fldeff_flash.c

8 files changed, 488 insertions, 1041 deletions

diff --git a/asm/fldeff_flash.s b/asm/fldeff_flash.s
deleted file mode 100644
index c6cc17f82..000000000
--- a/asm/fldeff_flash.s
+++ /dev/null
@@ -1,964 +0,0 @@
-	.include "asm/macros.inc"
-	.include "constants/constants.inc"
-
-	.syntax unified
-
-	.text
-
-	thumb_func_start SetUpFieldMove_Flash
-SetUpFieldMove_Flash: @ 80C9B2C
-	push {lr}
-	ldr r0, _080C9B54 @ =gMapHeader
-	ldrb r0, [r0, 0x15]
-	cmp r0, 0x1
-	bne _080C9B6C
-	ldr r0, _080C9B58 @ =0x00000806
-	bl FlagGet
-	lsls r0, 24
-	cmp r0, 0
-	bne _080C9B6C
-	ldr r1, _080C9B5C @ =gFieldCallback2
-	ldr r0, _080C9B60 @ =FieldCallback_PrepareFadeInFromMenu
-	str r0, [r1]
-	ldr r1, _080C9B64 @ =gPostMenuFieldCallback
-	ldr r0, _080C9B68 @ =sub_80C9B74
-	str r0, [r1]
-	movs r0, 0x1
-	b _080C9B6E
-	.align 2, 0
-_080C9B54: .4byte gMapHeader
-_080C9B58: .4byte 0x00000806
-_080C9B5C: .4byte gFieldCallback2
-_080C9B60: .4byte FieldCallback_PrepareFadeInFromMenu
-_080C9B64: .4byte gPostMenuFieldCallback
-_080C9B68: .4byte sub_80C9B74
-_080C9B6C:
-	movs r0, 0
-_080C9B6E:
-	pop {r1}
-	bx r1
-	thumb_func_end SetUpFieldMove_Flash
-
-	thumb_func_start sub_80C9B74
-sub_80C9B74: @ 80C9B74
-	push {r4,lr}
-	bl CreateFieldEffectShowMon
-	adds r4, r0, 0
-	lsls r4, 24
-	lsrs r4, 24
-	bl GetCursorSelectionMonId
-	ldr r1, _080C9BA4 @ =gFieldEffectArguments
-	lsls r0, 24
-	lsrs r0, 24
-	str r0, [r1]
-	ldr r1, _080C9BA8 @ =gTasks
-	lsls r0, r4, 2
-	adds r0, r4
-	lsls r0, 3
-	adds r0, r1
-	ldr r2, _080C9BAC @ =sub_80C9BB0
-	lsrs r1, r2, 16
-	strh r1, [r0, 0x18]
-	strh r2, [r0, 0x1A]
-	pop {r4}
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080C9BA4: .4byte gFieldEffectArguments
-_080C9BA8: .4byte gTasks
-_080C9BAC: .4byte sub_80C9BB0
-	thumb_func_end sub_80C9B74
-
-	thumb_func_start sub_80C9BB0
-sub_80C9BB0: @ 80C9BB0
-	push {lr}
-	movs r0, 0xC8
-	bl PlaySE
-	ldr r0, _080C9BC8 @ =0x00000806
-	bl FlagSet
-	ldr r0, _080C9BCC @ =EventScript_FldEffFlash
-	bl ScriptContext1_SetupScript
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080C9BC8: .4byte 0x00000806
-_080C9BCC: .4byte EventScript_FldEffFlash
-	thumb_func_end sub_80C9BB0
-
-	thumb_func_start sub_80C9BD0
-sub_80C9BD0: @ 80C9BD0
-	push {lr}
-	bl RunTasks
-	bl AnimateSprites
-	bl BuildOamBuffer
-	bl UpdatePaletteFade
-	pop {r0}
-	bx r0
-	thumb_func_end sub_80C9BD0
-
-	thumb_func_start sub_80C9BE8
-sub_80C9BE8: @ 80C9BE8
-	push {lr}
-	bl LoadOam
-	bl ProcessSpriteCopyRequests
-	bl TransferPlttBuffer
-	pop {r0}
-	bx r0
-	thumb_func_end sub_80C9BE8
-
-	thumb_func_start sub_80C9BFC
-sub_80C9BFC: @ 80C9BFC
-	push {lr}
-	sub sp, 0x8
-	movs r0, 0
-	bl SetVBlankCallback
-	movs r0, 0
-	movs r1, 0
-	bl SetGpuReg
-	movs r0, 0xC
-	movs r1, 0
-	bl SetGpuReg
-	movs r0, 0xA
-	movs r1, 0
-	bl SetGpuReg
-	movs r0, 0x8
-	movs r1, 0
-	bl SetGpuReg
-	movs r0, 0x18
-	movs r1, 0
-	bl SetGpuReg
-	movs r0, 0x1A
-	movs r1, 0
-	bl SetGpuReg
-	movs r0, 0x14
-	movs r1, 0
-	bl SetGpuReg
-	movs r0, 0x16
-	movs r1, 0
-	bl SetGpuReg
-	movs r0, 0x10
-	movs r1, 0
-	bl SetGpuReg
-	movs r0, 0x12
-	movs r1, 0
-	bl SetGpuReg
-	mov r1, sp
-	movs r0, 0
-	strh r0, [r1]
-	ldr r1, _080C9CC8 @ =0x040000d4
-	mov r0, sp
-	str r0, [r1]
-	movs r0, 0xC0
-	lsls r0, 19
-	str r0, [r1, 0x4]
-	ldr r0, _080C9CCC @ =0x8100c000
-	str r0, [r1, 0x8]
-	ldr r0, [r1, 0x8]
-	movs r2, 0
-	str r2, [sp, 0x4]
-	add r0, sp, 0x4
-	str r0, [r1]
-	movs r0, 0xE0
-	lsls r0, 19
-	str r0, [r1, 0x4]
-	ldr r0, _080C9CD0 @ =0x85000100
-	str r0, [r1, 0x8]
-	ldr r0, [r1, 0x8]
-	mov r0, sp
-	strh r2, [r0]
-	str r0, [r1]
-	ldr r0, _080C9CD4 @ =0x05000002
-	str r0, [r1, 0x4]
-	ldr r0, _080C9CD8 @ =0x810001ff
-	str r0, [r1, 0x8]
-	ldr r0, [r1, 0x8]
-	bl ResetPaletteFade
-	bl ResetTasks
-	bl ResetSpriteData
-	movs r0, 0x1
-	bl EnableInterrupts
-	ldr r0, _080C9CDC @ =sub_80C9BE8
-	bl SetVBlankCallback
-	ldr r0, _080C9CE0 @ =sub_80C9BD0
-	bl SetMainCallback2
-	bl sub_80C9CE8
-	lsls r0, 24
-	cmp r0, 0
-	bne _080C9CC2
-	ldr r0, _080C9CE4 @ =gMain
-	ldr r0, [r0, 0x8]
-	bl SetMainCallback2
-_080C9CC2:
-	add sp, 0x8
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080C9CC8: .4byte 0x040000d4
-_080C9CCC: .4byte 0x8100c000
-_080C9CD0: .4byte 0x85000100
-_080C9CD4: .4byte 0x05000002
-_080C9CD8: .4byte 0x810001ff
-_080C9CDC: .4byte sub_80C9BE8
-_080C9CE0: .4byte sub_80C9BD0
-_080C9CE4: .4byte gMain
-	thumb_func_end sub_80C9BFC
-
-	thumb_func_start sub_80C9CE8
-sub_80C9CE8: @ 80C9CE8
-	push {r4-r7,lr}
-	bl get_map_light_from_warp0
-	lsls r0, 24
