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6f226f584c
pokecrystal-board/audio/engine.asm
aljohnston112 7b9d8767d4
Identified two magic numbers and cleaned up some comments (#783) 
Improve the audio engine's comments and replace some magic numbers with constants
2020-12-07 12:44:16 -05:00

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; The entire sound engine. Uses section "audio" in WRAM.
; Interfaces are in bank 0.
; Notable functions:
; FadeMusic
; PlayStereoSFX
_InitSound::
; restart sound operation
; clear all relevant hardware registers & wram
push hl
push de
push bc
push af
call MusicOff
ld hl, rNR50 ; channel control registers
xor a
ld [hli], a ; rNR50 ; volume/vin
ld [hli], a ; rNR51 ; sfx channels
ld a, $80 ; all channels on
ld [hli], a ; rNR52 ; music channels
ld hl, rNR10 ; sound channel registers
ld e, NUM_MUSIC_CHANS
.clearsound
; sound channel 1 2 3 4
xor a
ld [hli], a ; rNR10, rNR20, rNR30, rNR40 ; sweep = 0
ld [hli], a ; rNR11, rNR21, rNR31, rNR41 ; length/wavepattern = 0
ld a, $8
ld [hli], a ; rNR12, rNR22, rNR32, rNR42 ; envelope = 0
xor a
ld [hli], a ; rNR13, rNR23, rNR33, rNR43 ; frequency lo = 0
ld a, $80
ld [hli], a ; rNR14, rNR24, rNR34, rNR44 ; restart sound (freq hi = 0)
dec e
jr nz, .clearsound
ld hl, wAudio
ld de, wAudioEnd - wAudio
.clearaudio
xor a
ld [hli], a
dec de
ld a, e
or d
jr nz, .clearaudio
ld a, MAX_VOLUME
ld [wVolume], a
call MusicOn
pop af
pop bc
pop de
pop hl
ret
MusicFadeRestart:
; restart but keep the music id to fade in to
ld a, [wMusicFadeID + 1]
push af
ld a, [wMusicFadeID]
push af
call _InitSound
pop af
ld [wMusicFadeID], a
pop af
ld [wMusicFadeID + 1], a
ret
MusicOn:
ld a, 1
ld [wMusicPlaying], a
ret
MusicOff:
xor a
ld [wMusicPlaying], a
ret
_UpdateSound::
; called once per frame
; no use updating audio if it's not playing
ld a, [wMusicPlaying]
and a
ret z
; start at ch1
xor a
ld [wCurChannel], a ; just
ld [wSoundOutput], a ; off
ld bc, wChannel1
.loop
; is the channel active?
ld hl, CHANNEL_FLAGS1
add hl, bc
bit SOUND_CHANNEL_ON, [hl]
jp z, .nextchannel
; check time left in the current note
ld hl, CHANNEL_NOTE_DURATION
add hl, bc
ld a, [hl]
cp 2 ; 1 or 0?
jr c, .noteover
dec [hl]
jr .continue_sound_update
.noteover
; reset vibrato delay
ld hl, CHANNEL_VIBRATO_DELAY
add hl, bc
ld a, [hl]
ld hl, CHANNEL_VIBRATO_DELAY_COUNT
add hl, bc
ld [hl], a
; turn vibrato off for now
ld hl, CHANNEL_FLAGS2
add hl, bc
res SOUND_PITCH_SLIDE, [hl]
; get next note
call ParseMusic
.continue_sound_update
call ApplyPitchSlide
; duty cycle
ld hl, CHANNEL_DUTY_CYCLE
add hl, bc
ld a, [hli]
ld [wCurTrackDuty], a
; volume envelope
ld a, [hli]
ld [wCurTrackVolumeEnvelope], a
; frequency
ld a, [hli]
ld [wCurTrackFrequency], a
ld a, [hl]
ld [wCurTrackFrequency + 1], a
; vibrato, noise
call HandleTrackVibrato ; handle vibrato and other things
call HandleNoise
; turn off music when playing sfx?
ld a, [wSFXPriority]
and a
jr z, .next
; are we in a sfx channel right now?
ld a, [wCurChannel]
cp NUM_MUSIC_CHANS
jr nc, .next
; are any sfx channels active?
; if so, mute
ld hl, wChannel5Flags1
bit SOUND_CHANNEL_ON, [hl]
jr nz, .restnote
ld hl, wChannel6Flags1
bit SOUND_CHANNEL_ON, [hl]
jr nz, .restnote
ld hl, wChannel7Flags1
bit SOUND_CHANNEL_ON, [hl]
jr nz, .restnote
ld hl, wChannel8Flags1
bit SOUND_CHANNEL_ON, [hl]
jr z, .next
.restnote
ld hl, CHANNEL_NOTE_FLAGS
add hl, bc
set NOTE_REST, [hl] ; Rest
.next
; are we in a sfx channel right now?
ld a, [wCurChannel]
cp NUM_MUSIC_CHANS
jr nc, .sfx_channel
ld hl, CHANNEL_STRUCT_LENGTH * NUM_MUSIC_CHANS + CHANNEL_FLAGS1
add hl, bc
bit SOUND_CHANNEL_ON, [hl]
jr nz, .sound_channel_on
.sfx_channel
call UpdateChannels
ld hl, CHANNEL_TRACKS
add hl, bc
ld a, [wSoundOutput]
or [hl]
ld [wSoundOutput], a
.sound_channel_on
; clear note flags
ld hl, CHANNEL_NOTE_FLAGS
add hl, bc
xor a
ld [hl], a
.nextchannel
; next channel
ld hl, CHANNEL_STRUCT_LENGTH
add hl, bc
ld c, l
ld b, h
ld a, [wCurChannel]
inc a
ld [wCurChannel], a
cp NUM_CHANNELS ; are we done?
jp nz, .loop ; do it all again
call PlayDanger
; fade music in/out
call FadeMusic
; write volume to hardware register
ld a, [wVolume]
ldh [rNR50], a
; write SO on/off to hardware register
ld a, [wSoundOutput]
ldh [rNR51], a
ret
UpdateChannels:
ld hl, .ChannelFnPtrs
ld a, [wCurChannel]
maskbits NUM_CHANNELS
add a
ld e, a
ld d, 0
add hl, de
ld a, [hli]
ld h, [hl]
ld l, a
jp hl
.ChannelFnPtrs:
dw .Channel1
dw .Channel2
dw .Channel3
dw .Channel4
; sfx ch ptrs are identical to music chs
; ..except 5
dw .Channel5
dw .Channel6
dw .Channel7
dw .Channel8
.Channel1:
ld a, [wLowHealthAlarm]
bit DANGER_ON_F, a
ret nz
.Channel5:
ld hl, CHANNEL_NOTE_FLAGS
add hl, bc
bit NOTE_PITCH_SWEEP, [hl]
jr z, .noPitchSweep
;
ld a, [wPitchSweep]
ldh [rNR10], a
.noPitchSweep
bit NOTE_REST, [hl] ; rest
jr nz, .ch1_rest
bit NOTE_NOISE_SAMPLING, [hl]
jr nz, .ch1_noise_sampling
bit NOTE_FREQ_OVERRIDE, [hl]
jr nz, .ch1_frequency_override
bit NOTE_VIBRATO_OVERRIDE, [hl]
jr nz, .ch1_vibrato_override
jr .ch1_check_duty_override
.ch1_frequency_override
ld a, [wCurTrackFrequency]
ldh [rNR13], a
ld a, [wCurTrackFrequency + 1]
ldh [rNR14], a
.ch1_check_duty_override
bit NOTE_DUTY_OVERRIDE, [hl]
ret z
ld a, [wCurTrackDuty]
ld d, a
ldh a, [rNR11]
and $3f ; sound length
or d
ldh [rNR11], a
ret
.ch1_vibrato_override
ld a, [wCurTrackDuty]
ld d, a
ldh a, [rNR11]
and $3f ; sound length
or d
ldh [rNR11], a
ld a, [wCurTrackFrequency]
ldh [rNR13], a
ret
.ch1_rest
ldh a, [rNR52]
and %10001110 ; ch1 off
ldh [rNR52], a
ld hl, rNR10
call ClearChannel
ret
.ch1_noise_sampling
