sound/isa/gus/gus

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This source file includes following definitions.
snd_gf1_lvol_to_gvol_raw
snd_gf1_gvol_to_lvol_raw
snd_gf1_calc_ramp_rate
snd_gf1_translate_freq
snd_gf1_compute_vibrato
snd_gf1_compute_pitchbend
snd_gf1_compute_freq
   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
   4  */
   5 
   6 #include <linux/time.h>
   7 #include <linux/export.h>
   8 #include <sound/core.h>
   9 #include <sound/gus.h>
  10 #define __GUS_TABLES_ALLOC__
  11 #include "gus_tables.h"
  12 
  13 EXPORT_SYMBOL(snd_gf1_atten_table); /* for snd-gus-synth module */
  14 
  15 unsigned short snd_gf1_lvol_to_gvol_raw(unsigned int vol)
  16 {
  17         unsigned short e, m, tmp;
  18 
  19         if (vol > 65535)
  20                 vol = 65535;
  21         tmp = vol;
  22         e = 7;
  23         if (tmp < 128) {
  24                 while (e > 0 && tmp < (1 << e))
  25                         e--;
  26         } else {
  27                 while (tmp > 255) {
  28                         tmp >>= 1;
  29                         e++;
  30                 }
  31         }
  32         m = vol - (1 << e);
  33         if (m > 0) {
  34                 if (e > 8)
  35                         m >>= e - 8;
  36                 else if (e < 8)
  37                         m <<= 8 - e;
  38                 m &= 255;
  39         }
  40         return (e << 8) | m;
  41 }
  42 
  43 #if 0
  44 
  45 unsigned int snd_gf1_gvol_to_lvol_raw(unsigned short gf1_vol)
  46 {
  47         unsigned int rvol;
  48         unsigned short e, m;
  49 
  50         if (!gf1_vol)
  51                 return 0;
  52         e = gf1_vol >> 8;
  53         m = (unsigned char) gf1_vol;
  54         rvol = 1 << e;
  55         if (e > 8)
  56                 return rvol | (m << (e - 8));
  57         return rvol | (m >> (8 - e));
  58 }
  59 
  60 unsigned int snd_gf1_calc_ramp_rate(struct snd_gus_card * gus,
  61                                     unsigned short start,
  62                                     unsigned short end,
  63                                     unsigned int us)
  64 {
  65         static unsigned char vol_rates[19] =
  66         {
  67                 23, 24, 26, 28, 29, 31, 32, 34,
  68                 36, 37, 39, 40, 42, 44, 45, 47,
  69                 49, 50, 52
  70         };
  71         unsigned short range, increment, value, i;
  72 
  73         start >>= 4;
  74         end >>= 4;
  75         if (start < end)
  76                 us /= end - start;
  77         else
  78                 us /= start - end;
  79         range = 4;
  80         value = gus->gf1.enh_mode ?
  81             vol_rates[0] :
  82             vol_rates[gus->gf1.active_voices - 14];
  83         for (i = 0; i < 3; i++) {
  84                 if (us < value) {
  85                         range = i;
  86                         break;
  87                 } else
  88                         value <<= 3;
  89         }
  90         if (range == 4) {
  91                 range = 3;
  92                 increment = 1;
  93         } else
  94                 increment = (value + (value >> 1)) / us;
  95         return (range << 6) | (increment & 0x3f);
  96 }
  97 
  98 #endif  /*  0  */
  99 
 100 unsigned short snd_gf1_translate_freq(struct snd_gus_card * gus, unsigned int freq16)
 101 {
 102         freq16 >>= 3;
 103         if (freq16 < 50)
 104                 freq16 = 50;
 105         if (freq16 & 0xf8000000) {
 106                 freq16 = ~0xf8000000;
 107                 snd_printk(KERN_ERR "snd_gf1_translate_freq: overflow - freq = 0x%x\n", freq16);
 108         }
 109         return ((freq16 << 9) + (gus->gf1.playback_freq >> 1)) / gus->gf1.playback_freq;
 110 }
 111 
 112 #if 0
 113 
 114 short snd_gf1_compute_vibrato(short cents, unsigned short fc_register)
 115 {
 116         static short vibrato_table[] =
