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pokered/audio/engine_1.asm
Preeyan Parmar d38cf5281a
Add comment about audio engine perfect pitch bug (#451) 
Co-authored-by: preeyan <preeyan>
2024-05-23 11:43:54 -05:00

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; The first of three duplicated sound engines.
Audio1_UpdateMusic::
ld c, CHAN1
.loop
ld b, 0
ld hl, wChannelSoundIDs
add hl, bc
ld a, [hl]
and a
jr z, .nextChannel
ld a, c
cp CHAN5
jr nc, .applyAffects ; if sfx channel
ld a, [wMuteAudioAndPauseMusic]
and a
jr z, .applyAffects
bit 7, a
jr nz, .nextChannel
set 7, a
ld [wMuteAudioAndPauseMusic], a
xor a ; disable all channels' output
ldh [rNR51], a
ldh [rNR30], a
ld a, $80
ldh [rNR30], a
jr .nextChannel
.applyAffects
call Audio1_ApplyMusicAffects
.nextChannel
ld a, c
inc c ; inc channel number
cp CHAN8
jr nz, .loop
ret
; this routine checks flags for music effects currently applied
; to the channel and calls certain functions based on flags.
Audio1_ApplyMusicAffects:
ld b, $0
ld hl, wChannelNoteDelayCounters ; delay until next note
add hl, bc
ld a, [hl]
cp 1 ; if the delay is 1, play next note
jp z, Audio1_PlayNextNote
dec a ; otherwise, decrease the delay timer
ld [hl], a
ld a, c
cp CHAN5
jr nc, .startChecks ; if a sfx channel
ld hl, wChannelSoundIDs + CHAN5
add hl, bc
ld a, [hl]
and a
jr z, .startChecks
ret
.startChecks
ld hl, wChannelFlags1
add hl, bc
bit BIT_ROTATE_DUTY_CYCLE, [hl]
jr z, .checkForExecuteMusic
call Audio1_ApplyDutyCyclePattern
.checkForExecuteMusic
ld b, 0
ld hl, wChannelFlags2
add hl, bc
bit BIT_EXECUTE_MUSIC, [hl]
jr nz, .checkForPitchSlide
ld hl, wChannelFlags1
add hl, bc
bit BIT_NOISE_OR_SFX, [hl]
jr nz, .skipPitchSlideVibrato
.checkForPitchSlide
ld hl, wChannelFlags1
add hl, bc
bit BIT_PITCH_SLIDE_ON, [hl]
jr z, .checkVibratoDelay
jp Audio1_ApplyPitchSlide
.checkVibratoDelay
ld hl, wChannelVibratoDelayCounters
add hl, bc
ld a, [hl]
and a ; check if delay is over
jr z, .checkForVibrato
dec [hl] ; otherwise, dec delay
.skipPitchSlideVibrato
ret
.checkForVibrato
ld hl, wChannelVibratoExtents
add hl, bc
ld a, [hl]
and a
jr nz, .vibrato
ret ; no vibrato
.vibrato
ld d, a
ld hl, wChannelVibratoRates
add hl, bc
ld a, [hl]
and $f
and a
jr z, .applyVibrato
dec [hl] ; decrement counter
ret
.applyVibrato
ld a, [hl]
swap [hl]
or [hl]
ld [hl], a ; reload the counter
ld hl, wChannelFrequencyLowBytes
add hl, bc
ld e, [hl] ; get note pitch
ld hl, wChannelFlags1
add hl, bc
; This is the only code that sets/resets the vibrato direction bit, so it
; continuously alternates which path it takes.
bit BIT_VIBRATO_DIRECTION, [hl]
jr z, .unset
res BIT_VIBRATO_DIRECTION, [hl]
ld a, d
and $f
ld d, a
ld a, e
sub d
jr nc, .noCarry
ld a, 0
.noCarry
jr .done
.unset
set BIT_VIBRATO_DIRECTION, [hl]
ld a, d
and $f0
swap a
add e
jr nc, .done
ld a, $ff
.done
ld d, a
ld b, REG_FREQUENCY_LO
call Audio1_GetRegisterPointer
ld [hl], d
ret
; this routine executes all music commands that take up no time,
; like tempo changes, duty cycle changes etc. and doesn't return
; until the first note is reached
Audio1_PlayNextNote:
; reload the vibrato delay counter
ld hl, wChannelVibratoDelayCounterReloadValues
add hl, bc
ld a, [hl]
ld hl, wChannelVibratoDelayCounters
add hl, bc
ld [hl], a
ld hl, wChannelFlags1
add hl, bc
res BIT_PITCH_SLIDE_ON, [hl]
res BIT_PITCH_SLIDE_DECREASING, [hl]
call Audio1_sound_ret
ret
Audio1_sound_ret:
call Audio1_GetNextMusicByte
ld d, a
cp sound_ret_cmd
jp nz, Audio1_sound_call
ld b, 0
ld hl, wChannelFlags1
add hl, bc
bit BIT_SOUND_CALL, [hl]
jr nz, .returnFromCall
ld a, c
cp CHAN4
jr nc, .noiseOrSfxChannel
jr .disableChannelOutput
.noiseOrSfxChannel
res BIT_NOISE_OR_SFX, [hl]
ld hl, wChannelFlags2
add hl, bc
res BIT_EXECUTE_MUSIC, [hl]
cp CHAN7
jr nz, .skipSfxChannel3
; restart hardware channel 3 (wave channel) output
ld a, $0
ldh [rNR30], a
ld a, $80
ldh [rNR30], a
.skipSfxChannel3
jr nz, .dontDisable
ld a, [wDisableChannelOutputWhenSfxEnds]
and a
