diff --git a/asm/field_map_obj.s b/asm/field_map_obj.s
index 31b522467..f9366b2e9 100644
--- a/asm/field_map_obj.s
+++ b/asm/field_map_obj.s
@@ -5,96 +5,6 @@
 
 	.text
 
-	thumb_func_start GetAvailableFieldObjectSlot
-@ bool8 GetAvailableFieldObjectSlot(u16 localId, u8 mapId, u8 mapGroupId, u8 *fieldObjectId)
-GetAvailableFieldObjectSlot: @ 808D810
-	push {r4-r7,lr}
-	mov r12, r3
-	lsls r0, 16
-	lsrs r6, r0, 16
-	lsls r1, 24
-	lsrs r5, r1, 24
-	lsls r2, 24
-	lsrs r4, r2, 24
-	movs r2, 0
-	ldr r1, =gMapObjects
-	ldrb r0, [r1]
-	lsls r0, 31
-	adds r7, r1, 0
-	cmp r0, 0
-	beq _0808D864
-	adds r3, r1, 0
-_0808D830:
-	lsls r0, r2, 3
-	adds r0, r2
-	lsls r0, 2
-	adds r1, r0, r3
-	ldrb r0, [r1, 0x8]
-	cmp r0, r6
-	bne _0808D84A
-	ldrb r0, [r1, 0x9]
-	cmp r0, r5
-	bne _0808D84A
-	ldrb r0, [r1, 0xA]
-	cmp r0, r4
-	beq _0808D868
-_0808D84A:
-	adds r0, r2, 0x1
-	lsls r0, 24
-	lsrs r2, r0, 24
-	cmp r2, 0xF
-	bhi _0808D868
-	lsls r0, r2, 3
-	adds r0, r2
-	lsls r0, 2
-	adds r0, r7
-	ldrb r0, [r0]
-	lsls r0, 31
-	cmp r0, 0
-	bne _0808D830
-_0808D864:
-	cmp r2, 0xF
-	bls _0808D870
-_0808D868:
-	movs r0, 0x1
-	b _0808D8A4
-	.pool
-_0808D870:
-	mov r0, r12
-	strb r2, [r0]
-	ldr r1, =gMapObjects
-_0808D876:
-	lsls r0, r2, 3
-	adds r0, r2
-	lsls r0, 2
-	adds r3, r0, r1
-	ldrb r0, [r3]
-	lsls r0, 31
-	cmp r0, 0
-	beq _0808D898
-	ldrb r0, [r3, 0x8]
-	cmp r0, r6
-	bne _0808D898
-	ldrb r0, [r3, 0x9]
-	cmp r0, r5
-	bne _0808D898
-	ldrb r0, [r3, 0xA]
-	cmp r0, r4
-	beq _0808D868
-_0808D898:
-	adds r0, r2, 0x1
-	lsls r0, 24
-	lsrs r2, r0, 24
-	cmp r2, 0xF
-	bls _0808D876
-	movs r0, 0
-_0808D8A4:
-	pop {r4-r7}
-	pop {r1}
-	bx r1
-	.pool
-	thumb_func_end GetAvailableFieldObjectSlot
-
 	thumb_func_start RemoveFieldObject
 @ void RemoveFieldObject(npc_state *fieldObject)
 RemoveFieldObject: @ 808D8B0
diff --git a/src/field_map_obj.c b/src/field_map_obj.c
index b33cf0669..28f001b5d 100644
--- a/src/field_map_obj.c
+++ b/src/field_map_obj.c
@@ -387,3 +387,26 @@ u8 unref_sub_808D77C(u8 localId)
     }
     return ARRAY_COUNT(gMapObjects);
 }
+
+bool8 GetAvailableFieldObjectSlot(u16 localId, u8 mapNum, u8 mapGroup, u8 *result)
+{
+    u8 i = 0;
+
+    for (i = 0; i < ARRAY_COUNT(gMapObjects); i ++)
+    {
+        if (!gMapObjects[i].active)
+            break;
+        if (gMapObjects[i].localId == localId && gMapObjects[i].mapNum == mapNum && gMapObjects[i].mapGroup == mapGroup)
+            return TRUE;
+    }
+    if (i >= ARRAY_COUNT(gMapObjects))
+        return TRUE;
+    *result = i;
+    do
+    {
+        if (gMapObjects[i].active && gMapObjects[i].localId == localId && gMapObjects[i].mapNum == mapNum && gMapObjects[i].mapGroup == mapGroup)
+            return TRUE;
+        i ++;
+    } while (i < ARRAY_COUNT(gMapObjects));
+    return FALSE;
+}