 117         {
 118                 0, 0, 32, 592, 61, 1175, 93, 1808,
 119                 124, 2433, 152, 3007, 182, 3632, 213, 4290,
 120                 241, 4834, 255, 5200
 121         };
 122 
 123         long depth;
 124         short *vi1, *vi2, pcents, v1;
 125 
 126         pcents = cents < 0 ? -cents : cents;
 127         for (vi1 = vibrato_table, vi2 = vi1 + 2; pcents > *vi2; vi1 = vi2, vi2 += 2);
 128         v1 = *(vi1 + 1);
 129         /* The FC table above is a list of pairs. The first number in the pair     */
 130         /* is the cents index from 0-255 cents, and the second number in the       */
 131         /* pair is the FC adjustment needed to change the pitch by the indexed     */
 132         /* number of cents. The table was created for an FC of 32768.              */
 133         /* The following expression does a linear interpolation against the        */
 134         /* approximated log curve in the table above, and then scales the number   */
 135         /* by the FC before the LFO. This calculation also adjusts the output      */
 136         /* value to produce the appropriate depth for the hardware. The depth      */
 137         /* is 2 * desired FC + 1.                                                  */
 138         depth = (((int) (*(vi2 + 1) - *vi1) * (pcents - *vi1) / (*vi2 - *vi1)) + v1) * fc_register >> 14;
 139         if (depth)
 140                 depth++;
 141         if (depth > 255)
 142                 depth = 255;
 143         return cents < 0 ? -(short) depth : (short) depth;
 144 }
 145 
 146 unsigned short snd_gf1_compute_pitchbend(unsigned short pitchbend, unsigned short sens)
 147 {
 148         static long log_table[] = {1024, 1085, 1149, 1218, 1290, 1367, 1448, 1534, 1625, 1722, 1825, 1933};
 149         int wheel, sensitivity;
 150         unsigned int mantissa, f1, f2;
 151         unsigned short semitones, f1_index, f2_index, f1_power, f2_power;
 152         char bend_down = 0;
 153         int bend;
 154 
 155         if (!sens)
 156                 return 1024;
 157         wheel = (int) pitchbend - 8192;
 158         sensitivity = ((int) sens * wheel) / 128;
 159         if (sensitivity < 0) {
 160                 bend_down = 1;
 161                 sensitivity = -sensitivity;
 162         }
 163         semitones = (unsigned int) (sensitivity >> 13);
 164         mantissa = sensitivity % 8192;
 165         f1_index = semitones % 12;
 166         f2_index = (semitones + 1) % 12;
 167         f1_power = semitones / 12;
 168         f2_power = (semitones + 1) / 12;
 169         f1 = log_table[f1_index] << f1_power;
 170         f2 = log_table[f2_index] << f2_power;
 171         bend = (int) ((((f2 - f1) * mantissa) >> 13) + f1);
 172         if (bend_down)
 173                 bend = 1048576L / bend;
 174         return bend;
 175 }
 176 
 177 unsigned short snd_gf1_compute_freq(unsigned int freq,
 178                                     unsigned int rate,
 179                                     unsigned short mix_rate)
 180 {
 181         unsigned int fc;
 182         int scale = 0;
 183 
 184         while (freq >= 4194304L) {
 185                 scale++;
 186                 freq >>= 1;
 187         }
 188         fc = (freq << 10) / rate;
 189         if (fc > 97391L) {
 190                 fc = 97391;
 191                 snd_printk(KERN_ERR "patch: (1) fc frequency overflow - %u\n", fc);
 192         }
 193         fc = (fc * 44100UL) / mix_rate;
 194         while (scale--)
 195                 fc <<= 1;
 196         if (fc > 65535L) {
 197                 fc = 65535;
 198                 snd_printk(KERN_ERR "patch: (2) fc frequency overflow - %u\n", fc);
 199         }
 200         return (unsigned short) fc;
 201 }
 202 
 203 #endif  /*  0  */
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root/sound/isa/gus/gus_volume.c

DEFINITIONS