jr z, .dontDisable
xor a
ld [wDisableChannelOutputWhenSfxEnds], a
jr .disableChannelOutput
.dontDisable
jr .afterDisable
.returnFromCall
res 1, [hl]
ld d, $0
ld a, c
add a
ld e, a
ld hl, wChannelCommandPointers
add hl, de
push hl ; store current channel address
ld hl, wChannelReturnAddresses
add hl, de
ld e, l
ld d, h
pop hl
ld a, [de]
ld [hli], a
inc de
ld a, [de]
ld [hl], a ; loads channel address to return to
jp Audio1_sound_ret
.disableChannelOutput
ld hl, Audio1_HWChannelDisableMasks
add hl, bc
ldh a, [rNR51]
and [hl]
ldh [rNR51], a
.afterDisable
ld a, [wChannelSoundIDs + CHAN5]
cp CRY_SFX_START
jr nc, .maybeCry
jr .skipCry
.maybeCry
ld a, [wChannelSoundIDs + CHAN5]
cp CRY_SFX_END
jr z, .skipCry
jr c, .cry
jr .skipCry
.cry
ld a, c
cp CHAN5
jr z, .skipRewind
call Audio1_GoBackOneCommandIfCry
ret c
.skipRewind
ld a, [wSavedVolume]
ldh [rNR50], a
xor a
ld [wSavedVolume], a
.skipCry
ld hl, wChannelSoundIDs
add hl, bc
ld [hl], b
ret
Audio1_sound_call:
cp sound_call_cmd
jp nz, Audio1_sound_loop
call Audio1_GetNextMusicByte
push af
call Audio1_GetNextMusicByte
ld d, a
pop af
ld e, a
push de ; store pointer
ld d, $0
ld a, c
add a
ld e, a
ld hl, wChannelCommandPointers
add hl, de
push hl
ld hl, wChannelReturnAddresses
add hl, de
ld e, l
ld d, h
pop hl
ld a, [hli]
ld [de], a
inc de
ld a, [hld]
ld [de], a ; copy current channel address
pop de
ld [hl], e
inc hl
ld [hl], d ; overwrite current address with pointer
ld b, $0
ld hl, wChannelFlags1
add hl, bc
set BIT_SOUND_CALL, [hl] ; set the call flag
jp Audio1_sound_ret
Audio1_sound_loop:
cp sound_loop_cmd
jp nz, Audio1_note_type
call Audio1_GetNextMusicByte
ld e, a
and a
jr z, .infiniteLoop
ld b, 0
ld hl, wChannelLoopCounters
add hl, bc
ld a, [hl]
cp e
jr nz, .loopAgain
ld a, $1 ; if no more loops to make,
ld [hl], a
call Audio1_GetNextMusicByte ; skip pointer
call Audio1_GetNextMusicByte
jp Audio1_sound_ret
.loopAgain ; inc loop count
inc a
ld [hl], a
; fall through
.infiniteLoop ; overwrite current address with pointer
call Audio1_GetNextMusicByte
push af
call Audio1_GetNextMusicByte
ld b, a
ld d, $0
ld a, c
add a
ld e, a
ld hl, wChannelCommandPointers
add hl, de
pop af
ld [hli], a
ld [hl], b
jp Audio1_sound_ret
Audio1_note_type:
and $f0
cp note_type_cmd
jp nz, Audio1_toggle_perfect_pitch
ld a, d
and $f
ld b, $0
ld hl, wChannelNoteSpeeds
add hl, bc
ld [hl], a ; store low nibble as speed
ld a, c
cp CHAN4
jr z, .noiseChannel ; noise channel has 0 params
call Audio1_GetNextMusicByte
ld d, a
ld a, c
cp CHAN3
jr z, .musicChannel3
cp CHAN7
jr nz, .skipChannel3
ld hl, wSfxWaveInstrument
jr .channel3
.musicChannel3
ld hl, wMusicWaveInstrument
.channel3
ld a, d
and $f
ld [hl], a ; store low nibble of param as wave instrument
ld a, d
and $30
sla a
ld d, a
; fall through
; if channel 3, store high nibble as volume
; else, store volume (high nibble) and fade (low nibble)
.skipChannel3
ld b, 0
ld hl, wChannelVolumes
add hl, bc
ld [hl], d
.noiseChannel
jp Audio1_sound_ret
Audio1_toggle_perfect_pitch:
ld a, d
cp toggle_perfect_pitch_cmd
jr nz, Audio1_vibrato
ld b, 0
ld hl, wChannelFlags1
add hl, bc
ld a, [hl]
xor $1
ld [hl], a ; flip bit 0 of wChannelFlags1
jp Audio1_sound_ret
Audio1_vibrato:
cp vibrato_cmd
jr nz, Audio1_pitch_slide
call Audio1_GetNextMusicByte
ld b, 0
ld hl, wChannelVibratoDelayCounters
add hl, bc
ld [hl], a ; store delay
ld hl, wChannelVibratoDelayCounterReloadValues
add hl, bc
ld [hl], a ; store delay
call Audio1_GetNextMusicByte
ld d, a
; The high nybble of the command byte is the extent of the vibrato.
; Let n be the extent.
; The upper nybble of the channel's byte in the wChannelVibratoExtents
; array will store the extent above the note: (n / 2) + (n % 2).
; The lower nybble will store the extent below the note: (n / 2).
; These two values add to the total extent, n.
and $f0
swap a
ld b, 0
ld hl, wChannelVibratoExtents
add hl, bc
srl a
ld e, a
adc b
swap a
or e
ld [hl], a
; The low nybble of the command byte is the rate of the vibrato.
