Start working on bank20 audio

Note: Address labels aren't correct.

3 files changed, 199 insertions, 8 deletions

diff --git a/audio.asm b/audio.asm
index ee334c02..4cc10b34 100644
--- a/audio.asm
+++ b/audio.asm
@@ -2,6 +2,7 @@
 AUDIO_1 EQU $2
 AUDIO_2 EQU $8
 AUDIO_3 EQU $1f
+AUDIO_4 EQU $20
 
 PCM_1  EQU $21
 PCM_2  EQU $22
@@ -653,7 +654,16 @@ INCLUDE "audio/music/halloffame.asm"
 INCLUDE "audio/music/credits.asm"
 INCLUDE "audio/music/yellowintro.asm"
 
+SECTION "Music 4", ROMX, BANK[AUDIO_4]
+SFX_Headers_4: ; 80000 (20:4000)
+	dr $80000,$80f14
 
+SurfingPikachu1Graphics:  INCBIN "gfx/surfing_pikachu_1.t4.2bpp"
+
+INCLUDE "audio/engine_4.asm"
+
+	dr $82ce8,$84000
+	
 SECTION "Pikachu Cries 1",ROMX,BANK[PCM_1]
 PikachuCry1:: ; 84000 (21:4000)
 	dw (PikachuCry1_End - PikachuCry1) - 2 ; length of pcm data
diff --git a/audio/engine_4.asm b/audio/engine_4.asm
new file mode 100644
index 00000000..c4c1c9dd
--- /dev/null
+++ b/audio/engine_4.asm
@@ -0,0 +1,189 @@
+Audio4_PlaySound:: ; 82bd4 (20:6bd4)
+; Duplicate of Audio3_PlaySound
+	ld [wSoundID], a
+	ld a, [wSoundID]
+	cp $ff
+	jp z, Audio4_7d18e
+	cp $98
+	jp z, Audio4_7d12d
+	jp c, Audio4_7d12d
+	cp $a3
+	jr z, .asm_7d127
+	jp nc, Audio4_7d12d
+.asm_7d127
+	call InitMusicVariables
+	jp Audio4_7d192
+
+Audio4_7d12d: ; 7d12d (1f:512d)
+	ld l, a
+	ld e, a
+	ld h, $0
+	ld d, h
+	add hl, hl
+	add hl, de
+	ld de, SFX_Headers_4
+	add hl, de
+	ld a, h
+	ld [wSfxHeaderPointer], a
+	ld a, l
+	ld [wSfxHeaderPointer + 1], a
+	ld a, [hl]
+	and $c0
+	rlca
+	rlca
+	ld c, a
+.asm_7d146
+	ld d, c
+	ld a, c
+	add a
+	add c
+	ld c, a
+	ld b, $0
+	ld a, [wSfxHeaderPointer]
+	ld h, a
+	ld a, [wSfxHeaderPointer + 1]
+	ld l, a
+	add hl, bc
+	ld c, d
+	ld a, [hl]
+	and $f
+	ld e, a
+	ld d, $0
+	ld hl, wChannelSoundIDs
+	add hl, de
+	ld a, [hl]
+	and a
+	jr z, .asm_7d182
+	ld a, e
+	cp $7
+	jr nz, .asm_7d179
+	ld a, [wSoundID]
+	cp $14
+	jr nc, .asm_7d172
+	ret
+.asm_7d172
+	ld a, [hl]
+	cp $14
+	jr z, .asm_7d182
+	jr c, .asm_7d182
+.asm_7d179
+	ld a, [wSoundID]
+	cp [hl]
+	jr z, .asm_7d182
+	jr c, .asm_7d182
+	ret
+.asm_7d182
+	call InitSFXVariables
+	ld a, c
+	and a
+	jp z, Audio4_7d192
+	dec c
+	jp .asm_7d146
+
+Audio4_7d18e: ; 7d18e (1f:518e)
+	call StopAllAudio
+	ret
+
+Audio4_7d192: ; 7d192 (1f:5192)
+	ld a, [wSoundID]
+	ld l, a
+	ld e, a
+	ld h, $0
+	ld d, h
+	add hl, hl
+	add hl, de
+	ld de, SFX_Headers_4
+	add hl, de
+	ld e, l
+	ld d, h
+	ld hl, wChannelCommandPointers
+	ld a, [de] ; get channel number
+	ld b, a
+	rlca
+	rlca
+	and $3
+	ld c, a
+	ld a, b
+	and $f
+	ld b, c
+	inc b
+	inc de
+	ld c, $0
+.asm_7d1b4
+	cp c
+	jr z, .asm_7d1bc
+	inc c
+	inc hl
+	inc hl
+	jr .asm_7d1b4
+.asm_7d1bc
+	push af
+	push hl
+	push bc
+	ld b, $0
+	ld c, a
+	cp $3
+	jr c, .asm_7d1cc
+	ld hl, wChannelFlags1
+	add hl, bc
+	set 2, [hl]
+.asm_7d1cc
+	pop bc
+	pop hl
+	ld a, [de] ; get channel pointer
+	ld [hli], a
+	inc de
+	ld a, [de]
+	ld [hli], a
+	inc de
+	pop af
+	push hl
+	push bc
+	ld b, $0
+	ld c, a
+	ld hl, wChannelSoundIDs
+	add hl, bc
+	ld a, [wSoundID]
+	ld [hl], a
+	pop bc
+	pop hl
+	inc c
+	dec b
+	ld a, b
+	and a
+	ld a, [de]
+	inc de
+	jr nz, .asm_7d1b4
+	ld a, [wSoundID]
+	cp $14
+	jr nc, .asm_7d1f5
+	jr .asm_7d21f
+.asm_7d1f5
+	ld a, [wSoundID]
+	cp $86
+	jr z, .asm_7d21f
+	jr c, .asm_7d200
+	jr .asm_7d21f
+.asm_7d200
+	ld hl, wChannelSoundIDs + CH4
+	ld [hli], a
+	ld [hli], a
+	ld [hli], a
+	ld [hl], a
+	ld hl, wChannelCommandPointers + CH6 * 2 ; sfx noise channel pointer
+	ld de, Noise4_endchannel
+	ld [hl], e
+	inc hl
+	ld [hl], d ; overwrite pointer to point to endchannel
+	ld a, [wSavedVolume]
+	and a
+	jr nz, .asm_7d21f
+	ld a, [rNR50]
+	ld [wSavedVolume], a
+	ld a, $77
+	ld [rNR50], a
+.asm_7d21f
+	ret
+
+Noise4_endchannel: ; 7d220 (1f:5220)
+	endchannel
\ No newline at end of file
diff --git a/yellow/main.asm b/yellow/main.asm
index e9c5bbf8..81e7005b 100755
--- a/yellow/main.asm
+++ b/yellow/main.asm
@@ -827,14 +827,6 @@ AttackAnimationPointers: ; 7a22a (1e:622a)
 SubanimationPointers: ; 7a915 (1e:6915)
 	dr $7a915,$7c000
 
-SECTION "bank20",ROMX,BANK[$20]
-
-	dr $80000,$80f14
-
-SurfingPikachu1Graphics:  INCBIN "gfx/surfing_pikachu_1.t4.2bpp"
-Audio4_PlaySound: ; 82bd4 (20:6bd4)
-	dr $82bd4,$84000
-
 SECTION "bank2f",ROMX[$5000],BANK[$2F]
 
 INCLUDE "engine/bg_map_attributes.asm"