-	lsrs r7, r0, 24
-	bl GetCurrentMapType
-	lsls r0, 24
-	lsrs r6, r0, 24
-	movs r4, 0
-	bl sub_80561B4
-	ldr r5, _080C9D24 @ =gMapHeader
-	lsls r0, 24
-	lsrs r0, 24
-	ldrb r1, [r5, 0x14]
-	cmp r0, r1
-	beq _080C9D36
-	ldrb r0, [r5, 0x14]
-	movs r1, 0
-	bl sub_80F8154
-	cmp r0, 0x1
-	bne _080C9D36
-	ldrb r0, [r5, 0x14]
-	bl sub_80CA160
-	movs r0, 0x1
-	b _080C9D70
-	.align 2, 0
-_080C9D24: .4byte gMapHeader
-_080C9D28:
-	adds r0, r3, 0x4
-	adds r0, r2, r0
-	ldr r0, [r0]
-	bl _call_via_r0
-	movs r0, 0x1
-	b _080C9D70
-_080C9D36:
-	ldr r5, _080C9D78 @ =gUnknown_83F5738
-	lsls r1, r4, 1
-	adds r0, r1, r4
-	lsls r0, 2
-	adds r0, r5
-	ldrb r0, [r0]
-	cmp r0, 0
-	beq _080C9D6E
-	adds r3, r5, 0
-_080C9D48:
-	adds r0, r1, r4
-	lsls r2, r0, 2
-	adds r1, r2, r3
-	ldrb r0, [r1]
-	cmp r0, r7
-	bne _080C9D5A
-	ldrb r0, [r1, 0x1]
-	cmp r0, r6
-	beq _080C9D28
-_080C9D5A:
-	adds r0, r4, 0x1
-	lsls r0, 24
-	lsrs r4, r0, 24
-	lsls r1, r4, 1
-	adds r0, r1, r4
-	lsls r0, 2
-	adds r0, r5
-	ldrb r0, [r0]
-	cmp r0, 0
-	bne _080C9D48
-_080C9D6E:
-	movs r0, 0
-_080C9D70:
-	pop {r4-r7}
-	pop {r1}
-	bx r1
-	.align 2, 0
-_080C9D78: .4byte gUnknown_83F5738
-	thumb_func_end sub_80C9CE8
-
-	thumb_func_start sub_80C9D7C
-sub_80C9D7C: @ 80C9D7C
-	push {r4-r6,lr}
-	lsls r0, 24
-	lsls r1, 24
-	lsrs r5, r0, 24
-	lsrs r4, r1, 24
-	movs r3, 0
-	ldr r1, _080C9DAC @ =gUnknown_83F5738
-	ldrb r0, [r1]
-	cmp r0, 0
-	beq _080C9DC4
-	adds r6, r1, 0
-_080C9D92:
-	lsls r0, r3, 1
-	adds r0, r3
-	lsls r0, 2
-	adds r2, r0, r6
-	ldrb r0, [r2]
-	cmp r0, r5
-	bne _080C9DB0
-	ldrb r0, [r2, 0x1]
-	cmp r0, r4
-	bne _080C9DB0
-	ldrb r0, [r2, 0x2]
-	b _080C9DC6
-	.align 2, 0
-_080C9DAC: .4byte gUnknown_83F5738
-_080C9DB0:
-	adds r0, r3, 0x1
-	lsls r0, 24
-	lsrs r3, r0, 24
-	lsls r0, r3, 1
-	adds r0, r3
-	lsls r0, 2
-	adds r0, r1
-	ldrb r0, [r0]
-	cmp r0, 0
-	bne _080C9D92
-_080C9DC4:
-	movs r0, 0
-_080C9DC6:
-	pop {r4-r6}
-	pop {r1}
-	bx r1
-	thumb_func_end sub_80C9D7C
-
-	thumb_func_start sub_80C9DCC
-sub_80C9DCC: @ 80C9DCC
-	push {r4-r6,lr}
-	lsls r0, 24
-	lsls r1, 24
-	lsrs r5, r0, 24
-	lsrs r4, r1, 24
-	movs r3, 0
-	ldr r1, _080C9DFC @ =gUnknown_83F5738
-	ldrb r0, [r1]
-	cmp r0, 0
-	beq _080C9E14
-	adds r6, r1, 0
-_080C9DE2:
-	lsls r0, r3, 1
-	adds r0, r3
-	lsls r0, 2
-	adds r2, r0, r6
-	ldrb r0, [r2]
-	cmp r0, r5
-	bne _080C9E00
-	ldrb r0, [r2, 0x1]
-	cmp r0, r4
-	bne _080C9E00
-	ldrb r0, [r2, 0x3]
-	b _080C9E16
-	.align 2, 0
-_080C9DFC: .4byte gUnknown_83F5738
-_080C9E00:
-	adds r0, r3, 0x1
-	lsls r0, 24
-	lsrs r3, r0, 24
-	lsls r0, r3, 1
-	adds r0, r3
-	lsls r0, 2
-	adds r0, r1
-	ldrb r0, [r0]
-	cmp r0, 0
-	bne _080C9DE2
-_080C9E14:
-	movs r0, 0
-_080C9E16:
-	pop {r4-r6}
-	pop {r1}
-	bx r1
-	thumb_func_end sub_80C9DCC
-
-	thumb_func_start sub_80C9E1C
-sub_80C9E1C: @ 80C9E1C
-	push {lr}
-	ldr r0, _080C9E2C @ =sub_80C9E30
-	movs r1, 0
-	bl CreateTask
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080C9E2C: .4byte sub_80C9E30
-	thumb_func_end sub_80C9E1C
-
-	thumb_func_start sub_80C9E30
-sub_80C9E30: @ 80C9E30
-	lsls r0, 24
-	lsrs r0, 24
-	ldr r2, _080C9E44 @ =gTasks
-	lsls r1, r0, 2
-	adds r1, r0
-	lsls r1, 3
-	adds r1, r2
-	ldr r0, _080C9E48 @ =sub_80C9E4C
-	str r0, [r1]
-	bx lr
-	.align 2, 0
-_080C9E44: .4byte gTasks
-_080C9E48: .4byte sub_80C9E4C
-	thumb_func_end sub_80C9E30
-
-	thumb_func_start sub_80C9E4C
-sub_80C9E4C: @ 80C9E4C
-	push {r4,lr}
-	adds r4, r0, 0
-	lsls r4, 24
-	lsrs r4, 24
-	movs r0, 0
-	movs r1, 0
-	bl SetGpuReg
-	ldr r0, _080C9EC8 @ =gUnknown_83F5A44
-	ldr r1, _080C9ECC @ =0x0600c000
-	bl LZ77UnCompVram
-	ldr r0, _080C9ED0 @ =gUnknown_83F5864
-	ldr r1, _080C9ED4 @ =0x0600f800
-	bl LZ77UnCompVram
-	ldr r0, _080C9ED8 @ =gUnknown_83F5804
-	movs r1, 0xE0
-	movs r2, 0x20
-	bl LoadPalette
-	ldr r0, _080C9EDC @ =gUnknown_83F5844 + 0x10
-	movs r1, 0xE0
-	movs r2, 0x10
-	bl LoadPalette
-	ldr r1, _080C9EE0 @ =0x00003e41
-	movs r0, 0x50
-	bl SetGpuReg
-	movs r0, 0x52
-	movs r1, 0
-	bl SetGpuReg
-	movs r0, 0x54
-	movs r1, 0
-	bl SetGpuReg
-	ldr r1, _080C9EE4 @ =0x00001f0c =BGCNT_PRIORITY(0) | BGCNT_CHARBASE(3) | BGCNT_SCREENBASE(31)
-	movs r0, 0x8
-	bl SetGpuReg
-	movs r1, 0x8A
-	lsls r1, 5
-	movs r0, 0
-	bl SetGpuReg
-	ldr r1, _080C9EE8 @ =gTasks
-	lsls r0, r4, 2
-	adds r0, r4
-	lsls r0, 3
-	adds r0, r1
-	ldr r1, _080C9EEC @ =sub_80C9EF0
-	str r1, [r0]
-	movs r2, 0
-	movs r1, 0x10
-	strh r1, [r0, 0x8]
-	strh r2, [r0, 0xA]
-	pop {r4}
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080C9EC8: .4byte gUnknown_83F5A44
-_080C9ECC: .4byte 0x0600c000
