HPAVC/HPAVC CD-ROM.iso/pc/UGPRG.ZIP/SOUND/GUS.DOC

Text File | 1994-05-10 | 40.6 KB | 1,404 lines

┌────────┬───────────────────────────────────────────────────────────────────
│ GUSDOC │
└────────┘





                               THE OFFICAL



                GRAVIS ULTRASOUND PROGRAMMERS ENCYCLOPEDIA

                               ( G.U.P.E )



                                 v 0.1


                           Written by Mark Dixon.






  -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

 INTRODUCTION
 ~~~~~~~~~~~~
    The Gravis Ultrasound is by far the best & easiest sound card to
  program. Why? Because the card does all the hard stuff for you, leaving
  you and the CPU to do other things! This reference will document some
  (but not all) of the Gravis Ultrasound's hardware functions, allowing
  you to play music & sound effects on your GUS.

    We will not be going into great detail as to the theory behind
  everything - if you want to get technical information then read the
  GUS SDK. We will be merely providing you with the routines necessary
  to play samples on the GUS, and a basic explanation of how they work.

    This document will NOT go into DMA transfer or MIDI specifications.
  If someone knows something about them, and would like to write some
  info on them, we would appreciate it very much.

    All source code is in Pascal (tested under Turbo Pascal v7.0, but
  should work with TP 6.0 and possibly older versions). This document
  will assume reasonable knowledge of programming, and some knowledge of
  soundcards & music.


 INITIALISATION & AUTODETECTION
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   Since we are not using DMA, we only need to find the GUS's I/O port,
 which can be done from the DOS environment space, or preferably from a
 routine that will scan all possible I/O ports until it finds a GUS.

   The theory behind the detection routine is to store some values into
 GUS memory, and then read them back. If we have the I/O port correct,
 we will read back exactly what we wrote. So first, we need a routine
 that will write data to the memory of the GUS :


  Function  GUSPeek(Loc : Longint) : Byte;

  { Read a value from GUS memory }

  Var
    B : Byte;
    AddLo : Word;
    AddHi : Byte;
  Begin
    AddLo := Loc AND $FFFF;
    AddHi := LongInt(Loc AND $FF0000) SHR 16;

    Port [Base+$103] := $43;
    Portw[Base+$104] := AddLo;
    Port [Base+$103] := $44;
    Port [Base+$105] := AddHi;

    B := Port[Base+$107];
    GUSPeek := B;
  End;


  Procedure GUSPoke(Loc : Longint; B : Byte);

  { Write a value into GUS memory }

  Var
    AddLo : Word;
    AddHi : Byte;
  Begin
    AddLo := Loc AND $FFFF;
    AddHi := LongInt(Loc AND $FF0000) SHR 16;
    Port [Base+$103] := $43;
    Portw[Base+$104] := AddLo;
    Port [Base+$103] := $44;
    Port [Base+$105] := AddHi;
    Port [Base+$107] := B;
  End;


   Since the GUS can have up to 1meg of memory, we need to use a 32bit
 word to address all possible memory locations. However, the hardware of
 the GUS will only accept a 24bit word, which means we have to change
 the 32bit address into a 24bit address. The first two lines of each
 procedure does exactly that.

   The rest of the procedures simply send commands and data out through
 the GUS I/O port defined by the variable BASE (A word). So to test for
 the presence of the GUS, we simply write a routine to read/write memory
 for all possible values of BASE :


  Function GUSProbe : Boolean;

  { Returns TRUE if there is a GUS at I/O address BASE }

  Var
    B : Byte;
  Begin
    Port [Base+$103] := $4C;
    Port [Base+$105] := 0;
    GUSDelay;
    GUSDelay;
    Port [Base+$103] := $4C;
    Port [Base+$105] := 1;
    GUSPoke(0, $AA);
    GUSPoke($100, $55);
    B := GUSPeek(0);
    If B = $AA then GUSProbe := True else GUSProbe := False;
  End;


  Procedure GUSFind;

  { Search all possible I/O addresses for the GUS }

  Var
    I : Word;
  Begin
    for I := 1 to 8 do
    Begin
      Base := $200 + I*$10;
      If GUSProbe then I := 8;
    End;
    If Base < $280 then
      Write('Found your GUS at ', Base, ' ');
  End;


   The above routines will obviously need to be customised for your own
 use - for example, setting a boolean flag to TRUE if you find a GUS,
 rather than just displaying a message.

   It is also a good idea to find out exactly how much RAM is on the
 GUS, and this can be done in a similar process to the above routine.
 Since the memory can either be 256k, 512k, 768k or 1024k, all we have
 to do is to read/write values on the boundaries of these memory
 addresses. If we read the same value as we wrote, then we know exactly
 how much memory is available.


  Function  GUSFindMem : Longint;

  { Returns how much RAM is available on the GUS }

  Var
    I : Longint;
    B : Byte;
  Begin
    GUSPoke($40000, $AA);
    If GUSPeek($40000) <> $AA then I := $3FFFF
      else
    Begin
      GUSPoke($80000, $AA);
      If GUSPeek($80000) <> $AA then I := $8FFFF
        else
      Begin
        GUSPoke($C0000, $AA);
        If GUSPeek($C0000) <> $AA then I := $CFFFF
          else I := $FFFFF;
      End;
    End;
    GUSFindMem := I;
  End;


   Now that we know where the GUS is, and how much memory it has, we
 need to initialise it for output. Unfortunately, the below routine is
 slightly buggy. If you run certain programs (I discovered this after
 running Second Reality demo) that use the GUS, and then your program
 using this init routine, it will not initialise the GUS correctly.

   It appears that I am not doing everything that is necessary to
 initialise the GUS. However, I managed to correct the problem by
 either re-booting (not a brilliant solution) or running Dual Module
 Player, which seems to initialise it properly. If someone knows where
 i'm going wrong, please say so!

   Anyway, the following routine should be called after you have found
 the GUS, and before you start doing anything else with the GUS.



  Procedure GUSDelay; Assembler;

  { Pause for approx. 7 cycles. }

  ASM
    mov   dx, 0300h
    in    al, dx
    in    al, dx
    in    al, dx
    in    al, dx
    in    al, dx
    in    al, dx
    in    al, dx
  End;


  Procedure GUSReset;

  { An incomplete routine to initialise the GUS for output. }

  Begin
    port [Base+$103]   := $4C;
    port [Base+$105] := 1;
    GUSDelay;
    port [Base+$103]   := $4C;
    port [Base+$105] := 7;
    port [Base+$103]   := $0E;
    port [Base+$105] := (14 OR $0C0);
  End;


   Now you have all the routine necessary to find and initialise the
 GUS, let's see just what we can get the GUS to do!


 MAKING SOUNDS
 ~~~~~~~~~~~~~
   The GUS is unique in that it allows you to store the data to be
 played in it's onboard DRAM. To play the sample, you then tell it what
 frequency to play it at, what volume and pan position, and which sample
 to play. The GUS will then do everything in the background, it will
 interpolate the data to give an effective 44khz (or less, depending on
 how many active voices) sample. This means that an 8khz sample will
 sound better on the GUS than most other cards, since the GUS will play
 it at 44khz!

