opl3.c

内核是系统的心脏

  if (map->voice_mode == 2 && instr->key == OPL3_PATCH)
    return 0;			/* Cannot play */

  voice_mode = map->voice_mode;

  if (voice_mode == 4)
    {
      int             voice_shift;

      voice_shift = (map->ioaddr == left_address) ? 0 : 3;
      voice_shift += map->voice_num;

      if (instr->key != OPL3_PATCH)	/* Just 2 OP patch */
	{
	  voice_mode = 2;
	  connection_mask &= ~(1 << voice_shift);
	}
      else
	{
	  connection_mask |= (1 << voice_shift);
	}

      opl3_command (right_address, CONNECTION_SELECT_REGISTER, connection_mask);
    }

  /* Set Sound Characteristics */
  opl3_command (map->ioaddr, AM_VIB + map->op[0], instr->operators[0]);
  opl3_command (map->ioaddr, AM_VIB + map->op[1], instr->operators[1]);

  /* Set Attack/Decay */
  opl3_command (map->ioaddr, ATTACK_DECAY + map->op[0], instr->operators[4]);
  opl3_command (map->ioaddr, ATTACK_DECAY + map->op[1], instr->operators[5]);

  /* Set Sustain/Release */
  opl3_command (map->ioaddr, SUSTAIN_RELEASE + map->op[0], instr->operators[6]);
  opl3_command (map->ioaddr, SUSTAIN_RELEASE + map->op[1], instr->operators[7]);

  /* Set Wave Select */
  opl3_command (map->ioaddr, WAVE_SELECT + map->op[0], instr->operators[8]);
  opl3_command (map->ioaddr, WAVE_SELECT + map->op[1], instr->operators[9]);

  /* Set Feedback/Connection */
  fpc = instr->operators[10];
  if (!(fpc & 0x30))
    fpc |= 0x30;		/* Ensure that at least one chn is enabled */
  opl3_command (map->ioaddr, FEEDBACK_CONNECTION + map->voice_num,
		fpc);

  /*
   * If the voice is a 4 OP one, initialize the operators 3 and 4 also
   */

  if (voice_mode == 4)
    {

      /* Set Sound Characteristics */
      opl3_command (map->ioaddr, AM_VIB + map->op[2], instr->operators[OFFS_4OP + 0]);
      opl3_command (map->ioaddr, AM_VIB + map->op[3], instr->operators[OFFS_4OP + 1]);

      /* Set Attack/Decay */
      opl3_command (map->ioaddr, ATTACK_DECAY + map->op[2], instr->operators[OFFS_4OP + 4]);
      opl3_command (map->ioaddr, ATTACK_DECAY + map->op[3], instr->operators[OFFS_4OP + 5]);

      /* Set Sustain/Release */
      opl3_command (map->ioaddr, SUSTAIN_RELEASE + map->op[2], instr->operators[OFFS_4OP + 6]);
      opl3_command (map->ioaddr, SUSTAIN_RELEASE + map->op[3], instr->operators[OFFS_4OP + 7]);

      /* Set Wave Select */
      opl3_command (map->ioaddr, WAVE_SELECT + map->op[2], instr->operators[OFFS_4OP + 8]);
      opl3_command (map->ioaddr, WAVE_SELECT + map->op[3], instr->operators[OFFS_4OP + 9]);

      /* Set Feedback/Connection */
      fpc = instr->operators[OFFS_4OP + 10];
      if (!(fpc & 0x30))
	fpc |= 0x30;		/* Ensure that at least one chn is enabled */
      opl3_command (map->ioaddr, FEEDBACK_CONNECTION + map->voice_num + 3, fpc);
    }

  voices[voice].mode = voice_mode;

  set_voice_volume (voice, volume);

  freq = voices[voice].orig_freq = note_to_freq (note) / 1000;

  /*
   * Since the pitch bender may have been set before playing the note, we
   * have to calculate the bending now.
   */

  freq = compute_finetune (voices[voice].orig_freq, voices[voice].bender, voices[voice].bender_range);
  voices[voice].current_freq = freq;

  freq_to_fnum (freq, &block, &fnum);

  /* Play note */

  data = fnum & 0xff;		/* Least significant bits of fnumber */
  opl3_command (map->ioaddr, FNUM_LOW + map->voice_num, data);

  data = 0x20 | ((block & 0x7) << 2) | ((fnum >> 8) & 0x3);
  voices[voice].keyon_byte = data;
  opl3_command (map->ioaddr, KEYON_BLOCK + map->voice_num, data);
  if (voice_mode == 4)
    opl3_command (map->ioaddr, KEYON_BLOCK + map->voice_num + 3, data);

  return 0;
}

static void
freq_to_fnum (int freq, int *block, int *fnum)
{
  int             f, octave;