ld hl, wCurTrackDuty
ld a, $3f ; sound length
or [hl]
ldh [rNR11], a
ld a, [wCurTrackVolumeEnvelope]
ldh [rNR12], a
ld a, [wCurTrackFrequency]
ldh [rNR13], a
ld a, [wCurTrackFrequency + 1]
or $80
ldh [rNR14], a
ret
.Channel2:
.Channel6:
ld hl, CHANNEL_NOTE_FLAGS
add hl, bc
bit NOTE_REST, [hl] ; rest
jr nz, .ch2_rest
bit NOTE_NOISE_SAMPLING, [hl]
jr nz, .ch2_noise_sampling
bit NOTE_VIBRATO_OVERRIDE, [hl]
jr nz, .ch2_vibrato_override
bit NOTE_DUTY_OVERRIDE, [hl]
ret z
ld a, [wCurTrackDuty]
ld d, a
ldh a, [rNR21]
and $3f ; sound length
or d
ldh [rNR21], a
ret
.ch2_frequency_override ; unreferenced
ld a, [wCurTrackFrequency]
ldh [rNR23], a
ld a, [wCurTrackFrequency + 1]
ldh [rNR24], a
ret
.ch2_vibrato_override
ld a, [wCurTrackDuty]
ld d, a
ldh a, [rNR21]
and $3f ; sound length
or d
ldh [rNR21], a
ld a, [wCurTrackFrequency]
ldh [rNR23], a
ret
.ch2_rest
ldh a, [rNR52]
and %10001101 ; ch2 off
ldh [rNR52], a
ld hl, rNR20
call ClearChannel
ret
.ch2_noise_sampling
ld hl, wCurTrackDuty
ld a, $3f ; sound length
or [hl]
ldh [rNR21], a
ld a, [wCurTrackVolumeEnvelope]
ldh [rNR22], a
ld a, [wCurTrackFrequency]
ldh [rNR23], a
ld a, [wCurTrackFrequency + 1]
or $80 ; initial (restart)
ldh [rNR24], a
ret
.Channel3:
.Channel7:
ld hl, CHANNEL_NOTE_FLAGS
add hl, bc
bit NOTE_REST, [hl]
jr nz, .ch3_rest
bit NOTE_NOISE_SAMPLING, [hl]
jr nz, .ch3_noise_sampling
bit NOTE_VIBRATO_OVERRIDE, [hl]
jr nz, .ch3_vibrato_override
ret
.ch3_frequency_override ; unreferenced
ld a, [wCurTrackFrequency]
ldh [rNR33], a
ld a, [wCurTrackFrequency + 1]
ldh [rNR34], a
ret
.ch3_vibrato_override
ld a, [wCurTrackFrequency]
ldh [rNR33], a
ret
.ch3_rest
ldh a, [rNR52]
and %10001011 ; ch3 off
ldh [rNR52], a
ld hl, rNR30
call ClearChannel
ret
.ch3_noise_sampling
ld a, $3f ; sound length
ldh [rNR31], a
xor a
ldh [rNR30], a
call .load_wave_pattern
ld a, $80
ldh [rNR30], a
ld a, [wCurTrackFrequency]
ldh [rNR33], a
ld a, [wCurTrackFrequency + 1]
or $80
ldh [rNR34], a
ret
.load_wave_pattern
push hl
ld a, [wCurTrackVolumeEnvelope]
and $f ; only 0-9 are valid
ld l, a
ld h, 0
; hl << 4
; each wavepattern is $f bytes long
; so seeking is done in $10s
rept 4
add hl, hl
endr
ld de, WaveSamples
add hl, de
; load wavepattern into rWave_0-rWave_f
ld a, [hli]
ldh [rWave_0], a
ld a, [hli]
ldh [rWave_1], a
ld a, [hli]
ldh [rWave_2], a
ld a, [hli]
ldh [rWave_3], a
ld a, [hli]
ldh [rWave_4], a
ld a, [hli]
ldh [rWave_5], a
ld a, [hli]
ldh [rWave_6], a
ld a, [hli]
ldh [rWave_7], a
ld a, [hli]
ldh [rWave_8], a
ld a, [hli]
ldh [rWave_9], a
ld a, [hli]
ldh [rWave_a], a
ld a, [hli]
ldh [rWave_b], a
ld a, [hli]
ldh [rWave_c], a
ld a, [hli]
ldh [rWave_d], a
ld a, [hli]
ldh [rWave_e], a
ld a, [hli]
ldh [rWave_f], a
pop hl
ld a, [wCurTrackVolumeEnvelope]
and $f0
sla a
ldh [rNR32], a
ret
.Channel4:
.Channel8:
ld hl, CHANNEL_NOTE_FLAGS
add hl, bc
bit NOTE_REST, [hl]
jr nz, .ch4_rest
bit NOTE_NOISE_SAMPLING, [hl]
jr nz, .ch4_noise_sampling
ret
.ch4_frequency_override ; unreferenced
ld a, [wCurTrackFrequency]
ldh [rNR43], a
ret
.ch4_rest
ldh a, [rNR52]
and %10000111 ; ch4 off
ldh [rNR52], a
ld hl, rNR40
call ClearChannel
ret
.ch4_noise_sampling
ld a, $3f ; sound length
ldh [rNR41], a
ld a, [wCurTrackVolumeEnvelope]
ldh [rNR42], a
ld a, [wCurTrackFrequency]
ldh [rNR43], a
ld a, $80
ldh [rNR44], a
ret
_CheckSFX:
; return carry if any sfx channels are active
ld hl, wChannel5Flags1
bit SOUND_CHANNEL_ON, [hl]
jr nz, .sfxon
ld hl, wChannel6Flags1
bit SOUND_CHANNEL_ON, [hl]
jr nz, .sfxon
ld hl, wChannel7Flags1
bit SOUND_CHANNEL_ON, [hl]
jr nz, .sfxon
ld hl, wChannel8Flags1
bit SOUND_CHANNEL_ON, [hl]
jr nz, .sfxon
and a
ret
.sfxon
scf
ret
PlayDanger:
ld a, [wLowHealthAlarm]
bit DANGER_ON_F, a
ret z
; Don't do anything if SFX is being played
and $ff ^ (1 << DANGER_ON_F)
ld d, a
call _CheckSFX
jr c, .increment
; Play the high tone
and a
jr z, .begin
; Play the low tone
cp 16
jr z, .halfway
jr .increment
.halfway
ld hl, DangerSoundLow
jr .applychannel
.begin
ld hl, DangerSoundHigh
.applychannel
xor a
ldh [rNR10], a
ld a, [hli]
ldh [rNR11], a
ld a, [hli]
ldh [rNR12], a
ld a, [hli]
ldh [rNR13], a
ld a, [hli]
ldh [rNR14], a
.increment
ld a, d
inc a
cp 30 ; Ending frame
jr c, .noreset
xor a
.noreset
; Make sure the danger sound is kept on
or 1 << DANGER_ON_F
ld [wLowHealthAlarm], a
; Enable channel 1 if it's off
ld a, [wSoundOutput]
and $11
ret nz
ld a, [wSoundOutput]
or $11
ld [wSoundOutput], a
ret
DangerSoundHigh:
db $80 ; duty 50%
db $e2 ; volume 14, envelope decrease sweep 2
db $50 ; frequency: $750
db $87 ; restart sound
DangerSoundLow:
db $80 ; duty 50%
db $e2 ; volume 14, envelope decrease sweep 2
db $ee ; frequency: $6ee
db $86 ; restart sound
FadeMusic:
; fade music if applicable
; usage:
; write to wMusicFade
; song fades out at the given rate
; load song id in wMusicFadeID
; fade new song in
; notes:
; max # frames per volume level is $3f
; fading?
ld a, [wMusicFade]
and a
ret z
; has the count ended?
ld a, [wMusicFadeCount]
and a
jr z, .update
; count down
dec a
ld [wMusicFadeCount], a
ret
.update
ld a, [wMusicFade]
ld d, a
; get new count
and $3f
ld [wMusicFadeCount], a
; get SO1 volume
ld a, [wVolume]
and VOLUME_SO1_LEVEL
; which way are we fading?
bit MUSIC_FADE_IN_F, d
jr nz, .fadein
; fading out
and a
jr z, .novolume
dec a
jr .updatevolume
.novolume
; make sure volume is off
xor a
ld [wVolume], a
; did we just get on a bike?
ld a, [wPlayerState]
cp PLAYER_BIKE
jr z, .bicycle
push bc
; restart sound
call MusicFadeRestart
; get new song id
ld a, [wMusicFadeID]
and a
jr z, .quit ; this assumes there are fewer than 256 songs!