   The GUS also has 32 seperate digital channels (that are mixed by a
 processor on the GUS) which all have their own individual samples,
 frequencies, volumes and panning positions. For some reason, however,
 the GUS can only maintain 44khz output with 16 channels - the more
 channels, the lower the playback rate (which basically means, lower
 quality). If you are using all 32 channels (unlikely), then playback is
 reduced to 22khz.

   Since you allready know how to store samples in the GUS dram (simply
 use the GUSPoke routine to store the bytes) we will now look at various
 routines to change the way the gus plays a sample. The first routine we
 will look at will set the volume of an individual channel :

  Procedure GUSSetVolume( Voi : Byte; Vol : Word);

  { Set the volume of channel VOI to Vol, a 16bit logarithmic scale
    volume value -  0 is off, $ffff is full volume, $e0000 is half
    volume, etc }

  Begin
    Port [Base+$102] := Voi;
    Port [Base+$102] := Voi;
    Port [Base+$102] := Voi;
    Port [Base+$103] := 9;
    Portw[Base+$104] := Vol;  { 0-0ffffh, log scale not linear }
  End;

   The volume (and pan position & frequency) can be changed at ANY time
 regardless of weather the GUS is allready playing the sample or not.
 This means that to fade out a sample, you simply make several calls to
 the GUSSetVolume routine with exponentially (to account for the
 logarithmic scale) decreasing values.

   The next two routines will set the pan position (from 0 to 15, 0
   being left, 15 right and 7 middle) and the frequency respectively :

  Procedure GUSSetBalance( V, B : Byte);
  Begin
    Port [Base+$102] := V;
    Port [Base+$102] := V;
    Port [Base+$102] := V;
    Port [Base+$103] := $C;
    Port [Base+$105] := B;
  End;

  Procedure GUSSetFreq( V : Byte; F : Word);
  Begin
    Port [Base+$102] := V;
    Port [Base+$102] := V;
    Port [Base+$102] := V;
    Port [Base+$103] := 1;
    Portw[Base+$104] := F;
  End;

   I'm not sure the the value F in the set frequency procedure. The GUS
 SDK claims that it is the exact frequency at which the sample should be
 played.

   When playing a sample, it is necessary to set the volume, position
 and frequency BEFORE playing the sample. In order to start playing a
 sample, you need to tell the GUS where abouts in memory the sample is
 stored, and how big the sample is  :


  Procedure GUSPlayVoice( V, Mode : Byte;VBegin, VStart, VEnd : Longint);

  { This routine tells the GUS to play a sample commencing at VBegin,
    starting at location VStart, and stopping at VEnd }

  Var
    GUS_Register : Word;
  Begin
    Port [Base+$102] := V;
    Port [Base+$102] := V;
    Port [Base+$103] := $0A;
    Portw[Base+$104] := (VBegin SHR 7) AND 8191;
    Port [Base+$103] := $0B;
    Portw[Base+$104] := (VBegin AND $127) SHL 8;
    Port [Base+$103] := $02;
    Portw[Base+$104] := (VStart SHR 7) AND 8191;
    Port [Base+$103] := $03;
    Portw[Base+$104] := (VStart AND $127) SHL 8;
    Port [Base+$103] := $04;
    Portw[Base+$104] := ((VEnd)   SHR 7) AND 8191;
    Port [Base+$103] := $05;
    Portw[Base+$104] := ((VEnd)   AND $127) SHL 8;
    Port [Base+$103] := $0;
    Port [Base+$105] := Mode;

    { The below part isn't mentioned as necessary, but the card won't
      play anything without it! }

    Port[Base] := 1;
    Port[Base+$103] := $4C;
    Port[Base+$105] := 3;
  end;

   There are a few important things to note about this routine. Firstly,
 the value VEnd refers to the location in memory, not the length of the
 sample. So if the sample commenced at location 1000, and was 5000 bytes
 long, the VEnd would be 6000 if you wanted the sample to play to the
 end. VBegin and VStart are two weird values, one of them defines the
 start of the sample, and the other defines where abouts to actually
 start playing. I'm not sure why both are needed, since I have allways
 set them to the same value.