-_080C9ED0: .4byte gUnknown_83F5864
-_080C9ED4: .4byte 0x0600f800
-_080C9ED8: .4byte gUnknown_83F5804
-_080C9EDC: .4byte gUnknown_83F5844 + 0x10
-_080C9EE0: .4byte 0x00003e41
-_080C9EE4: .4byte 0x00001f0c
-_080C9EE8: .4byte gTasks
-_080C9EEC: .4byte sub_80C9EF0
-	thumb_func_end sub_80C9E4C
-
-	thumb_func_start sub_80C9EF0
-sub_80C9EF0: @ 80C9EF0
-	push {r4,r5,lr}
-	lsls r0, 24
-	lsrs r0, 24
-	ldr r2, _080C9F20 @ =gTasks
-	lsls r1, r0, 2
-	adds r1, r0
-	lsls r1, 3
-	adds r5, r1, r2
-	ldrh r4, [r5, 0xA]
-	movs r0, 0x80
-	lsls r0, 5
-	adds r1, r4, r0
-	lsls r1, 16
-	lsrs r1, 16
-	movs r0, 0x52
-	bl SetGpuReg
-	cmp r4, 0x10
-	bhi _080C9F24
-	ldrh r0, [r5, 0xA]
-	adds r0, 0x1
-	strh r0, [r5, 0xA]
-	b _080C9F2C
-	.align 2, 0
-_080C9F20: .4byte gTasks
-_080C9F24:
-	movs r0, 0
-	strh r0, [r5, 0xC]
-	ldr r0, _080C9F34 @ =sub_80C9F38
-	str r0, [r5]
-_080C9F2C:
-	pop {r4,r5}
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080C9F34: .4byte sub_80C9F38
-	thumb_func_end sub_80C9EF0
-
-	thumb_func_start sub_80C9F38
-sub_80C9F38: @ 80C9F38
-	push {r4,lr}
-	adds r4, r0, 0
-	lsls r4, 24
-	lsrs r4, 24
-	ldr r1, _080C9F74 @ =0x00001010
-	movs r0, 0x52
-	bl SetGpuReg
-	ldr r1, _080C9F78 @ =gTasks
-	lsls r0, r4, 2
-	adds r0, r4
-	lsls r0, 3
-	adds r4, r0, r1
-	ldrh r1, [r4, 0xC]
-	cmp r1, 0x7
-	bhi _080C9F80
-	adds r0, r1, 0x1
-	strh r0, [r4, 0xC]
-	lsls r1, 1
-	ldr r0, _080C9F7C @ =gUnknown_83F5844 + 0x10
-	adds r0, r1, r0
-	movs r2, 0x10
-	subs r2, r1
-	lsls r2, 16
-	lsrs r2, 16
-	movs r1, 0xE0
-	bl LoadPalette
-	b _080C9F92
-	.align 2, 0
-_080C9F74: .4byte 0x00001010
-_080C9F78: .4byte gTasks
-_080C9F7C: .4byte gUnknown_83F5844 + 0x10
-_080C9F80:
-	ldr r0, _080C9F98 @ =gUnknown_83F5804
-	movs r1, 0
-	movs r2, 0x20
-	bl LoadPalette
-	ldr r0, _080C9F9C @ =sub_80C9FA0
-	str r0, [r4]
-	movs r0, 0x8
-	strh r0, [r4, 0xC]
-_080C9F92:
-	pop {r4}
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080C9F98: .4byte gUnknown_83F5804
-_080C9F9C: .4byte sub_80C9FA0
-	thumb_func_end sub_80C9F38
-
-	thumb_func_start sub_80C9FA0
-sub_80C9FA0: @ 80C9FA0
-	push {lr}
-	lsls r0, 24
-	lsrs r0, 24
-	ldr r2, _080C9FC0 @ =gTasks
-	lsls r1, r0, 2
-	adds r1, r0
-	lsls r1, 3
-	adds r1, r2
-	ldrh r2, [r1, 0xC]
-	movs r3, 0xC
-	ldrsh r0, [r1, r3]
-	cmp r0, 0
-	beq _080C9FC4
-	subs r0, r2, 0x1
-	strh r0, [r1, 0xC]
-	b _080C9FCC
-	.align 2, 0
-_080C9FC0: .4byte gTasks
-_080C9FC4:
-	ldr r0, _080C9FD0 @ =gMain
-	ldr r0, [r0, 0x8]
-	bl SetMainCallback2
-_080C9FCC:
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080C9FD0: .4byte gMain
-	thumb_func_end sub_80C9FA0
-
-	thumb_func_start sub_80C9FD4
-sub_80C9FD4: @ 80C9FD4
-	push {lr}
-	ldr r0, _080C9FE4 @ =sub_80C9FE8
-	movs r1, 0
-	bl CreateTask
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080C9FE4: .4byte sub_80C9FE8
-	thumb_func_end sub_80C9FD4
-
-	thumb_func_start sub_80C9FE8
-sub_80C9FE8: @ 80C9FE8
-	lsls r0, 24
-	lsrs r0, 24
-	ldr r2, _080C9FFC @ =gTasks
-	lsls r1, r0, 2
-	adds r1, r0
-	lsls r1, 3
-	adds r1, r2
-	ldr r0, _080CA000 @ =sub_80CA004
-	str r0, [r1]
-	bx lr
-	.align 2, 0
-_080C9FFC: .4byte gTasks
-_080CA000: .4byte sub_80CA004
-	thumb_func_end sub_80C9FE8
-
-	thumb_func_start sub_80CA004
-sub_80CA004: @ 80CA004
-	push {r4,lr}
-	adds r4, r0, 0
-	lsls r4, 24
-	lsrs r4, 24
-	movs r0, 0
-	movs r1, 0
-	bl SetGpuReg
-	ldr r0, _080CA080 @ =gUnknown_83F5A44
-	ldr r1, _080CA084 @ =0x0600c000
-	bl LZ77UnCompVram
-	ldr r0, _080CA088 @ =gUnknown_83F5864
-	ldr r1, _080CA08C @ =0x0600f800
-	bl LZ77UnCompVram
-	movs r0, 0x50
-	movs r1, 0
-	bl SetGpuReg
-	movs r0, 0x52
-	movs r1, 0
-	bl SetGpuReg
-	movs r0, 0x54
-	movs r1, 0
-	bl SetGpuReg
-	ldr r1, _080CA090 @ =0x00001f0c
-	movs r0, 0x8
-	bl SetGpuReg
-	movs r1, 0x8A
-	lsls r1, 5
-	movs r0, 0
-	bl SetGpuReg
-	ldr r0, _080CA094 @ =gUnknown_83F5804
-	movs r1, 0xE0
-	movs r2, 0x20
-	bl LoadPalette
-	ldr r0, _080CA098 @ =gUnknown_83F5824
-	movs r1, 0
-	movs r2, 0x20
-	bl LoadPalette
-	ldr r1, _080CA09C @ =gTasks
-	lsls r0, r4, 2
-	adds r0, r4
-	lsls r0, 3
-	adds r0, r1
-	ldr r1, _080CA0A0 @ =sub_80CA0A4
-	str r1, [r0]
-	movs r2, 0
-	movs r1, 0x10
-	strh r1, [r0, 0x8]
-	strh r2, [r0, 0xA]
-	strh r2, [r0, 0xC]
-	pop {r4}
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080CA080: .4byte gUnknown_83F5A44
-_080CA084: .4byte 0x0600c000
-_080CA088: .4byte gUnknown_83F5864
-_080CA08C: .4byte 0x0600f800
-_080CA090: .4byte 0x00001f0c
-_080CA094: .4byte gUnknown_83F5804
-_080CA098: .4byte gUnknown_83F5824
-_080CA09C: .4byte gTasks
-_080CA0A0: .4byte sub_80CA0A4