  /* Converts the note frequency to block and fnum values for the FM chip */
  /* First try to compute the block -value (octave) where the note belongs */

  f = freq;

  octave = 5;

  if (f == 0)
    octave = 0;
  else if (f < 261)
    {
      while (f < 261)
	{
	  octave--;
	  f <<= 1;
	}
    }
  else if (f > 493)
    {
      while (f > 493)
	{
	  octave++;
	  f >>= 1;
	}
    }

  if (octave > 7)
    octave = 7;

  *fnum = freq * (1 << (20 - octave)) / 49716;
  *block = octave;
}

static void
opl3_command (int io_addr, unsigned int addr, unsigned int val)
{
  int             i;

  /*
   * The original 2-OP synth requires a quite long delay after writing to a
   * register. The OPL-3 survives with just two INBs
   */

  OUTB ((unsigned char)(addr & 0xff), io_addr);	/* Select register	 */

  if (!opl3_enabled)
    tenmicrosec ();
  else
    for (i = 0; i < 2; i++)
      INB (io_addr);

  OUTB ((unsigned char)(val & 0xff), io_addr + 1); /* Write to register	 */

  if (!opl3_enabled)
    {
      tenmicrosec ();
      tenmicrosec ();
      tenmicrosec ();
    }
  else
    for (i = 0; i < 2; i++)
      INB (io_addr);
}

static void
opl3_reset (int dev)
{
  int             i;

  for (i = 0; i < nr_voices; i++)
    {
      opl3_command (physical_voices[logical_voices[i]].ioaddr,
		KSL_LEVEL + physical_voices[logical_voices[i]].op[0], 0xff);	/* OP1 volume to min */

      opl3_command (physical_voices[logical_voices[i]].ioaddr,
		KSL_LEVEL + physical_voices[logical_voices[i]].op[1], 0xff);	/* OP2 volume to min */

      if (physical_voices[logical_voices[i]].voice_mode == 4)	/* 4 OP voice */
	{
	  opl3_command (physical_voices[logical_voices[i]].ioaddr,
		KSL_LEVEL + physical_voices[logical_voices[i]].op[2], 0xff);	/* OP3 volume to min */

	  opl3_command (physical_voices[logical_voices[i]].ioaddr,
		KSL_LEVEL + physical_voices[logical_voices[i]].op[3], 0xff);	/* OP4 volume to min */
	}

      opl3_kill_note (dev, i, 64);
    }

  if (opl3_enabled)
    {
      nr_voices = 18;

      for (i = 0; i < 18; i++)
	logical_voices[i] = i;

      for (i = 0; i < 18; i++)
	physical_voices[i].voice_mode = 2;

    }

}

static int
opl3_open (int dev, int mode)
{
  if (!opl3_ok)
    return RET_ERROR (ENXIO);
  if (opl3_busy)
    return RET_ERROR (EBUSY);
  opl3_busy = 1;

  connection_mask = 0x00;	/* Just 2 OP voices */
  if (opl3_enabled)
    opl3_command (right_address, CONNECTION_SELECT_REGISTER, connection_mask);
  return 0;
}

static void
opl3_close (int dev)
{
  opl3_busy = 0;
  nr_voices = opl3_enabled ? 18 : 9;
  fm_info.nr_drums = 0;
  fm_info.perc_mode = 0;

  opl3_reset (dev);
}

static void
opl3_hw_control (int dev, unsigned char *event)
{
}

static int
opl3_load_patch (int dev, int format, snd_rw_buf * addr,
		 int offs, int count, int pmgr_flag)
{
  struct sbi_instrument ins;

  if (count < sizeof (ins))
    {
      printk ("FM Error: Patch record too short\n");
      return RET_ERROR (EINVAL);
    }

  COPY_FROM_USER (&((char *) &ins)[offs], (char *) addr, offs, sizeof (ins) - offs);

  if (ins.channel < 0 || ins.channel >= SBFM_MAXINSTR)
    {
      printk ("FM Error: Invalid instrument number %d\n", ins.channel);
      return RET_ERROR (EINVAL);
    }
  ins.key = format;

  return store_instr (ins.channel, &ins);
}

static void
opl3_panning (int dev, int voice, int pressure)
{
}

#define SET_VIBRATO(cell) { \
      tmp = instr->operators[(cell-1)+(((cell-1)/2)*OFFS_4OP)]; \
      if (pressure > 110) \
	tmp |= 0x40;		/* Vibrato on */ \
      opl3_command (map->ioaddr, AM_VIB + map->op[cell-1], tmp);}

static void
opl3_aftertouch (int dev, int voice, int pressure)
{
  int             tmp;
  struct sbi_instrument *instr;
  struct physical_voice_info *map;

  if (voice < 0 || voice >= nr_voices)
    return;

  map = &physical_voices[logical_voices[voice]];