   Now that the gus is buisy playing a sample, the CPU is totally free
 to be doing other things. We might, for example, want to spy on the gus
 and see where it is currently up to in playing the sample :

  Function VoicePos( V : Byte) : Longint;
  Var
    P : Longint;
    Temp0, Temp1 : Word;
  Begin
    Port [Base+$102] := V;
    Port [Base+$102] := V;
    Port [Base+$102] := V;
    Port [Base+$103] := $8A;
    Temp0 := Portw[Base+$104];
    Port [Base+$103] := $8B;
    Temp1 := Portw[Base+$104];
    VoicePos := (Temp0 SHL 7)+ (Temp1 SHR 8);
  End;

   This routine will return the memory location that the channel V is
 currently playing. If the GUS has reached the end of the sample, then
 the returned value will be VEnd. If you want to see what BYTE value is
 currently being played (for visual output of the sample's waveform),
 then you simply PEEK the location pointed to by this routine.

   Finally, we might want to stop playing the sample before it has
 reached it's end - the following routine will halt the playback on
 channel V.


  Procedure GUSStopVoice( V : Byte);
  Var
    Temp : Byte;
  Begin
    Port [Base+$102] := V;
    Port [Base+$102] := V;
    Port [Base+$102] := V;
    Port [Base+$103] := $80;
    Temp := Port[Base+$105];
    Port [Base+$103] := 0;
    Port [Base+$105] := (Temp AND $df) OR 3;
    GUSDelay;
    Port [Base+$103] := 0;
    Port [Base+$105] := (Temp AND $df) OR 3;
  End;


 SPECIAL EFFECTS
 ~~~~~~~~~~~~~~~
   There are a few extra features of the GUS that are worthy of mention,
 the main one being hardware controlled sample looping. The GUS has a
 control byte for each of the 32 channels. This control byte consists of
 8 flags that effect the way the sample is played, as follows :
  ( The table is taken directly from the GUS Software Developers Kit )

           =================================
           | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
           =================================
             |   |   |   |   |   |   |   |
             |   |   |   |   |   |   |   +---- Voice Stopped
             |   |   |   |   |   |   +-------- Stop Voice
             |   |   |   |   |   +------------ 16 bit data
             |   |   |   |   +---------------- Loop enable
             |   |   |   +-------------------- Bi-directional loop enable
             |   |   +------------------------ Wave table IRQ
             |   +---------------------------- Direction of movement
             +-------------------------------- IRQ pending
        (*)Bit 0 = 1 : Voice is stopped. This gets set by hitting the end
                   address (not looping) or by setting bit 1 in this reg.
           Bit 1 = 1 : Stop Voice. Manually force voice to stop.
           Bit 2 = 1 : 16 bit wave data, 0 = 8 bit data
           Bit 3 = 1 : Loop to begin address when it hits the end address.
           Bit 4 = 1 : Bi-directional looping enabled
           Bit 5 = 1 : Enable wavetable IRQ. Generate an irq when the voice
                       hits the end address. Will generate irq even if looping
                       is enabled.
        (*)Bit 6 = 1 - Decreasing addresses, 0 = increasing addresses. It is
                       self-modifying because it might shift directions when
                       it hits one of the loop boundaries and looping is enabled.
        (*)Bit 7 = 1 - Wavetable IRQ pending. If IRQ's are enabled and
                       looping is NOT enabled, an IRQ will be constantly
                       generated until voice is stopped. This means that
                       you may get more than 1 IRQ if it isn't handled
                       properly.


  Procedure GUSVoiceControl( V, B : Byte);
  Begin
    Port [Base+$102] := V;
    Port [Base+$102] := V;
    Port [Base+$103] := $0;
    Port [Base+$105] := B;
  End;


   The above routine will set the Voice Control byte for the channel
 defined in V. For example, if you want channel 1 to play the sample in
 a continuous loop, you would use the procedure like this :

    GUSVoiceControl( 1, $F );  { Bit 3 ON = $F }


 CONCLUSION
 ~~~~~~~~~~

   The above routines are all that is necessary to get the GUS to start
 playing music. To prove this, I have included my 669 player & source
 code in the package as a practical example. The GUSUnit contains all
 the routines discussed above. I won't go into the theory of the 669
 player, but it is a good starting point if you want to learn about
 modplayers. The player is contained within the archive 669UNIT.ARJ



┌────────┬───────────────────────────────────────────────────────────────────
│ README │
└────────┘


  GUS669 Unit  v0.2b
  Copyright 1994 Mark Dixon.
  (aka C.D. of Silicon Logic)


  LEGAL STUFF
  ~~~~~~~~~~~
  I'd like to avoid this, but it has to be done. Basically, if anything
  in this archive causes any kind of damage, I cannot be held
  responsable - USE AT YOUR OWN RISK.

  In adition, since I spent long hours working on this project, and
  attempting to decode the GUS SDK, I would appreciate it if people
  didn't rip off my work. Give me credit for what I have done, and if
  your planning to use my routines for commercial purposes, talk to me
  first, or you might find yourself on the wrong side of a legal battle.
  (Hey, let's sound tough while i'm at it, I have lawyer's in the
  family, so it's not gonna cost me much to sue someone. And don't
  criticise my spelling! :)



  BORING STUFF
  ~~~~~~~~~~~~
  Well, if your the sort of person who likes to ignore all the rubishy
  bits that go into a README text file, then you'd better stop now and
  go and try out the source code!