; The high and low nybbles of the channel's byte in the wChannelVibratoRates
; array are both initialised to this value because the high nybble is the
; counter reload value and the low nybble is the counter itself, which should
; start at its value upon reload.
ld a, d
and $f
ld d, a
ld hl, wChannelVibratoRates
add hl, bc
swap a
or d
ld [hl], a
jp Audio1_sound_ret
Audio1_pitch_slide:
cp pitch_slide_cmd
jr nz, Audio1_duty_cycle
call Audio1_GetNextMusicByte
ld b, 0
ld hl, wChannelPitchSlideLengthModifiers
add hl, bc
ld [hl], a
call Audio1_GetNextMusicByte
ld d, a
and $f0
swap a
ld b, a
ld a, d
and $f
call Audio1_CalculateFrequency
ld b, 0
ld hl, wChannelPitchSlideTargetFrequencyHighBytes
add hl, bc
ld [hl], d
ld hl, wChannelPitchSlideTargetFrequencyLowBytes
add hl, bc
ld [hl], e
ld b, 0
ld hl, wChannelFlags1
add hl, bc
set BIT_PITCH_SLIDE_ON, [hl]
call Audio1_GetNextMusicByte
ld d, a
jp Audio1_note_length
Audio1_duty_cycle:
cp duty_cycle_cmd
jr nz, Audio1_tempo
call Audio1_GetNextMusicByte
rrca
rrca
and $c0
ld b, 0
ld hl, wChannelDutyCycles
add hl, bc
ld [hl], a ; store duty cycle
jp Audio1_sound_ret
Audio1_tempo:
cp tempo_cmd
jr nz, Audio1_stereo_panning
ld a, c
cp CHAN5
jr nc, .sfxChannel
call Audio1_GetNextMusicByte
ld [wMusicTempo], a ; store first param
call Audio1_GetNextMusicByte
ld [wMusicTempo + 1], a ; store second param
xor a
ld [wChannelNoteDelayCountersFractionalPart], a ; clear RAM
ld [wChannelNoteDelayCountersFractionalPart + 1], a
ld [wChannelNoteDelayCountersFractionalPart + 2], a
ld [wChannelNoteDelayCountersFractionalPart + 3], a
jr .musicChannelDone
.sfxChannel
call Audio1_GetNextMusicByte
ld [wSfxTempo], a ; store first param
call Audio1_GetNextMusicByte
ld [wSfxTempo + 1], a ; store second param
xor a
ld [wChannelNoteDelayCountersFractionalPart + 4], a ; clear RAM
ld [wChannelNoteDelayCountersFractionalPart + 5], a
ld [wChannelNoteDelayCountersFractionalPart + 6], a
ld [wChannelNoteDelayCountersFractionalPart + 7], a
.musicChannelDone
jp Audio1_sound_ret
Audio1_stereo_panning:
cp stereo_panning_cmd
jr nz, Audio1_unknownmusic0xef
call Audio1_GetNextMusicByte
ld [wStereoPanning], a ; store panning
jp Audio1_sound_ret
; this appears to never be used
Audio1_unknownmusic0xef:
cp unknownmusic0xef_cmd
jr nz, Audio1_duty_cycle_pattern
call Audio1_GetNextMusicByte
push bc
call Audio1_PlaySound
pop bc
ld a, [wDisableChannelOutputWhenSfxEnds]
and a
jr nz, .skip
ld a, [wChannelSoundIDs + CHAN8]
ld [wDisableChannelOutputWhenSfxEnds], a
xor a
ld [wChannelSoundIDs + CHAN8], a
.skip
jp Audio1_sound_ret
Audio1_duty_cycle_pattern:
cp duty_cycle_pattern_cmd
jr nz, Audio1_volume
call Audio1_GetNextMusicByte
ld b, 0
ld hl, wChannelDutyCyclePatterns
add hl, bc
ld [hl], a ; store full pattern
and %11000000
ld hl, wChannelDutyCycles
add hl, bc
ld [hl], a ; store first duty cycle
ld hl, wChannelFlags1
add hl, bc
set BIT_ROTATE_DUTY_CYCLE, [hl]
jp Audio1_sound_ret
Audio1_volume:
cp volume_cmd
jr nz, Audio1_execute_music
call Audio1_GetNextMusicByte
ldh [rNR50], a ; store volume
jp Audio1_sound_ret
Audio1_execute_music:
cp execute_music_cmd
jr nz, Audio1_octave
ld b, $0
ld hl, wChannelFlags2
add hl, bc
set BIT_EXECUTE_MUSIC, [hl]
jp Audio1_sound_ret
Audio1_octave:
and $f0
cp octave_cmd
jr nz, Audio1_sfx_note
ld hl, wChannelOctaves
ld b, 0
add hl, bc
ld a, d
and $f
ld [hl], a ; store low nibble as octave
jp Audio1_sound_ret
; sfx_note is either square_note or noise_note depending on the channel
Audio1_sfx_note:
cp sfx_note_cmd
jr nz, Audio1_pitch_sweep
ld a, c
cp CHAN4 ; is this a noise or sfx channel?
jr c, Audio1_pitch_sweep ; no
ld b, 0
ld hl, wChannelFlags2
add hl, bc
bit BIT_EXECUTE_MUSIC, [hl] ; is execute_music being used?
jr nz, Audio1_pitch_sweep ; yes
call Audio1_note_length
; This code seems to do the same thing as what Audio1_ApplyDutyCycleAndSoundLength
; does below.
ld d, a
ld b, 0
ld hl, wChannelDutyCycles
add hl, bc
ld a, [hl]
or d
ld d, a
ld b, REG_DUTY_SOUND_LEN
call Audio1_GetRegisterPointer
ld [hl], d
call Audio1_GetNextMusicByte
ld d, a
ld b, REG_VOLUME_ENVELOPE
call Audio1_GetRegisterPointer
ld [hl], d
call Audio1_GetNextMusicByte
ld e, a
ld a, c
cp CHAN8
ld a, 0
jr z, .skip
; Channels 1 through 3 have 2 registers that control frequency, but the noise
; channel a single register (the polynomial counter) that controls frequency,
; so this command has one less byte on the noise channel.