-	thumb_func_end sub_80CA004
-
-	thumb_func_start sub_80CA0A4
-sub_80CA0A4: @ 80CA0A4
-	push {r4,lr}
-	lsls r0, 24
-	lsrs r0, 24
-	ldr r2, _080CA0D8 @ =gTasks
-	lsls r1, r0, 2
-	adds r1, r0
-	lsls r1, 3
-	adds r4, r1, r2
-	ldrh r1, [r4, 0xC]
-	cmp r1, 0xF
-	bhi _080CA0E0
-	adds r2, r1, 0x1
-	adds r0, r2, 0x1
-	strh r0, [r4, 0xC]
-	movs r0, 0xF
-	subs r0, r1
-	lsls r0, 1
-	ldr r1, _080CA0DC @ =gUnknown_83F5844
-	adds r0, r1
-	lsls r2, 17
-	lsrs r2, 16
-	movs r1, 0xE0
-	bl LoadPalette
-	b _080CA0F4
-	.align 2, 0
-_080CA0D8: .4byte gTasks
-_080CA0DC: .4byte gUnknown_83F5844
-_080CA0E0:
-	ldr r1, _080CA0FC @ =0x00001010
-	movs r0, 0x52
-	bl SetGpuReg
-	ldr r1, _080CA100 @ =0x00003e41
-	movs r0, 0x50
-	bl SetGpuReg
-	ldr r0, _080CA104 @ =sub_80CA108
-	str r0, [r4]
-_080CA0F4:
-	pop {r4}
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080CA0FC: .4byte 0x00001010
-_080CA100: .4byte 0x00003e41
-_080CA104: .4byte sub_80CA108
-	thumb_func_end sub_80CA0A4
-
-	thumb_func_start sub_80CA108
-sub_80CA108: @ 80CA108
-	push {r4,r5,lr}
-	lsls r0, 24
-	lsrs r0, 24
-	ldr r2, _080CA13C @ =gTasks
-	lsls r1, r0, 2
-	adds r1, r0
-	lsls r1, 3
-	adds r5, r1, r2
-	ldrh r0, [r5, 0xA]
-	movs r1, 0x10
-	subs r1, r0
-	lsls r1, 16
-	lsrs r4, r1, 16
-	movs r0, 0x80
-	lsls r0, 21
-	adds r1, r0
-	lsrs r1, 16
-	movs r0, 0x52
-	bl SetGpuReg
-	cmp r4, 0
-	beq _080CA140
-	ldrh r0, [r5, 0xA]
-	adds r0, 0x1
-	strh r0, [r5, 0xA]
-	b _080CA152
-	.align 2, 0
-_080CA13C: .4byte gTasks
-_080CA140:
-	ldr r0, _080CA158 @ =gUnknown_83F5824
-	movs r1, 0
-	movs r2, 0x20
-	bl LoadPalette
-	ldr r0, _080CA15C @ =gMain
-	ldr r0, [r0, 0x8]
-	bl SetMainCallback2
-_080CA152:
-	pop {r4,r5}
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080CA158: .4byte gUnknown_83F5824
-_080CA15C: .4byte gMain
-	thumb_func_end sub_80CA108
-
-	thumb_func_start sub_80CA160
-sub_80CA160: @ 80CA160
-	push {r4,lr}
-	adds r4, r0, 0
-	lsls r4, 24
-	lsrs r4, 24
-	ldr r0, _080CA188 @ =sub_80CA190
-	movs r1, 0
-	bl CreateTask
-	lsls r0, 24
-	lsrs r0, 24
-	ldr r2, _080CA18C @ =gTasks
-	lsls r1, r0, 2
-	adds r1, r0
-	lsls r1, 3
-	adds r1, r2
-	strh r4, [r1, 0xE]
-	pop {r4}
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080CA188: .4byte sub_80CA190
-_080CA18C: .4byte gTasks
-	thumb_func_end sub_80CA160
-
-	thumb_func_start sub_80CA190
-sub_80CA190: @ 80CA190
-	push {r4-r6,lr}
-	sub sp, 0x4
-	lsls r0, 24
-	lsrs r5, r0, 24
-	lsls r0, r5, 2
-	adds r0, r5
-	lsls r0, 3
-	ldr r1, _080CA1B8 @ =gTasks+0x8
-	adds r4, r0, r1
-	movs r1, 0
-	ldrsh r0, [r4, r1]
-	cmp r0, 0x5
-	bls _080CA1AC
-	b _080CA2D2
-_080CA1AC:
-	lsls r0, 2
-	ldr r1, _080CA1BC @ =_080CA1C0
-	adds r0, r1
-	ldr r0, [r0]
-	mov pc, r0
-	.align 2, 0
-_080CA1B8: .4byte gTasks+0x8
-_080CA1BC: .4byte _080CA1C0
-	.align 2, 0
-_080CA1C0:
-	.4byte _080CA1D8
-	.4byte _080CA208
-	.4byte _080CA224
-	.4byte _080CA24E
-	.4byte _080CA262
-	.4byte _080CA2A4
-_080CA1D8:
-	ldr r0, _080CA204 @ =gMain
-	ldr r2, [r0, 0xC]
-	adds r0, r5, 0
-	movs r1, 0x5
-	bl SetWordTaskArg
-	movs r0, 0
-	bl SetVBlankCallback
-	bl sub_80F8180
-	ldrb r0, [r4, 0x6]
-	bl sub_80F819C
-	movs r0, 0x1
-	negs r0, r0
-	movs r1, 0x10
-	movs r2, 0
-	bl BlendPalettes
-	b _080CA294
-	.align 2, 0
-_080CA204: .4byte gMain
-_080CA208:
-	bl sub_80F8258
-	cmp r0, 0
-	bne _080CA2D2
-	ldrb r0, [r4, 0x6]
-	bl sub_80F8318
-	strh r0, [r4, 0x8]
-	lsls r0, 24
-	lsrs r0, 24
-	movs r1, 0x3
-	bl CopyWindowToVram
-	b _080CA294
-_080CA224:
-	bl IsDma3ManagerBusyWithBgCopy
-	lsls r0, 24
-	lsrs r0, 24
-	cmp r0, 0
-	bne _080CA2D2
-	movs r1, 0x1
-	negs r1, r1
-	str r0, [sp]
-	adds r0, r1, 0
-	movs r2, 0x10
-	movs r3, 0
-	bl BeginNormalPaletteFade
-	adds r0, r5, 0
-	movs r1, 0x5
-	bl GetWordTaskArg
-	bl SetVBlankCallback
-	b _080CA294
-_080CA24E:
-	bl UpdatePaletteFade
-	lsls r0, 24
-	cmp r0, 0
-	bne _080CA2D2
-	ldrb r0, [r4, 0x6]
-	bl sub_80F856C
-	strh r0, [r4, 0x4]
-	b _080CA294
-_080CA262:
-	ldrh r0, [r4, 0x2]
-	adds r0, 0x1
-	strh r0, [r4, 0x2]
-	lsls r0, 16
-	asrs r0, 16
-	movs r2, 0x4
-	ldrsh r1, [r4, r2]
-	cmp r0, r1
-	bgt _080CA280
-	ldr r0, _080CA29C @ =gMain
-	ldrh r1, [r0, 0x2C]
-	movs r0, 0x2
-	ands r0, r1
-	cmp r0, 0
-	beq _080CA2D2
-_080CA280:
-	movs r0, 0x1
-	negs r0, r0
-	movs r1, 0x2
-	negs r1, r1
-	ldr r2, _080CA2A0 @ =0x00007fff
-	str r2, [sp]
-	movs r2, 0
-	movs r3, 0x10
-	bl BeginNormalPaletteFade
-_080CA294:
-	ldrh r0, [r4]
-	adds r0, 0x1
-	strh r0, [r4]
-	b _080CA2D2
-	.align 2, 0
-_080CA29C: .4byte gMain
-_080CA2A0: .4byte 0x00007fff
-_080CA2A4:
-	bl UpdatePaletteFade