  Basically, this readme isn't going to say much more than what the
  source code is, and then go dribling on for five pages about
  absolutely nothing.


  SOURCE CODE! DID SOMEONE SAY - SOURCE CODE!! - ????
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  Yes, that's right, free with every download of this wonderful archive
  comes the complete Pascal source code to a 669 module player for the
  GUS. I'd have included my MOD player, but I haven't been able to get
  all the MOD commands working, so you'll just have to make do with a
  669 player :)

  Feel free to make use of this source code for any non-commercial
  purposes you might be able to think of - and mention my name while
  your at it! Since the source code is here, people are bound to modify
  it for their personal uses. If you do this, I would very much like to
  see your modifications - so that I can include them in the next
  release of the player.


  Well, I don't want to bore you anymore, and it's getting late (not!)
  so i'd better let you go and play around with the source code :)


  SILICON LOGIC
  ~~~~~~~~~~~~~
  What ever happened to Silicon Logic? Well, after being killed off over
  in Perth, a major revival is underway here in Canberra, with a more
  commercial view - more on that later.

  For those of you who have never heard of Silicon Logic, then you're
  either not Australian, or not into the ausie demo scene. But then,
  that covers about 99.999999999999% of the world population :)


  GREETINGS
  ~~~~~~~~~
  I've allways wanted to dribble some thanks, so here goes.

   Thanks go to...

    Darren Lyon    - Who got me into this programming lark in the first
                     place. Finally wrote myself a mod player :)
    Tran           - Your source code really helped!
    Kitsune        - Love those mods, keep up the good work!

    ... and Advanced Gravis, for making the best sound card ever.

   Greetings to...

    FiRE members   - I'll probably never join you guys, but good luck
                     anyway!
    UNiQUE         - How's the board going?
    CRaSH          - Still ripping other peoples source code?
    Old SL members - Thanks for the support, good luck with your new
                     group!
    Oliver White   - G'day... just thought i'd say hi, since you so
                     kindly beta tested the player for me.
    Murray Head    - Rick Price sux! :-) SoundBlaster sux too! :-)
    Perth people   - I'm coming back... someday!


    THE PICK / MINNOW   -  Hey, give me a call sometime, long time no
                           talk...



  INTERESTED IN A DEMO GROUP IN CANBERRA?
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  If there is anyone interested in joining a demo / coding group in
  Canberra (ACT), then drop me a line.



┌────────────┬───────────────────────────────────────────────────────────────
│ GUSUNIT.PAS│
└────────────┘

Unit  GUSUnit;

{
  GUS DigiUnit  v1.0
  Copyright 1994 Mark Dixon.

  This product is "Learnware".

  All contents of this archive, including source and executables, are the
  intellectual property of the author, Mark Dixon. Use of this product for
  commercial programs, or commercial gain in ANY way, is illegal. Private
  use, or non-commercial use (such as demos, PD games, etc) is allowed,
  provided you give credit to the author for these routines.

  Feel free to make any modifications to these routines, but I would
  appreciate it if you sent me these modifications, so that I can include
  them in the next version of the Gus669 Unit.

  If you wish to use these routines for commercial purposes, then you will
  need a special agreement. Please contact me, Mark Dixon, and we can work
  something out.

  What's "Learnware"? Well, I think I just made it up actually. What i'm
  getting at is that the source code is provided for LEARNING purposes only.
  I'd get really angry if someone ripped off my work and tried to make out
  that they wrote a mod player.

  As of this release (Gus699 Unit), the Gus DigiUnit has moved to version
  1.0, and left the beta stage. I feel these routines are fairly sound,
  and I haven't made any changes to them in weeks.


  Notice the complete absence of comments here? Well, that's partially
  the fault of Gravis and their SDK, since it was so hard to follow, I
  was more worried about getting it working than commenting it. No offense
  to Gravis though, since they created this wonderful card! :-) It helps
  a lot if you have the SDK as a reference when you read this code,
  otherwise you might as well not bother reading it.

}



INTERFACE

Procedure GUSPoke(Loc : Longint; B : Byte);
Function  GUSPeek(Loc : Longint) : Byte;
Procedure GUSSetFreq( V : Byte; F : Word);
Procedure GUSSetBalance( V, B : Byte);
Procedure GUSSetVolume( Voi : Byte; Vol : Word);
Procedure GUSPlayVoice( V, Mode : Byte;VBegin, VStart, VEnd : Longint);
Procedure GUSVoiceControl( V, B : Byte);
Procedure GUSReset;
Function VoicePos( V : Byte) : Longint;

Const
  Base : Word = $200;
  Mode : Byte = 0;

IMPLEMENTATION


Uses Crt;

Function Hex( W : Word) : String;
Var
  I, J : Word;
  S : String;
  C : Char;
Const
  H : Array[0..15] of Char = ('0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F');
Begin
  S := '';
  S := S + H[(W DIV $1000) MOD 16];
  S := S + H[(W DIV $100 ) MOD 16];
  S := S + H[(W DIV $10  ) MOD 16];
  S := S + H[(W DIV $1   ) MOD 16];
  Hex := S+'h';
End;


