diff --git a/asm/code_08000108.s b/asm/code_08000108.s
index 7fb9b84d..db7cb020 100644
--- a/asm/code_08000108.s
+++ b/asm/code_08000108.s
@@ -33,7 +33,7 @@ _08000136:
 	pop {r4, pc}
 _08000138:
 _08000138: .4byte gUnk_030056F1
-_0800013C: .4byte sub_0807D280
+_0800013C: .4byte sub_0807D280 @ layer 1, 2, 3?
 _08000140: .4byte sub_0807D46C
 _08000144: .4byte sub_0807D6D8
 
@@ -55,8 +55,8 @@ sub_08000152: @ 0x08000152
 	lsrs r2, r2, #2
 
 	non_word_aligned_thumb_func_start SetTile
-SetTile: @ 0x0800015E
-	push {r4, r5, r6, r7, lr}
+SetTile: @ r0 = tile type, r1, = tile position, r2 = layer
+	push {r4-r7, lr}
 	lsls r3, r2, #3
 	ldr r4, _08000208 @ =gUnk_08000228
 	ldr r5, [r4, r3]
@@ -75,7 +75,7 @@ SetTile: @ 0x0800015E
 	ldrb r0, [r3, r4]
 	lsrs r2, r2, #2
 	bl sub_08000148
-	pop {r0, r1}
+	pop {r0, r1} # tilepos, layer
 	push {r0, r1}
 	bl DeleteLoadedTileEntity
 	adds r0, r7, #0
@@ -170,8 +170,8 @@ gUnk_08000278::
 @ call 0x80B19CC
 @ ========
 @ Unused? Doesn't seem to be called by anything in Ghidra.
-	thumb_func_start sub_08000288
-sub_08000288: @ 0x08000288
+	thumb_func_start GetTileAtEntityPos
+GetTileAtEntityPos: @ 0x08000288
 	ldr r3, _080002F4 @ =gUnk_03005740
 	bx r3
 
diff --git a/asm/code_08016B30.s b/asm/code_08016B30.s
index 4b1079c9..059e1c4c 100644
--- a/asm/code_08016B30.s
+++ b/asm/code_08016B30.s
@@ -13,7 +13,7 @@ sub_08016B30: @ 0x08016B30
 	thumb_func_start sub_08016B34
 sub_08016B34: @ 0x08016B34
 	ldr r1, _08016B54 @ =0x03007FFC
-	ldr r0, _08016B58 @ =gUnk_03005D90
+	ldr r0, _08016B58 @ =IntrMain
 	str r0, [r1]
 	ldr r1, _08016B5C @ =0x04000004
 	ldr r2, _08016B60 @ =0x00005028
@@ -29,7 +29,7 @@ sub_08016B34: @ 0x08016B34
 	bx lr
 	.align 2, 0
 _08016B54: .4byte 0x03007FFC
-_08016B58: .4byte gUnk_03005D90
+_08016B58: .4byte IntrMain
 _08016B5C: .4byte 0x04000004
 _08016B60: .4byte 0x00005028
 _08016B64: .4byte 0x04000200
diff --git a/asm/crt0.s b/asm/crt0.s
index aa94b6fd..73578ef5 100644
--- a/asm/crt0.s
+++ b/asm/crt0.s
@@ -1,32 +1,31 @@
 	.include "asm/macros.inc"
 	.include "constants/constants.inc"
-
 	.syntax unified
-
 	.text
 