-	lsls r0, 24
-	cmp r0, 0
-	bne _080CA2D2
-	lsls r6, r5, 2
-	movs r1, 0
-	adds r0, r4, 0
-	adds r0, 0x1E
-_080CA2B6:
-	strh r1, [r0]
-	subs r0, 0x2
-	cmp r0, r4
-	bge _080CA2B6
-	movs r1, 0x8
-	ldrsh r0, [r4, r1]
-	bl sub_80F8234
-	ldr r1, _080CA2DC @ =gTasks
-	adds r0, r6, r5
-	lsls r0, 3
-	adds r0, r1
-	ldr r1, _080CA2E0 @ =sub_80CA004
-	str r1, [r0]
-_080CA2D2:
-	add sp, 0x4
-	pop {r4-r6}
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080CA2DC: .4byte gTasks
-_080CA2E0: .4byte sub_80CA004
-	thumb_func_end sub_80CA190
-
-	.align 2, 0 @ Don't pad with nop.
diff --git a/data/fldeff_flash.s b/data/fldeff_flash.s
deleted file mode 100644
index ddffff5c1..000000000
--- a/data/fldeff_flash.s
+++ /dev/null
@@ -1,74 +0,0 @@
-#include "constants/species.h"
-#include "constants/items.h"
-	.include "asm/macros.inc"
-	.include "constants/constants.inc"
-	.section .rodata
-	.align 2
-
-gUnknown_83F5738:: @ 83F5738
-	.byte 1, 4, 1, 0
-	.4byte sub_80C9FD4
-	.4byte sub_80CA160
-	.byte 2, 4, 1, 0
-	.4byte sub_80C9FD4
-	.4byte sub_80CA160
-	.byte 3, 4, 1, 0
-	.4byte sub_80C9FD4
-	.4byte sub_80CA160
-	.byte 5, 4, 1, 0
-	.4byte sub_80C9FD4
-	.4byte sub_80CA160
-	.byte 6, 4, 1, 0
-	.4byte sub_80C9FD4
-	.4byte sub_80CA160
-	.byte 7, 4, 1, 0
-	.4byte sub_80C9FD4
-	.4byte sub_80CA160
-	.byte 8, 4, 1, 0
-	.4byte sub_80C9FD4
-	.4byte sub_80CA160
-	.byte 9, 4, 1, 0
-	.4byte sub_80C9FD4
-	.4byte sub_80CA160
-	.byte 4, 1, 0, 1
-	.4byte sub_80C9E1C
-	.4byte sub_80CA160
-	.byte 4, 2, 0, 1
-	.4byte sub_80C9E1C
-	.4byte sub_80CA160
-	.byte 4, 3, 0, 1
-	.4byte sub_80C9E1C
-	.4byte sub_80CA160
-	.byte 4, 5, 0, 1
-	.4byte sub_80C9E1C
-	.4byte sub_80CA160
-	.byte 4, 6, 0, 1
-	.4byte sub_80C9E1C
-	.4byte sub_80CA160
-	.byte 4, 7, 0, 1
-	.4byte sub_80C9E1C
-	.4byte sub_80CA160
-	.byte 4, 8, 0, 1
-	.4byte sub_80C9E1C
-	.4byte sub_80CA160
-	.byte 4, 9, 0, 1
-	.4byte sub_80C9E1C
-	.4byte sub_80CA160
-	.byte 0, 0, 0, 0
-	.4byte NULL
-	.4byte NULL
-
-gUnknown_83F5804:: @ 83F5804
-	.incbin "graphics/field_effects/flash_white.gbapal"
-
-gUnknown_83F5824:: @ 83F5824
-	.incbin "graphics/field_effects/flash_black.gbapal"
-
-gUnknown_83F5844:: @ 83F5844
-	.incbin "graphics/field_effects/flash_gradient.gbapal"
-
-gUnknown_83F5864:: @ 83F5864
-	.incbin "graphics/field_effects/flash_effect_map.bin.lz"
-
-gUnknown_83F5A44:: @ 83F5A44
-	.incbin "graphics/field_effects/flash_effect_tiles.4bpp.lz"
diff --git a/include/event_scripts.h b/include/event_scripts.h
index 3fda94a5f..c211e3a34 100644
--- a/include/event_scripts.h
+++ b/include/event_scripts.h
@@ -1209,4 +1209,7 @@ extern const u8 CableClub_Text_AwaitingLinkupBCancel[];
 extern const u8 CableClub_Text_StartLinkWithXPlayersAConfirmBCancel[];
 extern const u8 CableClub_Text_PleaseWaitBCancel[];
 
+// fldeff_flash
+extern const u8 EventScript_FldEffFlash[];
+
 #endif //GUARD_EVENT_SCRIPTS_H
diff --git a/include/map_preview_screen.h b/include/map_preview_screen.h
index ea85baf71..195e86929 100644
--- a/include/map_preview_screen.h
+++ b/include/map_preview_screen.h
@@ -50,5 +50,10 @@ u16 sub_80F856C(u8 id);
 bool8 sub_80F8110(u8 mapsec, bool8 forceFirstTime);
 bool32 sub_80F83B0(void);
 const struct MapPreviewScreen * GetDungeonMapPreviewScreenInfo(u8 mapsec);
+bool32 sub_80F8154(u8 mapsec, u8 forceFirstTime);
+void sub_80F8180(void);
+void sub_80F819C(u8 mapsec);
+bool32 sub_80F8258(void);
+void sub_80F8234(s32 windowId);
 
 #endif //GUARD_MAP_PREVIEW_SCREEN_H
diff --git a/include/overworld.h b/include/overworld.h
index daaa5e6e8..06d4bcb8e 100644
--- a/include/overworld.h
+++ b/include/overworld.h
@@ -192,6 +192,7 @@ void sub_8057F48(void);
 void SetMainCallback1(MainCallback cb);
 void CB1_Overworld(void);
 void sub_80568C4(void);
+u8 sub_80561B4(void);
 
 extern u16 gHeldKeyCodeToSend;
 
diff --git a/ld_script.txt b/ld_script.txt
index b919db2ef..c2b35f7a2 100644
--- a/ld_script.txt
+++ b/ld_script.txt
@@ -183,7 +183,7 @@ SECTIONS {
         src/battle_ai_script_commands.o(.text);
         src/fldeff_rocksmash.o(.text);
         src/fldeff_dig.o(.text);
-        asm/fldeff_flash.o(.text);
+        src/fldeff_flash.o(.text);
         src/post_battle_event_funcs.o(.text);
         src/prof_pc.o(.text);
         src/hof_pc.o(.text);
@@ -489,7 +489,7 @@ SECTIONS {
         src/region_map.o(.rodata);
         src/image_processing_effects.o(.rodata);
         src/battle_ai_script_commands.o(.rodata);
-        data/fldeff_flash.o(.rodata);
+        src/fldeff_flash.o(.rodata);