Procedure GUSDelay; Assembler;
ASM
  mov   dx, 0300h
  in    al, dx
  in    al, dx
  in    al, dx
  in    al, dx
  in    al, dx
  in    al, dx
  in    al, dx
End;



Function VoicePos( V : Byte) : Longint;
Var
  P : Longint;
  I, Temp0, Temp1 : Word;
Begin
  Port [Base+$102] := V;
  Port [Base+$103] := $8A;
  Temp0 := Portw[Base+$104];
  Port [Base+$103] := $8B;
  Temp1 := Portw[Base+$104];
  VoicePos := (Temp0 SHL 7)+ (Temp1 SHR 8);
  For I := 1 to 10 do GusDelay;
End;


Function  GUSPeek(Loc : Longint) : Byte;
Var
  B : Byte;
  AddLo : Word;
  AddHi : Byte;
Begin
  AddLo := Loc AND $FFFF;
  AddHi := LongInt(Loc AND $FF0000) SHR 16;

  Port [Base+$103] := $43;
  Portw[Base+$104] := AddLo;
  Port [Base+$103] := $44;
  Port [Base+$105] := AddHi;

  B := Port[Base+$107];
  GUSPeek := B;
End;


Procedure GUSPoke(Loc : Longint; B : Byte);
Var
  AddLo : Word;
  AddHi : Byte;
Begin
  AddLo := Loc AND $FFFF;
  AddHi := LongInt(Loc AND $FF0000) SHR 16;
{  Write('POKE  HI :', AddHi:5, '  LO : ', AddLo:5, '    ');}
  Port [Base+$103] := $43;
  Portw[Base+$104] := AddLo;
  Port [Base+$103] := $44;
  Port [Base+$105] := AddHi;
  Port [Base+$107] := B;
{  Writeln(B:3);}
End;


Function GUSProbe : Boolean;
Var
  B : Byte;
Begin
  Port [Base+$103] := $4C;
  Port [Base+$105] := 0;
  GUSDelay;
  GUSDelay;
  Port [Base+$103] := $4C;
  Port [Base+$105] := 1;
  GUSPoke(0, $AA);
  GUSPoke($100, $55);
  B := GUSPeek(0);
{  Port [Base+$103] := $4C;
  Port [Base+$105] := 0;}
  { Above bit disabled since it appears to prevent the GUS from accessing
    it's memory correctly.. in some bizare way.... }

  If B = $AA then GUSProbe := True else GUSProbe := False;
End;


Procedure GUSFind;
Var
  I : Word;
Begin
  for I := 1 to 8 do
  Begin
    Base := $200 + I*$10;
    If GUSProbe then I := 8;
  End;
  If Base < $280 then
    Write('Found your GUS at ', Hex(Base), ' ');
End;


Function  GUSFindMem : Longint;
{ Returns how much RAM is available on the GUS }
Var
  I : Longint;
  B : Byte;
Begin
  GUSPoke($40000, $AA);
  If GUSPeek($40000) <> $AA then I := $3FFFF
    else
  Begin
    GUSPoke($80000, $AA);
    If GUSPeek($80000) <> $AA then I := $8FFFF
      else
    Begin
      GUSPoke($C0000, $AA);
      If GUSPeek($C0000) <> $AA then I := $CFFFF
        else I := $FFFFF;
    End;
  End;
  GUSFindMem := I;
End;


Procedure GUSSetFreq( V : Byte; F : Word);
Begin
  Port [Base+$102] := V;
  Port [Base+$102] := V;
  Port [Base+$102] := V;
  Port [Base+$103] := 1;
  Portw[Base+$104] := (F { DIV 19}); { actual frequency / 19.0579083837 }
End;

Procedure GUSVoiceControl( V, B : Byte);
Begin
  Port [Base+$102] := V;
  Port [Base+$102] := V;
  Port [Base+$103] := $0;
  Port [Base+$105] := B;
End;



Procedure GUSSetBalance( V, B : Byte);
Begin
  Port [Base+$102] := V;
  Port [Base+$102] := V;
  Port [Base+$102] := V;
  Port [Base+$103] := $C;
  Port [Base+$105] := B;
End;


Procedure GUSSetVolume( Voi : Byte; Vol : Word);
Begin
  Port [Base+$102] := Voi;
  Port [Base+$102] := Voi;
  Port [Base+$102] := Voi;
  Port [Base+$103] := 9;
  Portw[Base+$104] := Vol;  { 0-0ffffh, log ... not linear }
End;


Procedure GUSSetLoopMode( V : Byte);
Var
  Temp : Byte;
Begin
  Port [Base+$102] := V;
  Port [Base+$102] := V;
  Port [Base+$102] := V;
  Port [Base+$103] := $80;
  Temp := Port[Base+$105];
  Port [Base+$103] := 0;
  Port [Base+$105] := (Temp AND $E7) OR Mode;
End;


Procedure GUSStopVoice( V : Byte);
Var
  Temp : Byte;
Begin
  Port [Base+$102] := V;
  Port [Base+$102] := V;
  Port [Base+$102] := V;
  Port [Base+$103] := $80;
  Temp := Port[Base+$105];
  Port [Base+$103] := 0;
  Port [Base+$105] := (Temp AND $df) OR 3;
  GUSDelay;
  Port [Base+$103] := 0;
  Port [Base+$105] := (Temp AND $df) OR 3;
End;


