outdev.c

/*
 * Wrapper for outputing MIDI commands to different devices.
 *
 * Copyright (c) 2015, Mateusz Viste
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <conio.h> /* outp(), inp() */
#include <dos.h>

#include "mpu401.h"

#include "outdev.h" /* include self for control */


static enum outdev_types outdev = DEV_NONE;
static unsigned short outport = 0;


/* inits the out device, also selects the out device, from one of these:
 *  DEV_MPU401
 *  DEV_OPL2
 *  DEV_NONE
 *
 * This should be called only ONCE, when program starts.
 * Returns 0 on success, non-zero otherwise.
 */
int dev_init(enum outdev_types dev, unsigned short port) {
  outdev = dev;
  outport = port;
  switch (outdev) {
    case DEV_MPU401:
      /* reset the MPU401 */
      if (mpu401_rst(outport) != 0) return(-1);
      /* put it into UART mode */
      mpu401_uart(outport);
      break;
    case DEV_OPL2:
      break;
    case DEV_NONE:
      break;
  }
  dev_clear();
  return(0);
}


/* close/deinitializes the out device */
void dev_close(void) {
  switch (outdev) {
    case DEV_MPU401:
      mpu401_rst(outport); /* resets it to intelligent mode */
      break;
    case DEV_OPL2:
      break;
    case DEV_NONE:
      break;
  }
}


/* clears/reinits the out device (turns all sounds off...). this can be used
 * often (typically: between each song). */
void dev_clear(void) {
  unsigned char buff[4] = {0, 0, 0, 0};
  unsigned char far *buffptr;
  int i;
  switch (outdev) {
    case DEV_MPU401:
      buffptr = buff;
      /* iterate on MIDI channels and send messages */
      for (buff[0] = 0xB0; buff[0] <= 0xBF; buff[0] += 1) {
        /* Send "all notes off" (second byte is zero) */
        buff[1] = 0x7B;
        dev_rawmidi(buffptr, 3);
        /* Send "all sounds off" (second byte is zero) */
        buff[1] = 0x78;
        dev_rawmidi(buffptr, 3);
        /* "all controllers off" */
        buff[1] = 0x79;
        dev_rawmidi(buffptr, 3);
      }
      break;
    case DEV_OPL2:
      break;
    case DEV_NONE:
      break;
  }
  /* load default GM instruments (even real MIDI synths do not always reset those) */
  for (i = 0; i < 16; i++) dev_setprog(i, i);
}


/* activate note on channel */
void dev_noteon(int channel, int note, int velocity) {
  switch (outdev) {
    case DEV_MPU401:
      mpu401_waitwrite(outport);      /* Wait for port ready */
      outp(outport, 0x90 | channel);  /* Send note ON code on selected channel */
      mpu401_waitwrite(outport);      /* Wait for port ready */
      outp(outport, note);            /* Send note Number to turn ON */
      mpu401_waitwrite(outport);      /* Wait for port ready */
      outp(outport, velocity);        /* Send velocity */
      break;
    case DEV_OPL2:
      break;
    case DEV_NONE:
      break;
  }
}


/* disable note on channel */
void dev_noteoff(int channel, int note) {
  switch (outdev) {
    case DEV_MPU401:
      mpu401_waitwrite(outport);      /* Wait for port ready */
      outp(outport, 0x80 | channel);  /* Send note OFF code on selected channel */
      mpu401_waitwrite(outport);      /* Wait for port ready */
      outp(outport, note);            /* Send note number to turn OFF */
      mpu401_waitwrite(outport);      /* Wait for port ready */
      outp(outport, 64);              /* Send velocity */
      break;
    case DEV_OPL2:
      break;
    case DEV_NONE:
      break;
  }
}


/* sends raw midi message */
void dev_rawmidi(unsigned char far *rawdata, int rawlen) {
  int i;
  switch (outdev) {
    case DEV_MPU401:
      for (i = 0; i < rawlen; i++) {
        mpu401_waitwrite(outport);     /* Wait for port ready */
        outp(outport, rawdata[i]);     /* Send the raw byte over the wire */
      }
      break;
    case DEV_OPL2:
      break;
    case DEV_NONE:
      break;
  }
}


/* should be called by the application from time to time */
void dev_tick(void) {
  switch (outdev) {
    case DEV_MPU401:
      mpu401_flush(outport);
      break;
    case DEV_OPL2:
      break;
    case DEV_NONE:
      break;
  }
}


/* sets a "program" (meaning an instrument) on a channel */
void dev_setprog(int channel, int program) {
  switch (outdev) {
    case DEV_MPU401:
      mpu401_waitwrite(outport);     /* Wait for port ready */
      outp(outport, 0xC0 | channel); /* Send channel */
      mpu401_waitwrite(outport);     /* Wait for port ready */
      outp(outport, program);        /* Send patch id */
      break;
    case DEV_OPL2:
      break;
    case DEV_NONE:
      break;
  }
}