 	arm_func_start __start
-__start: @ 0x08000000
-	b _080000C0
-_08000004:
+__start:
+	b start_vector
+
+header:
 	.include "asm/rom_header.inc"
-_080000C0:
+
+start_vector:
 	mov r0, #0x12
 	msr cpsr_fc, r0
-	ldr sp, _080000F4 @ =gUnk_03007FA0
+	ldr sp, sp_irq
 	mov r0, #0x1f
 	msr cpsr_fc, r0
-	ldr sp, _080000F8 @ =gUnk_03007F00
-	ldr r1, _080000FC @ =0x03007FFC
-	ldr r0, _08000100 @ =gUnk_03005D90
+	ldr sp, sp_usr
+	ldr r1, INTR_VECTOR_BUF
+	ldr r0, intr_main
 	str r0, [r1]
-	ldr r1, _08000104 @ =MainLoop
+	ldr r1, =AgbMain
 	mov lr, pc
 	bx r1
 _080000F0:
-	b _080000C0
-_080000F4: .4byte gUnk_03007FA0
-_080000F8: .4byte gUnk_03007F00
-_080000FC: .4byte 0x03007FFC
-_08000100: .4byte gUnk_03005D90
-_08000104: .4byte MainLoop
+	b start_vector
+sp_irq: .4byte gUnk_03007FA0
+sp_usr: .4byte gUnk_03007F00
+INTR_VECTOR_BUF: .4byte 0x03007FFC
+intr_main: .4byte IntrMain
diff --git a/asm/intr.s b/asm/intr.s
index 388274a3..3332c380 100644
--- a/asm/intr.s
+++ b/asm/intr.s
@@ -49,16 +49,17 @@ _080B19C0: .4byte gRoomControls
 _080B19C4: .4byte 0x80000020
 _080B19C8: .4byte 0x040000D4
 
-	arm_func_start sub_080B19CC
-sub_080B19CC: @ 0x080B19CC
-	ldrb r2, [r0, #0x38]
-	ldrh r1, [r0, #0x32]
-	ldrh r0, [r0, #0x2e]
+@ r0 = entity*
+	arm_func_start _GetTileAtEntityPos
+_GetTileAtEntityPos: @ 0x080B19CC
+	ldrb r2, [r0, #0x38] @ obj layer
+	ldrh r1, [r0, #0x32] @ obj y
+	ldrh r0, [r0, #0x2e] @ obj x
 	ldr ip, _080B1C10 @ =gRoomControls
 	ldrh r3, [ip, #6]
-	sub r0, r0, r3
+	sub r0, r0, r3 @ obj x - room x
 	ldrh r3, [ip, #8]
-	sub r1, r1, r3
+	sub r1, r1, r3 @ obj y - room y
 	lsl r0, r0, #0x16
 	lsr r0, r0, #0x1a
 	lsl r1, r1, #0x16
@@ -102,7 +103,7 @@ _080B1A64:
 	ldr r1, [r2]
 	lsl r0, r0, #1
 	ldrh r0, [r1, r0]
-	cmp r0, #0x4000
+	cmp r0, #0x4000 @ return tile index is OOB
 	bxhs lr
 	ldr r1, [r2, #4]
 	lsl r0, r0, #1
diff --git a/linker.ld b/linker.ld
index 01c96243..d8d2d2ee 100644
--- a/linker.ld
+++ b/linker.ld
@@ -258,7 +258,7 @@ SECTIONS {
         . = 0x00005D24; gUnk_03005D24 = .;
         . = 0x00005D58; gUnk_03005D58 = .;
         . = 0x00005D5C; gUnk_03005D5C = .;
-        . = 0x00005D90; gUnk_03005D90 = .;
+        . = 0x00005D90; IntrMain = .;
         . = 0x00005E60; gUnk_03005E60 = .;
         . = 0x00005E98; gUnk_03005E98 = .;
         . = 0x00005F24; _EntUpdate = .;
diff --git a/src/main.c b/src/main.c
index c05d9945..c00ce322 100644
--- a/src/main.c
+++ b/src/main.c
@@ -21,7 +21,7 @@ static void (*const sScreenHandlers[])(void) = {
     [SCREEN_CREDITS] = HandleCreditsScreen,   [SCREEN_DEBUG_TEXT] = HandleDebugTextScreen,
 };
 
-void MainLoop(void) {
+void AgbMain(void) {
     int var0;
 
     sub_08055F70();