Procedure GUSPlayVoice( V, Mode : Byte;VBegin, VStart, VEnd : Longint);
Var
  GUS_Register : Word;
Begin
  Port [Base+$102] := V;
  Port [Base+$102] := V;
  Port [Base+$103] := $0A;
  Portw[Base+$104] := (VBegin SHR 7) AND 8191;
  Port [Base+$103] := $0B;
  Portw[Base+$104] := (VBegin AND $127) SHL 8;
  Port [Base+$103] := $02;
  Portw[Base+$104] := (VStart SHR 7) AND 8191;
  Port [Base+$103] := $03;
  Portw[Base+$104] := (VStart AND $127) SHL 8;
  Port [Base+$103] := $04;
  Portw[Base+$104] := ((VEnd)   SHR 7) AND 8191;
  Port [Base+$103] := $05;
  Portw[Base+$104] := ((VEnd)   AND $127) SHL 8;
  Port [Base+$103] := $0;
  Port [Base+$105] := Mode;

  { The below part isn't mentioned as necessary, but the card won't
    play anything without it! }

  Port[Base] := 1;
  Port[Base+$103] := $4C;
  Port[Base+$105] := 3;

end;


Procedure GUSReset;
Begin
  port [Base+$103]   := $4C;
  port [Base+$105] := 1;
  GUSDelay;
  port [Base+$103]   := $4C;
  port [Base+$105] := 7;
  port [Base+$103]   := $0E;
  port [Base+$105] := (14 OR $0C0);
End;



Var
  I : Longint;
  F : File;
  Buf : Array[1..20000] of Byte;
  S : Word;


Begin
  Clrscr;
  Writeln('GUS DigiUnit V1.0');
  Writeln('Copyright 1994 Mark Dixon.');
  Writeln;
  GUSFind;
  Writeln('with ', GUSFindMem, ' bytes onboard.');
  Writeln;
  GUSReset;
End.


┌────────────┬───────────────────────────────────────────────────────────────
│ GUS669.PAS │
└────────────┘

UNIT Gus669;

{
  GUS669 Unit  v0.2b
  Copyright 1994 Mark Dixon.

  This product is "Learnware".

  All contents of this archive, including source and executables, are the
  intellectual property of the author, Mark Dixon. Use of this product for
  commercial programs, or commercial gain in ANY way, is illegal. Private
  use, or non-commercial use (such as demos, PD games, etc) is allowed,
  provided you give credit to the author for these routines.

  Feel free to make any modifications to these routines, but I would
  appreciate it if you sent me these modifications, so that I can include
  them in the next version of the Gus669 Unit.

  If you wish to use these routines for commercial purposes, then you will
  need a special agreement. Please contact me, Mark Dixon, and we can work
  something out.

  What's "Learnware"? Well, I think I just made it up actually. What i'm
  getting at is that the source code is provided for LEARNING purposes only.
  I'd get really angry if someone ripped off my work and tried to make out
  that they wrote a mod player.

  Beta version? Yes, since the product is still slightly unstable, I feel
  it is right to keep it under beta status until I find and fix a few
  bugs.

  FEATURES
    - Only works with the GUS!
    - 8 channel, 669 music format.
    - That's about it really.
    - Oh, 100% Pascal high level source code = NO ASSEMBLER!
      (So if you want to learn about how to write your own MOD player, this
       should make it easier for you)
    - Tested & compiled with Turbo Pascal v7.0

  BUGS
    - Not yet, give me a chance!
      (If you find any, I would very much appreciate it if you could take
       the time to notify me)
    - Doesn't sound right with some modules, advice anyone??
    - Could do with some better I/O handling routines when loading the
      669 to give better feedback to the user about what went wrong
      if the module didn't load.


 You can contact me at any of the following :

 FidoNet  : Mark Dixon  3:620/243
 ItnerNet : [e-mail]         ( prefered )
            [e-mail]    ( might not work for mail :) )
            [e-mail]      ( Don't use this one often )
            [e-mail]    ( Might not exist any more,
                                             that's how often it's used! )
            I collect internet accounts.... :)

 If you happen to live in the Australian Capital Territory, you can
 call me on  231-2000, but at respectable hours please.


 "Want more comments? Write em!"
 Sorry, I just had to quote that. I'm not in the mood for writing lots
 of comments just yet. The main reason for writing it in Pascal is so
 that it would be easy to understand. Comments may (or may not) come later
 on.

 Okay, enough of me dribbling, here's the source your after!

}




Interface

Procedure Load669(N : String);
Procedure PlayMusic;
Procedure StopMusic;

Type
  { This is so that we can keep a record of what each channel is
    currently doing, so that we can inc/dec the Frequency or volume,
    or pan left/right, etc }
  Channel_Type    = Record
                      Vol : Word;
                      Freq : Word;
                      Pan : Byte;
                    End;

Var
  Channels : Array[1..8] of Channel_Type;
  Flags : Array[0..15] of Byte;
  { Programmer flags. This will be explained when it is fully implemented. }

Const
  Loaded : Boolean = False;    { Is a module loaded? }
  Playing : Boolean = False;   { Is a module playing? }
  WaitState : Boolean = False; { Set to TRUE whenever a new note is played }
                               { Helpful for timing in with the player }


Const
  NumChannels = 8;