         src/field_specials.o(.rodata);
         src/battle_records.o(.rodata);
         src/evolution_scene.o(.rodata);
diff --git a/src/fldeff_flash.c b/src/fldeff_flash.c
new file mode 100644
index 000000000..7f40558d9
--- /dev/null
+++ b/src/fldeff_flash.c
@@ -0,0 +1,476 @@
+#include "global.h"
+#include "gflib.h"
+#include "event_data.h"
+#include "event_scripts.h"
+#include "fldeff.h"
+#include "field_effect.h"
+#include "map_preview_screen.h"
+#include "overworld.h"
+#include "party_menu.h"
+#include "script.h"
+#include "constants/songs.h"
+
+struct FlashStruct
+{
+    u8 fromType;
+    u8 toType;
+    bool8 isEnter;
+    bool8 isExit;
+    void (*func1)(void);
+    void (*func2)(u8 mapSecId);
+};
+
+static void sub_80C9B74(void);
+static void sub_80C9BB0(void);
+static bool8 sub_80C9CE8(void);
+static void sub_80C9E1C(void);
+static void sub_80C9E30(u8 taskId);
+static void sub_80C9E4C(u8 taskId);
+static void sub_80C9EF0(u8 taskId);
+static void sub_80C9F38(u8 taskId);
+static void sub_80C9FA0(u8 taskId);
+static void sub_80C9FD4(void);
+static void sub_80C9FE8(u8 taskId);
+static void sub_80CA004(u8 taskId);
+static void sub_80CA0A4(u8 taskId);
+static void sub_80CA108(u8 taskId);
+static void sub_80CA160(u8 mapsecId);
+static void sub_80CA190(u8 taskId);
+
+static const struct FlashStruct gUnknown_83F5738[] = {
+    {
+        .fromType = 1,
+        .toType = 4,
+        .isEnter = TRUE,
+        .isExit = FALSE,
+        .func1 = sub_80C9FD4,
+        .func2 = sub_80CA160
+    }, {
+        .fromType = 2,
+        .toType = 4,
+        .isEnter = TRUE,
+        .isExit = FALSE,
+        .func1 = sub_80C9FD4,
+        .func2 = sub_80CA160
+    }, {
+        .fromType = 3,
+        .toType = 4,
+        .isEnter = TRUE,
+        .isExit = FALSE,
+        .func1 = sub_80C9FD4,
+        .func2 = sub_80CA160
+    }, {
+        .fromType = 5,
+        .toType = 4,
+        .isEnter = TRUE,
+        .isExit = FALSE,
+        .func1 = sub_80C9FD4,
+        .func2 = sub_80CA160
+    }, {
+        .fromType = 6,
+        .toType = 4,
+        .isEnter = TRUE,
+        .isExit = FALSE,
+        .func1 = sub_80C9FD4,
+        .func2 = sub_80CA160
+    }, {
+        .fromType = 7,
+        .toType = 4,
+        .isEnter = TRUE,
+        .isExit = FALSE,
+        .func1 = sub_80C9FD4,
+        .func2 = sub_80CA160
+    }, {
+        .fromType = 8,
+        .toType = 4,
+        .isEnter = TRUE,
+        .isExit = FALSE,
+        .func1 = sub_80C9FD4,
+        .func2 = sub_80CA160
+    }, {
+        .fromType = 9,
+        .toType = 4,
+        .isEnter = TRUE,
+        .isExit = FALSE,
+        .func1 = sub_80C9FD4,
+        .func2 = sub_80CA160
+    }, {
+        .fromType = 4,
+        .toType = 1,
+        .isEnter = FALSE,
+        .isExit = TRUE,
+        .func1 = sub_80C9E1C,
+        .func2 = sub_80CA160
+    }, {
+        .fromType = 4,
+        .toType = 2,
+        .isEnter = FALSE,
+        .isExit = TRUE,
+        .func1 = sub_80C9E1C,
+        .func2 = sub_80CA160
+    }, {
+        .fromType = 4,
+        .toType = 3,
+        .isEnter = FALSE,
+        .isExit = TRUE,
+        .func1 = sub_80C9E1C,
+        .func2 = sub_80CA160
+    }, {
+        .fromType = 4,
+        .toType = 5,
+        .isEnter = FALSE,
+        .isExit = TRUE,
+        .func1 = sub_80C9E1C,
+        .func2 = sub_80CA160
+    }, {
+        .fromType = 4,
+        .toType = 6,
+        .isEnter = FALSE,
+        .isExit = TRUE,
+        .func1 = sub_80C9E1C,
+        .func2 = sub_80CA160
+    }, {
+        .fromType = 4,
+        .toType = 7,
+        .isEnter = FALSE,
+        .isExit = TRUE,
+        .func1 = sub_80C9E1C,
+        .func2 = sub_80CA160
+    }, {
+        .fromType = 4,
+        .toType = 8,
+        .isEnter = FALSE,
+        .isExit = TRUE,
+        .func1 = sub_80C9E1C,
+        .func2 = sub_80CA160
+    }, {
+        .fromType = 4,
+        .toType = 9,
+        .isEnter = FALSE,
+        .isExit = TRUE,
+        .func1 = sub_80C9E1C,
+        .func2 = sub_80CA160
+    }, {0}
+};
+
+static const u16 gUnknown_83F5804[] = INCBIN_U16("graphics/field_effects/flash_white.gbapal");
+static const u16 gUnknown_83F5824[] = INCBIN_U16("graphics/field_effects/flash_black.gbapal");
+static const u16 gUnknown_83F5844[] = INCBIN_U16("graphics/field_effects/flash_gradient.gbapal");
+static const u32 gUnknown_83F5864[] = INCBIN_U32("graphics/field_effects/flash_effect_map.bin.lz");
+static const u32 gUnknown_83F5A44[] = INCBIN_U32("graphics/field_effects/flash_effect_tiles.4bpp.lz");
