ref: 1aefbfa5230fe188417e52674f79a6d5b009a51e
dir: /audio/engine_1.asm/
; The first of three duplicated sound engines. Audio1_UpdateMusic:: ld c, Ch0 .loop ld b, 0 ld hl, wChannelSoundIDs add hl, bc ld a, [hl] and a jr z, .nextChannel ld a, c cp Ch4 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 ld [rNR51], a ld [rNR30], a ld a, $80 ld [rNR30], a jr .nextChannel .applyAffects call Audio1_ApplyMusicAffects .nextChannel ld a, c inc c ; inc channel number cp Ch7 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 Ch4 jr nc, .startChecks ; if a sfx channel ld hl, wChannelSoundIDs + Ch4 add hl, bc ld a, [hl] and a jr z, .startChecks ret .startChecks ld hl, wChannelFlags1 add hl, bc bit BIT_ROTATE_DUTY, [hl] jr z, .checkForExecuteMusic call Audio1_ApplyDutyCycle .checkForExecuteMusic ld b, 0 ld hl, wChannelFlags2 add hl, bc bit BIT_EXECUTE_MUSIC, [hl] jr nz, .checkForPitchBend ld hl, wChannelFlags1 add hl, bc bit BIT_NOISE_OR_SFX, [hl] jr nz, .skipPitchBendVibrato .checkForPitchBend ld hl, wChannelFlags1 add hl, bc bit BIT_PITCH_BEND_ON, [hl] jr z, .checkVibratoDelay jp Audio1_ApplyPitchBend .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 .skipPitchBendVibrato 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 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_BEND_ON, [hl] res BIT_PITCH_BEND_DECREASING, [hl] call Audio1_endchannel ret Audio1_endchannel: call Audio1_GetNextMusicByte ld d, a cp $ff ; is this command an endchannel? jp nz, Audio1_callchannel ; no ld b, 0 ld hl, wChannelFlags1 add hl, bc bit BIT_CHANNEL_CALL, [hl] jr nz, .returnFromCall ld a, c cp Ch3 jr nc, .noiseOrSfxChannel jr .disableChannelOutput .noiseOrSfxChannel res BIT_NOISE_OR_SFX, [hl] ld hl, wChannelFlags2 add hl, bc res BIT_EXECUTE_MUSIC, [hl] cp Ch6 jr nz, .skipSfxChannel3 ; restart hardware channel 3 (wave channel) output ld a, $0 ld [rNR30], a ld a, $80 ld [rNR30], a .skipSfxChannel3 jr nz, .asm_9222 ld a, [wDisableChannelOutputWhenSfxEnds] and a jr z, .asm_9222 xor a ld [wDisableChannelOutputWhenSfxEnds], a jr .disableChannelOutput .asm_9222 jr .asm_9248 .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_endchannel .disableChannelOutput ld hl, Audio1_HWChannelDisableMasks add hl, bc ld a, [rNR51] and [hl] ld [rNR51], a .asm_9248 ld a, [wChannelSoundIDs + Ch4] cp CRY_SFX_START jr nc, .asm_9251 jr .skipCry .asm_9251 ld a, [wChannelSoundIDs + Ch4] cp CRY_SFX_END jr z, .skipCry jr c, .cry jr .skipCry .cry ld a, c cp Ch4 jr z, .asm_9265 call Audio1_GoBackOneCommandIfCry ret c .asm_9265 ld a, [wSavedVolume] ld [rNR50], a xor a ld [wSavedVolume], a .skipCry ld hl, wChannelSoundIDs add hl, bc ld [hl], b ret Audio1_callchannel: cp $fd ; is this command a callchannel? jp nz, Audio1_loopchannel ; no 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_CHANNEL_CALL, [hl] ; set the call flag jp Audio1_endchannel Audio1_loopchannel: cp $fe ; is this command a loopchannel? jp nz, Audio1_notetype ; no 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_endchannel .