1 files changed, 159 insertions, 0 deletions
diff --git a/audio/engine.asm b/audio/engine.asm
new file mode 100644
index 0000000..e008e9d
--- /dev/null
+++ b/audio/engine.asm
@@ -0,0 +1,159 @@
+_DisableAudio:: ; 3a:4000
+    push hl
+    push de
+    push bc
+    push af
+    ld hl, rNR50
+    xor a
+    ld [hli], a
+    ld [hli], a
+    ld a, $80
+    ld [hli], a
+    ld hl, rNR10
+    ld e, 4
+.init_channel
+    xor a
+    ld [hli], a
+    ld [hli], a
+    ld a, 8
+    ld [hli], a
+    xor a
+    ld [hli], a
+    ld a, $80
+    ld [hli], a
+    dec e
+    jr nz, .init_channel
+
+    ld hl, wMusic
+    ld de, wMusicInitEnd - wMusic
+.clear
+    xor a
+    ld [hli], a
+    dec de
+    ld a, d
+    or e
+    jr nz, .clear
+
+    ld a, $77
+    ld [wVolume], a
+
+    pop af
+    pop bc
+    pop de
+    pop hl
+    ret
+
+
+_UpdateSound:: ; 3a:4037
+    xor a
+    ; So, I'm being told I need to disassemble this...
+    ; OH HELL NO
+
+    ; ... TODO :/
+
+
+
+SECTION "Audio engine, part 2", ROMX[$4CEE],BANK[$3A] ; TODO: disassemble what's above (gulp) and remove this
+
+SetGlobalTempo: ; 3a:4cee
+    push bc
+    ld a, [wCurChannel]
+    cp CHAN5
+    jr nc, .sfxchannels
+    ld bc, wChannel1
+    call Tempo
+    ld bc, wChannel2
+    call Tempo
+    ld bc, wChannel3
+    call Tempo
+    ld bc, wChannel4
+    call Tempo
+    jr .end
+
+.sfxchannels
+    ld bc, wChannel5
+    call Tempo
+    ld bc, wChannel6
+    call Tempo
+    ld bc, wChannel7
+    call Tempo
+    ld bc, wChannel8
+    call Tempo
+
+.end
+    pop bc
+    ret
+
+Tempo: ; 3a:4d2a
+    ld hl, wChannel1Tempo - wChannel1
+    add hl, bc
+    ld [hl], e
+    inc hl
+    ld [hl], d
+    xor a
+    ld hl, wChannel1Field16 - wChannel1
+    add hl, bc
+    ld [hl], a
+    ret
+
+
+StartChannel: ; 3a:4d38
+    call SetLRTracks
+    ld hl, wChannel1Flags - wChannel1
+    add hl, bc
+    set SOUND_CHANNEL_ON, [hl]
+    ret
+
+
+StopChannel: ; 3a:4d42
+    ld hl, wChannel1Flags - wChannel1
+    add hl, bc
+    res SOUND_CHANNEL_ON, [hl]
+    ld hl, wChannel1MusicID - wChannel1
+    add hl, bc
+    xor a
+    ld [hli], a
+    ld [hli], a
+    ld [hli], a
+    ret
+
+
+SetLRTracks: ; 3a:4d51
+    push de
+    ld a, [wCurChannel]
+    maskbits NUM_MUSIC_CHANS
+    ld e, a
+    ld d, 0
+    ld hl, 52B3 ; FIXME
+    add hl, de
+    ld a, [hl]
+    ld hl, wChannel1Tracks - wChannel1
+    add hl, bc
+    ld [hl], a
+    pop de
+    ret
+
+
+_PlayMusic:: ; 3a:4d66
+    ld hl, wMusicID
+    ld [hl], e
+    inc hl
+    ld [hl], d
+    ld hl, Music
+    add hl, de
+    add hl, de
+    add hl, de
+    ld a, [hli]
+    ld [wMusicBank], a
+    ld e, [hl]
+    inc hl
+    ld d, [hl]
+    call LoadMusicByte
+    rlca
+    rlca
+    maskbits NUM_MUSIC_CHANS
+    inc a
+.loop
+    push af
+    call LoadChannel
+    call StartChannel