+
+bool8 SetUpFieldMove_Flash(void)
+{
+    if (gMapHeader.cave != TRUE)
+        return FALSE;
+
+    if (FlagGet(FLAG_SYS_FLASH_ACTIVE))
+        return FALSE;
+
+    gFieldCallback2 = FieldCallback_PrepareFadeInFromMenu;
+    gPostMenuFieldCallback = sub_80C9B74;
+    return TRUE;
+}
+
+static void sub_80C9B74(void)
+{
+    u8 taskId = CreateFieldEffectShowMon();
+    gFieldEffectArguments[0] = GetCursorSelectionMonId();
+    gTasks[taskId].data[8] = ((uintptr_t)sub_80C9BB0) >> 16;
+    gTasks[taskId].data[9] = ((uintptr_t)sub_80C9BB0);
+}
+
+static void sub_80C9BB0(void)
+{
+    PlaySE(SE_W115);
+    FlagSet(FLAG_SYS_FLASH_ACTIVE);
+    ScriptContext1_SetupScript(EventScript_FldEffFlash);
+}
+
+static void sub_80C9BD0(void)
+{
+    RunTasks();
+    AnimateSprites();
+    BuildOamBuffer();
+    UpdatePaletteFade();
+}
+
+static void sub_80C9BE8(void)
+{
+    LoadOam();
+    ProcessSpriteCopyRequests();
+    TransferPlttBuffer();
+}
+
+void sub_80C9BFC(void)
+{
+    SetVBlankCallback(NULL);
+
+    SetGpuReg(REG_OFFSET_DISPCNT, 0);
+    SetGpuReg(REG_OFFSET_BG2CNT, 0);
+    SetGpuReg(REG_OFFSET_BG1CNT, 0);
+    SetGpuReg(REG_OFFSET_BG0CNT, 0);
+    SetGpuReg(REG_OFFSET_BG2HOFS, 0);
+    SetGpuReg(REG_OFFSET_BG2VOFS, 0);
+    SetGpuReg(REG_OFFSET_BG1HOFS, 0);
+    SetGpuReg(REG_OFFSET_BG1VOFS, 0);
+    SetGpuReg(REG_OFFSET_BG0HOFS, 0);
+    SetGpuReg(REG_OFFSET_BG0VOFS, 0);
+
+    DmaFill16(3, 0, (void *)VRAM, VRAM_SIZE);
+    DmaFill32(3, 0, (void *)OAM, OAM_SIZE);
+    DmaFill16(3, 0, (void *)(PLTT + 2), PLTT_SIZE - 2);
+    ResetPaletteFade();
+    ResetTasks();
+    ResetSpriteData();
+    EnableInterrupts(INTR_FLAG_VBLANK);
+    SetVBlankCallback(sub_80C9BE8);
+    SetMainCallback2(sub_80C9BD0);
+    if (!sub_80C9CE8())
+        SetMainCallback2(gMain.savedCallback);
+}
+
+static bool8 sub_80C9CE8(void)
+{
+    u8 fromType = get_map_light_from_warp0();
+    u8 toType = GetCurrentMapType();
+    u8 i = 0;
+    if (sub_80561B4() != gMapHeader.regionMapSectionId && sub_80F8154(gMapHeader.regionMapSectionId, FALSE) == TRUE)
+    {
+        sub_80CA160(gMapHeader.regionMapSectionId);
+        return TRUE;
+    }
+    for (; gUnknown_83F5738[i].fromType != 0; i++)
+    {
+        if (gUnknown_83F5738[i].fromType == fromType && gUnknown_83F5738[i].toType == toType)
+        {
+            gUnknown_83F5738[i].func1();
+            return TRUE;
+        }
+    }
+    return FALSE;
+}
+
+bool8 sub_80C9D7C(u8 _fromType, u8 _toType)
+{
+    u8 fromType = _fromType;
+    u8 toType = _toType;
+    u8 i = 0;
+    for (; gUnknown_83F5738[i].fromType != 0; i++)
+    {
+        if (gUnknown_83F5738[i].fromType == fromType && gUnknown_83F5738[i].toType == toType)
+        {
+            return gUnknown_83F5738[i].isEnter;
+        }
+    }
+    return FALSE;
+}
+
+bool8 sub_80C9DCC(u8 _fromType, u8 _toType)
+{
+    u8 fromType = _fromType;
+    u8 toType = _toType;
+    u8 i = 0;
+    for (; gUnknown_83F5738[i].fromType != 0; i++)
+    {
+        if (gUnknown_83F5738[i].fromType == fromType && gUnknown_83F5738[i].toType == toType)
+        {
+            return gUnknown_83F5738[i].isExit;
+        }
+    }
+    return FALSE;
+}
+
+static void sub_80C9E1C(void)
+{
+    CreateTask(sub_80C9E30, 0);
+}
+
+static void sub_80C9E30(u8 taskId)
+{
+    gTasks[taskId].func = sub_80C9E4C;
+}
+
+static void sub_80C9E4C(u8 taskId)
+{
+    SetGpuReg(REG_OFFSET_DISPCNT, 0);
+    LZ77UnCompVram(gUnknown_83F5A44, (void *)BG_CHAR_ADDR(3));
+    LZ77UnCompVram(gUnknown_83F5864, (void *)BG_SCREEN_ADDR(31));
+    LoadPalette(gUnknown_83F5804, 0xE0, 0x20);
+    LoadPalette(gUnknown_83F5844 + 8, 0xE0, 0x10);
+    SetGpuReg(REG_OFFSET_BLDCNT, BLDCNT_TGT1_BG0 | BLDCNT_EFFECT_BLEND | BLDCNT_TGT2_BG1 | BLDCNT_TGT2_BG2 | BLDCNT_TGT2_BG3 | BLDCNT_TGT2_OBJ | BLDCNT_TGT2_BD);
+    SetGpuReg(REG_OFFSET_BLDALPHA, 0);
+    SetGpuReg(REG_OFFSET_BLDY, 0);
+    SetGpuReg(REG_OFFSET_BG0CNT, BGCNT_PRIORITY(0) | BGCNT_CHARBASE(3) | BGCNT_SCREENBASE(31));
+    SetGpuReg(REG_OFFSET_DISPCNT, DISPCNT_MODE_0 | DISPCNT_OBJ_1D_MAP | DISPCNT_BG0_ON | DISPCNT_OBJ_ON);
+    gTasks[taskId].func = sub_80C9EF0;
+    gTasks[taskId].data[0] = 16;
+    gTasks[taskId].data[1] = 0;
+}
+
+static void sub_80C9EF0(u8 taskId)
+{
+    u16 r4 = gTasks[taskId].data[1];
+    SetGpuReg(REG_OFFSET_BLDALPHA, (16 << 8) + r4);
+    if (r4 <= 16)
+    {
+        gTasks[taskId].data[1]++;
+    }
+    else
+    {
+        gTasks[taskId].data[2] = 0;
