Merge branch 'master' into refactor-preprocessor

11 files changed, 2064 insertions, 33 deletions

diff --git a/engine/copy.asm b/engine/copy.asm
index c5ba92c65..ad25c96e6 100644
--- a/engine/copy.asm
+++ b/engine/copy.asm
@@ -248,13 +248,13 @@ Request2bpp: ; eba
 
 .asm_edc
 	ld a, e
-	ld [$cf68], a
+	ld [Requested2bppSource], a
 	ld a, d
-	ld [$cf69], a
+	ld [Requested2bppSource + 1], a
 	ld a, l
-	ld [$cf6a], a
+	ld [Requested2bppDest], a
 	ld a, h
-	ld [$cf6b], a
+	ld [Requested2bppDest + 1], a
 
 .asm_eec
 	ld a, c
@@ -262,10 +262,10 @@ Request2bpp: ; eba
 	cp [hl]
 	jr nc, .asm_f08
 
-	ld [$cf67], a
+	ld [Requested2bpp], a
 .wait
 	call DelayFrame
-	ld a, [$cf67]
+	ld a, [Requested2bpp]
 	and a
 	jr nz, .wait
 
@@ -281,10 +281,10 @@ Request2bpp: ; eba
 
 .asm_f08
 	ld a, [$ffd3]
-	ld [$cf67], a
+	ld [Requested2bpp], a
 .asm_f0d
 	call DelayFrame
-	ld a, [$cf67]
+	ld a, [Requested2bpp]
 	and a
 	jr nz, .asm_f0d
 	ld a, c
@@ -322,23 +322,23 @@ Request1bpp: ; f1e
 
 .asm_f40
 	ld a, e
-	ld [$cf6d], a
+	ld [Requested1bppSource], a
 	ld a, d
-	ld [$cf6e], a
+	ld [Requested1bppSource + 1], a
 	ld a, l
-	ld [$cf6f], a
+	ld [Requested1bppDest], a
 	ld a, h
-	ld [$cf70], a
+	ld [Requested1bppDest + 1], a
 .asm_f50
 	ld a, c
 	ld hl, $ffd3
 	cp [hl]
 	jr nc, .asm_f6c
 
-	ld [$cf6c], a
+	ld [Requested1bpp], a
 .wait
 	call DelayFrame
-	ld a, [$cf6c]
+	ld a, [Requested1bpp]
 	and a
 	jr nz, .wait
 