  DEB (printk ("Aftertouch %d\n", voice));

  if (map->voice_mode == 0)
    return;

  /*
   * Adjust the amount of vibrato depending the pressure
   */

  instr = active_instrument[voice];

  if (!instr)
    instr = &instrmap[0];

  if (voices[voice].mode == 4)
    {
      int             connection = ((instr->operators[10] & 0x01) << 1) | (instr->operators[10 + OFFS_4OP] & 0x01);

      switch (connection)
	{
	case 0:
	  SET_VIBRATO (4);
	  break;

	case 1:
	  SET_VIBRATO (2);
	  SET_VIBRATO (4);
	  break;

	case 2:
	  SET_VIBRATO (1);
	  SET_VIBRATO (4);
	  break;

	case 3:
	  SET_VIBRATO (1);
	  SET_VIBRATO (3);
	  SET_VIBRATO (4);
	  break;

	}
      /* Not implemented yet */
    }
  else
    {
      SET_VIBRATO (1);

      if ((instr->operators[10] & 0x01))	/* Additive synthesis */
	SET_VIBRATO (2);
    }
}

#undef SET_VIBRATO

static void
opl3_controller (int dev, int voice, int ctrl_num, int value)
{
  unsigned char   data;
  int             block, fnum, freq;
  struct physical_voice_info *map;

  if (voice < 0 || voice >= nr_voices)
    return;

  map = &physical_voices[logical_voices[voice]];

  if (map->voice_mode == 0)
    return;

  switch (ctrl_num)
    {
    case CTRL_PITCH_BENDER:
      voices[voice].bender = value;
      if (!value)
	return;
      if (!(voices[voice].keyon_byte & 0x20))
	return;			/* Not keyed on */

      freq = compute_finetune (voices[voice].orig_freq, voices[voice].bender, voices[voice].bender_range);
      voices[voice].current_freq = freq;

      freq_to_fnum (freq, &block, &fnum);

      data = fnum & 0xff;	/* Least significant bits of fnumber */
      opl3_command (map->ioaddr, FNUM_LOW + map->voice_num, data);

      data = 0x20 | ((block & 0x7) << 2) | ((fnum >> 8) & 0x3);	/* KEYON|OCTAVE|MS bits
								 * of f-num */
      voices[voice].keyon_byte = data;
      opl3_command (map->ioaddr, KEYON_BLOCK + map->voice_num, data);
      break;

    case CTRL_PITCH_BENDER_RANGE:
      voices[voice].bender_range = value;
      break;
    }
}

static int
opl3_patchmgr (int dev, struct patmgr_info *rec)
{
  return RET_ERROR (EINVAL);
}

static struct synth_operations opl3_operations =
{
  &fm_info,
  SYNTH_TYPE_FM,
  FM_TYPE_ADLIB,
  opl3_open,
  opl3_close,
  opl3_ioctl,
  opl3_kill_note,
  opl3_start_note,
  opl3_set_instr,
  opl3_reset,
  opl3_hw_control,
  opl3_load_patch,
  opl3_aftertouch,
  opl3_controller,
  opl3_panning,
  opl3_patchmgr
};

long
opl3_init (long mem_start)
{
  int             i;

  PERMANENT_MALLOC(struct sbi_instrument*, instrmap, 
  		   SBFM_MAXINSTR*sizeof(*instrmap), mem_start);

  synth_devs[num_synths++] = &opl3_operations;
  fm_model = 0;
  opl3_ok = 1;
  if (opl3_enabled)
    {
      printk (" <Yamaha OPL-3 FM>");
      fm_model = 2;
      nr_voices = 18;
      fm_info.nr_drums = 0;
      fm_info.capabilities |= SYNTH_CAP_OPL3;
#ifndef SCO
      strcpy (fm_info.name, "Yamaha OPL-3");
#endif

      for (i = 0; i < 18; i++)
	if (physical_voices[i].ioaddr == USE_LEFT)
	  physical_voices[i].ioaddr = left_address;
	else
	  physical_voices[i].ioaddr = right_address;


      opl3_command (right_address, OPL3_MODE_REGISTER, OPL3_ENABLE);	/* Enable OPL-3 mode */
      opl3_command (right_address, CONNECTION_SELECT_REGISTER, 0x00);	/* Select all 2-OP
									 * voices */
    }
  else
    {
      printk (" <Yamaha 2-OP FM>");
      fm_model = 1;
      nr_voices = 9;
      fm_info.nr_drums = 0;

      for (i = 0; i < 18; i++)
	physical_voices[i].ioaddr = left_address;
    };

  already_initialized = 1;
  for (i = 0; i < SBFM_MAXINSTR; i++)
    instrmap[i].channel = -1;

  return mem_start;
}

#endif