MODULE_MASK = $fc

SUBTUNE_MASK = $03

MUSIC_SILENCE = $00

MUSICHEADERSIZE = 7

FIXUP_SONGSIZE = 0

FIXUP_PATTSIZE = 4

FIXUP_INSSIZE = 8

FIXUP_LEGATOINSSIZE = 12

FIXUP_WAVESIZE = 16

FIXUP_PULSESIZE = 20

FIXUP_FILTSIZE = 24

FIXUP_NOSIZE = 28

FIXUP_ZERO = 0

FIXUP_MINUS1 = 1

FIXUP_MINUS81 = 2

NUMFIXUPS = 30

TRANS = $80

SONGJUMP = 0

ENDPATT = 0

DUR = $101

WAVEPTR = $7c

KEYOFF = $7e

REST = $7f

SFXEND = $00

SFXINIT = $01

SFXPULSE = $02

SFXWAVE = $04

SFXFREQ = $08

SFXFREQMOD = $10

SFXDELAY = $100

FADESPEED = $30

chnWave = playRoutineVars+0

chnWavePos = playRoutineVars+1

chnPulsePos = playRoutineVars+2

chnPattPos = playRoutineVars+3

chnNote = playRoutineVars+4

chnCounter = playRoutineVars+5

chnDuration = playRoutineVars+6

chnIns = playRoutineVars+21

chnTrans = playRoutineVars+22

chnSongPos = playRoutineVars+23

chnWaveTime = playRoutineVars+24

chnPulse = playRoutineVars+25

chnFreqLo = playRoutineVars+26

chnFreqHi = playRoutineVars+27

chnSfxNum = playRoutineVars+42

chnSfxPos = playRoutineVars+43

chnSfxTime = playRoutineVars+44

chnSfxFreqMod = playRoutineVars+45

; Request playback of sound effect, to be played only when music is off (e.g. footsteps)

;

; Parameters: A sound effect number

; Returns: -

; Modifies: A

QueueSfxNoMusic:sta QSNM_SoundNum+1

lda nextChnTbl ;If nextChnTbl points to just first channel, music is being played

beq QSfx_Done

QSNM_SoundNum: lda #$00

; Request playback of sound effect. Will actually be played during next update IRQ

;

; Parameters: A sound effect number

; Returns: -

; Modifies: A

QueueSfx: cmp Irq5_SfxNum+1 ;Since only one sound can be started per frame, check priority

bcc QSfx_Done

QSfx_Store: sta Irq5_SfxNum+1

QSfx_Done: rts

; Fade out current song. Note: sounds will not play before a new song (at least silence tune)

; is initialized

;

; Parameters: -

; Returns: -

; Modifies: A

FadeSongIfDifferent:

cmp RestartSong+1

beq FS_Skip

FadeSong: lda nextChnTbl ;When silence subtune is active, do not fade,

bne FS_Silence ;as it causes SID master volume noises

sta PS_CurrentSong+1 ;Current song must be reset in case the same song will be played again

lda #FADESPEED

sta Play_FadeSpd+1

FS_Skip:

FS_Silence: rts

; Restart last played song

;

; Parameters: -

; Returns: -

; Modifies: A,X,Y,loader/file temp vars

RestartSong: lda #$00

; Play a song. Load if necessary. Does not reinit if already playing

;

; Parameters: A song number, $00-$03 in first music module, $04-$07 in second etc.