@@ -354,10 +354,10 @@ Request1bpp: ; f1e
 
 .asm_f6c
 	ld a, [$ffd3]
-	ld [$cf6c], a
+	ld [Requested1bpp], a
 .asm_f71
 	call DelayFrame
-	ld a, [$cf6c]
+	ld a, [Requested1bpp]
 	and a
 	jr nz, .asm_f71
 	ld a, c
diff --git a/engine/delay.asm b/engine/delay.asm
new file mode 100644
index 000000000..4e8b2147c
--- /dev/null
+++ b/engine/delay.asm
@@ -0,0 +1,23 @@
+DelayFrame: ; 45a
+; Wait for one frame
+	ld a, 1
+	ld [VBlankOccurred], a
+
+; Wait for the next VBlank, halting to conserve battery
+.halt
+	halt ; rgbasm adds a nop after this instruction by default
+	ld a, [VBlankOccurred]
+	and a
+	jr nz, .halt
+	ret
+; 468
+
+
+DelayFrames: ; 468
+; Wait c frames
+	call DelayFrame
+	dec c
+	jr nz, DelayFrames
+	ret
+; 46f
+
diff --git a/engine/farcall.asm b/engine/farcall.asm
new file mode 100644
index 000000000..bdee3bf38
--- /dev/null
+++ b/engine/farcall.asm
@@ -0,0 +1,55 @@
+FarCall_de: ; 2d54
+; Call a:de.
+; Preserves other registers.
+
+	ld [hBuffer], a
+	ld a, [hROMBank]
+	push af
+	ld a, [hBuffer]
+	rst Bankswitch
+	call .de
+	jr ReturnFarCall
+
+.de
+	push de
+	ret
+; 2d63
+
+
+FarCall_hl: ; 2d63
+; Call a:hl.
+; Preserves other registers.
+
+	ld [hBuffer], a
+	ld a, [hROMBank]
+	push af
+	ld a, [hBuffer]
+	rst Bankswitch
+	call Function2d82
+; 2d6e
+
+ReturnFarCall: ; 2d6e
+; We want to retain the contents of f.
+; To do this, we can pop to bc instead of af.
+	
+	ld a, b
+	ld [$cfb9], a
+	ld a, c
+	ld [$cfba], a
+	
+; Restore the working bank.
+	pop bc
+	ld a, b
+	rst Bankswitch
+	
+	ld a, [$cfb9]
+	ld b, a
+	ld a, [$cfba]
+	ld c, a
+	ret
+; 2d82
+
+Function2d82: ; 2d82
+	jp [hl]
+; 2d83
+
diff --git a/engine/game_time.asm b/engine/game_time.asm
new file mode 100644
index 000000000..ee52488f4
--- /dev/null
+++ b/engine/game_time.asm
@@ -0,0 +1,132 @@
+ResetGameTime: ; 208a
+	xor a
+	ld [GameTimeCap], a
+	ld [GameTimeHours], a
+	ld [GameTimeHours + 1], a
+	ld [GameTimeMinutes], a
+	ld [GameTimeSeconds], a
+	ld [GameTimeFrames], a
+	ret
+; 209e
+
+
+GameTimer: ; 209e
+
+	nop
+
+	ld a, [rSVBK]
+	push af
+	ld a, 1
+	ld [rSVBK], a
+
+	call UpdateGameTimer
+
+	pop af
+	ld [rSVBK], a
+	ret
+; 20ad
+
+
+UpdateGameTimer: ; 20ad
+; Increment the game timer by one frame.
+; The game timer is capped at 999:59:59.00.
+
+
+; Don't update if game logic is paused.
+	ld a, [$c2cd]
+	and a
+	ret nz
+
+; Is the timer paused?
+	ld hl, GameTimerPause
+	bit 0, [hl]
+	ret z
+
+; Is the timer already capped?
+	ld hl, GameTimeCap
+	bit 0, [hl]
+	ret nz
+
+
+; +1 frame
+	ld hl, GameTimeFrames
+	ld a, [hl]
+	inc a
+
+	cp 60 ; frames/second
+	jr nc, .second
+
+	ld [hl], a
+	ret
+
+
+.second
+	xor a
+	ld [hl], a
+
+; +1 second
+	ld hl, GameTimeSeconds
+	ld a, [hl]
+	inc a
+
+	cp 60 ; seconds/minute
+	jr nc, .minute
+
+	ld [hl], a
+	ret
+
+
+.minute
+	xor a
+	ld [hl], a
+
+; +1 minute
+	ld hl, GameTimeMinutes
+	ld a, [hl]
+	inc a
+
+	cp 60 ; minutes/hour
+	jr nc, .hour
+
+	ld [hl], a
+	ret
+
+
+.hour
+	xor a
+	ld [hl], a
+
+; +1 hour
+	ld a, [GameTimeHours]
+	ld h, a
+	ld a, [GameTimeHours + 1]
+	ld l, a
+	inc hl
+
+
+; Cap the timer after 1000 hours.
+	ld a, h
+	cp 1000 / $100
+	jr c, .ok
+
+	ld a, l
+	cp 1000 % $100
+	jr c, .ok
+
+	ld hl, GameTimeCap
+	set 0, [hl]
+
+	ld a, 59 ; 999:59:59.00
+	ld [GameTimeMinutes], a
+	ld [GameTimeSeconds], a
+	ret
+
+
+.ok
+	ld a, h
+	ld [GameTimeHours], a
+	ld a, l
+	ld [GameTimeHours + 1], a
+	ret
+; 210f
+
diff --git a/engine/map_objects.asm b/engine/map_objects.asm
new file mode 100644
index 000000000..3ebc1b597
--- /dev/null
+++ b/engine/map_objects.asm
@@ -0,0 +1,683 @@
+; Functions handling map objects.
+
+
+GetSpritePalette: ; 17ff
+	push hl
+	push de
+	push bc
+	ld c, a
+	callba _GetSpritePalette
+	ld a, c
+	pop bc
+	pop de
+	pop hl
+	ret
+; 180e
+
+
+Function180e: ; 180e
+	push hl
+	push bc
+	ld hl, $d156
+	ld c, $1f
+	ld b, a
+	ld a, [hConnectionStripLength]
+	cp $0
+	jr z, .asm_182b
+	ld a, b
+.asm_181d
+	cp [hl]
+	jr z, .asm_1830
+	inc hl
+	inc hl
+	dec c
+	jr nz, .asm_181d
+	ld a, [$d155]
+	scf
+	jr .asm_1833
+
+.asm_182b
+	ld a, [$d155]
+	jr .asm_1833
+
+.asm_1830
+	inc hl
+	xor a
+	ld a, [hl]
+
+.asm_1833