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_endchannel Audio1_notetype: and $f0 cp $d0 ; is this command a notetype? jp nz, Audio1_toggleperfectpitch ; no 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 Ch3 jr z, .noiseChannel ; noise channel has 0 params call Audio1_GetNextMusicByte ld d, a ld a, c cp Ch2 jr z, .musicChannel3 cp Ch6 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_endchannel Audio1_toggleperfectpitch: ld a, d cp $e8 ; is this command a toggleperfectpitch? jr nz, Audio1_vibrato ; no ld b, 0 ld hl, wChannelFlags1 add hl, bc ld a, [hl] xor $1 ld [hl], a ; flip bit 0 of wChannelFlags1 jp Audio1_endchannel Audio1_vibrato: cp $ea ; is this command a vibrato? jr nz, Audio1_pitchbend ; no 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_endchannel Audio1_pitchbend: cp $eb ; is this command a pitchbend? jr nz, Audio1_duty ; no call Audio1_GetNextMusicByte ld b, 0 ld hl, wChannelPitchBendLengthModifiers 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, wChannelPitchBendTargetFrequencyHighBytes add hl, bc ld [hl], d ld hl, wChannelPitchBendTargetFrequencyLowBytes add hl, bc ld [hl], e ld b, 0 ld hl, wChannelFlags1 add hl, bc set BIT_PITCH_BEND_ON, [hl] call Audio1_GetNextMusicByte ld d, a jp Audio1_notelength Audio1_duty: cp $ec ; is this command a duty? jr nz, Audio1_tempo ; no call Audio1_GetNextMusicByte rrca rrca and $c0 ld b, 0 ld hl, wChannelDuties add hl, bc ld [hl], a ; store duty jp Audio1_endchannel Audio1_tempo: cp $ed ; is this command a tempo? jr nz, Audio1_stereopanning ; no ld a, c cp Ch4 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_endchannel Audio1_stereopanning: cp $ee ; is this command a stereopanning? jr nz, Audio1_unknownmusic0xef ; no call Audio1_GetNextMusicByte ld [wStereoPanning], a ; store panning jp Audio1_endchannel ; this appears to never be used Audio1_unknownmusic0xef: cp $ef ; is this command an unknownmusic0xef? jr nz, Audio1_dutycycle ; no call Audio1_GetNextMusicByte push bc call Audio1_PlaySound pop bc ld a, [wDisableChannelOutputWhenSfxEnds] and a jr nz, .skip ld a, [wChannelSoundIDs + Ch7] ld [wDisableChannelOutputWhenSfxEnds], a xor a ld [wChannelSoundIDs + Ch7], a .skip jp Audio1_endchannel Audio1_dutycycle: cp $fc ; is this command a dutycycle? jr nz, Audio1_volume ; no call Audio1_GetNextMusicByte ld b, 0 ld hl, wChannelDutyCycles add hl, bc ld [hl], a ; store full cycle and $c0 ld hl, wChannelDuties add hl, bc ld [hl], a ; store first duty ld hl, wChannelFlags1 add hl, bc set BIT_ROTATE_DUTY, [hl] jp Audio1_endchannel Audio1_volume: cp $f0 ; is this command a volume? jr nz, Audio1_executemusic ; no call Audio1_GetNextMusicByte ld [rNR50], a ; store volume jp Audio1_endchannel Audio1_executemusic: cp $f8 ; is this command an executemusic? jr nz, Audio1_octave ; no ld b, $0 ld hl, wChannelFlags2 add hl, bc set BIT_EXECUTE_MUSIC, [hl] jp Audio1_endchannel Audio1_octave: and $f0 cp $e0 ; is this command an octave? jr nz, Audio1_unknownsfx0x20 ; no ld hl, wChannelOctaves ld b, 0 add hl, bc ld a, d and $f ld [hl], a ; store low nibble as octave jp Audio1_endchannel Audio1_unknownsfx0x20: cp $20 ; is this command an unknownsfx0x20? jr nz, Audio1_unknownsfx0x10 ld a, c cp Ch3 ; is this a noise or sfx channel? jr c, Audio1_unknownsfx0x10 ; no ld b, 0 ld hl, wChannelFlags2 add hl, bc bit BIT_EXECUTE_MUSIC, [hl] ; is executemusic being used? jr nz, Audio1_unknownsfx0x10 ; yes call Audio1_notelength ; This code seems to do the same thing as what Audio1_ApplyDutyAndSoundLength ; does below. ld d, a ld b, 0 ld hl, wChannelDuties 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 Ch7 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_ApplyDutyAndSoundLength call Audio1_EnableChannelOutput pop de call