Dave Lowe: Intro 1 of 2 Adlib

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Assembly Source File | 1993-01-22 | 19.0 KB | 1,129 lines

;-------------------------------------------------------------------------------- ; ;AdLib specific routines ;-------------------------------------------------------------------------------- ;-------------------------------------------------------------------------------- ;PlaySongAdLib ; ;plays a song from the list ;after setting up all voices ; ;Inputs: ; ;ax: Song No. ; ;-------------------------------------------------------------------------------- PlaySongAdLib proc near sub al,15 ;seventeen roland files in front mov currentSong,ax mov bx,ax shl bx,1 ;transfer song parameters ;to AdLib driver mov ax,ds mov es,ax mov si,SongAdNVoices[bx] mov di,offset ChanNVoices mov cx,8 rep movsb mov si,SongAdCVoices[bx] mov di,offset ChanVoices mov cx,8*4 rep movsb mov si,SongAdPatches[bx] mov di,offset SongV0 mov cx,8 rep movsb mov si,SongAdTransp[bx] mov di,offset AdTransposes mov cx,9 rep movsb shr bx,1 mov al,SongAdPercs[bx] mov Percussion,al ;initialise AdLib call InitAdLib call WriteGlobals call InitAllVoices ;Set up voices for this song mov si,offset SongV0 call SetUpSongVoices mov MusicPlayFlg,0 call InstallTimer mov ax,csongseg1 mov es,ax mov si,offset MIDIPlayBuffer1 mov bx,CurrentSong mov al,SongTempos[bx] xor ah,ah call PlayMIDIFileAdLib ret PlaySongAdLib endp ;-------------------------------------------------------------------------------- ;routines for playing MIDI files on AdLib ;-------------------------------------------------------------------------------- ;-------------------------------------------------------------------------------- ;PlayMIDIFileAdLib ; ;Inputs: ; ;es:si pointer to MIDI file start ;ax temp beats per min. ; ;plays until end of file or ;until StopMIDIPlayAdLib is called ; ;-------------------------------------------------------------------------------- PlayMIDIFileAdLib proc near mov PlaySeg,es mov PlayPtr,si mov Tempo,ax call SetTimerTempo call ReadMIDIHeader ;get all header info mov si,PlayPtr call GetVarLength ;get first delay mov ax,10 mov PlayPtr,si mov cs:EventDelay,1 mov MusicPlayFlg,-1 ret PlayMIDIFileAdLib endp StopMIDIPlayAdLib proc near mov MusicPlayFlg,0 call RemoveTimer call AllNotesOff call InitAdLib ret StopMIDIPlayAdLib endp SetTimerTempo proc near mul TicksPQ ;ticks per min. mov bx,60 div bx ;ticks per second mov bx,ax mov ax,13089 ;1192737Hz basic freq. mov dx,18 div bx or ax,1 call TimerRate ;set up interrupt rate ret SetTimerTempo endp ;-------------------------------------------------------------------------------- ;EventRoutine: ; ;This routine is called after (EventDelay) interrupts ; ;returns: ; ;ax: new EventDelay ; ;-------------------------------------------------------------------------------- EventRoutine proc near cmp MusicPlayFlg,0 jne DoEvents mov ax,1 ;not playing yet ret DoEvents: cmp BoardFlg,0 jne ContEvents ;play music on ADLIB BOARD ; ; must be music or fx on ROLAND ; cmp fx_flag,0 je rol_music jmp rol_fx_driver rol_music: jmp RolEventRoutine ;play music on ROLAND BOARD ContEvents: ;do current event cld mov es,PlaySeg mov si,PlayPtr cmp byte ptr es:[si],080h jb ProcessMIDIEvent ;using running status mov al,es:[si] inc si cmp al,0FFh jne NotAMeta mov al,es:[si] ;Meta event type inc si call ProcessMetaEvent cmp ax,0 je JND jmp DoneAMPlay ;end of track JND: jmp NextDelay NotAMeta: cmp al,0F0h