push de
call Audio1_GetNextMusicByte
pop de
.skip
ld d, a
push de
call Audio1_ApplyDutyCycleAndSoundLength
call Audio1_EnableChannelOutput
pop de
call Audio1_ApplyWavePatternAndFrequency
ret
Audio1_pitch_sweep:
ld a, c
cp CHAN5
jr c, Audio1_note ; if not a sfx
ld a, d
cp pitch_sweep_cmd
jr nz, Audio1_note
ld b, $0
ld hl, wChannelFlags2
add hl, bc
bit BIT_EXECUTE_MUSIC, [hl]
jr nz, Audio1_note ; no
call Audio1_GetNextMusicByte
ldh [rNR10], a
jp Audio1_sound_ret
Audio1_note:
ld a, c
cp CHAN4
jr nz, Audio1_note_length ; if not noise channel
ld a, d
and $f0
cp drum_note_cmd
jr z, .drum_note
jr nc, Audio1_note_length
; this executes when on the noise channel and
; the command id is less than drum_note_cmd ($b0)
; in this case, the upper nybble is used as the noise instrument ($1-$a)
; and the lower nybble is the length minus 1 (0-15)
; however, this doesn't work for instrument #2 because the command id
; is captured by the noise_note command (command id $2x)
; this essentially acts like a drum_note command that is only 1 byte
; instead of 2 and can only be used with instruments 1 and 3 through 10
; this is unused by the game
swap a
ld b, a
ld a, d
and $f
ld d, a
ld a, b
push de
push bc
jr .playDnote
.drum_note
ld a, d
and $f
push af
push bc
call Audio1_GetNextMusicByte ; get drum_note instrument
.playDnote
ld d, a
ld a, [wDisableChannelOutputWhenSfxEnds]
and a
jr nz, .skipDnote
ld a, d
call Audio1_PlaySound
.skipDnote
pop bc
pop de
Audio1_note_length:
ld a, d
push af
and $f
inc a
ld b, 0
ld e, a ; store note length (in 16ths)
ld d, b
ld hl, wChannelNoteSpeeds
add hl, bc
ld a, [hl]
ld l, b
call Audio1_MultiplyAdd
ld a, c
cp CHAN5
jr nc, .sfxChannel
ld a, [wMusicTempo]
ld d, a
ld a, [wMusicTempo + 1]
ld e, a
jr .skip
.sfxChannel
ld d, $1
ld e, $0
cp CHAN8
jr z, .skip ; if noise channel
call Audio1_SetSfxTempo
ld a, [wSfxTempo]
ld d, a
ld a, [wSfxTempo + 1]
ld e, a
.skip
ld a, l ; a = note_length * note_speed
ld b, 0
ld hl, wChannelNoteDelayCountersFractionalPart
add hl, bc
ld l, [hl]
call Audio1_MultiplyAdd
ld e, l
ld d, h ; de = note_delay_frac_part + (note_length * note_speed * tempo)
ld hl, wChannelNoteDelayCountersFractionalPart
add hl, bc
ld [hl], e
ld a, d
ld hl, wChannelNoteDelayCounters
add hl, bc
ld [hl], a
ld hl, wChannelFlags2
add hl, bc
bit BIT_EXECUTE_MUSIC, [hl]
jr nz, Audio1_note_pitch
ld hl, wChannelFlags1
add hl, bc
bit BIT_NOISE_OR_SFX, [hl]
jr z, Audio1_note_pitch
pop hl
ret
Audio1_note_pitch:
pop af
and $f0
cp rest_cmd
jr nz, .notRest
ld a, c
cp CHAN5
jr nc, .next
; If this isn't an SFX channel, try the corresponding SFX channel.
ld hl, wChannelSoundIDs + CHAN5
add hl, bc
ld a, [hl]
and a
jr nz, .done
; fall through
.next
ld a, c
cp CHAN3
jr z, .channel3
cp CHAN7
jr nz, .notChannel3
.channel3
ld b, 0
ld hl, Audio1_HWChannelDisableMasks
add hl, bc
ldh a, [rNR51]
and [hl]
ldh [rNR51], a ; disable hardware channel 3's output
jr .done
.notChannel3
ld b, REG_VOLUME_ENVELOPE
call Audio1_GetRegisterPointer
ld a, $8 ; fade in sound
ld [hli], a
inc hl
ld a, $80 ; restart sound
ld [hl], a
.done
ret
.notRest
swap a
ld b, 0
ld hl, wChannelOctaves
add hl, bc
ld b, [hl]
call Audio1_CalculateFrequency
ld b, 0
ld hl, wChannelFlags1
add hl, bc
bit BIT_PITCH_SLIDE_ON, [hl]
jr z, .skipPitchSlide
call Audio1_InitPitchSlideVars
.skipPitchSlide
push de
ld a, c
cp CHAN5
jr nc, .sfxChannel ; if sfx channel
; If this isn't an SFX channel, try the corresponding SFX channel.
ld hl, wChannelSoundIDs + CHAN5
ld d, 0
ld e, a
add hl, de
ld a, [hl]
and a
jr nz, .noSfx
jr .sfxChannel
.noSfx
pop de
ret
.sfxChannel
ld b, 0
ld hl, wChannelVolumes
add hl, bc
ld d, [hl]
ld b, REG_VOLUME_ENVELOPE
call Audio1_GetRegisterPointer
ld [hl], d
call Audio1_ApplyDutyCycleAndSoundLength
call Audio1_EnableChannelOutput
pop de
ld b, $0
ld hl, wChannelFlags1
add hl, bc
bit BIT_PERFECT_PITCH, [hl] ; has toggle_perfect_pitch been used?
jr z, .skipFrequencyInc
inc e ; if yes, increment the frequency by 1
jr nc, .skipFrequencyInc ; Likely a mistake, because `inc` does not set flag C.
