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    {$IFNDEF DPMI}
    'This program run only in DOS Protected Mode (Compile - Target = Protected)!'
    {$ENDIF}

    Unit sbdpmi; {SBDPMI Unit, by GLM, release 1.1}
    (*
      A simple unit to play VOC files via DMA in Protected mode.

      WARNING! This file can be compile only by Borland Pascal 7.00 in DOS
      Protected Mode. It needs the RTM.EXE and DPMI16BI.OVL!

      Note that this program use a buffer. That's not for better quality but=
     only
      because the DMA can't access memory above 640 KB. We must allocate 32 KB=
     of
      standard DOS memory and use this buffer.

      Donnated by LE MIGNOT Ga=89l to SWAGS and the Public Domain.

      For any questions, bugs or commenatry: kilobug@mail.planetepc.fr

      Great thanks to: PC-Interdit (c) Micro Application, 1995

      There is two files:   SBSPMI unit        line 1
                            And a demo program line 378
    *)

    Interface
    uses crt, dos, winapi; (* WINAPI =3D DPMI Memory Unit for MS-DOS *)
    type str70=3Dstring[70];
    const sbirq:byte=3D$7;
          sbdma:byte=3D1;
          sbport:word=3D$220;
          sb:boolean=3Dfalse; (* Is there a soundcard? *)

    var t_w:word;        (* Simple tempory variables *)
        t_b:byte;
        t_l:longint;

    Function InitSb:boolean;  (* Allocate memory, reset DSP, set the IRQ. *)
    Procedure SendBlock(size:word); (* Send the blk1 block to the DMA. *)
    Procedure LoadVoc(n:str70); (* Load a VOC file into memory *)
    Procedure PlayVoc(n:str70); (* Load a Voc and then play it *)
    Procedure PlayLoadedVoc; (* Play the loaded VOC *)
    Procedure PausePlay; (* Pause the VOC Playing *)
    Procedure ContinuePlay; (* Contiune playing after a pause *)
    Procedure StopPlay; (* Stop VOC Playing and free VOC memory *)
    Procedure RestoreSb; (* Release all memory, restore SB IRQ and reset the DSP=
     *)
    Procedure SetSample(sr:word); (* Set the sampling rate (legal values: 4000 -=
     44000) *)
    Procedure SpeakOn;
    Procedure SpeakOff;
    Procedure AllocateSbMem; (* Allocate memory, called by INITSB *)

    type pt=3Drecord     (* A simple way to adress pointers *)
         ofs,sg:word;
         end;

    var blk1:pointer;  (* Memory block to send to the DMA *)
        size:longint;  (* Size of VOC File *)
        cbloc,nbbloc:byte; (* Number of blocks in VOC File *)
        buff:array[1..200]of pointer; (* Buffer to load VOC. Limited to 6 MO *)
        wasinit, (* Is the soundcard initialised ? *)
        nbloc,
        ready, (* Is the soundcard ready? (false while playing) *)
        playing, (* Is the soundcard playing anything? *)
        paused, (* Is the VOC paused? *)
        lastone (* Are we sending the lastest block? *) :boolean;
        oldirq:pointer; (* Save the old IRQ value *)
        value:byte; (* Wich value to send to the DSP? *)
        irqmsk:byte;
        vocsample:word; (* Sample rate of the vco *)
        sndhdl:longint; (* Physical adress of BLK1 *)

    Implementation
    const dma_page:array[0..3] of byte=3D($87,$83,$81,$81);
    var   f:file;

    Procedure NewSBIrq;interrupt; (* This will be called each time the SB has
                                          played a block *)
    begin
         ASM  (* Preparing the sound card *)
         mov dx,20h
         mov ax,dx
         out dx,al
         mov cl,100
         mov bx,sbport
         add bx,0Ah
         @bcl:
         dec cl
         mov dx,bx
         in al,dx
         add dx,4
         in al,dx
         or cl,cl
         jz @finb
         cmp al,0AAh
         jnz @bcl
         @finb:
         end;
         ready:=3Dtrue;
         if(lastone)then begin playing:=3Dfalse;ready:=3Dtrue;exit;end;
         (* If we have played the last block, exiting procedure *)
         if(cbloc<nbbloc)then t_w:=3D32000
         else begin t_w:=3Dsize mod 32000;lastone:=3Dtrue;end;
         if(t_w=3D0)then t_w:=3D32000;
         (* t_w is size of the next block *)
         inc(cbloc);Move(buff[cbloc]^,blk1^,t_w);
         SendBlock(t_w);
         nbloc:=3Dtrue;
    end;

    Procedure WDsp;assembler;  (* This procedure write "value" to the DSP *)
    ASM
       mov dx,sbport
       add dx,0ch
       @bcl:
       in al,dx
       and al,80h
       jnz @bcl
       mov al,value
       out dx,al
       (* Equivalent to Pascal code:
       repeat until (port[sbport+$C]<>$80);
       port[sbport+$c]:=3Dvalue;
       *)
    end;