  { Thanks to Tran for releasing the Hell demo source code, from which
    I managed to find these very helpfull volume and frequency value
    tables, without which this player would not have worked! }

  voltbl : Array[0..15] of Byte =
                     (  $004,$0a0,$0b0,$0c0,$0c8,$0d0,$0d8,$0e0,
                        $0e4,$0e8,$0ec,$0f1,$0f4,$0f6,$0fa,$0ff);
  freqtbl : Array[1..60] of Word = (
                        56,59,62,66,70,74,79,83,88,94,99,105,
                        112,118,125,133,141,149,158,167,177,188,199,211,
                        224,237,251,266,282,299,317,335,355,377,399,423,
                        448,475,503,532,564,598,634,671,711,754,798,846,
                        896,950,1006,1065,1129,1197,1268,1343,1423,1508,1597,1692 );



Type
  Header_669_Type = Record
                      Marker      : Word;
                      Title       : Array[1..108] of Char;
                      NOS,                     { No of Samples  0 - 64 }
                      NOP         : Byte;      { No of Patterns 0 - 128 }
                      LoopOrder   : Byte;
                      Order       : Array[0..127] of Byte;
                      Tempo       : Array[0..127] of Byte;
                      Break       : Array[0..127] of Byte;
                    End;
  Sample_Type     = Record
                      FileName  : Array[1..13] of Char;
                      Length    : Longint;
                      LoopStart : Longint;
                      LoopLen   : Longint;
                    End;
  Sample_Pointer  = ^Sample_Type;
  Note_Type       = Record
                      Info,  { <- Don't worry about this little bit here }
                      Note,
                      Sample,
                      Volume,
                      Command,
                      Data    : Byte;
                    End;
  Event_Type      = Array[1..8] of Note_Type;
  Pattern_Type    = Array[0..63] of Event_Type;
  Pattern_Pointer = ^Pattern_Type;



Var
  Header : Header_669_Type;
  Samples : Array[0..64] of Sample_Pointer;
  Patterns : Array[0..128] of Pattern_Pointer;
  GusTable : Array[0..64] of Longint;
  GusPos : Longint;
  Speed : Byte;
  Count : Word;
  OldTimer : Procedure;
  CurrentPat, CurrentEvent : Byte;


Implementation

Uses Dos, Crt, GUSUnit;


Procedure Load669(N : String);
Var
  F : File;
  I, J, K : Byte;
  T : Array[1..8,1..3] of Byte;

  Procedure LoadSample(No, Size : Longint);
  Var
    Buf : Array[1..1024] of Byte;
    I : Longint;
    J, K : Integer;
  Begin
    GusTable[No] := GusPos;

    I := Size;
    While I > 1024 do
    Begin
      BlockRead(F, Buf, SizeOf(Buf), J);
      For K := 1 to J do GusPoke(GusPos+K-1, Buf[K] XOR 127);
      Dec(I, J);
      Inc(GusPos, J);
    End;
    BlockRead(F, Buf, I, J);
    For K := 1 to J do GusPoke(GusPos+K-1, Buf[K] XOR 127);
    Inc(GusPos, J);
  End;

Begin
  {$I-}
  Assign(F, N);
  Reset(F, 1);
  BlockRead(F, Header, SizeOf(Header));
  If Header.Marker = $6669 then
  Begin
    For I := 1 to Header.NOS do
    Begin
      New(Samples[I-1]);
      BlockRead(F, Samples[I-1]^, SizeOf(Samples[I-1]^));
    End;

    For I := 0 to Header.NOP-1 do
    Begin
      New(Patterns[I]);
      For J := 0 to 63 do
      Begin
        BlockRead(F, T, SizeOf(T));
        For K := 1 to 8 do
        Begin
          Patterns[I]^[J,K].Info    := t[K,1];
          Patterns[I]^[J,K].Note    := ( t[K,1] shr 2);
          Patterns[I]^[J,K].Sample  := ((t[K,1] AND 3) SHL 4) +  (t[K,2] SHR 4);
          Patterns[I]^[J,K].Volume  := ( t[K,2] AND 15);
          Patterns[I]^[J,K].Command := ( t[K,3] shr 4);
          Patterns[I]^[J,K].Data    := ( t[K,3] AND 15);
        End;
      End;
    End;

    For I := 1 to Header.NOS do
      LoadSample(I-1, Samples[I-1]^.Length);
  End;

  Close(F);
  {$I+}
  If (IOResult <> 0) OR (Header.Marker <> $6669) then
    Loaded := False else Loaded := True;

End;




Procedure UpDateNotes;
Var
  I : Word;
  Inst : Byte;
  Note : Word;
Begin
  WaitState := True;
  For I := 1 to NumChannels do
  With Patterns[Header.Order[CurrentPat]]^[CurrentEvent, I] do

  For I := 1 to NumChannels do
  If (Patterns[Header.Order[CurrentPat]]^[CurrentEvent, I].Info < $FE) then
  Begin
    Inst := Patterns[Header.Order[CurrentPat]]^[CurrentEvent, I].Sample;
    Note := Patterns[Header.Order[CurrentPat]]^[CurrentEvent, I].Note;
    Channels[I].Freq := FreqTbl[Note];
{    Channels[I].Pan  := (1-(I AND 1)) * 15;}
    Channels[I].Vol  := $100*VolTbl[Patterns[Header.Order[CurrentPat]]^[CurrentEvent, I].Volume];
{    Write(Note:3,Inst:3,' -');}

    GUSSetVolume    (I, 0);
    GUSVoiceControl (I, 1);
    GUSSetBalance   (I, Channels[I].Pan);
    GusSetFreq      ( I, Channels[I].Freq);
{    GUSPlayVoice    ( I, 0, GusTable[Inst],
                            GusTable[Inst],
                            GusTable[Inst]+Samples[Inst]^.Length  );}