; Fortunately this does not seem to affect any notes that actually occur.
inc d
.skipFrequencyInc
ld hl, wChannelFrequencyLowBytes
add hl, bc
ld [hl], e
call Audio1_ApplyWavePatternAndFrequency
ret
Audio1_EnableChannelOutput:
ld b, 0
ld hl, Audio1_HWChannelEnableMasks
add hl, bc
ldh a, [rNR51]
or [hl] ; set this channel's bits
ld d, a
ld a, c
cp CHAN8
jr z, .noiseChannelOrNoSfx
cp CHAN5
jr nc, .skip ; if sfx channel
; If this isn't an SFX channel, try the corresponding SFX channel.
ld hl, wChannelSoundIDs + CHAN5
add hl, bc
ld a, [hl]
and a
jr nz, .skip
.noiseChannelOrNoSfx
; If this is the SFX noise channel or a music channel whose corresponding
; SFX channel is off, apply stereo panning.
ld a, [wStereoPanning]
ld hl, Audio1_HWChannelEnableMasks
add hl, bc
and [hl]
ld d, a
ldh a, [rNR51]
ld hl, Audio1_HWChannelDisableMasks
add hl, bc
and [hl] ; reset this channel's output bits
or d ; set this channel's output bits that enabled in [wStereoPanning]
ld d, a
.skip
ld a, d
ldh [rNR51], a
ret
Audio1_ApplyDutyCycleAndSoundLength:
ld b, 0
ld hl, wChannelNoteDelayCounters ; use the note delay as sound length
add hl, bc
ld d, [hl]
ld a, c
cp CHAN3
jr z, .skipDuty ; if music channel 3
cp CHAN7
jr z, .skipDuty ; if sfx channel 3
; include duty cycle (except on channel 3 which doesn't have it)
ld a, d
and $3f
ld d, a
ld hl, wChannelDutyCycles
add hl, bc
ld a, [hl]
or d
ld d, a
.skipDuty
ld b, REG_DUTY_SOUND_LEN
call Audio1_GetRegisterPointer
ld [hl], d
ret
Audio1_ApplyWavePatternAndFrequency:
ld a, c
cp CHAN3
jr z, .channel3
cp CHAN7
jr nz, .notChannel3
; fall through
.channel3
push de
ld de, wMusicWaveInstrument
cp CHAN3
jr z, .next
ld de, wSfxWaveInstrument
.next
ld a, [de]
add a
ld d, 0
ld e, a
ld hl, Audio1_WavePointers
add hl, de
ld e, [hl]
inc hl
ld d, [hl]
ld hl, rWave_0
ld b, $f
ld a, $0 ; stop hardware channel 3
ldh [rNR30], a
.loop
ld a, [de]
inc de
ld [hli], a
ld a, b
dec b
and a
jr nz, .loop
ld a, $80 ; start hardware channel 3
ldh [rNR30], a
pop de
.notChannel3
ld a, d
or $80 ; use counter mode (i.e. disable output when the counter reaches 0)
and $c7 ; zero the unused bits in the register
ld d, a
ld b, REG_FREQUENCY_LO
call Audio1_GetRegisterPointer
ld [hl], e ; store frequency low byte
inc hl
ld [hl], d ; store frequency high byte
call Audio1_ApplyFrequencyModifier
ret
Audio1_SetSfxTempo:
call Audio1_IsCry
jr nc, .notCry
ld d, 0
ld a, [wTempoModifier]
add $80
jr nc, .next
inc d
.next
ld [wSfxTempo + 1], a
ld a, d
ld [wSfxTempo], a
jr .done
.notCry
xor a
ld [wSfxTempo + 1], a
ld a, $1
ld [wSfxTempo], a
.done
ret
Audio1_ApplyFrequencyModifier:
call Audio1_IsCry
jr nc, .done
; if playing a cry, add the cry's frequency modifier
ld a, [wFrequencyModifier]
add e
jr nc, .noCarry
inc d
.noCarry
dec hl
ld e, a
ld [hl], e
inc hl
ld [hl], d
.done
ret
Audio1_GoBackOneCommandIfCry:
call Audio1_IsCry
jr nc, .done
ld hl, wChannelCommandPointers
ld e, c
ld d, 0
sla e
rl d
add hl, de
ld a, [hl]
sub 1
ld [hl], a
inc hl
ld a, [hl]
sbc 0
ld [hl], a
scf
ret
.done
scf
ccf
ret
Audio1_IsCry:
; Returns whether the currently playing audio is a cry in carry.
