-	pop {r1}
-	bx r1
-	.align 2, 0
-_08058F18: .4byte gMapHeader
-	thumb_func_end sub_8058E48
-
 	thumb_func_start sub_8058F1C
 sub_8058F1C: @ 8058F1C
 	push {lr}
@@ -287,7 +41,7 @@ sub_8058F48: @ 8058F48
 	asrs r0, 16
 	lsls r1, 16
 	asrs r1, 16
-	bl sub_8058E48
+	bl MapGridGetMetatileIdAt
 	adds r1, r0, 0
 	lsls r1, 16
 	lsrs r1, 16

asm/fldeff_cut.s

@@ -380,7 +380,7 @@ sub_8097B50: @ 8097B50
 	asrs r0, 16
 	lsrs r7, r1, 16
 	asrs r1, 16
-	bl sub_8058E48
+	bl MapGridGetMetatileIdAt
 	lsls r0, 16
 	lsrs r2, r0, 16
 	ldr r1, _08097B84 @ =gUnknown_83D4100

asm/item_use.s

@@ -544,7 +544,7 @@ _080A13D4:
 	ldrsh r0, [r0, r1]
 	movs r2, 0
 	ldrsh r1, [r4, r2]
-	bl sub_8058DC4
+	bl MapGridIsImpassableAt
 	lsls r0, 24
 	cmp r0, 0
 	beq _080A13D0

asm/overworld.s

@@ -7829,7 +7829,7 @@ _08058854:
 	bls _08058810
 	asrs r0, r3, 16
 	asrs r1, r5, 16
-	bl sub_8058DC4
+	bl MapGridIsImpassableAt
 	lsls r0, 24
 	lsrs r0, 24
 _0805886A:

asm/shop.s

@@ -1632,7 +1632,7 @@ _0809B7B2:
 	movs r3, 0
 	ldrsh r1, [r2, r3]
 	adds r1, r7
-	bl sub_8058E48
+	bl MapGridGetMetatileIdAt
 	lsls r0, 16
 	lsrs r5, r0, 16
 	mov r0, sp
@@ -2940,7 +2940,7 @@ _0809C238:
 	adds r5, r1, r0
 	adds r0, r5, 0
 	adds r1, r6, 0
-	bl sub_8058E48
+	bl MapGridGetMetatileIdAt
 	movs r2, 0
 	ldrsh r1, [r7, r2]
 	lsls r0, 16
@@ -3006,7 +3006,7 @@ _0809C2B8:
 	adds r5, r1, r0
 	adds r0, r5, 0
 	adds r1, r6, 0
-	bl sub_8058E48
+	bl MapGridGetMetatileIdAt
 	movs r1, 0x2
 	subs r1, r7
 	lsls r1, 1

include/fieldmap.h

@@ -15,7 +15,7 @@ u32 MapGridGetMetatileBehaviorAt(int, int);
 void MapGridSetMetatileIdAt(int, int, u16);
 void MapGridSetMetatileEntryAt(int, int, u16);
 void GetCameraCoords(u16*, u16*);
-bool8 MapGridIsImpassableAt(s16, s16);
+bool8 MapGridIsImpassableAt(s32, s32);
 s32 GetMapBorderIdAt(s16, s16);
 bool32 CanCameraMoveInDirection(u8);
 u16 GetBehaviorByMetatileId(u16 metatileId);

include/global.fieldmap.h

@@ -63,6 +63,8 @@ struct MapData
     /*0x0c*/ u16 *map;
     /*0x10*/ struct Tileset *primaryTileset;
     /*0x14*/ struct Tileset *secondaryTileset;
+    /*0x18*/ u8 unk18;
+    /*0x19*/ u8 unk19;
 };
 
 struct BackupMapData

src/fieldmap.c

@@ -73,9 +73,9 @@ void map_copy_with_padding(u16 *map, u16 width, u16 height)
 
 void mapheader_copy_mapdata_of_adjacent_maps(struct MapHeader *mapHeader)
 {
-    int count;
+    s32 count;
     struct MapConnection *connection;
-    int i;
+    s32 i;
 
     gMapConnectionFlags = sDummyConnectionFlags;
 
@@ -119,10 +119,10 @@ void mapheader_copy_mapdata_of_adjacent_maps(struct MapHeader *mapHeader)
 
 void sub_8058B54(s32 x, s32 y, const struct MapHeader *connectedMapHeader, s32 x2, s32 y2, s32 width, s32 height)
 {
-    int i;
+    s32 i;
     u16 *src;
     u16 *dest;
-    int mapWidth;
+    s32 mapWidth;
 
     mapWidth = connectedMapHeader->mapData->width;
     src = &connectedMapHeader->mapData->map[mapWidth * y2 + x2];
@@ -138,10 +138,10 @@ void sub_8058B54(s32 x, s32 y, const struct MapHeader *connectedMapHeader, s32 x
 