{    Write(Samples[Inst]^.LoopLen:5);}
    If Samples[Inst]^.LoopLen < 1048575 then
    Begin
    GUSPlayVoice    ( I, 8, GusTable[Inst],
                            GusTable[Inst]+Samples[Inst]^.LoopStart,
                            GusTable[Inst]+Samples[Inst]^.LoopLen  );
    End
      Else
    Begin
    GUSPlayVoice    ( I, 0, GusTable[Inst],
                            GusTable[Inst],
                            GusTable[Inst]+Samples[Inst]^.Length  );
    End;


  End;

{  Writeln;}

  For I := 1 to NumChannels do
    If (Patterns[Header.Order[CurrentPat]]^[CurrentEvent, I].Info < $FF) then
      GUSSetVolume (I, $100*VolTbl[Patterns[Header.Order[CurrentPat]]^[CurrentEvent, I].Volume]);

  For I := 1 to NumChannels do
  With Patterns[Header.Order[CurrentPat]]^[CurrentEvent, I] do
  Case Command of
    5 : Speed := Data;
    3 : Begin
          Channels[I].Freq := Channels[I].Freq + 10;
          GUSSetFreq(I, Channels[I].Freq);
        End;
    8 : Inc(Flags[Data]);
    6 : Case Data of
          0 : If Channels[I].Pan > 0 then
              Begin
                Dec(Channels[I].Pan);
                GusSetBalance(I, Channels[I].Pan);
              End;
          1 : If Channels[I].Pan < 15 then
              Begin
                Inc(Channels[I].Pan);
                GusSetBalance(I, Channels[I].Pan);
              End;
        End;
  End;





  Inc(CurrentEvent);
  If CurrentEvent > Header.Break[CurrentPat] then Begin CurrentEvent := 0; Inc(CurrentPat) End;
  If Header.Order[CurrentPat] > (Header.NOP) then Begin CurrentEvent := 0; CurrentPat := 0; End;

End;


Procedure UpDateEffects;
Var
  I : Word;
Begin
  For I := 1 to 4 do
  With Patterns[Header.Order[CurrentPat]]^[CurrentEvent, I] do
  Begin
    Case Command of
      0 : Begin
            Inc(Channels[I].Freq, Data);
            GusSetFreq(I, Channels[I].Freq);
          End;
      1 : Begin
            Dec(Channels[I].Freq, Data);
            GusSetFreq(I, Channels[I].Freq);
          End;
    End;
  End;
End;




{ $ F+,S-,W-}
Procedure ModInterrupt; Interrupt;
Begin
  Inc(Count);
  If Count = Speed then
  Begin
    UpDateNotes;
    Count := 0;
  End;
  UpDateEffects;
  If (Count MOD 27) = 1 then
  Begin
    inline ($9C);
    OldTimer;
  End;
  Port[$20] := $20;
End;
{ $ F-,S+}

Procedure TimerSpeedup(Speed : Word);
Begin
  Port[$43] := $36;
  Port[$40] := Lo(Speed);
  Port[$40] := Hi(Speed);
end;

Procedure PlayMusic;
Begin
  If Loaded then
  Begin
    TimerSpeedUp( (1192755 DIV 32));
    GetIntVec($8, Addr(OldTimer));
    SetIntVec($8, Addr(ModInterrupt));
    Speed := Header.Tempo[0];
    Playing := True;
  End
  { If the module is not loaded, then the Playing flag will not be set,
    so your program should check the playing flag just after calling
    PlayMusic to see if everything was okay. }
End;


Procedure StopMusic;
Var
  I : Byte;
Begin
  If Playing then
  Begin
    SetIntVec($8, Addr(OldTimer));
    For I := 1 to NumChannels do GusSetVolume(I, 0);
  End;
  TimerSpeedUp($FFFF);
End;


Procedure Init;
Var
  I : Byte;
Begin
  GusPos := 1;
  Count := 0;
  Speed := 6;
  CurrentPat := 0;
  CurrentEvent := 0;
  For I := 1 to NumChannels do Channels[I].Pan  := (1-(I AND 1)) * 15;
  For I := 1 to NumChannels do GUSVoiceControl(I, 1);
  For I := 0 to 15 do Flags[I] := 0;
End;


Var
  I, J : Byte;


Begin
  Init;
  Writeln('GUS669 Unit V0.2b');
  Writeln('Copyright 1994 Mark Dixon.');
  Writeln;
End.


┌─────────────┬──────────────────────────────────────────────────────────────
│ PLAY669.PAS │
└─────────────┘

Program Testout_Gus669_Unit;

Uses Crt, GUS669;

Begin

  If ParamCount > 0 then Load669(Paramstr(1))
    else
  Begin
    Writeln;
    Writeln('Please specify the name of the 669 module you wish to play');
    Writeln('from the command line.');
    Writeln;
    Writeln('eg :    Play669  Hardwired.669 ');
    Writeln;
    Halt(1);
  End;
  PlayMusic;
  If Playing then
  Begin
    Writeln('Playing ', ParamStr(1) );
    Writeln('Press any key to stop and return to DOS.');
    Repeat
    Until Keypressed
  End
    else
  Begin
    Writeln;
    Writeln('Couldn''t load or play the module for some reason!');
    Writeln;
    Writeln('Please check your GUS is working correctly, and that you have');
    Writeln('correctly specified the 669 filename.');
    Writeln;
  End;
  StopMusic;
End.