ld a, [wChannelSoundIDs + CHAN5]
cp CRY_SFX_START
jr nc, .next
jr .no
.next
cp CRY_SFX_END
jr z, .no
jr c, .yes
.no
scf
ccf
ret
.yes
scf
ret
Audio1_ApplyPitchSlide:
ld hl, wChannelFlags1
add hl, bc
bit BIT_PITCH_SLIDE_DECREASING, [hl]
jp nz, .frequencyDecreasing
; frequency increasing
ld hl, wChannelPitchSlideCurrentFrequencyLowBytes
add hl, bc
ld e, [hl]
ld hl, wChannelPitchSlideCurrentFrequencyHighBytes
add hl, bc
ld d, [hl]
ld hl, wChannelPitchSlideFrequencySteps
add hl, bc
ld l, [hl]
ld h, b
add hl, de
ld d, h
ld e, l
ld hl, wChannelPitchSlideCurrentFrequencyFractionalPart
add hl, bc
push hl
ld hl, wChannelPitchSlideFrequencyStepsFractionalPart
add hl, bc
ld a, [hl]
pop hl
add [hl]
ld [hl], a
ld a, 0
adc e
ld e, a
ld a, 0
adc d
ld d, a
ld hl, wChannelPitchSlideTargetFrequencyHighBytes
add hl, bc
ld a, [hl]
cp d
jp c, .reachedTargetFrequency
jr nz, .applyUpdatedFrequency
ld hl, wChannelPitchSlideTargetFrequencyLowBytes
add hl, bc
ld a, [hl]
cp e
jp c, .reachedTargetFrequency
jr .applyUpdatedFrequency
.frequencyDecreasing
ld hl, wChannelPitchSlideCurrentFrequencyLowBytes
add hl, bc
ld a, [hl]
ld hl, wChannelPitchSlideCurrentFrequencyHighBytes
add hl, bc
ld d, [hl]
ld hl, wChannelPitchSlideFrequencySteps
add hl, bc
ld e, [hl]
sub e
ld e, a
ld a, d
sbc b
ld d, a
ld hl, wChannelPitchSlideFrequencyStepsFractionalPart
add hl, bc
ld a, [hl]
add a
ld [hl], a
ld a, e
sbc b
ld e, a
ld a, d
sbc b
ld d, a
ld hl, wChannelPitchSlideTargetFrequencyHighBytes
add hl, bc
ld a, d
cp [hl]
jr c, .reachedTargetFrequency
jr nz, .applyUpdatedFrequency
ld hl, wChannelPitchSlideTargetFrequencyLowBytes
add hl, bc
ld a, e
cp [hl]
jr c, .reachedTargetFrequency
.applyUpdatedFrequency
ld hl, wChannelPitchSlideCurrentFrequencyLowBytes
add hl, bc
ld [hl], e
ld hl, wChannelPitchSlideCurrentFrequencyHighBytes
add hl, bc
ld [hl], d
ld b, REG_FREQUENCY_LO
call Audio1_GetRegisterPointer
ld a, e
ld [hli], a
ld [hl], d
ret
.reachedTargetFrequency
; Turn off pitch slide when the target frequency has been reached.
ld hl, wChannelFlags1
add hl, bc
res BIT_PITCH_SLIDE_ON, [hl]
res BIT_PITCH_SLIDE_DECREASING, [hl]
ret
Audio1_InitPitchSlideVars:
ld hl, wChannelPitchSlideCurrentFrequencyHighBytes
add hl, bc
ld [hl], d
ld hl, wChannelPitchSlideCurrentFrequencyLowBytes
add hl, bc
ld [hl], e
ld hl, wChannelNoteDelayCounters
add hl, bc
ld a, [hl]
ld hl, wChannelPitchSlideLengthModifiers
add hl, bc
sub [hl]
jr nc, .next
ld a, 1
.next
ld [hl], a
ld hl, wChannelPitchSlideTargetFrequencyLowBytes
add hl, bc
ld a, e
sub [hl]
ld e, a
ld a, d
sbc b
ld hl, wChannelPitchSlideTargetFrequencyHighBytes
add hl, bc
sub [hl]
jr c, .targetFrequencyGreater
ld d, a
ld b, 0
ld hl, wChannelFlags1
add hl, bc
set BIT_PITCH_SLIDE_DECREASING, [hl]
jr .next2
.targetFrequencyGreater
; If the target frequency is greater, subtract the current frequency from
; the target frequency to get the absolute difference.
ld hl, wChannelPitchSlideCurrentFrequencyHighBytes
add hl, bc
ld d, [hl]
ld hl, wChannelPitchSlideCurrentFrequencyLowBytes
add hl, bc
ld e, [hl]
ld hl, wChannelPitchSlideTargetFrequencyLowBytes
add hl, bc
ld a, [hl]
sub e
ld e, a
; Bug. Instead of borrowing from the high byte of the target frequency as it
; should, it borrows from the high byte of the current frequency instead.
; This means that the result will be 0x200 greater than it should be if the
; low byte of the current frequency is greater than the low byte of the
; target frequency.
