/* ------------------------ DPMIDVT.H --------------------------- */
/* DPMI interface code to DemoVT v1.5 and higher.                 */
/* Written bye Jare of Iguana in 1994.                            */
/* -------------------------------------------------------------- */
/* Thanks to Yann for supplying all those specs, and also to Tran */
/* of nothing for getting me into this wonderful world of PMode.  */
/* -------------------------------------------------------------- */
/* This code will compile under Watcom C++ 9.5. I think it should */
/* work also with other versions and under other 32 bit compilers */
/* but I haven't bothered to test.                                */
/* -------------------------------------------------------------- */
/* You will find some general purpose DPMI code here. Use it!     */
/* Especially that RealModeMem variable.                          */
/* That variable is not necessary under DOS4GW, because the first */
/* megabyte is directly accesible using the default data seg. But */
/* I have included it to make this code fully portable to other,  */
/* more hostile environments.                                     */
/* You might need to translate it to assembly, but that should be */
/* easy. After all, it's your job! :)                             */
/* -------------------------------------------------------------- */

#ifndef _DPMIDVT_H_
#define _DPMIDVT_H_

// ------------------------------------------------------------------------
// ---------- DemoVT. The real thing.

#pragma pack(1)

typedef struct {
    word  period;             // Period of the playing note.
    byte  ins;                // Number of instrument, 1-31.
    byte  vol;                // Current volume, 0-63.
} TChanData;

typedef struct sDVT_info {    // DemoVT's info structure.
        // Written by DemoVT.
    byte  semaphores   [256]; // 256 semaphores used for synchronisation.
    byte  chansTrig    [32];  // Flags that indicate note triggered for
                              //  each channel. Useful for vu-meters.
    byte  numChannels;        // Number of channels of the current module.
    word  entryPointOff,      // Far pointer to the servicing routine
          entryPointSeg;      //  that receives params thru the stack.
    dword tickCounter;        // 50 Hz counter. Increments 50 times per second.
    word  entryPointAXOff,    // Far pointer to the servicing routine
          entryPointAXSeg;    //  that gets the parameter in AX. It's just
                              //  a PUSH AX; CALL FAR entryPointSeg:Off; RETF

    TChanData chansData[32];  // Info about all playing channels.

    byte  pos;                // Position of the current note in the pattern.
    byte  seq;                // Order number of playing pattern.

    byte  _reserved2   [81];

        // Read and written by DemoVT.
    byte  _reserved3   [3];
    byte  jumpNewPos,         // Boolean. 1 if song must jump.
          jumpPosSeq,         // Sequence and note values to jump to.
          jumpPosNote;
    byte  soundVolume;        // Volume of the sound output.
    byte  abortDvt;           // Set to 1 to abort the demo.
    byte  _reserved4   [248];
} TDVTInfo;

#pragma pack()

extern byte      _far *RealModeMem;     // This gives access to the 1st. Meg.
extern dword           DVTAppIdFound;   // Offset into RealModeMem of the
                                        // DemoVT data returned.
extern volatile TDVTInfo  _far *DVTInfo;         // Pointer to the info structure.
                                        // If DVT_Init fails, all these
                                        // will be 0/NULL.


   // DemoVT access functions.

extern int   DVT_Init(void);
  //         --------
  // Starts the interface variables, and returns if the DemoVT is present.
  // NOTE: check for DVTInfo != NULL even if the DemoVT is present, the
  // DPMI interface might fail (nobody's perfect).

extern void  DVT_CallDemoVT(int command);
  //         --------------
  // Calls DemoVT API entry point.

#define      DVT_CallMusic()       DVT_CallDemoVT(2)
  //         -------------

#define      DVT_ConnectTimer()    DVT_CallDemoVT(0)
  //         ----------------

#define      DVT_DisconnectTimer() DVT_CallDemoVT(1)
  //         -------------------

#define      DVT_BeginSync()       DVT_CallDemoVT(3)
  //         -------------

extern dword DVT_GetTickCounter(void);
  //         ------------------

extern void  DVT_WaitForStart(void);
  //         ----------------

extern void  DVT_JumpPos(byte pattern, byte note);
  //         -----------

extern byte  DVT_GetSemaphore(byte nsem);
  //         ----------------

extern void  DVT_SetSemaphore(byte nsem, byte value);
  //         ----------------

extern void  DVT_MiddleSync(byte nsem, byte pattern, byte note);
  //         --------------

extern byte  DVT_GetSoundVolume(void);
  //         ------------------

extern void  DVT_SetSoundVolume(byte vol);
  //         ------------------

#endif

/* ------------------------ DPMIDVT.H --------------------------- */