+	pop bc
+	pop hl
+	ret
+; 1836
+
+Function1836: ; 1836
+	push de
+	push hl
+
+	ld b, a
+	ld a, [hROMBank]
+	push af
+	ld a, BANK(Function142a7)
+	rst Bankswitch
+
+	ld a, b
+	call Function142a7
+	ld c, a
+
+	pop de
+	ld a, d
+	rst Bankswitch
+
+	pop hl
+	pop de
+	ret
+; 184a
+
+
+
+Function184a: ; 184a
+	ld a, [StandingTile]
+	call GetTileCollision
+	ld b, a
+	ret
+; 1852
+
+Function1852: ; 1852
+	ld a, [StandingTile]
+	call GetTileCollision
+	sub 1
+	ret z
+	and a
+	ret
+; 185d
+
+
+GetTileCollision: ; 185d
+; Get the collision type of tile a.
+
+	push de
+	push hl
+
+	ld hl, TileCollisionTable
+	ld e, a
+	ld d, 0
+	add hl, de
+
+	ld a, [hROMBank]
+	push af
+	ld a, BANK(TileCollisionTable)
+	rst Bankswitch
+	ld e, [hl]
+	pop af
+	rst Bankswitch
+
+	ld a, e
+	and $f ; lo nybble only
+
+	pop hl
+	pop de
+	ret
+; 1875
+
+
+Function1875: ; 1875
+	ld d, a
+	and $f0
+	cp $10
+	jr z, .asm_1882
+	cp $20
+	jr z, .asm_1888
+	scf
+	ret
+
+.asm_1882
+	ld a, d
+	and 7
+	ret z
+	scf
+	ret
+
+.asm_1888
+	ld a, d
+	and 7
+	ret z
+	scf
+	ret
+; 188e
+
+Function188e: ; 188e
+	cp $14
+	ret z
+	cp $1c
+	ret
+; 1894
+
+CheckCutTreeTile: ; 1894
+	cp $12
+	ret z
+	cp $1a
+	ret
+; 189a
+
+CheckHeadbuttTreeTile: ; 189a
+	cp $15
+	ret z
+	cp $1d
+	ret
+; 18a0
+
+CheckCounterTile: ; 18a0
+	cp $90
+	ret z
+	cp $98
+	ret
+; 18a6
+
+CheckPitTile: ; 18a6
+	cp $60
+	ret z
+	cp $68
+	ret
+; 18ac
+
+CheckIceTile: ; 18ac
+	cp $23
+	ret z
+	cp $2b
+	ret z
+	scf
+	ret
+; 18b4
+
+CheckWhirlpoolTile: ; 18b4
+	nop
+	cp $24
+	ret z
+	cp $2c
+	ret z
+	scf
+	ret
+; 18bd
+
+CheckWaterfallTile: ; 18bd
+	cp $33
+	ret z
+	cp $3b
+	ret
+; 18c3
+
+CheckStandingOnEntrance: ; 18c3
+	ld a, [StandingTile]
+	cp $71 ; door
+	ret z
+	cp $79
+	ret z
+	cp $7a ; stairs
+	ret z
+	cp $7b ; cave
+	ret
+; 18d2
+
+
+GetMapObject: ; 18d2
+; Return the location of map object a in bc.
+	ld hl, MapObjects
+	ld bc, $10
+	call AddNTimes
+	ld b, h
+	ld c, l
+	ret
+; 18de
+
+
+Function18de: ; 18de
+	ld [hConnectionStripLength], a
+	call GetMapObject
+	ld hl, $0000
+	add hl, bc
+	ld a, [hl]
+	cp $ff
+	jr z, .asm_18f3
+	ld [hConnectedMapWidth], a
+	call Function1ae5
+	and a
+	ret
+
+.asm_18f3
+	scf
+	ret
+; 18f5
+
+Function18f5: ; 18f5
+	ld hl, $0006
+	add hl, bc
+	ld a, [hl]
+	cp $ff
+	jr nz, .asm_1921
+	ld hl, $0007
+	add hl, bc
+	ld a, [hl]
+	cp $ff
+	jr z, .asm_191c
+	ld hl, .data_191e
+	ld a, [TimeOfDay]
+	add l
+	ld l, a
+	jr nc, .asm_1912
+	inc h
+
+.asm_1912
+	ld a, [hl]
+	ld hl, $0007
+	add hl, bc
+	and [hl]
+	jr nz, .asm_191c
+	scf
+	ret
+
+.asm_191c
+	and a
+	ret
+
+.data_191e
+	db $1
+	db $2
+	db $4
+
+.asm_1921
+	ld hl, $0006
+	add hl, bc
+	ld d, [hl]
+	ld hl, $0007
+	add hl, bc
+	ld e, [hl]
+	ld hl, hHours
+	ld a, d
+	cp e
+	jr z, .asm_1949
+	jr c, .asm_193f
+	ld a, [hl]
+	cp d
+	jr nc, .asm_1949
+	cp e
+	jr c, .asm_1949
+	jr z, .asm_1949
+	jr .asm_194b
+
+.asm_193f
+	ld a, e
+	cp [hl]
+	jr c, .asm_194b
+	ld a, [hl]
+	cp d
+	jr nc, .asm_1949
+	jr .asm_194b
+
+.asm_1949
+	and a
+	ret
+
+.asm_194b
+	scf
+	ret
+; 194d
+
+Function194d: ; 194d
+	ld [hConnectionStripLength], a
+	call GetMapObject
+	call $40e7
+	ret
+; 1956
+
+
+
+Function1956: ; 1956
+	ld [hConnectionStripLength], a
+	call Function271e
+	ld a, [hConnectionStripLength]
+	call GetMapObject
+	ld a, $2
+	ld hl, $40e7
+	rst FarCall
+	ret
+; 1967
+
+Function1967: ; 1967
+	ld [hConnectionStripLength], a
+	call GetMapObject
+	ld hl, $0000
+	add hl, bc
+	ld a, [hl]
+	cp $ff
+	ret z
+	ld [hl], $ff
+	push af
+	call Function1985
+	pop af
+	call Function1ae5
+	callba Function4357
+	ret
+; 1985
+
+Function1985: ; 1985
+	ld hl, $d4cd
+	cp [hl]
+	jr z, .asm_1990
+	ld hl, $d4ce
+	cp [hl]
+	ret nz
+
+.asm_1990
+	callba Function581f
+	ld a, $ff
+	ld [$d4cd], a
+	ld [$d4ce], a
+	ret
+; 199f
+
+Function199f: ; 199f
+	call Function1967
+	call Function2712
+	ret
+; 19a6
+
+Function19a6: ; 19a6
+	push hl
+	call GetMapObject
+	ld d, b
+	ld e, c
+	ld a, $ff
+	ld [de], a
+	inc de
+	pop hl
+	ld bc, $000f
+	call CopyBytes
+	ret
+; 19b8
+
+Function19b8: ; 19b8
+	call GetMapObject
+	ld hl, $0000
+	add hl, bc
+	ld a, [hl]
+	push af
+	ld [hl], $ff
+	inc hl
+	ld bc, $000f