    Function InitSb:boolean;
    begin
         AllocateSbMem;
         getintvec($8+sbirq,oldirq); (* Saving the old interrupt vector *)
         (* Reset the DSP *)
         port[sbport+$6]:=3D1;
         for t_b:=3D1 to 100 do begin end;
         port[sbport+$6]:=3D0;

         (* Waiting until DSP ready *)
         for t_b:=3D1 to 100 do begin
         value:=3Dport[sbport+$E];value:=3Dport[sbport+$A];if(value=3D$AA)then=
     break;end;

         (* DSP never ready? May be bad port! *)
         ready:=3Dvalue=3D$AA;initsb:=3Dready;wasinit:=3Dtrue;
         if(ready)then setintvec($8+sbirq,addr(newsbirq));
         irqmsk :=3D 1 shl sbirq;
         port[$21] :=3D port[$21] and not irqmsk;
    end;

    Procedure SendBlock(size:word); (* Send blk1 to the SB card, via DMA *)
    var seg_,ofs_:word;
    begin
         sndhdl:=3DGetSelectorBase(seg(blk1^)); (* Physical adresse *)
         seg_:=3Dpt(sndhdl).sg; (* Computing segment and offset for the DMA *)
         ofs_:=3Dpt(sndhdl).ofs;

         ASM
         mov al,ready
         or al,al
         jz @fin

         mov dx,0Ah  (* Sending Blk1 to the DMA *)
         mov al,sbdma  (* Pascal corresponding code: *)
         add al,4      (* port[$0A]:=3Dsbdma+4 *)
         out dx,al

         add dx,2      (* port[$0C]:=3Dsbdma+4 *)
         xor al,al
         out dx,al

         dec dx        (* port[$0B]:=3Dsbdma+$48 *)
         mov al,sbdma
         add al,48h
         out dx,al

         xor dx,dx     (* port[sbdma*2]:=3Dlo(ofs_) *)
         mov ax,ofs_
         mov dl,sbdma
         shl dl,1
         out dx,al

         mov al,ah     (* port[sbdma*2]:=3Dhi(ofs_) *)
         out dx,al

         inc dx        (* port[sbdma*2+1]:=3Dlo(size) *)
         mov ax,size
         dec ax
         mov cx,ax
         out dx,al

         mov al,ah     (* port[sbdma*2+1]:=3Dhi(size) *)
         out dx,al

         xor bx,bx     (* portw[sma_page[sbdma]]:=3Dseg_ *)
         mov bl,sbdma
         xor dx,dx
         mov dl,byte ptr dma_page[bx]
         mov ax,seg_
         out dx,ax

         mov dx,sbport {Envoie de la commande au DSP}
         add dx,0ch
         @bcl1:
         in al,dx
         and al,80h
         jnz @bcl1
         mov al,14h
         out dx,al
         @bcl2:
         in al,dx
         and al,80h
         jnz @bcl2
         mov ax,cx
         out dx,al
         @bcl3:
         in al,dx
         and al,80h
         jnz @bcl3
         mov al,ch
         out dx,al

         mov dx,0Ah
         mov al,sbdma
         out dx,al

         mov playing,1
         mov ready,0
         @fin:
         end;
    end;

    Procedure LoadVoc(n:str70);
    begin
         (* Desalocating all memory *)
         while(nbbloc>0)do begin freemem(buff[nbbloc],32000);dec(nbbloc);end;
         nbbloc:=3D0;
         (* Openning file *)
         assign(f,n+'.voc');size:=3D0;reset(f,1);
         seek(f,26);
         (* Finding first block *)
         repeat
         blockread(f,value,1);
         until (value=3D1);
         (* Reading and computing sample rate *)
         seek(f,filepos(f)+3);blockread(f,value,1);
         sndhdl:=3Dround(-1000000/(longint(value)-256));
         vocsample:=3Dsndhdl;
         (* Loading VOC to memory and allocating note that with DPMI we can=
     acces
            all the memory with getmem *)
         while not(eof(f)) do begin
         inc(nbbloc);getmem(buff[nbbloc],32000);
         blockread(f,buff[nbbloc]^,32000,t_w);
         size:=3Dsize+t_w;
         end;dec(nbbloc);
         (* And then close file. Voc is ready to be played. *)
         close(f);
    end;

    Procedure PlayVoc(n:str70);
    begin
         (* You understand??? *)
         LoadVoc(n);PlayLoadedVoc;
    end;

    Procedure PlayLoadedVoc;
    begin
         (* Initializing values *)
         lastone:=3Dfalse;ready:=3Dtrue;playing:=3Dtrue;
         cbloc:=3D1;if(nbbloc<1)then exit;
         (* Only one block ??? *)
         if(nbbloc>1)then t_w:=3D32000 else t_w:=3Dsize;
         (* Moving VOC to sound buffer *)
         Move(buff[cbloc]^,blk1^,t_w);
         if(cbloc=3Dnbbloc)then lastone:=3Dtrue;
         SetSample(vocsample);
         SendBlock(t_w);
    end;