ld e, a
ld a, [wMusicFadeID + 1]
ld d, a
; load new song
call _PlayMusic
.quit
; cleanup
pop bc
; stop fading
xor a
ld [wMusicFade], a
ret
.bicycle
push bc
; restart sound
call MusicFadeRestart
; this turns the volume up
; turn it back down
xor a
ld [wVolume], a
; get new song id
ld a, [wMusicFadeID]
ld e, a
ld a, [wMusicFadeID + 1]
ld d, a
; load new song
call _PlayMusic
pop bc
; fade in
ld hl, wMusicFade
set MUSIC_FADE_IN_F, [hl]
ret
.fadein
; are we done?
cp MAX_VOLUME & $f
jr nc, .maxvolume
; inc volume
inc a
jr .updatevolume
.maxvolume
; we're done
xor a
ld [wMusicFade], a
ret
.updatevolume
; hi = lo
ld d, a
swap a
or d
ld [wVolume], a
ret
LoadNote:
; wait for pitch slide to finish
ld hl, CHANNEL_FLAGS2
add hl, bc
bit SOUND_PITCH_SLIDE, [hl]
ret z
; get note duration
ld hl, CHANNEL_NOTE_DURATION
add hl, bc
ld a, [hl]
ld hl, wCurNoteDuration
sub [hl]
jr nc, .ok
ld a, 1
.ok
ld [hl], a
; get frequency
ld hl, CHANNEL_FREQUENCY
add hl, bc
ld e, [hl]
inc hl
ld d, [hl]
; get direction of pitch slide
ld hl, CHANNEL_PITCH_SLIDE_TARGET
add hl, bc
ld a, e
sub [hl]
ld e, a
ld a, d
sbc 0
ld d, a
ld hl, CHANNEL_PITCH_SLIDE_TARGET + 1
add hl, bc
sub [hl]
jr nc, .greater_than
ld hl, CHANNEL_FLAGS3
add hl, bc
set SOUND_PITCH_SLIDE_DIR, [hl]
; get frequency
ld hl, CHANNEL_FREQUENCY
add hl, bc
ld e, [hl]
inc hl
ld d, [hl]
; ????
ld hl, CHANNEL_PITCH_SLIDE_TARGET
add hl, bc
ld a, [hl]
sub e
ld e, a
ld a, d
sbc 0
ld d, a
; ????
ld hl, CHANNEL_PITCH_SLIDE_TARGET + 1
add hl, bc
ld a, [hl]
sub d
ld d, a
jr .resume
.greater_than
ld hl, CHANNEL_FLAGS3
add hl, bc
res SOUND_PITCH_SLIDE_DIR, [hl]
; get frequency
ld hl, CHANNEL_FREQUENCY
add hl, bc
ld e, [hl]
inc hl
ld d, [hl]
; get distance from pitch slide target
ld hl, CHANNEL_PITCH_SLIDE_TARGET
add hl, bc
ld a, e
sub [hl]
ld e, a
ld a, d
sbc 0
ld d, a
ld hl, CHANNEL_PITCH_SLIDE_TARGET + 1
add hl, bc
sub [hl]
ld d, a
.resume
; de = x * [wCurNoteDuration] + y
; x + 1 -> d
; y -> a
push bc
ld hl, wCurNoteDuration
ld b, 0 ; quotient
.loop
inc b
ld a, e
sub [hl]
ld e, a
jr nc, .loop
ld a, d
and a
jr z, .quit
dec d
jr .loop
.quit
ld a, e ; remainder
add [hl]
ld d, b ; quotient
pop bc
ld hl, CHANNEL_PITCH_SLIDE_AMOUNT
add hl, bc
ld [hl], d ; quotient
ld hl, CHANNEL_PITCH_SLIDE_AMOUNT_FRACTION
add hl, bc
ld [hl], a ; remainder
ld hl, CHANNEL_FIELD25
add hl, bc
xor a
ld [hl], a
ret
HandleTrackVibrato:
; handle duty, cry pitch, and vibrato
ld hl, CHANNEL_FLAGS2
add hl, bc
bit SOUND_DUTY_LOOP, [hl] ; duty cycle looping
jr z, .next
ld hl, CHANNEL_DUTY_CYCLE_PATTERN
add hl, bc
ld a, [hl]
rlca
rlca
ld [hl], a
and $c0
ld [wCurTrackDuty], a
ld hl, CHANNEL_NOTE_FLAGS
add hl, bc
set NOTE_DUTY_OVERRIDE, [hl]
.next
ld hl, CHANNEL_FLAGS2
add hl, bc
bit SOUND_PITCH_OFFSET, [hl]
jr z, .vibrato
ld hl, CHANNEL_PITCH_OFFSET
add hl, bc
ld e, [hl]
inc hl
ld d, [hl]
ld hl, wCurTrackFrequency
ld a, [hli]
ld h, [hl]
ld l, a
add hl, de
ld e, l
ld d, h
ld hl, wCurTrackFrequency
ld [hl], e
inc hl
ld [hl], d
.vibrato
; is vibrato on?
ld hl, CHANNEL_FLAGS2
add hl, bc
bit SOUND_VIBRATO, [hl] ; vibrato
jr z, .quit
; is vibrato active for this note yet?
; is the delay over?
ld hl, CHANNEL_VIBRATO_DELAY_COUNT
add hl, bc
ld a, [hl]
and a
jr nz, .subexit
; is the extent nonzero?
ld hl, CHANNEL_VIBRATO_EXTENT
add hl, bc
ld a, [hl]
and a
jr z, .quit
; save it for later
ld d, a
; is it time to toggle vibrato up/down?
ld hl, CHANNEL_VIBRATO_RATE
add hl, bc
ld a, [hl]
and $f ; count
jr z, .toggle
.subexit
dec [hl]
jr .quit
.toggle
; refresh count
ld a, [hl]
swap [hl]
or [hl]
ld [hl], a
; ????
ld a, [wCurTrackFrequency]
ld e, a
; toggle vibrato up/down
ld hl, CHANNEL_FLAGS3
add hl, bc
bit SOUND_VIBRATO_DIR, [hl] ; vibrato up/down
jr z, .down
; up
; vibrato down
res SOUND_VIBRATO_DIR, [hl]
; get the delay
ld a, d
and $f ; lo
;
ld d, a
ld a, e
sub d
jr nc, .no_carry
ld a, 0
jr .no_carry
.down
; vibrato up
set SOUND_VIBRATO_DIR, [hl]
; get the delay
ld a, d
and $f0 ; hi
swap a ; move it to lo
;
add e
jr nc, .no_carry
ld a, $ff
.no_carry
ld [wCurTrackFrequency], a
;
ld hl, CHANNEL_NOTE_FLAGS
add hl, bc
set NOTE_VIBRATO_OVERRIDE, [hl]
.quit
ret
ApplyPitchSlide:
; quit if pitch slide inactive
ld hl, CHANNEL_FLAGS2
add hl, bc
bit SOUND_PITCH_SLIDE, [hl]
ret z
; de = Frequency
ld hl, CHANNEL_FREQUENCY
add hl, bc
ld e, [hl]
inc hl
ld d, [hl]
; check whether pitch slide is going up or down
ld hl, CHANNEL_FLAGS3
add hl, bc
bit SOUND_PITCH_SLIDE_DIR, [hl]
jr z, .decreasing
; frequency += [Channel*PitchSlideAmount]
ld hl, CHANNEL_PITCH_SLIDE_AMOUNT
add hl, bc
ld l, [hl]
ld h, 0
add hl, de
ld d, h
ld e, l
; [Channel*Field25] += [Channel*PitchSlideAmountFraction]
; if rollover: Frequency += 1
ld hl, CHANNEL_PITCH_SLIDE_AMOUNT_FRACTION
add hl, bc
ld a, [hl]
ld hl, CHANNEL_FIELD25
add hl, bc
add [hl]
ld [hl], a
ld a, 0
adc e
ld e, a
ld a, 0
adc d
ld d, a
; Compare the dw at [Channel*PitchSlideTarget] to de.
; If frequency is greater, we're finished.
