release/src-rt-6.x.4708/linux/linux-2.6.36/sound/isa/gus/gus_volume.c

   1 /*
   2  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
   3  *
   4  *
   5  *   This program is free software; you can redistribute it and/or modify
   6  *   it under the terms of the GNU General Public License as published by
   7  *   the Free Software Foundation; either version 2 of the License, or
   8  *   (at your option) any later version.
   9  *
  10  *   This program is distributed in the hope that it will be useful,
  11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *   GNU General Public License for more details.
  14  *
  15  *   You should have received a copy of the GNU General Public License
  16  *   along with this program; if not, write to the Free Software
  17  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  18  *
  19  */
  20
  21 #include <linux/time.h>
  22 #include <sound/core.h>
  23 #include <sound/gus.h>
  24 #define __GUS_TABLES_ALLOC__
  25 #include "gus_tables.h"
  26
  27 EXPORT_SYMBOL(snd_gf1_atten_table); /* for snd-gus-synth module */
  28
  29 unsigned short snd_gf1_lvol_to_gvol_raw(unsigned int vol)
  30 {
  31         unsigned short e, m, tmp;
  32
  33         if (vol > 65535)
  34                 vol = 65535;
  35         tmp = vol;
  36         e = 7;
  37         if (tmp < 128) {
  38                 while (e > 0 && tmp < (1 << e))
  39                         e--;
  40         } else {
  41                 while (tmp > 255) {
  42                         tmp >>= 1;
  43                         e++;
  44                 }
  45         }
  46         m = vol - (1 << e);
  47         if (m > 0) {
  48                 if (e > 8)
  49                         m >>= e - 8;
  50                 else if (e < 8)
  51                         m <<= 8 - e;
  52                 m &= 255;
  53         }
  54         return (e << 8) | m;
  55 }
  56
  57
  58 unsigned short snd_gf1_translate_freq(struct snd_gus_card * gus, unsigned int freq16)
  59 {
  60         freq16 >>= 3;
  61         if (freq16 < 50)
  62                 freq16 = 50;
  63         if (freq16 & 0xf8000000) {
  64                 freq16 = ~0xf8000000;
  65                 snd_printk(KERN_ERR "snd_gf1_translate_freq: overflow - freq = 0x%x\n", freq16);
  66         }
  67         return ((freq16 << 9) + (gus->gf1.playback_freq >> 1)) / gus->gf1.playback_freq;
  68 }