ld a, d
sbc b
ld d, a
ld hl, wChannelPitchSlideTargetFrequencyHighBytes
add hl, bc
ld a, [hl]
sub d
ld d, a
ld b, 0
ld hl, wChannelFlags1
add hl, bc
res BIT_PITCH_SLIDE_DECREASING, [hl]
.next2
ld hl, wChannelPitchSlideLengthModifiers
add hl, bc
.divideLoop
inc b
ld a, e
sub [hl]
ld e, a
jr nc, .divideLoop
ld a, d
and a
jr z, .doneDividing
dec a
ld d, a
jr .divideLoop
.doneDividing
ld a, e ; a = remainder - dividend
add [hl]
ld d, b ; d = quotient + 1
ld b, 0
ld hl, wChannelPitchSlideFrequencySteps
add hl, bc
ld [hl], d ; store quotient + 1
ld hl, wChannelPitchSlideFrequencyStepsFractionalPart
add hl, bc
ld [hl], a ; store remainder - dividend
ld hl, wChannelPitchSlideCurrentFrequencyFractionalPart
add hl, bc
ld [hl], a ; store remainder - dividend
ret
Audio1_ApplyDutyCyclePattern:
ld b, 0
ld hl, wChannelDutyCyclePatterns
add hl, bc
ld a, [hl]
rlca
rlca
ld [hl], a
and $c0
ld d, a
ld b, REG_DUTY_SOUND_LEN
call Audio1_GetRegisterPointer
ld a, [hl]
and $3f
or d
ld [hl], a
ret
Audio1_GetNextMusicByte:
ld d, 0
ld a, c
add a
ld e, a
ld hl, wChannelCommandPointers
add hl, de
ld a, [hli]
ld e, a
ld a, [hld]
ld d, a
ld a, [de] ; get next music command
inc de
ld [hl], e ; store address of next command
inc hl
ld [hl], d
ret
Audio1_GetRegisterPointer:
; hl = address of hardware sound register b for software channel c
ld a, c
ld hl, Audio1_HWChannelBaseAddresses
add l
jr nc, .noCarry
inc h
.noCarry
ld l, a
ld a, [hl]
add b
ld l, a
ld h, $ff
ret
Audio1_MultiplyAdd:
; hl = l + (a * de)
ld h, 0
.loop
srl a
jr nc, .skipAdd
add hl, de
.skipAdd
sla e
rl d
and a
jr z, .done
jr .loop
.done
ret
Audio1_CalculateFrequency:
; return the frequency for note a, octave b in de
ld h, 0
ld l, a
add hl, hl
ld d, h
ld e, l
ld hl, Audio1_Pitches
add hl, de
ld e, [hl]
inc hl
ld d, [hl]
ld a, b
.loop
cp 7
jr z, .done
sra d
rr e
inc a
jr .loop
.done
ld a, 8
add d
ld d, a
ret
Audio1_PlaySound::
ld [wSoundID], a
cp SFX_STOP_ALL_MUSIC
jp z, .stopAllAudio
cp MAX_SFX_ID_1
jp z, .playSfx
jp c, .playSfx
cp $fe
jr z, .playMusic
jp nc, .playSfx
.playMusic
xor a
ld [wUnusedC000], a
ld [wDisableChannelOutputWhenSfxEnds], a
ld [wMusicTempo + 1], a
ld [wMusicWaveInstrument], a
ld [wSfxWaveInstrument], a
ld d, NUM_CHANNELS
ld hl, wChannelReturnAddresses
call .FillMem
ld hl, wChannelCommandPointers
call .FillMem
ld d, NUM_MUSIC_CHANS
ld hl, wChannelSoundIDs
call .FillMem
ld hl, wChannelFlags1
call .FillMem
ld hl, wChannelDutyCycles
call .FillMem
ld hl, wChannelDutyCyclePatterns
call .FillMem
ld hl, wChannelVibratoDelayCounters
call .FillMem
ld hl, wChannelVibratoExtents
call .FillMem
ld hl, wChannelVibratoRates
call .FillMem
ld hl, wChannelFrequencyLowBytes
call .FillMem
ld hl, wChannelVibratoDelayCounterReloadValues
call .FillMem
ld hl, wChannelFlags2
call .FillMem
ld hl, wChannelPitchSlideLengthModifiers
call .FillMem
ld hl, wChannelPitchSlideFrequencySteps
call .FillMem
ld hl, wChannelPitchSlideFrequencyStepsFractionalPart
call .FillMem
ld hl, wChannelPitchSlideCurrentFrequencyFractionalPart
call .FillMem
ld hl, wChannelPitchSlideCurrentFrequencyHighBytes
call .FillMem
ld hl, wChannelPitchSlideCurrentFrequencyLowBytes
call .FillMem
ld hl, wChannelPitchSlideTargetFrequencyHighBytes
call .FillMem
ld hl, wChannelPitchSlideTargetFrequencyLowBytes
call .FillMem
ld a, $1
ld hl, wChannelLoopCounters
call .FillMem
ld hl, wChannelNoteDelayCounters
call .FillMem
ld hl, wChannelNoteSpeeds
call .FillMem
ld [wMusicTempo], a
ld a, $ff
ld [wStereoPanning], a
xor a
ldh [rNR50], a
ld a, $8
ldh [rNR10], a
ld a, 0
ldh [rNR51], a
xor a
ldh [rNR30], a
ld a, $80
ldh [rNR30], a
ld a, $77
ldh [rNR50], a
jp .playSoundCommon
.playSfx
ld l, a
ld e, a
ld h, 0
ld d, h
add hl, hl
add hl, de
ld de, SFX_Headers_1
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
.sfxChannelLoop
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 ; software channel ID
ld d, 0
ld hl, wChannelSoundIDs
add hl, de
ld a, [hl]
and a
jr z, .playChannel
ld a, e
cp CHAN8
jr nz, .notNoiseChannel
ld a, [wSoundID]
cp NOISE_INSTRUMENTS_END
jr nc, .notNoiseInstrument
ret
.notNoiseInstrument
ld a, [hl]
cp NOISE_INSTRUMENTS_END
jr z, .playChannel
jr c, .playChannel
.notNoiseChannel
ld a, [wSoundID]
cp [hl]
jr z, .playChannel
jr c, .playChannel
ret
.playChannel
xor a
push de
ld h, d
ld l, e
add hl, hl
ld d, h
ld e, l
ld hl, wChannelReturnAddresses
add hl, de
ld [hli], a