jb NotASE call ProcessSysEx0 jmp NextDelay NotASE: mov MIDIStatus,al ProcessMIDIEvent: mov al,MIDIStatus mov bl,al and al,1111b ;channel mov MIDIChannel,al xor bh,bh mov cl,4 shr bx,cl ;form index mov cl,MIDIDataSizes[bx] xor ch,ch mov MIDIDataSiz,cx ;handle different midi events voff: cmp bx,8h ;note off jne NMidi8 mov bl,MidiChannel xor bh,bh cmp Percussion,0 je NoOffPerc cmp bx,9 jne NoOffPerc jmp NMidiE ;no note off for percussion voices NoOffPerc: ;find which voice carries the note to turn off mov cl,ChanNVoices[bx] xor ch,ch shl bx,1 shl bx,1 shl bx,1 ;index into ChanVoices cmp cx,0 jne VAllocd jmp NMidiE ;no voices allocated VAllocd: cmp cx,1 je NoOChoice PolyNOL: mov dl,ChanVoices[bx] xor dh,dh mov di,dx mov dl,VoiceNotes[di] cmp dl,es:[si] ;is it this note? je GotOffVoice ;yes it is inc bx loop PolyNOL ;keep trying GotOffVoice: mov ax,di ;this voice UseNoteOff: mov bl,es:[si] mov cl,es:[si+1] call NoteOff jmp NMidiE NoOChoice: mov al,ChanVoices[bx] ;the only one jmp UseNoteOff NMidi8: ;********************** push ax push bx inc si mov al,es:[si] cmp al,0 jne isnoteon bkp: pop bx pop ax mov bx,8h dec si jmp voff isnoteon: dec si pop bx pop ax cmp bx,9h ;note on je HNoteOn jmp NMidi9 HNoteOn: ;handle polyphony ;- scan available voices ;- if none free use earliest played mov bl,MidiChannel xor bh,bh mov di,bx shl di,1 inc MIDIChanCount[di] cmp Percussion,0 je NoPercMidi cmp bx,9 ;midi channel 10 is percussion channel je HandlePerc NoPercMidi: mov cl,ChanNVoices[bx] xor ch,ch shl bx,1 shl bx,1 shl bx,1 ;index into ChanVoices cmp cx,0 jne VNAllocd jmp NMidiE ;no voices allocated VNAllocd: cmp cx,1 je NoPChoice mov bp,0FFFFh ;this will contain earliest voice xor ax,ax ;voice to use PolyVL: mov dl,ChanVoices[bx] ;is this voice free? xor dh,dh mov di,dx shl di,1 mov dx,VoiceStatus[di] cmp dx,0 je GotVoice ;yes, it's free cmp dx,bp jae NotEarlV mov bp,dx ;this is earlier mov ax,di NotEarlV: inc bx loop PolyVL ;keep trying shr ax,1 jmp UseVoice ;use earliest GotVoice: mov ax,di shr ax,1 UseVoice: ; mov bx,ax ; xor bh,bh ; mov bl,AdTransposes[bx] ;use transpose mov bl,es:[si] mov cl,es:[si+1] push ax push bx push cx call NoteOff pop cx pop bx pop ax call NoteOn jmp NMidiE NoPChoice: mov al,ChanVoices[bx] ;the only one jmp UseVoice HandlePerc: ;deal with percussion sounds mov bl,es:[si] ;note no. sub bl,35 ;form index mov al,DrumSounds[bx] mov bl,24 jmp UseVoice NMidi9: cmp bx,0Ah ;note aftertouch jne NMidiA jmp NMidiE NMidiA: cmp bx,0Bh ;control change jne NMidiB jmp NMidiE NMidiB: cmp bx,0Ch ;program change jne NMidiC jmp NMidiE NMidiC: cmp bx,0Dh ;chan. aftertouch jne NMidiD jmp NMidiE NMidiD: cmp bx,0Eh ;pitch wheel jne NMidiE jmp NMidiE NMidiE: add si,MIDIDataSiz NextDelay: ;check for end of tune mov bx,si sub bx,StartPtr cmp bx,PlayLength jae DoneAMPlay play_aagain: call GetVarLength ;get delay to next event mov PlayPtr,si ret DoneAMPlay: mov si,startptr jmp play_aagain mov MusicPlayFlg,0 mov ax,1 ret EventRoutine endp ;-------------------------------------------------------------------------------- ;routines for playing notes on AdLib ;-------------------------------------------------------------------------------- ;-------------------------------------------------------------------------------- ;NoteOn ; ;inputs: ; ;al: voice 0-8 in melodic 0-10 in percussion mode ;bl: pitch 0-127 midi notes: 60 is Middle C (48 is AdLib mid C) ;cl: volume 0-127 ;-------------------------------------------------------------------------------- NoteOn proc near push si push es xor ah,ah xor bh,bh mov si,ax mov VoiceVolumes[si],cl mov VoiceNotes[si],bl add bl,AdTransposes[si] shl si,1 mov dx,PlayPtr mov VoiceStatus[si],dx ;flag it on sub bx,12 ;adlib pitch = midi pitch-12 jge NoteOK xor bx,bx NoteOK: mov cx,2000h cmp Percussion,0 jne PercNoteOn NormNoteOn: mov dx,1 ;note on call WriteAdLibFreq pop es pop si ret ;deal with percussion voices PercNoteOn: cmp ax,5 jle NormNoteOn ;not a perc push ax cmp ax,BD ;change bass drum freq. je BFreq cmp ax,TC ;can't change TC and HH freq je WrBits cmp ax,HH je WrBits cmp ax,SD ;influenced by TOM je WrBits push ax push bx push cx mov ax,SD add bx,7 ;pitch SD = pitch TOM+7 mov dx,0 call WriteAdLibFreq pop cx pop bx pop ax BFreq: mov dx,0 ;must be 0 for percussion call WriteAdLibFreq WrBits: pop bx sub bx,6 ;get offset mov al,PerckeyOns[bx] ;bit to set or PercBits,al call WriteAmVibPerc ;set perc bit pop es pop si ret NoteOn endp ;-------------------------------------------------------------------------------- ;NoteOff ; ;inputs: ; ;ax: voice 0-8 in melodic 0-10 in percussion mode ;bl: pitch 0-127 midi notes: 60 is Middle C (48 is AdLib mid C) ;cl: volume 0-127 ;-------------------------------------------------------------------------------- NoteOff proc near push si push es xor ah,ah xor bh,bh mov si,ax mov VoiceVolumes[si],cl mov VoiceNotes[si],bl add bl,AdTransposes[si] shl si,1 mov VoiceStatus[si],0 ;flag it off sub bx,12 ;adlib pitch = midi pitch-12 jge NoteOKO xor bx,bx NoteOKO: mov cx,2000h xor dx,dx ;voice off cmp Percussion,0 jne PercNoteOff NormNoteOff: call WriteAdLibFreq pop es pop si ret PercNoteOff: cmp ax,5 jle NormNoteOff ;not a perc mov bx,ax sub bx,6 ;get offset mov al,PerckeyOns[bx] ;bit to clear not al and PercBits,al call WriteAmVibPerc ;clear perc bit pop es pop si ret NoteOff endp ;-------------------------------------------------------------------------------- ;AllNotesOff ; ;turns off all voices ; ;-------------------------------------------------------------------------------- AllNotesOff proc near mov bp,8 xor ax,ax cmp Percussion,0 je NoteOLp mov bp,10 NoteOLp: push ax push bp call NoteOff pop bp pop ax inc ax cmp ax,bp jle NoteOLp ret AllNotesOff endp ;-------------------------------------------------------------------------------- ;routines for setting parameters in AdLib ;-------------------------------------------------------------------------------- ;-------------------------------------------------------------------------------- ; ;InitAdLib: ; ;clear all AdLib registers ; ;-------------------------------------------------------------------------------- InitAdLib proc near mov ax,1 IAdLp: push ax call AdLibWrite ;clear all reg.s pop ax inc al cmp al,0F5h jle IAdLp mov al,4 mov ah,60h ;reset Timer-1 & 2 call AdLibWrite mov al,4 mov ah,80h ;reset Timer-1 & 2 call AdLibWrite mov al,1 mov ah,00100000b ;enable wave-select call AdLibWrite ret InitAdLib endp ;-------------------------------------------------------------------------------- ; ;InitAllVoices: ; ;set up all slots to default ; ;-------------------------------------------------------------------------------- InitAllVoices proc near mov si,offset pianoOpr0 mov di,offset pianoOpr1 mov ax,0 mov bp,8 ;last voice cmp Percussion,0 je LoopIS mov bp,5 ;last voice LoopIS: push ax push bp call WriteVoice ;set up voices 0-8 pop bp pop ax inc ax cmp ax,bp jle LoopIS cmp Percussion,0 