; Otherwise, load the frequency and set two flags.
ld hl, CHANNEL_PITCH_SLIDE_TARGET + 1
add hl, bc
ld a, [hl]
cp d
jp c, .finished_pitch_slide
jr nz, .continue_pitch_slide
ld hl, CHANNEL_PITCH_SLIDE_TARGET
add hl, bc
ld a, [hl]
cp e
jp c, .finished_pitch_slide
jr .continue_pitch_slide
.decreasing
; frequency -= [Channel*PitchSlideAmount]
ld a, e
ld hl, CHANNEL_PITCH_SLIDE_AMOUNT
add hl, bc
ld e, [hl]
sub e
ld e, a
ld a, d
sbc 0
ld d, a
; [Channel*Field25] *= 2
; if rollover: Frequency -= 1
ld hl, CHANNEL_PITCH_SLIDE_AMOUNT_FRACTION
add hl, bc
ld a, [hl]
add a
ld [hl], a
ld a, e
sbc 0
ld e, a
ld a, d
sbc 0
ld d, a
; Compare the dw at [Channel*PitchSlideTarget] to de.
; If frequency is lower, we're finished.
; Otherwise, load the frequency and set two flags.
ld hl, CHANNEL_PITCH_SLIDE_TARGET + 1
add hl, bc
ld a, d
cp [hl]
jr c, .finished_pitch_slide
jr nz, .continue_pitch_slide
ld hl, CHANNEL_PITCH_SLIDE_TARGET
add hl, bc
ld a, e
cp [hl]
jr nc, .continue_pitch_slide
.finished_pitch_slide
ld hl, CHANNEL_FLAGS2
add hl, bc
res SOUND_PITCH_SLIDE, [hl]
ld hl, CHANNEL_FLAGS3
add hl, bc
res SOUND_PITCH_SLIDE_DIR, [hl]
ret
.continue_pitch_slide
ld hl, CHANNEL_FREQUENCY
add hl, bc
ld [hl], e
inc hl
ld [hl], d
ld hl, CHANNEL_NOTE_FLAGS
add hl, bc
set NOTE_FREQ_OVERRIDE, [hl]
set NOTE_DUTY_OVERRIDE, [hl]
ret
HandleNoise:
; is noise sampling on?
ld hl, CHANNEL_FLAGS1
add hl, bc
bit SOUND_NOISE, [hl] ; noise sampling
ret z
; are we in a sfx channel?
ld a, [wCurChannel]
bit NOISE_CHAN_F, a
jr nz, .next
; is ch8 on? (noise)
ld hl, wChannel8Flags1
bit SOUND_CHANNEL_ON, [hl] ; on?
jr z, .next
; is ch8 playing noise?
bit SOUND_NOISE, [hl]
ret nz ; quit if so
;
.next
ld a, [wNoiseSampleDelay]
and a
jr z, ReadNoiseSample
dec a
ld [wNoiseSampleDelay], a
ret
ReadNoiseSample:
; sample struct:
; [wx] [yy] [zz]
; w: ? either 2 or 3
; x: duration
; zz: volume envelope
; yy: frequency
; de = [wNoiseSampleAddress]
ld hl, wNoiseSampleAddress
ld e, [hl]
inc hl
ld d, [hl]
; is it empty?
ld a, e
or d
jr z, .quit
ld a, [de]
inc de
cp sound_ret_cmd
jr z, .quit
and $f
inc a
ld [wNoiseSampleDelay], a
ld a, [de]
inc de
ld [wCurTrackVolumeEnvelope], a
ld a, [de]
inc de
ld [wCurTrackFrequency], a
xor a
ld [wCurTrackFrequency + 1], a
ld hl, wNoiseSampleAddress
ld [hl], e
inc hl
ld [hl], d
ld hl, CHANNEL_NOTE_FLAGS
add hl, bc
set NOTE_NOISE_SAMPLING, [hl]
ret
.quit
ret
ParseMusic:
; parses until a note is read or the song is ended
call GetMusicByte ; store next byte in a
cp sound_ret_cmd
jr z, .sound_ret
cp FIRST_MUSIC_CMD
jr c, .readnote
.readcommand
call ParseMusicCommand
jr ParseMusic ; start over
.readnote
; wCurMusicByte contains current note
; special notes
ld hl, CHANNEL_FLAGS1
add hl, bc
bit SOUND_SFX, [hl]
jp nz, ParseSFXOrRest
bit SOUND_REST, [hl] ; rest
jp nz, ParseSFXOrRest
bit SOUND_NOISE, [hl] ; noise sample
jp nz, GetNoiseSample
; normal note
; set note duration (bottom nybble)
ld a, [wCurMusicByte]
and $f
call SetNoteDuration
; get note pitch (top nybble)
ld a, [wCurMusicByte]
swap a
and $f
jr z, .rest ; pitch 0 -> rest
; update pitch
ld hl, CHANNEL_PITCH
add hl, bc
ld [hl], a
; store pitch in e
ld e, a
; store octave in d
ld hl, CHANNEL_OCTAVE
add hl, bc
ld d, [hl]
; update frequency
call GetFrequency
ld hl, CHANNEL_FREQUENCY
add hl, bc
ld [hl], e
inc hl
ld [hl], d
; ????
ld hl, CHANNEL_NOTE_FLAGS
add hl, bc
set NOTE_NOISE_SAMPLING, [hl]
jp LoadNote
.rest
; note = rest
ld hl, CHANNEL_NOTE_FLAGS
add hl, bc
set NOTE_REST, [hl] ; Rest
ret
.sound_ret
; $ff is reached in music data
ld hl, CHANNEL_FLAGS1
add hl, bc
bit SOUND_SUBROUTINE, [hl] ; in a subroutine?
jr nz, .readcommand ; execute
ld a, [wCurChannel]
cp CHAN5
jr nc, .chan_5to8
; ????
ld hl, CHANNEL_STRUCT_LENGTH * NUM_MUSIC_CHANS + CHANNEL_FLAGS1
add hl, bc
bit SOUND_CHANNEL_ON, [hl]
jr nz, .ok
.chan_5to8
ld hl, CHANNEL_FLAGS1
add hl, bc
bit SOUND_REST, [hl]
call nz, RestoreVolume
; end music
ld a, [wCurChannel]
cp CHAN5
jr nz, .ok
; ????
xor a
ldh [rNR10], a ; sweep = 0
.ok
; stop playing
; turn channel off
ld hl, CHANNEL_FLAGS1
add hl, bc
res SOUND_CHANNEL_ON, [hl]
; note = rest
ld hl, CHANNEL_NOTE_FLAGS
add hl, bc
set NOTE_REST, [hl]
; clear music id & bank
ld hl, CHANNEL_MUSIC_ID
add hl, bc
xor a
ld [hli], a ; id hi
ld [hli], a ; id lo
ld [hli], a ; bank
ret
RestoreVolume:
; ch5 only
ld a, [wCurChannel]
cp CHAN5
ret nz
xor a
ld hl, wChannel6PitchOffset
ld [hli], a
ld [hl], a
ld hl, wChannel8PitchOffset
ld [hli], a
ld [hl], a
ld a, [wLastVolume]
ld [wVolume], a
xor a
ld [wLastVolume], a
ld [wSFXPriority], a
ret
ParseSFXOrRest:
; turn noise sampling on
ld hl, CHANNEL_NOTE_FLAGS
add hl, bc
set NOTE_NOISE_SAMPLING, [hl] ; noise sample
; update note duration
ld a, [wCurMusicByte]
call SetNoteDuration ; top nybble doesnt matter?
; update volume envelope from next param
call GetMusicByte
ld hl, CHANNEL_VOLUME_ENVELOPE
add hl, bc
ld [hl], a
; update lo frequency from next param
call GetMusicByte
ld hl, CHANNEL_FREQUENCY
add hl, bc
ld [hl], a
; are we on the last channel? (noise sampling)
ld a, [wCurChannel]
maskbits NUM_MUSIC_CHANS
cp CHAN4
ret z
; update hi frequency from next param
call GetMusicByte
ld hl, CHANNEL_FREQUENCY + 1
add hl, bc
ld [hl], a
ret
GetNoiseSample:
; load ptr to sample header in wNoiseSampleAddress
; are we on the last channel?
ld a, [wCurChannel]
and NUM_MUSIC_CHANS - 1
cp CHAN4
; ret if not
ret nz
; update note duration
ld a, [wCurMusicByte]
and $f
call SetNoteDuration
; check current channel
ld a, [wCurChannel]
bit NOISE_CHAN_F, a
jr nz, .sfx
ld hl, wChannel8Flags1
bit SOUND_CHANNEL_ON, [hl] ; is ch8 on? (noise)
ret nz
ld a, [wMusicNoiseSampleSet]
jr .next
.sfx
ld a, [wSFXNoiseSampleSet]
.next
; load noise sample set id into de
ld e, a
ld d, 0
; load ptr to noise sample set in hl
ld hl, Drumkits
add hl, de
add hl, de
ld a, [hli]
ld h, [hl]
ld l, a
; get pitch
ld a, [wCurMusicByte]
swap a
; non-rest note?