Audio1_ApplyWavePatternAndFrequency ret Audio1_unknownsfx0x10: ld a, c cp Ch4 jr c, Audio1_note ; if not a sfx ld a, d cp $10 ; is this command a unknownsfx0x10? jr nz, Audio1_note ; no ld b, $0 ld hl, wChannelFlags2 add hl, bc bit BIT_EXECUTE_MUSIC, [hl] jr nz, Audio1_note ; no call Audio1_GetNextMusicByte ld [rNR10], a jp Audio1_endchannel Audio1_note: ld a, c cp Ch3 jr nz, Audio1_notelength ; if not noise channel ld a, d and $f0 cp $b0 ; is this command a dnote? jr z, Audio1_dnote jr nc, Audio1_notelength ; no swap a ld b, a ld a, d and $f ld d, a ld a, b push de push bc jr asm_94fd Audio1_dnote: ld a, d and $f push af push bc call Audio1_GetNextMusicByte ; get dnote instrument asm_94fd ld d, a ld a, [wDisableChannelOutputWhenSfxEnds] and a jr nz, .asm_9508 ld a, d call Audio1_PlaySound .asm_9508 pop bc pop de Audio1_notelength: 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 Ch4 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 Ch7 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_notepitch ld hl, wChannelFlags1 add hl, bc bit BIT_NOISE_OR_SFX, [hl] jr z, Audio1_notepitch pop hl ret Audio1_notepitch: pop af and $f0 cp $c0 ; compare to rest jr nz, .notRest ld a, c cp Ch4 jr nc, .next ; If this isn't an SFX channel, try the corresponding SFX channel. ld hl, wChannelSoundIDs + Ch4 add hl, bc ld a, [hl] and a jr nz, .done ; fall through .next ld a, c cp Ch2 jr z, .channel3 cp Ch6 jr nz, .notChannel3 .channel3 ld b, 0 ld hl, Audio1_HWChannelDisableMasks add hl, bc ld a, [rNR51] and [hl] ld [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_BEND_ON, [hl] jr z, .skipPitchBend call Audio1_InitPitchBendVars .skipPitchBend push de ld a, c cp Ch4 jr nc, .sfxChannel ; if sfx channel ; If this isn't an SFX channel, try the corresponding SFX channel. ld hl, wChannelSoundIDs + Ch4 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_ApplyDutyAndSoundLength call Audio1_EnableChannelOutput pop de ld b, $0 ld hl, wChannelFlags1 add hl, bc bit BIT_PERFECT_PITCH, [hl] ; has toggleperfectpitch been used? jr z, .skipFrequencyInc inc e ; if yes, increment the frequency by 1 jr nc, .skipFrequencyInc 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 ld a, [rNR51] or [hl] ; set this channel's bits ld d, a ld a, c cp Ch7 jr z, .noiseChannelOrNoSfx cp Ch4 jr nc, .skip ; if sfx channel ; If this isn't an SFX channel, try the corresponding SFX channel. ld hl, wChannelSoundIDs + Ch4 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 ld 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 ld [rNR51], a ret Audio1_ApplyDutyAndSoundLength: ld b, 0 ld hl, wChannelNoteDelayCounters ; use the note delay as sound length add hl, bc ld d, [hl] ld a, c cp Ch2 jr z, .skipDuty ; if music channel 3 cp Ch6 jr z, .skipDuty ; if sfx channel 3 ; include duty (except on channel 3 which doesn't have it) ld a, d and $3f ld d, a ld hl, wChannelDuties 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 Ch2 jr z, .channel3 cp Ch6 jr nz, .notChannel3 ; fall through .channel3 push de ld de, wMusicWaveInstrument cp Ch2 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, $ff30 ; wave pattern RAM ld b, $f ld a, $0 ; stop hardware channel 3 ld [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 ld [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 + Ch4] 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_ApplyPitchBend: ld