+        gTasks[taskId].func = sub_80C9F38;
+    }
+}
+
+static void sub_80C9F38(u8 taskId)
+{
+    u16 r4;
+    SetGpuReg(REG_OFFSET_BLDALPHA, (16 << 8) + 16);
+    r4 = gTasks[taskId].data[2];
+    if (r4 < 8)
+    {
+        gTasks[taskId].data[2]++;
+        LoadPalette(gUnknown_83F5844 + 8 + r4, 0xE0, 0x10 - 2 * r4);
+    }
+    else
+    {
+        LoadPalette(gUnknown_83F5804, 0x00, 0x20);
+        gTasks[taskId].func = sub_80C9FA0;
+        gTasks[taskId].data[2] = 8;
+    }
+}
+
+static void sub_80C9FA0(u8 taskId)
+{
+    if (gTasks[taskId].data[2] != 0)
+        gTasks[taskId].data[2]--;
+    else
+        SetMainCallback2(gMain.savedCallback);
+}
+
+static void sub_80C9FD4(void)
+{
+    CreateTask(sub_80C9FE8, 0);
+}
+
+static void sub_80C9FE8(u8 taskId)
+{
+    gTasks[taskId].func = sub_80CA004;
+}
+
+static void sub_80CA004(u8 taskId)
+{
+    SetGpuReg(REG_OFFSET_DISPCNT, 0);
+    LZ77UnCompVram(gUnknown_83F5A44, (void *)BG_CHAR_ADDR(3));
+    LZ77UnCompVram(gUnknown_83F5864, (void *)BG_SCREEN_ADDR(31));
+    SetGpuReg(REG_OFFSET_BLDCNT, 0);
+    SetGpuReg(REG_OFFSET_BLDALPHA, 0);
+    SetGpuReg(REG_OFFSET_BLDY, 0);
+    SetGpuReg(REG_OFFSET_BG0CNT, BGCNT_PRIORITY(0) | BGCNT_CHARBASE(3) | BGCNT_SCREENBASE(31));
+    SetGpuReg(REG_OFFSET_DISPCNT, DISPCNT_MODE_0 | DISPCNT_OBJ_1D_MAP | DISPCNT_BG0_ON | DISPCNT_OBJ_ON);
+    LoadPalette(gUnknown_83F5804, 0xE0, 0x20);
+    LoadPalette(gUnknown_83F5824, 0, 0x20);
+    gTasks[taskId].func = sub_80CA0A4;
+    gTasks[taskId].data[0] = 16;
+    gTasks[taskId].data[1] = 0;
+    gTasks[taskId].data[2] = 0;
+}
+
+static void sub_80CA0A4(u8 taskId)
+{
+    u16 r4;
+    r4 = gTasks[taskId].data[2];
+    if (r4 < 16)
+    {
+        gTasks[taskId].data[2]++;
+        gTasks[taskId].data[2]++;
+        LoadPalette(&gUnknown_83F5844[16 - (r4 + 1)], 0xE0, 2 * (r4 + 1));
+    }
+    else
+    {
+        SetGpuReg(REG_OFFSET_BLDALPHA, (16 << 8) + 16);
+        SetGpuReg(REG_OFFSET_BLDCNT, BLDCNT_TGT1_BG0 | BLDCNT_EFFECT_BLEND | BLDCNT_TGT2_BG1 | BLDCNT_TGT2_BG2 | BLDCNT_TGT2_BG3 | BLDCNT_TGT2_OBJ | BLDCNT_TGT2_BD);
+        gTasks[taskId].func = sub_80CA108;
+    }
+}
+
+static void sub_80CA108(u8 taskId)
+{
+    u16 r4 = 16 - gTasks[taskId].data[1];
+    SetGpuReg(REG_OFFSET_BLDALPHA, (16 << 8) + r4);
+    if (r4 != 0)
+    {
+        gTasks[taskId].data[1]++;
+    }
+    else
+    {
+        LoadPalette(gUnknown_83F5824, 0x00, 0x20);
+        SetMainCallback2(gMain.savedCallback);
+    }
+}
+
+static void sub_80CA160(u8 mapSecId)
+{
+    u8 taskId = CreateTask(sub_80CA190, 0);
+    gTasks[taskId].data[3] = mapSecId;
+}
+
+static void sub_80CA190(u8 taskId)
+{
+    s16 *data = gTasks[taskId].data;
+    switch (data[0])
+    {
+    case 0:
+        SetWordTaskArg(taskId, 5, (uintptr_t)gMain.vblankCallback);
+        SetVBlankCallback(NULL);
+        sub_80F8180();
+        sub_80F819C(data[3]);
+        BlendPalettes(0xFFFFFFFF, 0x10, RGB_BLACK);
+        data[0]++;
+        break;
+    case 1:
+        if (!sub_80F8258())
+        {
+            data[4] = sub_80F8318(data[3]);
+            CopyWindowToVram(data[4], 3);
+            data[0]++;
+        }
+        break;
+    case 2:
+        if (!IsDma3ManagerBusyWithBgCopy())
+        {
+            BeginNormalPaletteFade(0xFFFFFFFF, -1, 16, 0, RGB_BLACK);
+            SetVBlankCallback((IntrCallback)GetWordTaskArg(taskId, 5));
+            data[0]++;
+        }
+        break;
+    case 3:
+        if (!UpdatePaletteFade())
+        {
+            data[2] = sub_80F856C(data[3]);
+            data[0]++;
+        }
+        break;
+    case 4:
+        data[1]++;
+        if (data[1] > data[2] || JOY_HELD(B_BUTTON))
+        {
+            BeginNormalPaletteFade(0xFFFFFFFF, -2, 0, 16, RGB_WHITE);
+            data[0]++;
+        }
+        break;
+    case 5:
+        if (!UpdatePaletteFade())
+        {
+            int i;
+            for (i = 0; i < 16; i++)
+            {
+                data[i] = 0;
+            }
+            sub_80F8234(data[4]);
+            gTasks[taskId].func = sub_80CA004;
+        }
+        break;
+    }
+}
diff --git a/src/map_preview_screen.c b/src/map_preview_screen.c
index b5c68acf9..a553ca122 100644
--- a/src/map_preview_screen.c
+++ b/src/map_preview_screen.c
@@ -364,7 +364,7 @@ bool8 sub_80F8110(u8 mapsec, u8 forceFirstTime)
     }
 }
 
-bool8 sub_80F8154(u8 mapsec, u8 forceFirstTime)
+bool32 sub_80F8154(u8 mapsec, u8 forceFirstTime)
 {
     if (gQuestLogState == 2)
     {