and $f
ret z
; use 'pitch' to seek noise sample set
ld e, a
ld d, 0
add hl, de
add hl, de
; load sample pointer into wNoiseSampleAddress
ld a, [hli]
ld [wNoiseSampleAddress], a
ld a, [hl]
ld [wNoiseSampleAddress + 1], a
; clear ????
xor a
ld [wNoiseSampleDelay], a
ret
ParseMusicCommand:
; reload command
ld a, [wCurMusicByte]
; get command #
sub FIRST_MUSIC_CMD
ld e, a
ld d, 0
; seek command pointer
ld hl, MusicCommands
add hl, de
add hl, de
; jump to the new pointer
ld a, [hli]
ld h, [hl]
ld l, a
jp hl
MusicCommands:
; entries correspond to audio constants (see macros/scripts/audio.asm)
dw Music_Octave8
dw Music_Octave7
dw Music_Octave6
dw Music_Octave5
dw Music_Octave4
dw Music_Octave3
dw Music_Octave2
dw Music_Octave1
dw Music_NoteType ; note length + volume envelope
dw Music_Transpose
dw Music_Tempo
dw Music_DutyCycle
dw Music_VolumeEnvelope
dw Music_PitchSweep
dw Music_DutyCyclePattern
dw Music_ToggleSFX
dw Music_PitchSlide
dw Music_Vibrato
dw MusicE2 ; unused
dw Music_ToggleNoise
dw Music_ForceStereoPanning
dw Music_Volume
dw Music_PitchOffset
dw MusicE7 ; unused
dw MusicE8 ; unused
dw Music_TempoRelative
dw Music_RestartChannel
dw Music_NewSong
dw Music_SFXPriorityOn
dw Music_SFXPriorityOff
dw MusicEE ; unused
dw Music_StereoPanning
dw Music_SFXToggleNoise
dw MusicF1 ; nothing
dw MusicF2 ; nothing
dw MusicF3 ; nothing
dw MusicF4 ; nothing
dw MusicF5 ; nothing
dw MusicF6 ; nothing
dw MusicF7 ; nothing
dw MusicF8 ; nothing
dw MusicF9 ; unused
dw Music_SetCondition
dw Music_JumpIf
dw Music_Jump
dw Music_Loop
dw Music_Call
dw Music_Ret
MusicF1:
MusicF2:
MusicF3:
MusicF4:
MusicF5:
MusicF6:
MusicF7:
MusicF8:
ret
Music_Ret:
; called when $ff is encountered w/ subroutine flag set
; end music stream
; return to caller of the subroutine
; reset subroutine flag
ld hl, CHANNEL_FLAGS1
add hl, bc
res SOUND_SUBROUTINE, [hl]
; copy LastMusicAddress to MusicAddress
ld hl, CHANNEL_LAST_MUSIC_ADDRESS
add hl, bc
ld e, [hl]
inc hl
ld d, [hl]
ld hl, CHANNEL_MUSIC_ADDRESS
add hl, bc
ld [hl], e
inc hl
ld [hl], d
ret
Music_Call:
; call music stream (subroutine)
; parameters: ll hh ; pointer to subroutine
; get pointer from next 2 bytes
call GetMusicByte
ld e, a
call GetMusicByte
ld d, a
push de
; copy MusicAddress to LastMusicAddress
ld hl, CHANNEL_MUSIC_ADDRESS
add hl, bc
ld e, [hl]
inc hl
ld d, [hl]
ld hl, CHANNEL_LAST_MUSIC_ADDRESS
add hl, bc
ld [hl], e
inc hl
ld [hl], d
; load pointer into MusicAddress
pop de
ld hl, CHANNEL_MUSIC_ADDRESS
add hl, bc
ld [hl], e
inc hl
ld [hl], d
; set subroutine flag
ld hl, CHANNEL_FLAGS1
add hl, bc
set SOUND_SUBROUTINE, [hl]
ret
Music_Jump:
; jump
; parameters: ll hh ; pointer
; get pointer from next 2 bytes
call GetMusicByte
ld e, a
call GetMusicByte
ld d, a
ld hl, CHANNEL_MUSIC_ADDRESS
add hl, bc
ld [hl], e
inc hl
ld [hl], d
ret
Music_Loop:
; loops xx - 1 times
; 00: infinite
; params: 3
; xx ll hh
; xx : loop count
; ll hh : pointer
; get loop count
call GetMusicByte
ld hl, CHANNEL_FLAGS1
add hl, bc
bit SOUND_LOOPING, [hl] ; has the loop been initiated?
jr nz, .checkloop
and a ; loop counter 0 = infinite
jr z, .loop
; initiate loop
dec a
set SOUND_LOOPING, [hl] ; set loop flag
ld hl, CHANNEL_LOOP_COUNT
add hl, bc
ld [hl], a ; store loop counter
.checkloop
ld hl, CHANNEL_LOOP_COUNT
add hl, bc
ld a, [hl]
and a ; are we done?
jr z, .endloop
dec [hl]
.loop
; get pointer
call GetMusicByte
ld e, a
call GetMusicByte
ld d, a
; load new pointer into MusicAddress
ld hl, CHANNEL_MUSIC_ADDRESS
add hl, bc
ld [hl], e
inc hl
ld [hl], d
ret
.endloop
; reset loop flag
ld hl, CHANNEL_FLAGS1
add hl, bc
res SOUND_LOOPING, [hl]
; skip to next command
ld hl, CHANNEL_MUSIC_ADDRESS
add hl, bc
ld e, [hl]
inc hl
ld d, [hl]
inc de ; skip
inc de ; pointer
ld [hl], d
dec hl
ld [hl], e
ret
Music_SetCondition:
; set condition for a jump
; used with FB
; params: 1
; xx ; condition
; set condition
call GetMusicByte
ld hl, CHANNEL_CONDITION
add hl, bc
ld [hl], a
ret
Music_JumpIf:
; conditional jump
; used with FA
; params: 3
; xx: condition
; ll hh: pointer
; check condition
; a = condition
call GetMusicByte
; if existing condition matches, jump to new address
ld hl, CHANNEL_CONDITION
add hl, bc
cp [hl]
jr z, .jump
; skip to next command
; get address
ld hl, CHANNEL_MUSIC_ADDRESS
add hl, bc
ld e, [hl]
inc hl
ld d, [hl]
; skip pointer
inc de
inc de
; update address
ld [hl], d
dec hl
ld [hl], e
ret
.jump
; jump to the new address
; get pointer
call GetMusicByte
ld e, a
call GetMusicByte
ld d, a
; update pointer in MusicAddress
ld hl, CHANNEL_MUSIC_ADDRESS
add hl, bc
ld [hl], e
inc hl
ld [hl], d
ret
MusicEE:
; unused
; conditional jump
; checks a byte in ram corresponding to the current channel
; params: 2
; ll hh ; pointer
; if ????, jump
; get channel
ld a, [wCurChannel]
maskbits NUM_MUSIC_CHANS
ld e, a
ld d, 0
; hl = wChannel1JumpCondition + channel id
ld hl, wChannel1JumpCondition
add hl, de
; if set, jump
ld a, [hl]
and a
jr nz, .jump
; skip to next command
; get address
ld hl, CHANNEL_MUSIC_ADDRESS
add hl, bc
ld e, [hl]
inc hl
ld d, [hl]
; skip pointer
inc de
inc de
; update address
ld [hl], d
dec hl
ld [hl], e
ret
.jump
; reset jump flag
ld [hl], 0
; de = pointer
call GetMusicByte
ld e, a
call GetMusicByte
ld d, a
; update address
ld hl, CHANNEL_MUSIC_ADDRESS
add hl, bc
ld [hl], e
inc hl
ld [hl], d
ret
MusicF9:
; unused
; sets some flag
; params: 0
ld a, TRUE
ld [wUnusedMusicF9Flag], a
ret
MusicE2:
; unused
; params: 1
call GetMusicByte
ld hl, CHANNEL_FIELD2C
add hl, bc
ld [hl], a
ld hl, CHANNEL_FLAGS2
add hl, bc
set SOUND_UNKN_0B, [hl]
ret
Music_Vibrato:
; vibrato
; params: 2
; 1: [xx]
; delay in frames
; 2: [yz]
; y: extent
; z: rate (# frames per cycle)
; set vibrato flag?