+	xor a
+	call ByteFill
+	pop af
+	cp $ff
+	ret z
+	cp $d
+	ret nc
+	ld b, a
+	ld a, [$d4cd]
+	cp b
+	jr nz, .asm_19de
+	ld a, $ff
+	ld [$d4cd], a
+
+.asm_19de
+	ld a, b
+	call Function1ae5
+	callba Function4357
+	ret
+; 19e9
+
+
+
+Function19e9: ; 19e9
+	ld [$c2e2], a
+	ld a, [hROMBank]
+	ld [$c2e3], a
+	ld a, l
+	ld [$c2e4], a
+	ld a, h
+	ld [$c2e5], a
+	ld a, [$c2e2]
+	call Function18de
+	ret c
+	ld hl, $0003
+	add hl, bc
+	ld [hl], $14
+	ld hl, $0009
+	add hl, bc
+	ld [hl], $0
+	ld hl, VramState
+	set 7, [hl]
+	and a
+	ret
+; 1a13
+
+
+
+Function1a13: ; 1a13
+	push bc
+	push de
+	ld hl, $d4d6
+	ld de, $0028
+	ld c, $d
+.asm_1a1d
+	ld a, [hl]
+	and a
+	jr z, .asm_1a28
+	add hl, de
+	dec c
+	jr nz, .asm_1a1d
+	xor a
+	jr .asm_1a2c
+
+.asm_1a28
+	ld a, $d
+	sub c
+	scf
+
+.asm_1a2c
+	pop de
+	pop bc
+	ret
+; 1a2f
+
+
+
+Function1a2f: ; 1a2f
+	ld hl, $0003
+	add hl, bc
+	ld a, [hl]
+	cp $25
+	jr c, .asm_1a39
+	xor a
+
+.asm_1a39
+	ld hl, Data4273
+	ld e, a
+	ld d, 0
+	add hl, de
+	add hl, de
+	add hl, de
+	add hl, de
+	add hl, de
+	add hl, de
+	ld a, [hl]
+	ret
+; 1a47
+
+Function1a47: ; 1a47
+	push bc
+	push de
+	ld e, a
+	ld d, 0
+	ld hl, Data4273 + 1
+	add hl, de
+	add hl, de
+	add hl, de
+	add hl, de
+	add hl, de
+	add hl, de
+	ld a, BANK(Data4273)
+	call GetFarByte
+	add a
+	add a
+	and $c
+	pop de
+	pop bc
+	ret
+; 1a61
+
+
+Function1a61: ; 1a61
+	ld l, a
+	ld a, [hROMBank]
+	push af
+	ld a, BANK(Data4273)
+	rst Bankswitch
+	ld a, l
+	push bc
+
+	call Function1a71
+
+	pop bc
+	pop af
+	rst Bankswitch
+
+	ret
+; 1a71
+
+Function1a71: ; 1a71
+	ld hl, $0003
+	add hl, de
+	ld [hl], a
+	push de
+	ld e, a
+	ld d, 0
+	ld hl, Data4273 + 1
+	add hl, de
+	add hl, de
+	add hl, de
+	add hl, de
+	add hl, de
+	add hl, de
+	ld b, h
+	ld c, l
+	pop de
+	ld a, [bc]
+	inc bc
+	rlca
+	rlca
+	and $c
+	ld hl, $0008
+	add hl, de
+	ld [hl], a
+	ld a, [bc]
+	inc bc
+	ld hl, $000b
+	add hl, de
+	ld [hl], a
+	ld a, [bc]
+	inc bc
+	ld hl, $0004
+	add hl, de
+	ld [hl], a
+	ld a, [bc]
+	inc bc
+	ld hl, $0005
+	add hl, de
+	ld [hl], a
+	ld a, [bc]
+	inc bc
+	ld hl, $0006
+	add hl, de
+	ld [hl], a
+	ret
+; 1aae
+
+Function1aae: ; 1aae
+	ld a, [hROMBank]
+	push af
+	ld a, [hli]
+	rst Bankswitch
+
+	ld a, [hli]
+	ld d, [hl]
+	ld hl, $001b
+	add hl, bc
+	add [hl]
+	ld e, a
+	ld a, d
+	adc $0
+	ld d, a
+	inc [hl]
+	ld a, [de]
+	ld h, a
+	pop af
+	rst Bankswitch
+
+	ld a, h
+	ret
+; 1ac6
+
+Function1ac6: ; 1ac6
+	ld hl, VramState
+	set 0, [hl]
+	ret
+; 1acc
+
+Function1acc: ; 1acc
+	ld hl, VramState
+	res 0, [hl]
+	ret
+; 1ad2
+
+
+Function1ad2: ; 1ad2
+	ld a, [VramState]
+	bit 0, a
+	ret z
+	callba Function55e0
+	callba Function5920
+	ret
+; 1ae5
+
+
+Function1ae5: ; 1ae5
+	ld bc, $0028
+	ld hl, $d4d6
+	call AddNTimes
+	ld b, h
+	ld c, l
+	ret
+; 1af1
+
+Function1af1: ; 1af1
+	ld hl, $0000
+	add hl, bc
+	ld a, [hl]
+	and a
+	ret
+; 1af8
+
+Function1af8: ; 1af8
+	push af
+	ld hl, $0008
+	add hl, bc
+	ld a, [hl]
+	and $f3
+	ld e, a
+	pop af
+	and $c
+	or e
+	ld [hl], a
+	ret
+; 1b07
+
+
+GetSpriteDirection: ; 1b07
+	ld hl, $0008
+	add hl, bc
+	ld a, [hl]
+	and $c
+	ret
+; 1b0f
+
diff --git a/engine/menu.asm b/engine/menu.asm
new file mode 100644
index 000000000..c761a927c
--- /dev/null
+++ b/engine/menu.asm
@@ -0,0 +1,603 @@
+; Functions used in displaying and handling menus.
+
+
+LoadMenuDataHeader: ; 0x1d35
+	call Function1d3c
+	call Function1c00
+	ret
+
+Function1d3c: ; 0x1d3c
+	ld de, $cf81
+	ld bc, $0010
+	call CopyBytes
+	ld a, [hROMBank]
+	ld [$cf8a], a
+	ret
+; 0x1d4b
+
+Function1d4b: ; 1d4b
+	ld [$cf88], a
+	ret
+; 1d4f
+
+
+Function1d4f: ; 1d4f
+	push hl
+	call Function1d58
+	pop hl
+	jp PrintText
+; 1d57
+
+Function1d57: ; 1d57
+	ret
+; 1d58
+
+Function1d58: ; 1d58
+	ld hl, MenuDataHeader_0x1d5f
+	call LoadMenuDataHeader
+	ret
+; 1d5f
+
+MenuDataHeader_0x1d5f: ; 1d5f
+	db $40 ; tile backup
+	db 12, 0 ; start coords
+	db 17, 19 ; end coords
+	dw VTiles0
+	db 0 ; default option
+; 1d67
+
+Function1d67: ; 1d67
+	call Function1d4f
+	call Function1c17
+	ret
+; 1d6e
+
+Function1d6e: ; 1d6e
+	ld hl, MenuDataHeader_0x1d75
+	call LoadMenuDataHeader
+	ret
+; 1d75
