Use constants for VBlank handlers

engine/battle/battle_transition.asm

@@ -22,7 +22,7 @@ DoBattleTransition:
 	ld a, [hl]
 	push af
 	vc_hook Reduce_battle_transition_flashing
-	ld [hl], $1
+	ld [hl], VBLANK_CUTSCENE
 
 .loop
 	ld a, [wJumptableIndex]

engine/battle_anims/anim_commands.asm

@@ -24,11 +24,11 @@ _PlayBattleAnim:
 	call BattleAnimRequestPals
 	call BattleAnimDelayFrame
 
-	ld c, 1
+	ld c, VBLANK_CUTSCENE
 	ldh a, [rKEY1]
 	bit 7, a ; check CGB double speed mode
 	jr nz, .got_speed
-	ld c, 3
+	ld c, VBLANK_CUTSCENE_CGB
 
 .got_speed
 	ld hl, hVBlank

engine/events/magnet_train.asm

@@ -38,7 +38,7 @@ MagnetTrain:
 	ld hl, hVBlank
 	ld a, [hl]
 	push af
-	ld [hl], 1
+	ld [hl], VBLANK_CUTSCENE
 .loop
 	ld a, [wJumptableIndex]
 	and a

engine/link/link.asm

@@ -537,6 +537,7 @@ LinkTimeout:
 	xor a
 	ld [hld], a
 	ld [hl], a
+	assert VBLANK_NORMAL == 0
 	ldh [hVBlank], a
 	push de
 	hlcoord 0, 12
@@ -2380,7 +2381,7 @@ CheckLinkTimeout_Receptionist:
 	xor a
 	ld [hl], a
 	call WaitBGMap
-	ld a, $2
+	ld a, VBLANK_SOUND_ONLY
 	ldh [hVBlank], a
 	call DelayFrame
 	call DelayFrame
@@ -2402,7 +2403,7 @@ CheckLinkTimeout_Gen2:
 	xor a
 	ld [hl], a
 	call WaitBGMap
-	ld a, $2
+	ld a, VBLANK_SOUND_ONLY
 	ldh [hVBlank], a
 	call DelayFrame
 	call DelayFrame
@@ -2630,7 +2631,7 @@ Link_EnsureSync:
 	add $d0
 	ld [wLinkPlayerSyncBuffer], a
 	ld [wLinkPlayerSyncBuffer + 1], a
-	ld a, $2
+	ld a, VBLANK_SOUND_ONLY
 	ldh [hVBlank], a
 	call DelayFrame
 	call DelayFrame

engine/movie/credits.asm

@@ -76,7 +76,7 @@ Credits::
 ; BUG: Credits sequence changes move selection menu behavior (see docs/bugs_and_glitches.md)
 	ldh a, [hVBlank]
 	push af
-	ld a, $5
+	ld a, VBLANK_CREDITS
 	ldh [hVBlank], a
 	ld a, TRUE
 	ldh [hInMenu], a

engine/movie/intro.asm

@@ -45,9 +45,10 @@ CrystalIntro:
 	ret
 
 .InitRAMAddrs:
+	assert VBLANK_NORMAL == 0
 	xor a
 	ldh [hVBlank], a
-	ld a, $1
+	ld a, TRUE
 	ldh [hInMenu], a
 	xor a
 	ldh [hMapAnims], a

engine/printer/printer.asm

@@ -71,7 +71,7 @@ PrintDexEntry:
 	ld hl, hVBlank
 	ld a, [hl]
 	push af
-	ld [hl], 4 ; vblank mode that calls AskSerial
+	ld [hl], VBLANK_SERIAL
 
 	ld a, 8 ; 16 rows
 	ld [wPrinterQueueLength], a
@@ -146,7 +146,7 @@ PrintPCBox:
 	ld hl, hVBlank
 	ld a, [hl]
 	push af
-	ld [hl], 4 ; vblank mode that calls AskSerial
+	ld [hl], VBLANK_SERIAL
 
 	xor a
 	ldh [hBGMapMode], a
@@ -227,7 +227,7 @@ PrintUnownStamp:
 	ld hl, hVBlank
 	ld a, [hl]
 	push af
-	ld [hl], 4 ; vblank mode that calls AskSerial
+	ld [hl], VBLANK_SERIAL
 
 	xor a
 	ldh [hBGMapMode], a
@@ -302,7 +302,7 @@ PrintMail:
 	ld hl, hVBlank
 	ld a, [hl]
 	push af
-	ld [hl], 4 ; vblank mode that calls AskSerial
+	ld [hl], VBLANK_SERIAL
 
 	ld a, 18 / 2
 	ld [wPrinterQueueLength], a
@@ -345,7 +345,7 @@ PrintPartymon:
 	ld hl, hVBlank
 	ld a, [hl]
 	push af
-	ld [hl], 4 ; vblank mode that calls AskSerial
+	ld [hl], VBLANK_SERIAL
 
 	ld a, 16 / 2
 	ld [wPrinterQueueLength], a
@@ -403,7 +403,7 @@ _PrintDiploma:
 	ld hl, hVBlank
 	ld a, [hl]
 	push af
-	ld [hl], 4 ; vblank mode that calls AskSerial
+	ld [hl], VBLANK_SERIAL
 
 	ln a, 1, 0 ; to be loaded to wPrinterMargins
 	call Printer_PrepareTilemapForPrint