hl, wChannelFlags1 add hl, bc bit BIT_PITCH_BEND_DECREASING, [hl] jp nz, .frequencyDecreasing ; frequency increasing ld hl, wChannelPitchBendCurrentFrequencyLowBytes add hl, bc ld e, [hl] ld hl, wChannelPitchBendCurrentFrequencyHighBytes add hl, bc ld d, [hl] ld hl, wChannelPitchBendFrequencySteps add hl, bc ld l, [hl] ld h, b add hl, de ld d, h ld e, l ld hl, wChannelPitchBendCurrentFrequencyFractionalPart add hl, bc push hl ld hl, wChannelPitchBendFrequencyStepsFractionalPart 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, wChannelPitchBendTargetFrequencyHighBytes add hl, bc ld a, [hl] cp d jp c, .reachedTargetFrequency jr nz, .applyUpdatedFrequency ld hl, wChannelPitchBendTargetFrequencyLowBytes add hl, bc ld a, [hl] cp e jp c, .reachedTargetFrequency jr .applyUpdatedFrequency .frequencyDecreasing ld hl, wChannelPitchBendCurrentFrequencyLowBytes add hl, bc ld a, [hl] ld hl, wChannelPitchBendCurrentFrequencyHighBytes add hl, bc ld d, [hl] ld hl, wChannelPitchBendFrequencySteps add hl, bc ld e, [hl] sub e ld e, a ld a, d sbc b ld d, a ld hl, wChannelPitchBendFrequencyStepsFractionalPart 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, wChannelPitchBendTargetFrequencyHighBytes add hl, bc ld a, d cp [hl] jr c, .reachedTargetFrequency jr nz, .applyUpdatedFrequency ld hl, wChannelPitchBendTargetFrequencyLowBytes add hl, bc ld a, e cp [hl] jr c, .reachedTargetFrequency .applyUpdatedFrequency ld hl, wChannelPitchBendCurrentFrequencyLowBytes add hl, bc ld [hl], e ld hl, wChannelPitchBendCurrentFrequencyHighBytes 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 bend when the target frequency has been reached. ld hl, wChannelFlags1 add hl, bc res BIT_PITCH_BEND_ON, [hl] res BIT_PITCH_BEND_DECREASING, [hl] ret Audio1_InitPitchBendVars: ld hl, wChannelPitchBendCurrentFrequencyHighBytes add hl, bc ld [hl], d ld hl, wChannelPitchBendCurrentFrequencyLowBytes add hl, bc ld [hl], e ld hl, wChannelNoteDelayCounters add hl, bc ld a, [hl] ld hl, wChannelPitchBendLengthModifiers add hl, bc sub [hl] jr nc, .next ld a, 1 .next ld [hl], a ld hl, wChannelPitchBendTargetFrequencyLowBytes add hl, bc ld a, e sub [hl] ld e, a ld a, d sbc b ld hl, wChannelPitchBendTargetFrequencyHighBytes add hl, bc sub [hl] jr c, .targetFrequencyGreater ld d, a ld b, 0 ld hl, wChannelFlags1 add hl, bc set BIT_PITCH_BEND_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, wChannelPitchBendCurrentFrequencyHighBytes add hl, bc ld d, [hl] ld hl, wChannelPitchBendCurrentFrequencyLowBytes add hl, bc ld e, [hl] ld hl, wChannelPitchBendTargetFrequencyLowBytes 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, wChannelPitchBendTargetFrequencyHighBytes add hl, bc ld a, [hl] sub d ld d, a ld b, 0 ld hl, wChannelFlags1 add hl, bc res BIT_PITCH_BEND_DECREASING, [hl] .next2 ld hl, wChannelPitchBendLengthModifiers 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, wChannelPitchBendFrequencySteps add hl, bc ld [hl], d ; store quotient + 1 ld hl, wChannelPitchBendFrequencyStepsFractionalPart add hl, bc ld [hl], a ; store remainder - dividend ld hl, wChannelPitchBendCurrentFrequencyFractionalPart add hl, bc ld [hl], a ; store remainder - dividend ret Audio1_ApplyDutyCycle: ld b, 0 ld hl, wChannelDutyCycles 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 $ff jp z, .stopAllAudio cp MAX_SFX_ID 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, $8 