+
+MenuDataHeader_0x1d75: ; 1d75
+	db $40 ; tile backup
+	db 0, 0 ; start coords
+	db 17, 19 ; end coords
+	dw $0000
+	db 1 ; default option
+; 1d7d
+
+Function1d7d: ; 1d7d
+	call Function1c07
+	ret
+; 1d81
+
+Function1d81: ; 0x1d81
+	xor a
+	ld [hBGMapMode], a
+	call Function1cbb
+	call Function1ad2
+	call Function1c89
+	call Function321c
+	call Function1c66
+	ld a, [$cf91]
+	bit 7, a
+	jr z, .asm_1da7 ; 0x1d98 $d
+	call Function1c10
+	call Function1bc9
+	call Function1ff8
+	bit 1, a
+	jr z, .asm_1da9 ; 0x1da5 $2
+.asm_1da7
+	scf
+	ret
+.asm_1da9
+	and a
+	ret
+; 0x1dab
+
+Function1dab: ; 1dab
+	call LoadMenuDataHeader
+	call Function1d81
+	call Function1c17
+	ld a, [$cfa9]
+	ret
+; 1db8
+
+Function1db8: ; 0x1db8
+	push hl
+	push bc
+	push af
+	ld hl, $cf86
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	inc hl
+	inc hl
+	pop af
+	call GetNthString
+	ld d, h
+	ld e, l
+	call CopyName1
+	pop bc
+	pop hl
+	ret
+; 0x1dcf
+
+
+Function1dcf: ; 1dcf
+	ld bc, $0e07
+
+Function1dd2: ; 1dd2
+	jr Function1dd9
+
+Function1dd4: ; 1dd4
+	call LoadMenuDataHeader
+	jr Function1dfe
+
+Function1dd9: ; 1dd9
+	push bc
+	ld hl, MenuDataHeader_0x1e1d
+	call Function1d3c
+	pop bc
+	ld a, b
+	cp $e
+	jr nz, .asm_1de9
+	ld a, $e
+	ld b, a
+
+.asm_1de9
+	ld a, b
+	ld [$cf83], a
+	add $5
+	ld [$cf85], a
+	ld a, c
+	ld [$cf82], a
+	add $4
+	ld [$cf84], a
+	call Function1c00
+
+Function1dfe: ; 1dfe
+	call Function1d81
+	push af
+	ld c, $f
+	call DelayFrames
+	call Function1c17
+	pop af
+	jr c, .asm_1e16
+	ld a, [$cfa9]
+	cp $2
+	jr z, .asm_1e16
+	and a
+	ret
+
+.asm_1e16
+	ld a, $2
+	ld [$cfa9], a
+	scf
+	ret
+; 1e1d
+
+MenuDataHeader_0x1e1d: ; 1e1d
+	db $40 ; tile backup
+	db 5, 10 ; start coords
+	db 9, 15 ; end coords
+	dw MenuData2_0x1e25
+	db 1 ; default option
+; 1e25
+
+MenuData2_0x1e25: ; 1e25
+	db $c0 ; flags
+	db 2
+	db "YES@"
+	db "NO@"
+; 1e2e
+
+Function1e2e: ; 1e2e
+	call Function1e35
+	call Function1c00
+	ret
+; 1e35
+
+Function1e35: ; 1e35
+	push de
+	call Function1d3c
+	pop de
+	ld a, [$cf83]
+	ld h, a
+	ld a, [$cf85]
+	sub h
+	ld h, a
+	ld a, d
+	ld [$cf83], a
+	add h
+	ld [$cf85], a
+	ld a, [$cf82]
+	ld l, a
+	ld a, [$cf84]
+	sub l
+	ld l, a
+	ld a, e
+	ld [$cf82], a
+	add l
+	ld [$cf84], a
+	ret
+; 1e5d
+
+Function1e5d: ; 1e5d
+	call MenuFunc_1e7f
+	call MenuWriteText
+	call Function1eff
+	call Function1f23
+	call Function1bdd
+	call Function1ff8
+	ret
+; 1e70
+
+SetUpMenu: ; 1e70
+	call MenuFunc_1e7f ; ???
+	call MenuWriteText
+	call Function1eff ; set up selection pointer
+	ld hl, $cfa5
+	set 7, [hl]
+	ret
+
+MenuFunc_1e7f: ; 0x1e7f
+	call Function1c66
+	call Function1ebd
+	call Function1ea6
+	call Function1cbb
+	ret
+
+MenuWriteText: ; 0x1e8c
+	xor a
+	ld [hBGMapMode], a
+	call Function1ebd ; sort out the text 
+	call Function1eda ; actually write it
+	call Function2e31
+	ld a, [hOAMUpdate]
+	push af
+	ld a, $1
+	ld [hOAMUpdate], a
+	call Function321c
+	pop af
+	ld [hOAMUpdate], a
+	ret
+; 0x1ea6
+
+Function1ea6: ; 1ea6
+	ld a, [$cf83]
+	ld c, a
+	ld a, [$cf85]
+	sub c
+	ld c, a
+	ld a, [$cf92]
+	add a
+	inc a
+	ld b, a
+	ld a, [$cf82]
+	add b
+	ld [$cf84], a
+	ret
+; 1ebd
+
+Function1ebd: ; 1ebd
+	ld hl, $cf93
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	ld a, [$cf76]
+	and a
+	jr z, .asm_1ed3
+	ld b, a
+	ld c, $ff
+.asm_1ecc
+	ld a, [hli]
+	cp c
+	jr nz, .asm_1ecc
+	dec b
+	jr nz, .asm_1ecc
+
+.asm_1ed3
+	ld d, h
+	ld e, l
+	ld a, [hl]
+	ld [$cf92], a
+	ret
+; 1eda
+
+Function1eda: ; 1eda
+	call Function1cfd
+	ld bc, $002a
+	add hl, bc
+.asm_1ee1
+	inc de
+	ld a, [de]
+	cp $ff
+	ret z
+	ld [MenuSelection], a
+	push de
+	push hl
+	ld d, h
+	ld e, l
+	ld hl, $cf95
+	call Function1efb
+	pop hl
+	ld de, $0028
+	add hl, de
+	pop de
+	jr .asm_1ee1
+; 1efb
+
+Function1efb: ; 1efb
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	jp [hl]
+; 1eff
+
+Function1eff: ; 1eff
+	call Function1c10
+	ld hl, $cfa8
+	ld a, [$cf91]
+	bit 3, a
+	jr z, .asm_1f0e
+	set 3, [hl]
+
+.asm_1f0e
+	ld a, [$cf91]
+	bit 2, a
+	jr z, .asm_1f19
+	set 5, [hl]
+	set 4, [hl]
+
+.asm_1f19
+	ret
+; 1f1a
+
+
+Function1f1a: ; 1f1a
+	call Function1bd3
+	ld hl, $cfa8
