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gus_volume.c

/*
 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
 *
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */

#include <linux/time.h>
#include <sound/core.h>
#include <sound/gus.h>
#define __GUS_TABLES_ALLOC__
#include "gus_tables.h"

EXPORT_SYMBOL(snd_gf1_atten_table); /* for snd-gus-synth module */

unsigned short snd_gf1_lvol_to_gvol_raw(unsigned int vol)
{
      unsigned short e, m, tmp;

      if (vol > 65535)
            vol = 65535;
      tmp = vol;
      e = 7;
      if (tmp < 128) {
            while (e > 0 && tmp < (1 << e))
                  e--;
      } else {
            while (tmp > 255) {
                  tmp >>= 1;
                  e++;
            }
      }
      m = vol - (1 << e);
      if (m > 0) {
            if (e > 8)
                  m >>= e - 8;
            else if (e < 8)
                  m <<= 8 - e;
            m &= 255;
      }
      return (e << 8) | m;
}

#if 0

unsigned int snd_gf1_gvol_to_lvol_raw(unsigned short gf1_vol)
{
      unsigned int rvol;
      unsigned short e, m;

      if (!gf1_vol)
            return 0;
      e = gf1_vol >> 8;
      m = (unsigned char) gf1_vol;
      rvol = 1 << e;
      if (e > 8)
            return rvol | (m << (e - 8));
      return rvol | (m >> (8 - e));
}

unsigned int snd_gf1_calc_ramp_rate(struct snd_gus_card * gus,
                            unsigned short start,
                            unsigned short end,
                            unsigned int us)
{
      static unsigned char vol_rates[19] =
      {
            23, 24, 26, 28, 29, 31, 32, 34,
            36, 37, 39, 40, 42, 44, 45, 47,
            49, 50, 52
      };
      unsigned short range, increment, value, i;

      start >>= 4;
      end >>= 4;
      if (start < end)
            us /= end - start;
      else
            us /= start - end;
      range = 4;
      value = gus->gf1.enh_mode ?
          vol_rates[0] :
          vol_rates[gus->gf1.active_voices - 14];
      for (i = 0; i < 3; i++) {
            if (us < value) {
                  range = i;
                  break;
            } else
                  value <<= 3;
      }
      if (range == 4) {
            range = 3;
            increment = 1;
      } else
            increment = (value + (value >> 1)) / us;
      return (range << 6) | (increment & 0x3f);
}

#endif  /*  0  */

unsigned short snd_gf1_translate_freq(struct snd_gus_card * gus, unsigned int freq16)
{
      freq16 >>= 3;
      if (freq16 < 50)
            freq16 = 50;
      if (freq16 & 0xf8000000) {
            freq16 = ~0xf8000000;
            snd_printk(KERN_ERR "snd_gf1_translate_freq: overflow - freq = 0x%x\n", freq16);
      }
      return ((freq16 << 9) + (gus->gf1.playback_freq >> 1)) / gus->gf1.playback_freq;
}

#if 0

short snd_gf1_compute_vibrato(short cents, unsigned short fc_register)
{
      static short vibrato_table[] =
      {
            0, 0, 32, 592, 61, 1175, 93, 1808,
            124, 2433, 152, 3007, 182, 3632, 213, 4290,
            241, 4834, 255, 5200
      };

      long depth;
      short *vi1, *vi2, pcents, v1;

      pcents = cents < 0 ? -cents : cents;
      for (vi1 = vibrato_table, vi2 = vi1 + 2; pcents > *vi2; vi1 = vi2, vi2 += 2);
      v1 = *(vi1 + 1);
      /* The FC table above is a list of pairs. The first number in the pair     */
      /* is the cents index from 0-255 cents, and the second number in the       */
      /* pair is the FC adjustment needed to change the pitch by the indexed     */
      /* number of cents. The table was created for an FC of 32768.              */
      /* The following expression does a linear interpolation against the        */
      /* approximated log curve in the table above, and then scales the number   */
      /* by the FC before the LFO. This calculation also adjusts the output      */
      /* value to produce the appropriate depth for the hardware. The depth      */
      /* is 2 * desired FC + 1.                                                  */
      depth = (((int) (*(vi2 + 1) - *vi1) * (pcents - *vi1) / (*vi2 - *vi1)) + v1) * fc_register >> 14;
      if (depth)
            depth++;
      if (depth > 255)
            depth = 255;
      return cents < 0 ? -(short) depth : (short) depth;
}

unsigned short snd_gf1_compute_pitchbend(unsigned short pitchbend, unsigned short sens)
{
      static long log_table[] = {1024, 1085, 1149, 1218, 1290, 1367, 1448, 1534, 1625, 1722, 1825, 1933};
      int wheel, sensitivity;
      unsigned int mantissa, f1, f2;
      unsigned short semitones, f1_index, f2_index, f1_power, f2_power;
      char bend_down = 0;
      int bend;

      if (!sens)
            return 1024;
      wheel = (int) pitchbend - 8192;
      sensitivity = ((int) sens * wheel) / 128;
      if (sensitivity < 0) {
            bend_down = 1;
            sensitivity = -sensitivity;
      }
      semitones = (unsigned int) (sensitivity >> 13);
      mantissa = sensitivity % 8192;
      f1_index = semitones % 12;
      f2_index = (semitones + 1) % 12;
      f1_power = semitones / 12;
      f2_power = (semitones + 1) / 12;
      f1 = log_table[f1_index] << f1_power;
      f2 = log_table[f2_index] << f2_power;
      bend = (int) ((((f2 - f1) * mantissa) >> 13) + f1);
      if (bend_down)
            bend = 1048576L / bend;
      return bend;
}

unsigned short snd_gf1_compute_freq(unsigned int freq,
                            unsigned int rate,
                            unsigned short mix_rate)
{
      unsigned int fc;
      int scale = 0;

      while (freq >= 4194304L) {
            scale++;
            freq >>= 1;
      }
      fc = (freq << 10) / rate;
      if (fc > 97391L) {
            fc = 97391;
            snd_printk(KERN_ERR "patch: (1) fc frequency overflow - %u\n", fc);
      }
      fc = (fc * 44100UL) / mix_rate;
      while (scale--)
            fc <<= 1;
      if (fc > 65535L) {
            fc = 65535;
            snd_printk(KERN_ERR "patch: (2) fc frequency overflow - %u\n", fc);
      }
      return (unsigned short) fc;
}

#endif  /*  0  */

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