 void fillSouthConnection(struct MapHeader const *mapHeader, struct MapHeader const *connectedMapHeader, s32 offset)
 {
-    int x, y;
+    s32 x, y;
-    int x2;
+    s32 x2;
-    int width;
+    s32 width;
-    int cWidth;
+    s32 cWidth;
 
     if (connectedMapHeader)
     {
@@ -185,10 +185,10 @@ void fillSouthConnection(struct MapHeader const *mapHeader, struct MapHeader con
 
 void fillNorthConnection(struct MapHeader const *mapHeader, struct MapHeader const *connectedMapHeader, s32 offset)
 {
-    int x;
+    s32 x;
-    int x2, y2;
+    s32 x2, y2;
-    int width;
+    s32 width;
-    int cWidth, cHeight;
+    s32 cWidth, cHeight;
 
     if (connectedMapHeader)
     {
@@ -234,10 +234,10 @@ void fillNorthConnection(struct MapHeader const *mapHeader, struct MapHeader con
 
 void fillWestConnection(struct MapHeader const *mapHeader, struct MapHeader const *connectedMapHeader, s32 offset)
 {
-    int y;
+    s32 y;
-    int x2, y2;
+    s32 x2, y2;
-    int height;
+    s32 height;
-    int cWidth, cHeight;
+    s32 cWidth, cHeight;
     if (connectedMapHeader)
     {
         cWidth = connectedMapHeader->mapData->width;
@@ -280,10 +280,10 @@ void fillWestConnection(struct MapHeader const *mapHeader, struct MapHeader cons
 
 void fillEastConnection(struct MapHeader const *mapHeader, struct MapHeader const *connectedMapHeader, s32 offset)
 {
-    int x, y;
+    s32 x, y;
-    int y2;
+    s32 y2;
-    int height;
+    s32 height;
-    int cHeight;
+    s32 cHeight;
     if (connectedMapHeader)
     {
         cHeight = connectedMapHeader->mapData->height;
@@ -322,3 +322,99 @@ void fillEastConnection(struct MapHeader const *mapHeader, struct MapHeader cons
             /*width*/ 8, height);
     }
 }
+
+union Block
+{
+    struct
+    {
+        u16 block:10;
+        u16 collision:2;
+        u16 elevation:4;
+    } block;
+    u16 value;
+};
+
+#define MapGridGetBorderTileAt(x, y) ({                            \
+        u16 block;                                                 \
+        s32 xprime;                                                \
+        s32 yprime;                                                \
+                                                                   \
+        struct MapData *mapData = gMapHeader.mapData;              \
+                                                                   \
+        xprime = x - 7;                                            \
+        xprime += 8 * mapData->unk18;                              \
+        xprime %= mapData->unk18;                                  \
+                                                                   \
+        yprime = y - 7;                                            \
+        yprime += 8 * mapData->unk19;                              \
+        yprime %= mapData->unk19;                                  \
+                                                                   \
+        block = mapData->border[xprime + yprime * mapData->unk18]; \
+        block |= 0xC00;                                            \
+        block;                                                     \
+})
+
+#define MapGridGetBorderTileAt2(x, y) ({                            \
+        u16 block;                                                 \
+        s32 xprime;                                                \
+        s32 yprime;                                                \
+                                                                   \
+        struct MapData *mapData = gMapHeader.mapData;              \
+                                                                   \
+        xprime = x - 7;                                            \
+        xprime += 8 * mapData->unk18;                              \
+        xprime %= mapData->unk18;                                  \
+                                                                   \
+        yprime = y - 7;                                            \
+        yprime += 8 * mapData->unk19;                              \
+        yprime %= mapData->unk19;                                  \
+                                                                   \
+        block = mapData->border[xprime + yprime * mapData->unk18] | 0xC00;                                           \
+        block;                                                     \
+})
+
+#define MapGridGetTileAt(x, y) ({              \
+    u16 block;                                 \
+    if (x >= 0 && x < VMap.Xsize               \
+        && y >= 0 && y < VMap.Ysize)           \
+        block = VMap.map[x + VMap.Xsize * y];  \
+    else                                       \
+        block = MapGridGetBorderTileAt2(x, y); \
+    block;                                     \
+})
+
+u8 MapGridGetZCoordAt(s32 x, s32 y)
+{
+    u16 block = MapGridGetTileAt(x, y);
+
+    if (block == 0x3ff)
+    {
+        return 0;
+    }
+
+    return block >> 12;
+}
+
+u8 MapGridIsImpassableAt(s32 x, s32 y)
+{
+
+    u16 block = MapGridGetTileAt(x, y);
+
+    if (block == 0x3ff)
+    {
+        return 1;
+    }
+
+    return (block & 0xc00) >> 10;
+}
+
+u32 MapGridGetMetatileIdAt(s32 x, s32 y)
+{
+    u16 block = MapGridGetTileAt(x, y);
+
+    if (block == 0x3FF)
+    {
+        return MapGridGetBorderTileAt(x, y) & 0x3FF;
+    }
+    return block & 0x3FF;
+}