+	and [hl]
+	jr Function1f2a
+; 1f23
+
+Function1f23: ; 1f23
+	xor a
+	ld [$cf73], a
+	call Function1bc9
+; 1f2a
+
+Function1f2a: ; 1f2a
+	bit 0, a
+	jr nz, .asm_1f52
+	bit 1, a
+	jr nz, .asm_1f6d
+	bit 3, a
+	jr nz, .asm_1f6d
+	bit 4, a
+	jr nz, .asm_1f44
+	bit 5, a
+	jr nz, .asm_1f4b
+	xor a
+	ld [$cf73], a
+	jr .asm_1f57
+
+.asm_1f44
+	ld a, $10
+	ld [$cf73], a
+	jr .asm_1f57
+
+.asm_1f4b
+	ld a, $20
+	ld [$cf73], a
+	jr .asm_1f57
+
+.asm_1f52
+	ld a, $1
+	ld [$cf73], a
+
+.asm_1f57
+	call Function1ebd
+	ld a, [$cfa9]
+	ld l, a
+	ld h, $0
+	add hl, de
+	ld a, [hl]
+	ld [MenuSelection], a
+	ld a, [$cfa9]
+	ld [$cf88], a
+	and a
+	ret
+
+.asm_1f6d
+	ld a, $2
+	ld [$cf73], a
+	ld a, $ff
+	ld [MenuSelection], a
+	scf
+	ret
+; 1f79
+
+Function1f79: ; 1f79
+	push de
+	ld hl, $cf97
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	ld a, [MenuSelection]
+	call GetNthString
+	ld d, h
+	ld e, l
+	pop hl
+	call PlaceString
+	ret
+; 1f8d
+
+Function1f8d: ; 1f8d
+	push de
+	ld a, [MenuSelection]
+	call Function1fb1
+	inc hl
+	inc hl
+	ld a, [hli]
+	ld d, [hl]
+	ld e, a
+	pop hl
+	call PlaceString
+	ret
+; 1f9e
+
+Function1f9e: ; 1f9e
+	call Function1fb1
+	inc hl
+	inc hl
+	ld a, [hli]
+	ld d, [hl]
+	ld e, a
+	ret
+; 1fa7
+
+Function1fa7: ; 1fa7
+	ld a, [MenuSelection]
+	call Function1fb1
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	jp [hl]
+; 1fb1
+
+Function1fb1: ; 1fb1
+	ld e, a
+	ld d, $0
+	ld hl, $cf97
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	add hl, de
+	add hl, de
+	add hl, de
+	add hl, de
+	ret
+; 1fbf
+
+Function1fbf: ; 1fbf
+	ld hl, $cf71
+	call Function1ff0
+	ld hl, $cf81
+	call Function1ff0
+	ld hl, $cf91
+	call Function1ff0
+	ld hl, $cfa1
+	call Function1ff0
+	ld a, [rSVBK]
+	push af
+	ld a, $7
+	ld [rSVBK], a
+	xor a
+	ld hl, $dfff
+	ld [hld], a
+	ld [hld], a
+	ld a, l
+	ld [$cf71], a
+	ld a, h
+	ld [$cf72], a
+	pop af
+	ld [rSVBK], a
+	ret
+; 1ff0
+
+Function1ff0: ; 1ff0
+	ld bc, $0010
+	xor a
+	call ByteFill
+	ret
+; 1ff8
+
+Function1ff8: ; 1ff8
+	push af
+	and $3
+	jr z, .asm_2007
+	ld hl, $cf81
+	bit 3, [hl]
+	jr nz, .asm_2007
+	call PlayClickSFX
+
+.asm_2007
+	pop af
+	ret
+; 2009
+
+
+PlayClickSFX: ; 2009 
+	push de
+	ld de, SFX_READ_TEXT_2
+	call StartSFX
+	pop de
+	ret
+; 0x2012
+
+Function2012: ; 2012
+	call Function1d4f
+	call Functiona46
+	call Function1c07
+	ret
+; 201c
+
+Function201c: ; 201c
+	ld [hBuffer], a
+	ld a, [hROMBank]
+	push af
+	ld a, [hBuffer]
+	rst Bankswitch
+
+	call PlaceString
+	pop af
+	rst Bankswitch
+
+	ret
+; 202a
+
+Function202a: ; 202a
+	ld a, [hROMBank]
+	ld [$cf94], a
+	ld a, $9
+	ld hl, $400e
+	rst FarCall
+	ld a, [$cf88]
+	ret
+; 2039
+
+Function2039: ; 2039
+	ld a, [hROMBank]
+	ld [$cf94], a
+	ld a, $9
+	ld hl, $4022
+	rst FarCall
+	ld a, [$cf88]
+	ret
+; 2048
+
+Function2048: ; 2048
+	ld a, [hROMBank]
+	ld [$cf94], a
+	ld a, $9
+	ld hl, $403c
+	rst FarCall
+	ld a, [$cf88]
+	ret
+; 2057
+
+Function2057: ; 2057
+	ld a, [hROMBank]
+	push af
+	ld a, $21
+	rst Bankswitch
+
+	call $42db
+	pop af
+	rst Bankswitch
+
+	ret
+; 2063
+
diff --git a/engine/rtc.asm b/engine/rtc.asm
new file mode 100644
index 000000000..91428d03b
--- /dev/null
+++ b/engine/rtc.asm
@@ -0,0 +1,25 @@
+RTC: ; 46f
+; update time and time-sensitive palettes
+
+; rtc enabled?
+	ld a, [$c2ce]
+	cp 0
+	ret z
+	
+	call UpdateTime
+	
+; obj update on?
+	ld a, [VramState]
+	bit 0, a ; obj update
+	ret z
+
+TimeOfDayPals: ; 47e
+	callab _TimeOfDayPals
+	ret
+; 485
+
+UpdateTimePals: ; 485
+	callab _UpdateTimePals
+	ret
+; 48c
+
diff --git a/engine/sine.asm b/engine/sine.asm
new file mode 100644
index 000000000..09d06ca89
--- /dev/null
+++ b/engine/sine.asm
@@ -0,0 +1,22 @@
+Cosine: ; 1b0f
+; Return d * cos(a) in hl
+	add $10 ; 90 degrees
+
+Sine: ; 1b11
+; Return d * sin(a) in hl
+; a is a signed 6-bit value.
+
+	ld e, a
+
+	ld a, [hROMBank]
+	push af
+	ld a, BANK(_Sine)
+	rst Bankswitch
+
+	call _Sine
+
+	pop af
+	rst Bankswitch
+	ret
+; 1b1e
+
diff --git a/engine/text.asm b/engine/text.asm
index ccc8623cf..4f39a95df 100644
--- a/engine/text.asm
+++ b/engine/text.asm
@@ -155,6 +155,7 @@ Function1052: ; 1052
 