ld [hl], a
ld hl, wChannelCommandPointers
add hl, de
ld [hli], a
ld [hl], a
pop de
ld hl, wChannelSoundIDs
add hl, de
ld [hl], a
ld hl, wChannelFlags1
add hl, de
ld [hl], a
ld hl, wChannelDutyCycles
add hl, de
ld [hl], a
ld hl, wChannelDutyCyclePatterns
add hl, de
ld [hl], a
ld hl, wChannelVibratoDelayCounters
add hl, de
ld [hl], a
ld hl, wChannelVibratoExtents
add hl, de
ld [hl], a
ld hl, wChannelVibratoRates
add hl, de
ld [hl], a
ld hl, wChannelFrequencyLowBytes
add hl, de
ld [hl], a
ld hl, wChannelVibratoDelayCounterReloadValues
add hl, de
ld [hl], a
ld hl, wChannelPitchSlideLengthModifiers
add hl, de
ld [hl], a
ld hl, wChannelPitchSlideFrequencySteps
add hl, de
ld [hl], a
ld hl, wChannelPitchSlideFrequencyStepsFractionalPart
add hl, de
ld [hl], a
ld hl, wChannelPitchSlideCurrentFrequencyFractionalPart
add hl, de
ld [hl], a
ld hl, wChannelPitchSlideCurrentFrequencyHighBytes
add hl, de
ld [hl], a
ld hl, wChannelPitchSlideCurrentFrequencyLowBytes
add hl, de
ld [hl], a
ld hl, wChannelPitchSlideTargetFrequencyHighBytes
add hl, de
ld [hl], a
ld hl, wChannelPitchSlideTargetFrequencyLowBytes
add hl, de
ld [hl], a
ld hl, wChannelFlags2
add hl, de
ld [hl], a
ld a, $1
ld hl, wChannelLoopCounters
add hl, de
ld [hl], a
ld hl, wChannelNoteDelayCounters
add hl, de
ld [hl], a
ld hl, wChannelNoteSpeeds
add hl, de
ld [hl], a
ld a, e
cp CHAN5
jr nz, .skipSweepDisable
ld a, $8
ldh [rNR10], a ; sweep off
.skipSweepDisable
ld a, c
and a
jp z, .playSoundCommon
dec c
jp .sfxChannelLoop
.stopAllAudio
ld a, $80
ldh [rNR52], a ; sound hardware on
ldh [rNR30], a ; wave playback on
xor a
ldh [rNR51], a ; no sound output
ldh [rNR32], a ; mute channel 3 (wave channel)
ld a, $8
ldh [rNR10], a ; sweep off
ldh [rNR12], a ; mute channel 1 (pulse channel 1)
ldh [rNR22], a ; mute channel 2 (pulse channel 2)
ldh [rNR42], a ; mute channel 4 (noise channel)
ld a, $40
ldh [rNR14], a ; counter mode
ldh [rNR24], a
ldh [rNR44], a
ld a, $77
ldh [rNR50], a ; full volume
xor a
ld [wUnusedC000], a
ld [wDisableChannelOutputWhenSfxEnds], a
ld [wMuteAudioAndPauseMusic], a
ld [wMusicTempo + 1], a
ld [wSfxTempo + 1], a
ld [wMusicWaveInstrument], a
ld [wSfxWaveInstrument], a
ld d, $a0
ld hl, wChannelCommandPointers
call .FillMem
ld a, $1
ld d, $18
ld hl, wChannelNoteDelayCounters
call .FillMem
ld [wMusicTempo], a
ld [wSfxTempo], a
ld a, $ff
ld [wStereoPanning], a
ret
; fills d bytes at hl with a
.FillMem
ld b, d
.loop
ld [hli], a
dec b
jr nz, .loop
ret
.playSoundCommon
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_1
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
.commandPointerLoop
cp c
jr z, .next
inc c
inc hl
inc hl
jr .commandPointerLoop
.next
push hl
push bc
push af
ld b, 0
ld c, a
ld hl, wChannelSoundIDs
add hl, bc
ld a, [wSoundID]
ld [hl], a
pop af
cp CHAN4
jr c, .skipSettingFlag
ld hl, wChannelFlags1
add hl, bc
set BIT_NOISE_OR_SFX, [hl]
.skipSettingFlag
pop bc
pop hl
ld a, [de] ; get channel pointer
ld [hli], a
inc de
ld a, [de]
ld [hli], a
inc de
inc c
dec b
ld a, b
and a
ld a, [de]
inc de
jr nz, .commandPointerLoop
ld a, [wSoundID]
cp CRY_SFX_START
jr nc, .maybeCry
jr .done
.maybeCry
ld a, [wSoundID]
cp CRY_SFX_END
jr z, .done
jr c, .cry
jr .done
.cry
ld hl, wChannelSoundIDs + CHAN5
ld [hli], a
ld [hli], a
ld [hli], a
ld [hl], a
ld hl, wChannelCommandPointers + CHAN7 * 2 ; sfx wave channel pointer
ld de, Audio1_CryRet
ld [hl], e
inc hl
ld [hl], d ; overwrite pointer to point to sound_ret
ld a, [wSavedVolume]
and a
jr nz, .done
ldh a, [rNR50]
ld [wSavedVolume], a
ld a, $77
ldh [rNR50], a ; full volume
.done
ret
Audio1_CryRet:
sound_ret
Audio1_HWChannelBaseAddresses:
; the low bytes of each HW channel's base address
db HW_CH1_BASE, HW_CH2_BASE, HW_CH3_BASE, HW_CH4_BASE ; channels 0-3
db HW_CH1_BASE, HW_CH2_BASE, HW_CH3_BASE, HW_CH4_BASE ; channels 4-7
Audio1_HWChannelDisableMasks:
db HW_CH1_DISABLE_MASK, HW_CH2_DISABLE_MASK, HW_CH3_DISABLE_MASK, HW_CH4_DISABLE_MASK ; channels 0-3
db HW_CH1_DISABLE_MASK, HW_CH2_DISABLE_MASK, HW_CH3_DISABLE_MASK, HW_CH4_DISABLE_MASK ; channels 4-7
Audio1_HWChannelEnableMasks:
db HW_CH1_ENABLE_MASK, HW_CH2_ENABLE_MASK, HW_CH3_ENABLE_MASK, HW_CH4_ENABLE_MASK ; channels 0-3
db HW_CH1_ENABLE_MASK, HW_CH2_ENABLE_MASK, HW_CH3_ENABLE_MASK, HW_CH4_ENABLE_MASK ; channels 4-7
Audio1_Pitches:
INCLUDE "audio/notes.asm"
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