    Procedure PausePlay;assembler; (* Stop playing but keep the VOC in memory=
     and
                                      the current position *)
    ASM
       mov al,playing
       or al,al
       jz @fin
       mov dx,sbport
       add dx,0ch
       @bcl:
       in al,dx
       and al,80h
       jnz @bcl
       mov al,0D0h
       out dx,al
       mov paused,1
       @fin:
    end;

    Procedure StopPlay; (* Stop playing, restore SB, disallocate memory *)
    begin
         if(not(wasinit))then exit;
         PausePlay;
         while(nbbloc>0)do begin freemem(buff[nbbloc],32000);dec(nbbloc);end;
         nbbloc:=3D0;
         ready:=3Dtrue;playing:=3Dfalse;
    end;

    Procedure RestoreSb; (* Restore SB IRQ *)
    begin
         StopPlay;
         port[sbport+$6]:=3D1;
         for t_b:=3D1 to 100 do port[sbport+$6]:=3D0;
         for t_b:=3D1 to 100 do begin
         value:=3Dport[sbport+$E];value:=3Dport[sbport+$A];if(value=3D$AA)then=
     break;end;
         setintvec($8+sbirq,oldirq);
        =
     globaldosfree(seg(blk1^));wasinit:=3Dfalse;playing:=3Dfalse;paused:=3Dfalse=
    ;ready:=3Dfalse;
    end;

    Procedure ContinuePlay;assembler; (* Continue a VOC after PausePlay *)
    ASM
       mov al,playing
       or al,al
       jz @fin
       mov al,paused
       or al,al
       mov dx,sbport
       add dx,0ch
       @bcl:
       in al,dx
       and al,80h
       jnz @bcl
       mov al,0D4h
       out dx,al
       mov paused,0
       @fin:
    end;

    Procedure SetSample(sr:word); (* Change the sampling rate.
                                     It normaly run with values lower than=
     22000,
                                     but should work with higher rate (up to=
     44000)
                                   *)
    var btc:byte;
    begin
       bTC  :=3D Byte ( 256 - ( ( 1000000 + ( sr div 2 ) ) div sr ) );
       value:=3D$40;
       WDSP;value:=3Dbtc;WDSP;
    end;

    Procedure SpeakOn;assembler; (* Turn on the sound output *)
    ASM
       mov dx,sbport
       add dx,0ch
       @bcl:
       in al,dx
       and al,80h
       jnz @bcl
       mov al,0D1h
       out dx,al
    end;

    Procedure SpeakOff;assembler; (* Turn off the sound output *)
    ASM
       mov dx,sbport
       add dx,0ch
       @bcl:
       in al,dx
       and al,80h
       jnz @bcl
       mov al,0D3h
       out dx,al
    end;

    Procedure AllocateSbMem; (* Allocate 32KB of memory below 640 KB*)
    var _t_l:longint;
        _t_w:word;
        seg_,ofs_:word;
    begin
         _t_l:=3DGlobalDosAlloc(32000);
         _t_w:=3D_t_l and $0FFFF;
         blk1:=3Dptr(_t_w,0);
         sndhdl:=3DGetSelectorBase(seg(blk1^));
         seg_:=3Dpt(sndhdl).sg;
         ofs_:=3Dpt(sndhdl).ofs;
         if(ofs_>32000)then begin
         GlobalDOSFree(_t_w);
         _t_l:=3DGlobalDosAlloc((65535-ofs_)+1000);
         _t_l:=3DGlobalDosAlloc(32000);
         _t_w:=3D_t_l and $0FFFF;
         blk1:=3Dptr(_t_w,0);
         sndhdl:=3DGetSelectorBase(seg(blk1^));
         seg_:=3Dpt(sndhdl).sg;
         ofs_:=3Dpt(sndhdl).ofs;
    end;

    begin
         ready:=3Dfalse;playing:=3Dfalse;paused:=3Dfalse;{xmshdl:=3D0;}nbloc:=3D=
    false;
         wasinit:=3Dfalse;nbbloc:=3D0;cbloc:=3D0;
    end.

    (* A simple program to play vocs with this unit *)

    uses crt, sbdpmi;

    begin
         writeln('DPMI Voc-Player, by The Kilogub Team, 1996');
         writeln;
         InitSb;
         LoadVoc(paramstr(1));writeln('Voc loaded. Press any key to exit.');
         repeat
         PlayLoadedVoc;
         repeat until (ready)or(keypressed);
         if(ready)then writeln('Voc played!');
         until keypressed;
         StopPlay;
         while keypressed do readkey;
    end.

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