; Returns: -

; Modifies: A,X,Y,loader/file temp vars

PlaySong: sta RestartSong+1

ldx musicMode ;If music off, always select silence tune

bne PS_MusicOn

and #MODULE_MASK ;Silence tune is the first in each module

PS_MusicOn:

PS_CurrentSong: cmp #$ff

beq PS_Done

sta PS_CurrentSong+1

jsr PrepareSong

lda PS_CurrentSong+1

and #SUBTUNE_MASK

tax

beq PS_SilenceSubTune ;Manipulate the "next soundFX channel" table according to

lda #$00 ;whether playing silence or an actual tune

tay

beq PS_StoreNextChn

PS_SilenceSubTune:

lda #7

ldy #14

PS_StoreNextChn:sta Irq5_ChnStart+1 ;When switching to an actual tune, make sure the first sound played

sta nextChnTbl ;isn't on channel 2 or 3

sty nextChnTbl+7

inx

stx PlayRoutine+1

PrS_Done:

PS_Done: rts

; Prepare song by loading its module, but do not start playback yet

;

; Parameters: A song number

; Returns: -

; Modifies: A,X,Y,loader/file temp vars

PrepareSong: lsr ;Get music module number

lsr

PrS_LoadedMusic:cmp #$ff ;Check if module already loaded

beq PrS_Done

sta PrS_LoadedMusic+1

ldx #F_MUSIC

jsr MakeFileNumber

lda Play_FadeSpd+1

beq PrS_NoFadeWait

lda $d01a ;Wait for fade to complete if we're already fading

lsr ;IRQs must be on so that we don't hang

bcc PrS_NoFadeWait

PrS_FadeWait: lda masterVol

bne PrS_FadeWait

PrS_NoFadeWait: lda #$ff

sta PlayRoutine+1 ;Silence during loading

lda fileNumber

jsr OpenFile ;Music files are Exomizer level mode output,

jsr GetByte ;meaning they start with startaddress hi/lo

sta musicDataHi ;Reset zonebuffer ptr. now

sta zoneBufferHi

jsr GetByte

sta musicDataLo

sta zoneBufferLo

jsr PurgeUntilFreeNoNew ;Purge files if necessary to fit the music

lda musicDataLo

ldx musicDataHi

jsr Depack ;Load the actual music data

; Set new music data

SetMusicData: lda #MUSICHEADERSIZE

clc

adc musicDataLo

sta trackPtrLo

lda #$00

tax

adc musicDataHi

sta trackPtrHi

SetMusicData_FixupLoop:

lda fixupDestLoTbl,x

sta pattPtrLo

lda fixupDestHiTbl,x

pha

and #$03

adc #>PlayRoutine

sta pattPtrHi

pla

lsr

lsr

pha

lsr

lsr

cmp #FIXUP_NOSIZE/4

bcs SetMusicData_AddDone

tay

lda (musicDataLo),y

adc trackPtrLo

sta trackPtrLo

bcc SetMusicData_AddDone

inc trackPtrHi

SetMusicData_AddDone:

pla

and #$03

tay

lda trackPtrLo

sec

sbc fixupSubTbl,y

ldy #$01

sta (pattPtrLo),y

iny

lda trackPtrHi

sbc #$00

sta (pattPtrLo),y

inx

cpx #NUMFIXUPS

bcc SetMusicData_FixupLoop

rts

; Silence SID by zeroing mastervolume

SilenceSID: lda #$00

sta $d418

rts

; Playroutine entrypoint.

;

; Write subtune number+1 to PlayRoutine+1 to initialize

PlayRoutine: ldx #$ff

bmi SilenceSID

beq Play_FadeSpd

Play_DoInit: dex

txa

sta pattPtrLo

asl

asl

adc pattPtrLo

tay

Play_SongTblAccess1:

lda songTbl,y

sta trackPtrLo

iny

Play_SongTblAccess2:

lda songTbl,y

sta trackPtrHi

iny

ldx #21

lda #$00

Play_ClearVars: sta chnWave-1,x

dex

bne Play_ClearVars

stx Play_FadeSpd+1

stx Play_FiltPos+1

stx Play_FiltType+1

stx $d417

stx PlayRoutine+1

jsr Play_ChnInit

ldx #$07

jsr Play_ChnInit

ldx #$0f

stx masterVol

dex

Play_ChnInit:

Play_SongTblAccess3:

lda songTbl,y

sta chnSongPos,x

iny

dec chnDuration,x

lda chnSfxNum,x ;If a sound effect is not playing, reset wave + SR to ensure starting from zero volume

bne Play_ChnInitSkip

sta $d404,x

sta $d406,x

Play_ChnInitSkip:

rts

Play_FiltInit:

Play_FiltSpdTblM81Access:

lda filtSpdTbl-$81,y

sta $d417

and #$70

sta Play_FiltType+1

Play_FiltNextTblM81Access:

lda filtNextTbl-$81,y

sta Play_FiltPos+1

Play_FiltLimitTblM81Access:

lda filtLimitTbl-$81,y

jmp Play_StoreCutoff

Play_FiltNext:

Play_FiltNextTblM1Access:

lda filtNextTbl-1,y

sta Play_FiltPos+1

jmp Play_FiltDone

Play_FadeSpd: lda #$00

beq Play_FiltPos

Play_FadeDelay: adc #$00

sta Play_FadeDelay+1

bcc Play_FiltPos

dec masterVol

bpl Play_FiltPos

stx masterVol

Play_FiltPos: ldy #$00

beq Play_FiltDone

bmi Play_FiltInit

Play_FiltCutoff:lda #$00

Play_FiltLimitTblM1Access:

cmp filtLimitTbl-1,y

beq Play_FiltNext

clc

Play_FiltSpdTblM1Access:

adc filtSpdTbl-1,y

Play_StoreCutoff:

sta Play_FiltCutoff+1

Play_ModifyCutoff8580:

sbc #$16

sta pattPtrLo

lsr

lsr

cmp #$10

bcc Play_CutoffOK

ora #$c0

adc pattPtrLo

Play_CutoffOK: sta $d416

Play_FiltDone:

Play_FiltType: lda #$00

Play_MasterVol: ora masterVol

sta $d418

jsr Play_ChnExec

ldx #$07

jsr Play_ChnExec

ldx #$0e

jmp Play_ChnExec

Play_NoNewIns: clc

adc chnTrans,x

ora #$80

sta chnNote,x

lda chnIns,x

bpl Play_HardRestart

bmi Play_Rest

Play_Commands: sbc #KEYOFF

bcc Play_WavePtr

ora chnSfxNum,x

beq Play_Keyoff

bne Play_Rest

Play_WavePtr: iny

lda (pattPtrLo),y

jsr Play_SetWavePos

beq Play_Rest ;Returns with A=0

Play_ChnExec: inc chnCounter,x

bmi Play_PulseExec

bne Play_Reload

ldy chnSongPos,x

Play_NewNotes: lda (trackPtrLo),y

tay

Play_PattTblLoM1Access:

lda pattTblLo-1,y

sta pattPtrLo

Play_PattTblHiM1Access:

lda pattTblHi-1,y

sta pattPtrHi

ldy chnPattPos,x

lda (pattPtrLo),y

cmp #WAVEPTR

bcs Play_Commands

lsr

bcs Play_NoNewIns

adc chnTrans,x

ora #$80

sta chnNote,x

iny

lda (pattPtrLo),y

sta chnIns,x

bmi Play_Rest ;Instruments $81-$ff are $01-$7f as legato

Play_HardRestart:

lda chnSfxNum,x

bne Play_Rest

lda #$0f

sta $d406,x

Play_Keyoff: lda chnWave,x

and #$fe

sta $d404,x

Play_Rest: iny

lda (pattPtrLo),y

beq Play_PattEnd

bpl Play_NoPattEnd

sta chnDuration,x

iny

lda (pattPtrLo),y

bne Play_NoPattEnd

Play_PattEnd: inc chnSongPos,x

dc.b $24 ;Skip next instruction

Play_NoPattEnd: tya

sta chnPattPos,x

ldy chnSfxNum,x

bne Play_JumpToSfx

rts

Play_Reload: lda chnDuration,x

sta chnCounter,x

lda chnPattPos,x

beq Play_Sequencer

Play_NoSequencer:

lda chnNote,x

bpl Play_PulseExec

jmp Play_NewNoteInit

Play_JumpToSfx: jmp Play_SfxExec

Play_PulseExec: ldy chnSfxNum,x

bne Play_JumpToSfx

ldy chnPulsePos,x

beq Play_WaveExec

bmi Play_PulseInit

lda chnPulse,x

Play_PulseLimitTblM1Access:

cmp pulseLimitTbl-1,y

beq Play_PulseNext

clc

Play_PulseSpdTblM1Access:

adc pulseSpdTbl-1,y

adc #$00

Play_StorePulse:

sta chnPulse,x

sta $d402,x

sta $d403,x

Play_WaveExec: ldy chnWavePos,x

beq Play_WaveDone

Play_WaveTblM1Access:

lda waveTbl-1,y

beq Play_Vibrato

cmp #$90

bcs Play_SlideOrDelay

Play_SetWave: sta chnWave,x

sta $d404,x

Play_NoWaveChange:

Play_WaveNextTblM1Access1:

lda waveNextTbl-1,y

sta chnWavePos,x

Play_NoteTblM1Access1:

lda noteTbl-1,y

bmi Play_AbsNote

adc chnNote,x

Play_AbsNote: asl

tay

lda freqTbl-2,y

sta chnFreqLo,x

sta $d400,x

lda freqTbl-1,y

Play_StoreFreqHi:

sta chnFreqHi,x

sta $d401,x

Play_WaveDone: rts

Play_WaveDelayNotOver:

inc chnWaveTime,x

rts

Play_Sequencer: ldy chnSongPos,x

lda (trackPtrLo),y

bmi Play_SongTrans

bne Play_SequencerDone

Play_SongJump: iny

lda (trackPtrLo),y

tay

lda (trackPtrLo),y

bpl Play_NoSongJumpTrans

Play_SongTrans: sta chnTrans,x

iny

Play_NoSongJumpTrans:

tya

sta chnSongPos,x

Play_SequencerDone:

ldy chnSfxNum,x

bne Play_JumpToSfx

lda chnNote,x

bpl Play_WaveExec

bmi Play_NewNoteInit

Play_PulseInit:

Play_PulseNextTblM81Access:

lda pulseNextTbl-$81,y

sta chnPulsePos,x

Play_PulseLimitTblM81Access:

lda pulseLimitTbl-$81,y

jmp Play_StorePulse

Play_PulseNext:

Play_PulseNextTblM1Access:

lda pulseNextTbl-1,y

sta chnPulsePos,x

jmp Play_WaveExec

Play_SlideOrDelay:

beq Play_Slide

Play_WaveDelay: adc chnWaveTime,x

bne Play_WaveDelayNotOver

clc

sta chnWaveTime,x

bcc Play_NoWaveChange

Play_Vibrato: lda chnWaveTime,x

bpl Play_VibNoDir

Play_NoteTblM1Access2:

cmp noteTbl-1,y

bcs Play_VibNoDir2

eor #$ff

Play_VibNoDir: sec

Play_VibNoDir2: sbc #$02

sta chnWaveTime,x

lsr

lda chnFreqLo,x

bcs Play_VibDown

Play_VibUp:

Play_WaveNextTblM1Access2:

adc waveNextTbl-1,y

sta chnFreqLo,x

sta $d400,x

bcc Play_VibDone

lda chnFreqHi,x

adc #$00

jmp Play_StoreFreqHi

Play_VibDown:

Play_WaveNextTblM1Access3:

sbc waveNextTbl-1,y

sta chnFreqLo,x

sta $d400,x

bcs Play_VibDone

lda chnFreqHi,x

sbc #$00

jmp Play_StoreFreqHi

Play_LegatoNoteInit:

tya

and #$7f

tay

bpl Play_FinishLegatoInit

Play_Slide: lda chnFreqLo,x

Play_NoteTblM1Access3:

adc noteTbl-1,y ;Note: speed must be stored as speed-1 due to C=1 here

sta chnFreqLo,x

sta $d400,x

Play_WaveNextTblM1Access4:

lda waveNextTbl-1,y

Play_SfxFreqMod:adc chnFreqHi,x

jmp Play_StoreFreqHi

Play_NewNoteInit:

and #$7f

sta chnNote,x ;Reset newnote-flag

ldy chnIns,x

bmi Play_LegatoNoteInit

Play_HRNoteInit:

Play_InsADM1Access:

lda insAD-1,y ;Instruments are 1-indexed just so that the converter can

sta $d405,x ;differentiate between "no instrument change" and the first

Play_InsSRM1Access: ;instrument. Strictly speaking they wouldn't need to be

lda insSR-1,y

sta $d406,x

Play_InsFirstWaveM1Access:

lda insFirstWave-1,y

sta $d404,x

Play_InsPulsePosM1Access:

lda insPulsePos-1,y

beq Play_SkipPulseInit

sta chnPulsePos,x

Play_SkipPulseInit:

Play_InsFiltPosM1Access:

lda insFiltPos-1,y

beq Play_SkipFiltInit

sta Play_FiltPos+1

Play_SkipFiltInit:

Play_FinishLegatoInit:

Play_InsWavePosM1Access:

lda insWavePos-1,y

Play_SetWavePos:sta chnWavePos,x

lda #$00

sta chnWaveTime,x

Play_SlideDelay:

Play_VibDone: rts

; Sound effect support code

Play_SfxDelay: sec

adc chnSfxTime,x

bne Play_SfxDelayOngoing

Play_SfxDelayDone:

sta chnSfxTime,x

inc chnSfxPos,x ;Delay ended, run still effects only this frame

bne Play_SfxEffects

Play_SfxDelayOngoing:

inc chnSfxTime,x

Play_SfxEffects:lda chnSfxFreqMod,x

clc

bne Play_SfxFreqMod

rts

Play_SfxEnd: sta chnSfxNum,x

sta chnWavePos,x ;Also reset wavepos when returning from sound FX to music

Play_SfxDone: rts

Play_SfxHR: lda #$0f

sta $d406,x

lda chnWave,x

and #$fe

sta $d404,x

lda #$00

sta chnSfxFreqMod,x

sta chnSfxTime,x

inc chnSfxPos,x

rts

Play_SfxExec: lda sfxTblLo-1,y

sta pattPtrLo

lda sfxTblHi-1,y

sta pattPtrHi

lda chnNote,x ;Prevent newnoteinit triggering during sound FX

bpl Play_SfxNoNewNote

and #$7f

sta chnNote,x

Play_SfxNoNewNote:

ldy chnSfxPos,x

beq Play_SfxHR

dey

lda (pattPtrLo),y

bmi Play_SfxDelay

beq Play_SfxEnd

Play_SfxCommand:sta sfxTemp

iny

lsr sfxTemp

bcc Play_NoSfxFirstFrame

lda (pattPtrLo),y

sta $d405,x

iny

lda (pattPtrLo),y

sta $d406,x

iny

lda #$09

sta $d404,x

Play_NoSfxFirstFrame:

lsr sfxTemp

bcc Play_NoSfxPulse

lda (pattPtrLo),y

sta $d402,x

sta $d403,x

iny

Play_NoSfxPulse:

lsr sfxTemp

bcc Play_NoSfxWave

lda (pattPtrLo),y

sta chnWave,x

sta $d404,x

iny

Play_NoSfxWave: lsr sfxTemp

bcc Play_NoSfxFreq

lda (pattPtrLo),y

sta chnFreqHi,x

sta $d400,x

sta $d401,x

iny

Play_NoSfxFreq: lsr sfxTemp

bcc Play_NoSfxFreqMod

lda (pattPtrLo),y

sta chnSfxFreqMod,x

iny

Play_NoSfxFreqMod:

iny

tya

sta chnSfxPos,x

jmp Play_SfxEffects