ld hl, CHANNEL_FLAGS2
add hl, bc
set SOUND_VIBRATO, [hl]
; start at lower frequency (extent is positive)
ld hl, CHANNEL_FLAGS3
add hl, bc
res SOUND_VIBRATO_DIR, [hl]
; get delay
call GetMusicByte
; update delay
ld hl, CHANNEL_VIBRATO_DELAY
add hl, bc
ld [hl], a
; update delay count
ld hl, CHANNEL_VIBRATO_DELAY_COUNT
add hl, bc
ld [hl], a
; update extent
; this is split into halves only to get added back together at the last second
; get extent/rate
call GetMusicByte
ld hl, CHANNEL_VIBRATO_EXTENT
add hl, bc
ld d, a
; get top nybble
and $f0
swap a
srl a ; halve
ld e, a
adc 0 ; round up
swap a
or e
ld [hl], a
; update rate
ld hl, CHANNEL_VIBRATO_RATE
add hl, bc
; get bottom nybble
ld a, d
and $f
ld d, a
swap a
or d
ld [hl], a
ret
Music_PitchSlide:
; set the target for pitch slide
; params: 2
; note duration
; target note
call GetMusicByte
ld [wCurNoteDuration], a
call GetMusicByte
; pitch in e
ld d, a
and $f
ld e, a
; octave in d
ld a, d
swap a
and $f
ld d, a
call GetFrequency
ld hl, CHANNEL_PITCH_SLIDE_TARGET
add hl, bc
ld [hl], e
ld hl, CHANNEL_PITCH_SLIDE_TARGET + 1
add hl, bc
ld [hl], d
ld hl, CHANNEL_FLAGS2
add hl, bc
set SOUND_PITCH_SLIDE, [hl]
ret
Music_PitchOffset:
; tone
; params: 1 (dw)
; offset to add to each note frequency
ld hl, CHANNEL_FLAGS2
add hl, bc
set SOUND_PITCH_OFFSET, [hl]
ld hl, CHANNEL_PITCH_OFFSET + 1
add hl, bc
call GetMusicByte
ld [hld], a
call GetMusicByte
ld [hl], a
ret
MusicE7:
; unused
; params: 1
ld hl, CHANNEL_FLAGS2
add hl, bc
set SOUND_UNKN_0E, [hl]
call GetMusicByte
ld hl, CHANNEL_FIELD29
add hl, bc
ld [hl], a
ret
Music_DutyCyclePattern:
; sequence of 4 duty cycles to be looped
; params: 1 (4 2-bit duty cycle arguments)
ld hl, CHANNEL_FLAGS2
add hl, bc
set SOUND_DUTY_LOOP, [hl] ; duty cycle looping
; sound duty sequence
call GetMusicByte
rrca
rrca
ld hl, CHANNEL_DUTY_CYCLE_PATTERN
add hl, bc
ld [hl], a
; update duty cycle
and $c0 ; only uses top 2 bits
ld hl, CHANNEL_DUTY_CYCLE
add hl, bc
ld [hl], a
ret
MusicE8:
; unused
; params: 1
ld hl, CHANNEL_FLAGS2
add hl, bc
set SOUND_UNKN_0D, [hl]
call GetMusicByte
ld hl, CHANNEL_FIELD2A
add hl, bc
ld [hl], a
ret
Music_ToggleSFX:
; toggle something
; params: none
ld hl, CHANNEL_FLAGS1
add hl, bc
bit SOUND_SFX, [hl]
jr z, .on
res SOUND_SFX, [hl]
ret
.on
set SOUND_SFX, [hl]
ret
Music_ToggleNoise:
; toggle music noise sampling
; can't be used as a straight toggle since the param is not read from on->off
; params:
; noise on: 1
; noise off: 0
; check if noise sampling is on
ld hl, CHANNEL_FLAGS1
add hl, bc
bit SOUND_NOISE, [hl]
jr z, .on
; turn noise sampling off
res SOUND_NOISE, [hl]
ret
.on
; turn noise sampling on
set SOUND_NOISE, [hl]
call GetMusicByte
ld [wMusicNoiseSampleSet], a
ret
Music_SFXToggleNoise:
; toggle sfx noise sampling
; params:
; on: 1
; off: 0
; check if noise sampling is on
ld hl, CHANNEL_FLAGS1
add hl, bc
bit SOUND_NOISE, [hl]
jr z, .on
; turn noise sampling off
res SOUND_NOISE, [hl]
ret
.on
; turn noise sampling on
set SOUND_NOISE, [hl]
call GetMusicByte
ld [wSFXNoiseSampleSet], a
ret
Music_NoteType:
; note length
; # frames per 16th note
; volume envelope: see Music_VolumeEnvelope
; params: 2
; note length
call GetMusicByte
ld hl, CHANNEL_NOTE_LENGTH
add hl, bc
ld [hl], a
ld a, [wCurChannel]
maskbits NUM_MUSIC_CHANS
cp CHAN4
ret z
; volume envelope
call Music_VolumeEnvelope
ret
Music_PitchSweep:
; update pitch sweep
; params: 1
call GetMusicByte
ld [wPitchSweep], a
ld hl, CHANNEL_NOTE_FLAGS
add hl, bc
set NOTE_PITCH_SWEEP, [hl]
ret
Music_DutyCycle:
; duty cycle
; params: 1
call GetMusicByte
rrca
rrca
and $c0
ld hl, CHANNEL_DUTY_CYCLE
add hl, bc
ld [hl], a
ret
Music_VolumeEnvelope:
; volume envelope
; params: 1
; hi: volume
; lo: fade
call GetMusicByte
ld hl, CHANNEL_VOLUME_ENVELOPE
add hl, bc
ld [hl], a
ret
Music_Tempo:
; global tempo
; params: 2
; de: tempo
call GetMusicByte
ld d, a
call GetMusicByte
ld e, a
call SetGlobalTempo
ret
Music_Octave8:
Music_Octave7:
Music_Octave6:
Music_Octave5:
Music_Octave4:
Music_Octave3:
Music_Octave2:
Music_Octave1:
; set octave based on lo nybble of the command
ld hl, CHANNEL_OCTAVE
add hl, bc
ld a, [wCurMusicByte]
and 7
ld [hl], a
ret
Music_Transpose:
; set starting octave
; this forces all notes up by the starting octave
; params: 1
call GetMusicByte
ld hl, CHANNEL_TRANSPOSITION
add hl, bc
ld [hl], a
ret
Music_StereoPanning:
; stereo panning
; params: 1
; stereo on?
ld a, [wOptions]
bit STEREO, a
jr nz, Music_ForceStereoPanning
; skip param
call GetMusicByte
ret
Music_ForceStereoPanning:
; force panning
; params: 1
call SetLRTracks
call GetMusicByte
ld hl, CHANNEL_TRACKS
add hl, bc
and [hl]
ld [hl], a
ret
Music_Volume:
; set volume
; params: 1
; see Volume
; read param even if it's not used
call GetMusicByte
; is the song fading?