 PrintText: ; 1057
 	call Function106c
+Function105a: ; 105a
 	push hl
 	hlcoord 1, 14
 	ld bc, 18 + 3<<8
diff --git a/engine/vblank.asm b/engine/vblank.asm
index 44b3195f8..71114964e 100644
--- a/engine/vblank.asm
+++ b/engine/vblank.asm
@@ -119,9 +119,9 @@ VBlank0: ; 2b1
 	call UpdateBGMap
 	
 ; these have their own timing checks
-	call SafeLoadTiles
-	call SafeLoadTiles2
-	call SafeTileAnimation
+	call Serve2bppRequest
+	call Serve1bppRequest
+	call AnimateTileset
 	
 .doneframeaction
 ; oam update off?
@@ -131,8 +131,8 @@ VBlank0: ; 2b1
 	
 ; update oam by dma transfer
 	call hPushOAM
-;	403f:
-;		ld a, $c4
+;	@PushOAM:
+;		ld a, Sprites >> 8
 ;		ld [rDMA], a
 ;		ld a, $28
 ;	.loop
@@ -230,11 +230,11 @@ VBlank1: ; 337
 	
 ; these have their own timing checks
 	call UpdateBGMap
-	call LoadTiles
+	call Serve2bppRequest@VBlank
 ; update oam by dma transfer
 	call hPushOAM
-;	403f:
-;		ld a, $c4
+;	@PushOAM:
+;		ld a, Sprites >> 8
 ;		ld [rDMA], a
 ;		ld a, $28
 ;	.loop
@@ -338,12 +338,12 @@ VBlank3: ; 396
 	jr c, .vblankoccurred
 ; else
 	call UpdateBGMap
-	call LoadTiles
+	call Serve2bppRequest@VBlank
 	
 ; update oam by dma transfer
 	call hPushOAM
-;	403f:
-;		ld a, $c4 ; Sprites / $100
+;	@PushOAM:
+;		ld a, Sprites >> 8
 ;		ld [rDMA], a
 ;		ld a, $28
 ;	.loop
@@ -410,12 +410,12 @@ VBlank4: ; 3df
 	ld [$ff8a], a
 	
 	call UpdateBGMap
-	call SafeLoadTiles
+	call Serve2bppRequest
 	
 ; update oam by dma transfer
 	call hPushOAM
-;	403f:
-;		ld a, $c4
+;	@PushOAM:
+;		ld a, Sprites >> 8
 ;		ld [rDMA], a
 ;		ld a, $28
 ;	.loop
@@ -465,7 +465,7 @@ VBlank5: ; 400
 	jr c, .vblankoccurred
 	
 	call UpdateBGMap
-	call SafeLoadTiles
+	call Serve2bppRequest
 	
 .vblankoccurred
 ; tell other fns vblank happened
@@ -521,8 +521,8 @@ VBlank6: ; 436
 	call UpdateCGBPals
 	jr c, .vblankoccurred
 	
-	call SafeLoadTiles
-	call SafeLoadTiles2
+	call Serve2bppRequest
+	call Serve1bppRequest
 	call DMATransfer
 	