je QuitIS SetUpPerc: mov si,offset bdOpr0 ;set up percussion voices mov di,offset bdOpr1 mov ax,6 call WriteVoice mov si,offset sdOpr mov ax,7 call WriteVoice mov si,offset tomOpr mov ax,8 call WriteVoice mov si,offset cymbOpr mov ax,9 call WriteVoice mov si,offset hhOpr mov ax,10 call WriteVoice QuitIS: ret InitAllVoices endp ;-------------------------------------------------------------------------------- ;SetUpSongVoices ; ;set up all voices for a song ; ;si: array of patch no.s for voices ; ;-------------------------------------------------------------------------------- SetUpSongVoices proc near mov ax,0 mov bp,8 ;last voice cmp Percussion,0 je LoopSV mov bp,5 ;last voice LoopSV: push ax push bp push si mov bl,[si] ;patch xor bh,bh shl bx,1 mov si,AdLibPatches[bx] mov di,si add di,14 ;operator 1 call WriteVoice pop si pop bp pop ax inc si inc ax cmp ax,bp jle LoopSV cmp Percussion,0 je NoSPerc call SetUpPerc NoSPerc: ret SetUpSongVoices endp ;-------------------------------------------------------------------------------- ;WriteVoice: ; ;sets up a voice for a patch ; ;ax: voice ;si: patch operator0 ;di: patch operator1 ; ;-------------------------------------------------------------------------------- WriteVoice proc near push si mov bx,offset VoiceSlots cmp Percussion,0 je VNPerc mov bx,offset VoiceSlotsPerc ;for percussion mode VNPerc: mov dx,ax ;voice shl ax,1 add bx,ax mov al,[bx] ;first slot (modulator) push bx push dx push di mov bx,dx ;voice call WriteSlot pop di pop dx pop bx cmp byte ptr [bx+1],0 ;no second slot (carrier) if <0 jl NoWriS push bx push dx push di call WriteFeedFM ;only once per voice pop di pop dx pop bx mov si,di ;operator1 mov al,[bx+1] ;second slot (carrier) mov bx,dx ;voice call WriteSlot NoWriS: pop si ret WriteVoice endp ;-------------------------------------------------------------------------------- ;WriteSlot: ; ;sets the AdLib up for: ; ;ax: slot ;bx: voice ;si: operator ; ;-------------------------------------------------------------------------------- WriteSlot proc near mov Voice,bl mov bx,ax xor bh,bh mov bl,SlotOffsets[bx] ;offset within chip ;make sure all params within range and byte ptr KSL[si],3 and byte ptr MULTI[si],15 and byte ptr FB[si],7 and byte ptr AR[si],15 and byte ptr SL[si],15 and byte ptr EG[si],1 and byte ptr DR[si],15 and byte ptr RR[si],15 and byte ptr TL[si],63 and byte ptr AM[si],1 and byte ptr VIB[si],1 and byte ptr KSR[si],1 and byte ptr C[si],1 and byte ptr WS[si],3 ;set Ksl,Level mov ah,KSL[si] mov cl,6 shl ah,cl mov al,TL[si] or ah,al mov al,40h add al,bl call AdLibWrite ;set Attack,Decay mov ah,AR[si] mov cl,4 shl ah,cl or ah,DR[si] mov al,60h add al,bl call AdLibWrite ;set Sustain,Release mov ah,SL[si] mov cl,4 shl ah,cl or ah,RR[si] mov al,80h add al,bl call AdLibWrite ;AM, VIB, EG-TYP (Sustaining), KSR, MULTI mov ah,AM[si] mov cl,7 shl ah,cl mov al,VIB[si] mov cl,6 shl al,cl or ah,al mov al,EG[si] mov cl,5 shl al,cl or ah,al mov al,KSR[si] mov cl,4 shl al,cl or ah,al or ah,MULTI[si] mov al,20h add al,bl call AdLibWrite ;Wave Select mov ah,WS[si] mov al,0E0h add al,bl call AdLibWrite ret WriteSlot endp ;set Feedback,Fm ;-only once per voice WriteFeedFM proc near mov ah,FB[si] shl ah,1 mov al,C[si] xor al,1 or ah,al ; or ah,C[si] mov al,0C0h add al,Voice call AdLibWrite ret WriteFeedFM endp ;------------------------------------------------------------------------------- ;WriteGlobals: ; ;sets up AdLib global parameters ; ;WriteAmVibPerc: ; ;sets the values: amplitude depth,vibrato depth,percussion and percussion keyons ; ;------------------------------------------------------------------------------- WriteGlobals proc near call WriteAmVibPerc mov ah,NoteSel mov cl,6 shl ah,cl mov al,08h call AdLibWrite ret WriteGlobals endp WriteAmVibPerc proc near mov ah,AmDepth mov cl,7 shl ah,cl mov al,VibDepth mov cl,6 shl al,cl or ah,al mov al,Percussion mov cl,5 shl al,cl or ah,al or ah,PercBits mov al,0BDh call AdLibWrite ret WriteAmVibPerc endp ;------------------------------------------------------------ ;WriteAdLibFreq ; ;set a voice's frequency ; ;inputs: ; ax: voice (0-8) ; bx: note (0-95) ; cx: pitchbend (0-4000h, 2000h no bend) ; dx: keyOn (0 disable 1 enable) ; ;sets volume to VoiceVolumes[voice] if keyOn=1 ; ;------------------------------------------------------------ WriteAdLibFreq proc near mov Voice,al mov Note,bl mov PitchBend,cx mov ax,cx mov cl,5 shl dl,cl ;shift KON to correct location mov keyOn,dl push ax cmp dl,0 je NoVV ;not if keyon=0 ;set voice volume jmp NoVV mov bx,offset VoiceSlots cmp Percussion,0 je NoVVPerc mov bx,offset VoiceSlotsPerc cmp Voice,6 jle NoVVPerc dec bx ;for single op. percussion NoVVPerc: mov al,Voice xor ah,ah shl ax,1 add bx,ax mov bl,[bx+1] ;carrier slot xor bh,bh mov al,SlotOffsets[bx] mov bl,Voice mov ah,VoiceVolumes[bx] shr ah,1 ;0-63 volume shr ah,1 ;0-31 shr ah,1 ;0-15 neg ah add ah,15 ;attenuation add al,40h call AdLibWrite NoVV: pop ax sub ax,2000h ;convert pitch bend to signed no. je NoMul ;no mul if =0 sar ax,1 ;scale to 0-255 sar ax,1 sar ax,1 sar ax,1 sar ax,1 imul PitchBendRange ;* by pitch bend range NoMul: add ah,Note ;add on note no. add ax,8 ;round to nearest 1/16 sar ax,1 ;scale to 4 bit fix point sar ax,1 sar ax,1 sar ax,1 jge Not0 ;<0? xor ax,ax ;=0 jmp Not95 Not0: cmp ax,(96*16)-1 ;note <=95? jl Not95 mov ax,(96*16)-1 ;=95 Not95: mov di,ax ;get half-tone value within 1 octave shr di,1 ;use integer part of note MOD 12 shr di,1 shr di,1 shr di,1 mov dx,di mov bl,MOD12Tab[di] xor bh,bh mov di,bx shl di,1 ;get offset in frequency table shl di,1 shl di,1 shl di,1 shl di,1 shl ax,1 and ax,31 add di,ax ;add in fractional part (lower 4 bits) mov ax,FNumTable[di] ;get frequency mov di,dx ;get octave number mov bl,DIV12Tab[di] ;DIV 12 dec bl or ax,ax ;if high bit set must inc octave jge NoIncO inc bl NoIncO: or bl,bl ;check for <0 jge BlokOK inc bl sar ax,1 ;must /2 BlokOK: ;finally write frequency info to AdLib push bx ;save block push ax ;save freq value mov ah,al mov al,FNUM_LOW add al,Voice call AdLibWrite pop ax pop bx mov al,ah ;set up for register and al,3 shl bl,1 shl bl,1 add al,bl add al,keyOn mov ah,al mov al,KEYON_BLOCK_FNUM add al,Voice call AdLibWrite ret WriteAdLibFreq endp ;------------------------------------------------------------ ;AdLibWrite ; ;write to AdLib board ; ;input: al - Register No. ; ah - Data ; ;delays an appropriate amount of ;time for AdLib hardware to catch up: ; ; 3.3 æsec after a register select write ; 23.0 æsec after a data write ; ;------------------------------------------------------------ AdLibWrite proc near mov dx,ADLIB_ADDR ;AdLib output port out dx,al ;at least 12 cycles delay (3.3 æsec at 3.6 Mhz) in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx inc dx ;data reg mov al,ah out dx,al dec dx ;84 cycles delay (23 æsec at 3.6 Mhz) in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx in al,dx ret AdLibWrite endp