ld a, [wMusicFade]
and a
ret nz
; reload param
ld a, [wCurMusicByte]
; set volume
ld [wVolume], a
ret
Music_TempoRelative:
; set global tempo to current channel tempo +/- param
; params: 1 signed
call GetMusicByte
ld e, a
; check sign
cp $80
jr nc, .negative
;positive
ld d, 0
jr .ok
.negative
ld d, -1
.ok
ld hl, CHANNEL_TEMPO
add hl, bc
ld a, [hli]
ld h, [hl]
ld l, a
add hl, de
ld e, l
ld d, h
call SetGlobalTempo
ret
Music_SFXPriorityOn:
; turn sfx priority on
; params: none
ld a, 1
ld [wSFXPriority], a
ret
Music_SFXPriorityOff:
; turn sfx priority off
; params: none
xor a
ld [wSFXPriority], a
ret
Music_RestartChannel:
; restart current channel from channel header (same bank)
; params: 2 (5)
; ll hh: pointer to new channel header
; header format: 0x yy zz
; x: channel # (0-3)
; zzyy: pointer to new music data
; update music id
ld hl, CHANNEL_MUSIC_ID
add hl, bc
ld a, [hli]
ld [wMusicID], a
ld a, [hl]
ld [wMusicID + 1], a
; update music bank
ld hl, CHANNEL_MUSIC_BANK
add hl, bc
ld a, [hl]
ld [wMusicBank], a
; get pointer to new channel header
call GetMusicByte
ld l, a
call GetMusicByte
ld h, a
ld e, [hl]
inc hl
ld d, [hl]
push bc ; save current channel
call LoadChannel
call StartChannel
pop bc ; restore current channel
ret
Music_NewSong:
; new song
; params: 2
; de: song id
call GetMusicByte
ld e, a
call GetMusicByte
ld d, a
push bc
call _PlayMusic
pop bc
ret
GetMusicByte:
; returns byte from current address in a
; advances to next byte in music data
; input: bc = start of current channel
push hl
push de
ld hl, CHANNEL_MUSIC_ADDRESS
add hl, bc
ld a, [hli]
ld e, a
ld d, [hl]
ld hl, CHANNEL_MUSIC_BANK
add hl, bc
ld a, [hl]
call _LoadMusicByte ; load data into [wCurMusicByte]
inc de ; advance to next byte for next time this is called
ld hl, CHANNEL_MUSIC_ADDRESS
add hl, bc
ld a, e
ld [hli], a
ld [hl], d
pop de
pop hl
ld a, [wCurMusicByte]
ret
GetFrequency:
; generate frequency
; input:
; d: octave
; e: pitch
; output:
; de: frequency
; get octave
; get starting octave
ld hl, CHANNEL_TRANSPOSITION
add hl, bc
ld a, [hl]
swap a ; hi nybble
and $f
; add current octave
add d
push af ; we'll use this later
; get starting octave
ld hl, CHANNEL_TRANSPOSITION
add hl, bc
ld a, [hl]
and $f ; lo nybble
ld l, a ; ok
ld d, 0
ld h, d
add hl, de ; add current pitch
add hl, hl ; skip 2 bytes for each
ld de, FrequencyTable
add hl, de
ld e, [hl]
inc hl
ld d, [hl]
; get our octave
pop af
; shift right by [7 - octave] bits
.loop
; [7 - octave] loops
cp $7
jr nc, .ok
; sra de
sra d
rr e
inc a
jr .loop
.ok
ld a, d
and $7 ; top 3 bits for frequency (11 total)
ld d, a
ret
SetNoteDuration:
; input: a = note duration in 16ths
; store delay units in de
inc a
ld e, a
ld d, 0
ld hl, CHANNEL_NOTE_LENGTH
add hl, bc
ld a, [hl]
; multiply NoteLength by delay units
ld l, 0 ; just multiply
call .Multiply
ld a, l ; low
; store Tempo in de
ld hl, CHANNEL_TEMPO
add hl, bc
ld e, [hl]
inc hl
ld d, [hl]
; add ???? to the next result
ld hl, CHANNEL_FIELD16
add hl, bc
ld l, [hl]
; multiply Tempo by last result (NoteLength * LOW(delay))
call .Multiply
; copy result to de
ld e, l
ld d, h
; store result in ????
ld hl, CHANNEL_FIELD16
add hl, bc
ld [hl], e
; store result in NoteDuration
ld hl, CHANNEL_NOTE_DURATION
add hl, bc
ld [hl], d
ret
.Multiply:
; multiplies a and de
; adds the result to l
; stores the result in hl
ld h, 0
.loop
; halve a
srl a
; is there a remainder?
jr nc, .skip
; add it to the result
add hl, de
.skip
; add de, de
sla e
rl d
; are we done?
and a
jr nz, .loop
ret
SetGlobalTempo:
push bc ; save current channel
; are we dealing with music or sfx?
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 ; restore current channel
ret
Tempo:
; input:
; de: note length
; update Tempo
ld hl, CHANNEL_TEMPO
add hl, bc
ld [hl], e
inc hl
ld [hl], d
; clear ????
xor a
ld hl, CHANNEL_FIELD16
add hl, bc
ld [hl], a
ret
StartChannel:
call SetLRTracks
ld hl, CHANNEL_FLAGS1
add hl, bc
set SOUND_CHANNEL_ON, [hl] ; turn channel on
ret
SetLRTracks:
; set tracks for a the current channel to default
; seems to be redundant since this is overwritten by stereo data later
push de
; store current channel in de
ld a, [wCurChannel]
maskbits NUM_MUSIC_CHANS
ld e, a
ld d, 0
call GetLRTracks
add hl, de ; de = channel 0-3
ld a, [hl]
; load lr tracks into Tracks
ld hl, CHANNEL_TRACKS
add hl, bc
ld [hl], a
pop de
ret
_PlayMusic::
; load music
call MusicOff
ld hl, wMusicID
ld [hl], e ; song number
inc hl
ld [hl], d ; (always 0)
ld hl, Music
add hl, de ; three
add hl, de ; byte
add hl, de ; pointer
ld a, [hli]
ld [wMusicBank], a
ld e, [hl]
inc hl
ld d, [hl] ; music header address
call LoadMusicByte ; store first byte of music header in a
rlca
rlca
maskbits NUM_MUSIC_CHANS
inc a
.loop
; start playing channels
push af
call LoadChannel
call StartChannel
pop af
dec a
jr nz, .loop
xor a
ld [wUnusedMusicF9Flag], a
ld [wChannel1JumpCondition], a
ld [wChannel2JumpCondition], a
ld [wChannel3JumpCondition], a
ld [wChannel4JumpCondition], a
ld [wNoiseSampleAddress], a
ld [wNoiseSampleAddress + 1], a
ld [wNoiseSampleDelay], a
ld [wMusicNoiseSampleSet], a
call MusicOn
ret
_PlayCry::
; Play cry de using parameters:
; wCryPitch
; wCryLength
call MusicOff
; Overload the music id with the cry id
ld hl, wMusicID
ld [hl], e
inc hl
ld [hl], d
; 3-byte pointers (bank, address)
ld hl, Cries
add hl, de
add hl, de
add hl, de
ld a, [hli]
ld [wMusicBank], a
ld e, [hl]
inc hl
ld d, [hl]
; Read the cry's sound header
call LoadMusicByte
; Top 2 bits contain the number of channels
rlca
rlca
maskbits NUM_MUSIC_CHANS
; For each channel:
inc a
.loop
push af
call LoadChannel ; bc = current channel
ld hl, CHANNEL_FLAGS1
add hl, bc
set SOUND_REST, [hl]
ld hl, CHANNEL_FLAGS2
add hl, bc
set SOUND_PITCH_OFFSET, [hl]
ld hl, CHANNEL_PITCH_OFFSET
add hl, bc
ld a, [wCryPitch]
ld [hli], a
ld a, [wCryPitch + 1]
ld [hl], a
; No tempo for channel 4
ld a, [wCurChannel]
maskbits NUM_MUSIC_CHANS
cp CHAN4
jr nc, .start
; Tempo is effectively length
ld hl, CHANNEL_TEMPO
add hl, bc
ld a, [wCryLength]
ld [hli], a
ld a, [wCryLength + 1]
ld [hl], a
.start
call StartChannel
ld a, [wStereoPanningMask]
and a
jr z, .next
; Stereo only: Play cry from the monster's side.
; This only applies in-battle.
ld a, [wOptions]
bit STEREO, a
jr z, .next
; [CHANNEL_TRACKS] &= [wCryTracks]
ld hl, CHANNEL_TRACKS
add hl, bc
ld a, [hl]
ld hl, wCryTracks
and [hl]
ld hl, CHANNEL_TRACKS
add hl, bc
ld [hl], a
.next
pop af
dec a
jr nz, .loop
; Cries play at max volume, so we save the current volume for later.
ld a, [wLastVolume]
and a
jr nz, .end
ld a, [wVolume]
ld [wLastVolume], a
ld a, MAX_VOLUME
ld [wVolume], a
.end
ld a, 1 ; stop playing music
ld [wSFXPriority], a
call MusicOn
ret
_PlaySFX::
; clear channels if they aren't already
call MusicOff
ld hl, wChannel5Flags1
bit SOUND_CHANNEL_ON, [hl] ; ch5 on?