 .vblankoccurred
diff --git a/engine/video.asm b/engine/video.asm
new file mode 100644
index 000000000..0d0aa272d
--- /dev/null
+++ b/engine/video.asm
@@ -0,0 +1,487 @@
+; Functions dealing with VRAM.
+
+DMATransfer: ; 15d8
+; Return carry if the transfer is completed.
+
+	ld a, [hDMATransfer]
+	and a
+	ret z
+
+; Start transfer
+	ld [rHDMA5], a
+
+; Execution is halted until the transfer is complete.
+
+	xor a
+	ld [hDMATransfer], a
+	scf
+	ret
+; 15e3
+
+
+UpdateBGMapBuffer: ; 15e3
+; Copy [$ffdc] 16x8 tiles from BGMapBuffer
+; to bg map addresses in BGMapBufferPtrs.
+
+; [$ffdc] must be even since this is done in pairs.
+
+; Return carry on success.
+
+	ld a, [hBGMapUpdate]
+	and a
+	ret z
+
+	ld a, [rVBK]
+	push af
+	ld [hSPBuffer], sp
+
+	ld hl, BGMapBufferPtrs
+	ld sp, hl
+
+; We can now pop the addresses of affected spots on the BG Map
+
+	ld hl, BGMapPalBuffer
+	ld de, BGMapBuffer
+
+
+.next
+; Copy a pair of 16x8 blocks (one 16x16 block)
+
+rept 2
+; Get our BG Map address
+	pop bc
+
+; Palettes
+	ld a, 1
+	ld [rVBK], a
+
+	ld a, [hli]
+	ld [bc], a
+	inc c
+	ld a, [hli]
+	ld [bc], a
+	dec c
+
+; Tiles
+	ld a, 0
+	ld [rVBK], a
+
+	ld a, [de]
+	inc de
+	ld [bc], a
+	inc c
+	ld a, [de]
+	inc de
+	ld [bc], a
+endr
+
+; We've done 2 16x8 blocks
+	ld a, [$ffdc]
+	dec a
+	dec a
+	ld [$ffdc], a
+
+	jr nz, .next
+
+
+	ld a, [hSPBuffer]
+	ld l, a
+	ld a, [hSPBuffer + 1]
+	ld h, a
+	ld sp, hl
+
+	pop af
+	ld [rVBK], a
+
+	xor a
+	ld [hBGMapUpdate], a
+	scf
+	ret
+; 163a
+
+
+WaitTop: ; 163a
+; Wait until the top third of the BG Map is being updated.
+
+	ld a, [hBGMapMode]
+	and a
+	ret z
+
+	ld a, [hBGMapThird]
+	and a
+	jr z, .done
+
+	call DelayFrame
+	jr WaitTop
+
+.done
+	xor a
+	ld [hBGMapMode], a
+	ret
+; 164c
+
+
+UpdateBGMap: ; 164c
+; Update the BG Map, in thirds, from TileMap and AttrMap.
+
+	ld a, [hBGMapMode]
+	and a
+	ret z
+
+; BG Map 0
+	dec a ; 1
+	jr z, .Tiles
+	dec a ; 2
+	jr z, .Attr
+
+; BG Map 1
+	dec a
+
+	ld a, [hBGMapAddress]
+	ld l, a
+	ld a, [hBGMapAddress + 1]
+	ld h, a
+	push hl
+
+	xor a
+	ld [hBGMapAddress], a
+	ld a, VBGMap1 >> 8
+	ld [hBGMapAddress + 1], a
+
+	ld a, [hBGMapMode]
+	push af
+	cp 3
+	call z, .Tiles
+	pop af
+	cp 4
+	call z, .Attr
+
+	pop hl
+	ld a, l
+	ld [hBGMapAddress], a
+	ld a, h
+	ld [hBGMapAddress + 1], a
+	ret
+
+
+.Attr
+	ld a, 1
+	ld [rVBK], a
+
+	ld hl, AttrMap
+	call .update
+
+	ld a, 0
+	ld [rVBK], a
+	ret
+
+
+.Tiles
+	ld hl, TileMap
+
+
+.update
+	ld [hSPBuffer], sp
+	
+; Which third?
+	ld a, [hBGMapThird]
+	and a ; 0
+	jr z, .top
+	dec a ; 1
+	jr z, .middle
+	; 2
+
+
+THIRD_HEIGHT EQU SCREEN_HEIGHT / 3
+
+
+.bottom
+	ld de, 2 * THIRD_HEIGHT * SCREEN_WIDTH
+	add hl, de
+	ld sp, hl
+
+	ld a, [hBGMapAddress + 1]
+	ld h, a
+	ld a, [hBGMapAddress]
+	ld l, a
+
+	ld de, 2 * THIRD_HEIGHT * BG_MAP_WIDTH
+	add hl, de
+
+; Next time: top third
+	xor a
+	jr .start
+
+
+.middle
+	ld de, THIRD_HEIGHT * SCREEN_WIDTH
+	add hl, de
+	ld sp, hl
+
+	ld a, [hBGMapAddress + 1]
+	ld h, a
+	ld a, [hBGMapAddress]
+	ld l, a
+
+	ld de, THIRD_HEIGHT * BG_MAP_WIDTH
+	add hl, de
+
+; Next time: bottom third
+	ld a, 2
+	jr .start
+
+
+.top
+	ld sp, hl
+
+	ld a, [hBGMapAddress + 1]
+	ld h, a
+	ld a, [hBGMapAddress]
+	ld l, a
+
+; Next time: middle third
+	ld a, 1
+
+
+.start
+; Which third to update next time
+	ld [hBGMapThird], a
+
+; Rows of tiles in a third
+	ld a, SCREEN_HEIGHT / 3
+
+; Discrepancy between TileMap and BGMap
+	ld bc, BG_MAP_WIDTH - (SCREEN_WIDTH - 1)
+
+
+.row
+; Copy a row of 20 tiles
+rept SCREEN_WIDTH / 2 - 1
+	pop de
+	ld [hl], e
+	inc l
+	ld [hl], d
+	inc l
+endr
+	pop de
+	ld [hl], e
+	inc l
+	ld [hl], d
+
+	add hl, bc
+	dec a
+	jr nz, .row
+
+
+	ld a, [hSPBuffer]
+	ld l, a
+	ld a, [hSPBuffer + 1]
+	ld h, a
+	ld sp, hl
+	ret
+; 170a
+
+
+Serve1bppRequest: ; 170a
+; Only call during the first fifth of VBlank
+
+	ld a, [Requested1bpp]
+	and a
+	ret z
+
+; Back out if we're too far into VBlank
+	ld a, [rLY]
+	cp 144
+	ret c
+	cp 146
+	ret nc
+
+; Copy [Requested1bpp] 1bpp tiles from [Requested1bppSource] to [Requested1bppDest]
+
+	ld [hSPBuffer], sp
+
+; Source
+	ld hl, Requested1bppSource
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	ld sp, hl
+	
+; Destination
+	ld hl, Requested1bppDest
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	
+; # tiles to copy
+	ld a, [Requested1bpp]
+	ld b, a
+
+	xor a
+	ld [Requested1bpp], a
+
+.next
+
+rept 3
+	pop de
+	ld [hl], e
+	inc l
+	ld [hl], e
+	inc l
+	ld [hl], d
+	inc l
+	ld [hl], d
+	inc l
+endr
+	pop de
+	ld [hl], e
+	inc l
+	ld [hl], e
+	inc l
+	ld [hl], d
+	inc l
+	ld [hl], d
+
+	inc hl
+	dec b
+	jr nz, .next
+
+
+	ld a, l
+	ld [Requested1bppDest], a
+	ld a, h
+	ld [Requested1bppDest + 1], a
+
+	ld [Requested1bppSource], sp
+
+	ld a, [hSPBuffer]
+	ld l, a
+	ld a, [hSPBuffer + 1]
+	ld h, a
+	ld sp, hl
+	ret
+; 1769
+
+
+Serve2bppRequest: ; 1769
+; Only call during the first fifth of VBlank
+
+	ld a, [Requested2bpp]
+	and a
+	ret z
+
+; Back out if we're too far into VBlank
+	ld a, [rLY]
+	cp 144
+	ret c
+	cp 146
+	ret nc
+	jr _Serve2bppRequest
+
+
+Serve2bppRequest@VBlank: ; 1778
+
+	ld a, [Requested2bpp]
+	and a
+	ret z
+
+_Serve2bppRequest: ; 177d
+; Copy [Requested2bpp] 2bpp tiles from [Requested2bppSource] to [Requested2bppDest]
+
+	ld [hSPBuffer], sp
+	
+; Source
+	ld hl, Requested2bppSource
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	ld sp, hl
+	
+; Destination
+	ld hl, Requested2bppDest
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	
+; # tiles to copy
+	ld a, [Requested2bpp]
+	ld b, a
+
+	xor a
+	ld [Requested2bpp], a
+	
+.next
+
+rept 7
+	pop de
+	ld [hl], e
+	inc l
+	ld [hl], d
+	inc l
+endr
+	pop de
+	ld [hl], e
+	inc l
+	ld [hl], d
+
+	inc hl
+	dec b
+	jr nz, .next
+
+
+	ld a, l
+	ld [Requested2bppDest], a
+	ld a, h
+	ld [Requested2bppDest + 1], a
+
+	ld [Requested2bppSource], sp
+
+	ld a, [hSPBuffer]
+	ld l, a
+	ld a, [hSPBuffer + 1]
+	ld h, a
+	ld sp, hl
+	ret
+; 17d3
+
+
+AnimateTileset: ; 17d3
+; Only call during the first fifth of VBlank
+
+	ld a, [$ffde]
+	and a
+	ret z
+	
+; Back out if we're too far into VBlank
+	ld a, [rLY]
+	cp 144
+	ret c
+	cp 151
+	ret nc
+
+	ld a, [hROMBank]
+	push af
+	ld a, BANK(_AnimateTileset)
+	rst Bankswitch
+
+	ld a, [rSVBK]
+	push af
+	ld a, 1
+	ld [rSVBK], a
+
+	ld a, [rVBK]
+	push af
+	ld a, 0
+	ld [rVBK], a
+
+	call _AnimateTileset
+
+	pop af
+	ld [rVBK], a
+	pop af
+	ld [rSVBK], a
+	pop af
+	rst Bankswitch
+	ret
+; 17ff
+