ld hl, wChannelReturnAddresses call .FillMem ld hl, wChannelCommandPointers call .FillMem ld d, $4 ld hl, wChannelSoundIDs call .FillMem ld hl, wChannelFlags1 call .FillMem ld hl, wChannelDuties call .FillMem ld hl, wChannelDutyCycles 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, wChannelPitchBendLengthModifiers call .FillMem ld hl, wChannelPitchBendFrequencySteps call .FillMem ld hl, wChannelPitchBendFrequencyStepsFractionalPart call .FillMem ld hl, wChannelPitchBendCurrentFrequencyFractionalPart call .FillMem ld hl, wChannelPitchBendCurrentFrequencyHighBytes call .FillMem ld hl, wChannelPitchBendCurrentFrequencyLowBytes call .FillMem ld hl, wChannelPitchBendTargetFrequencyHighBytes call .FillMem ld hl, wChannelPitchBendTargetFrequencyLowBytes 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 ld [rNR50], a ld a, $8 ld [rNR10], a ld a, 0 ld [rNR51], a xor a ld [rNR30], a ld a, $80 ld [rNR30], a ld a, $77 ld [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, .asm_99a3 ld a, e cp $7 jr nz, .asm_999a ld a, [wSoundID] cp $14 jr nc, .asm_9993 ret .asm_9993 ld a, [hl] cp $14 jr z, .asm_99a3 jr c, .asm_99a3 .asm_999a ld a, [wSoundID] cp [hl] jr z, .asm_99a3 jr c, .asm_99a3 ret .asm_99a3 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, wChannelDuties add hl, de ld [hl], a ld hl, wChannelDutyCycles 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, wChannelPitchBendLengthModifiers add hl, de ld [hl], a ld hl, wChannelPitchBendFrequencySteps add hl, de ld [hl], a ld hl, wChannelPitchBendFrequencyStepsFractionalPart add hl, de ld [hl], a ld hl, wChannelPitchBendCurrentFrequencyFractionalPart add hl, de ld [hl], a ld hl, wChannelPitchBendCurrentFrequencyHighBytes add hl, de ld [hl], a ld hl, wChannelPitchBendCurrentFrequencyLowBytes add hl, de ld [hl], a ld hl, wChannelPitchBendTargetFrequencyHighBytes add hl, de ld [hl], a ld hl, wChannelPitchBendTargetFrequencyLowBytes 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 Ch4 jr nz, .asm_9a2b ld a, $8 ld [rNR10], a ; sweep off .asm_9a2b ld a, c and a jp z, .playSoundCommon dec c jp .sfxChannelLoop .stopAllAudio ld a, $80 ld [rNR52], a ; sound hardware on ld [rNR30], a ; wave playback on xor a ld [rNR51], a ; no sound output ld [rNR32], a ; mute channel 3 (wave channel) ld a, $8 ld [rNR10], a ; sweep off ld [rNR12], a ; mute channel 1 (pulse channel 1) ld [rNR22], a ; mute channel 2 (pulse channel 2) ld [rNR42], a ; mute channel 4 (noise channel) ld a, $40 ld [rNR14], a ; counter mode ld [rNR24], a ld [rNR44], a ld a, $77 ld [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 Ch3 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, .asm_9aeb jr .done .asm_9aeb ld a, [wSoundID] cp CRY_SFX_END jr z, .done jr c, .cry jr .done .cry ld hl, wChannelSoundIDs + Ch4 ld [hli], a ld [hli], a ld [hli], a ld [hl], a ld hl, wChannelCommandPointers + Ch6 * 2 ; sfx wave channel pointer ld de, Audio1_CryEndchannel ld [hl], e inc hl ld [hl], d ; overwrite pointer to point to endchannel ld a, [wSavedVolume] and a jr nz, .done ld a, [rNR50] ld [wSavedVolume], a ld a, $77 ld [rNR50], a ; full volume .done ret Audio1_CryEndchannel: endchannel 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: dw $F82C ; C_ dw $F89D ; C# dw $F907 ; D_ dw $F96B ; D# dw $F9CA ; E_ dw $FA23 ; F_ dw $FA77 ; F# dw $FAC7 ; G_ dw $FB12 ; G# dw $FB58 ; A_ dw $FB9B ; A# dw $FBDA ; B_