jr z, .ch6
res SOUND_CHANNEL_ON, [hl] ; turn it off
xor a
ldh [rNR11], a ; length/wavepattern = 0
ld a, $8
ldh [rNR12], a ; envelope = 0
xor a
ldh [rNR13], a ; frequency lo = 0
ld a, $80
ldh [rNR14], a ; restart sound (freq hi = 0)
xor a
ld [wPitchSweep], a ; pitch sweep off
ldh [rNR10], a ; pitch sweep off
.ch6
ld hl, wChannel6Flags1
bit SOUND_CHANNEL_ON, [hl]
jr z, .ch7
res SOUND_CHANNEL_ON, [hl] ; turn it off
xor a
ldh [rNR21], a ; length/wavepattern = 0
ld a, $8
ldh [rNR22], a ; envelope = 0
xor a
ldh [rNR23], a ; frequency lo = 0
ld a, $80
ldh [rNR24], a ; restart sound (freq hi = 0)
.ch7
ld hl, wChannel7Flags1
bit SOUND_CHANNEL_ON, [hl]
jr z, .ch8
res SOUND_CHANNEL_ON, [hl] ; turn it off
xor a
ldh [rNR30], a ; sound mode #3 off
ldh [rNR31], a ; length/wavepattern = 0
ld a, $8
ldh [rNR32], a ; envelope = 0
xor a
ldh [rNR33], a ; frequency lo = 0
ld a, $80
ldh [rNR34], a ; restart sound (freq hi = 0)
.ch8
ld hl, wChannel8Flags1
bit SOUND_CHANNEL_ON, [hl]
jr z, .chscleared
res SOUND_CHANNEL_ON, [hl] ; turn it off
xor a
ldh [rNR41], a ; length/wavepattern = 0
ld a, $8
ldh [rNR42], a ; envelope = 0
xor a
ldh [rNR43], a ; frequency lo = 0
ld a, $80
ldh [rNR44], a ; restart sound (freq hi = 0)
xor a
ld [wNoiseSampleAddress], a
ld [wNoiseSampleAddress + 1], a
.chscleared
; start reading sfx header for # chs
ld hl, wMusicID
ld [hl], e
inc hl
ld [hl], d
ld hl, SFX
add hl, de ; three
add hl, de ; byte
add hl, de ; pointers
; get bank
ld a, [hli]
ld [wMusicBank], a
; get address
ld e, [hl]
inc hl
ld d, [hl]
; get # channels
call LoadMusicByte
rlca ; top 2
rlca ; bits
maskbits NUM_MUSIC_CHANS
inc a ; # channels -> # loops
.startchannels
push af
call LoadChannel ; bc = current channel
ld hl, CHANNEL_FLAGS1
add hl, bc
set SOUND_SFX, [hl]
call StartChannel
pop af
dec a
jr nz, .startchannels
call MusicOn
xor a
ld [wSFXPriority], a
ret
PlayStereoSFX::
; play sfx de
call MusicOff
; standard procedure if stereo's off
ld a, [wOptions]
bit STEREO, a
jp z, _PlaySFX
; else, let's go ahead with this
ld hl, wMusicID
ld [hl], e
inc hl
ld [hl], d
; get sfx ptr
ld hl, SFX
add hl, de
add hl, de
add hl, de
; bank
ld a, [hli]
ld [wMusicBank], a
; address
ld e, [hl]
inc hl
ld d, [hl]
; bit 2-3
call LoadMusicByte
rlca
rlca
maskbits NUM_MUSIC_CHANS
inc a
.loop
push af
call LoadChannel
ld hl, CHANNEL_FLAGS1
add hl, bc
set SOUND_SFX, [hl]
push de
; get tracks for this channel
ld a, [wCurChannel]
maskbits NUM_MUSIC_CHANS
ld e, a
ld d, 0
call GetLRTracks
add hl, de
ld a, [hl]
ld hl, wStereoPanningMask
and [hl]
ld hl, CHANNEL_TRACKS
add hl, bc
ld [hl], a
ld hl, CHANNEL_FIELD30
add hl, bc
ld [hl], a
ld a, [wCryTracks]
cp 2 ; ch 1-2
jr c, .skip
; ch3-4
ld a, [wSFXDuration]
ld hl, CHANNEL_FIELD2E
add hl, bc
ld [hl], a
ld hl, CHANNEL_FIELD2F
add hl, bc
ld [hl], a
ld hl, CHANNEL_FLAGS2
add hl, bc
set SOUND_UNKN_0F, [hl]
.skip
pop de
; turn channel on
ld hl, CHANNEL_FLAGS1
add hl, bc
set SOUND_CHANNEL_ON, [hl] ; on
; done?
pop af
dec a
jr nz, .loop
; we're done
call MusicOn
ret
LoadChannel:
; input: de = audio pointer
; sets bc to current channel pointer
call LoadMusicByte
inc de
maskbits NUM_CHANNELS
ld [wCurChannel], a
ld c, a
ld b, 0
ld hl, ChannelPointers
add hl, bc
add hl, bc
ld c, [hl]
inc hl
ld b, [hl] ; bc = channel pointer
ld hl, CHANNEL_FLAGS1
add hl, bc
res SOUND_CHANNEL_ON, [hl] ; channel off
call ChannelInit
; load music pointer
ld hl, CHANNEL_MUSIC_ADDRESS
add hl, bc
call LoadMusicByte
ld [hli], a
inc de
call LoadMusicByte
ld [hl], a
inc de
; load music id
ld hl, CHANNEL_MUSIC_ID
add hl, bc
ld a, [wMusicID]
ld [hli], a
ld a, [wMusicID + 1]
ld [hl], a
; load music bank
ld hl, CHANNEL_MUSIC_BANK
add hl, bc
ld a, [wMusicBank]
ld [hl], a
ret
ChannelInit:
; make sure channel is cleared
; set default tempo and note length in case nothing is loaded
; input:
; bc = channel struct pointer
push de
xor a
; get channel struct location and length
ld hl, CHANNEL_MUSIC_ID ; start
add hl, bc
ld e, CHANNEL_STRUCT_LENGTH ; channel struct length
; clear channel
.loop
ld [hli], a
dec e
jr nz, .loop
; set tempo to default ($100)
ld hl, CHANNEL_TEMPO
add hl, bc
xor a
ld [hli], a
inc a
ld [hl], a
; set note length to default ($1) (fast)
ld hl, CHANNEL_NOTE_LENGTH
add hl, bc
ld [hl], a
pop de
ret
LoadMusicByte::
; input:
; de = current music address
; output:
; a = wCurMusicByte
ld a, [wMusicBank]
call _LoadMusicByte
ld a, [wCurMusicByte]
ret
INCLUDE "audio/notes.asm"
INCLUDE "audio/wave_samples.asm"
INCLUDE "audio/drumkits.asm"
GetLRTracks:
; gets the default sound l/r channels
; stores mono/stereo table in hl
ld a, [wOptions]
bit STEREO, a
; made redundant, could have had a purpose in gold
jr nz, .stereo
ld hl, MonoTracks
ret
.stereo
ld hl, StereoTracks
ret
MonoTracks:
; bit corresponds to track #
; hi: left channel
; lo: right channel
db $11, $22, $44, $88
StereoTracks:
; made redundant
; seems to be modified on a per-song basis
db $11, $22, $44, $88
ChannelPointers:
; music channels
dw wChannel1
dw wChannel2
dw wChannel3
dw wChannel4
; sfx channels
dw wChannel5
dw wChannel6
dw wChannel7
dw wChannel8
ClearChannels::
; runs ClearChannel for all 4 channels
; doesn't seem to be used, but functionally identical to InitSound
ld hl, rNR50
xor a
ld [hli], a
ld [hli], a
ld a, $80
ld [hli], a
ld hl, rNR10
ld e, NUM_MUSIC_CHANS
.loop
call ClearChannel
dec e
jr nz, .loop
ret
ClearChannel:
; input: hl = beginning hw sound register (rNR10, rNR20, rNR30, rNR40)
; output: 00 00 80 00 80
; sound channel 1 2 3 4
xor a
ld [hli], a ; rNR10, rNR20, rNR30, rNR40 ; sweep = 0
ld [hli], a ; rNR11, rNR21, rNR31, rNR41 ; length/wavepattern = 0
ld a, $8
ld [hli], a ; rNR12, rNR22, rNR32, rNR42 ; envelope = 0
xor a
ld [hli], a ; rNR13, rNR23, rNR33, rNR43 ; frequency lo = 0
ld a, $80
ld [hli], a ; rNR14, rNR24, rNR34, rNR44 ; restart sound (freq hi = 0)
ret
PlayTrainerEncounterMusic::
; input: e = trainer type
; turn fade off
xor a
ld [wMusicFade], a
; play nothing for one frame
push de
ld de, MUSIC_NONE
call PlayMusic
call DelayFrame
; play new song
call MaxVolume
pop de
ld d, $00
ld hl, TrainerEncounterMusic
add hl, de
ld e, [hl]
call PlayMusic
ret
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