Shamusworld >> Repos - virtualjaguar/blob - src/pcm.cpp

   1 //
   2 // PCM Handler
   3 //
   4 // by cal2
   5 // GCC/SDL port by Niels Wagenaar (Linux/WIN32) and Caz (BeOS)
   6 // Cleanups by James L. Hammons
   7 //
   8
   9 #include "pcm.h"
  10
  11 //#define PCM_DUMP
  12
  13 #define sample_rate 44100
  14 #define sample_bits 16
  15 #define buffer_size 4
  16 #define buffer_modulo (sample_rate * buffer_size)
  17
  18 static int16 * pcm_left;
  19 static int16 * pcm_right;
  20 static uint32 pcm_left_pos;
  21 static uint32 pcm_right_pos;
  22 static uint32 pcm_left_playback_pos;
  23 static uint32 pcm_right_playback_pos;
  24 static uint32 pcm_sample_rate = sample_rate;
  25 static uint32 pcm_inc = (pcm_sample_rate << 8) / sample_rate;
  26 #ifdef PCM_DUMP
  27 static FILE * fp_left;
  28 static FILE * fp_right;
  29 #endif
  30
  31
  32 void pcm_set_sample_rate(int rate)
  33 {
  34         pcm_sample_rate = rate;
  35         pcm_inc = (pcm_sample_rate << 8) / sample_rate;
  36 //      fprintf(log_get(),"pcm: sample rate is %i hz, sample increment is %i (%f)\n",pcm_sample_rate,pcm_inc,((float)pcm_inc)/256.0f);
  37 }
  38
  39 void pcm_updateOne(int channel, int16 * data, uint32 length)
  40 {
  41         if (channel == 0)
  42         {
  43                 while (length)
  44                 {
  45                         *data++ = pcm_left[(pcm_left_playback_pos >> 8) % buffer_modulo];
  46                         pcm_left_playback_pos += pcm_inc;
  47                         length--;
  48                 }
  49         }
  50         else
  51         {
  52                 while (length)
  53                 {
  54                         *data++ = pcm_right[(pcm_right_playback_pos >> 8) % buffer_modulo];
  55                         pcm_right_playback_pos += pcm_inc;
  56                         length--;
  57                 }
  58         }
  59 }
  60
  61 void pcm_init(void)
  62 {
  63         memory_malloc_secure((void **)&pcm_left, buffer_modulo * sizeof(int16), "Left DAC buffer");
  64         memory_malloc_secure((void **)&pcm_right, buffer_modulo * sizeof(int16), "Right DAC buffer");
  65         pcm_reset();
  66 #ifdef PCM_DUMP
  67         fp_left = fopen("leftdac.raw", "wb");
  68         fp_right = fopen("rightdac.raw", "wb");
  69 #endif
  70 }
  71
  72 void pcm_reset(void)
  73 {
  74         pcm_left_pos = 0;
  75         pcm_right_pos = 0;
  76         pcm_left_playback_pos = 0;
  77         pcm_right_playback_pos = 0;
  78 }
  79
  80 void pcm_done(void)
  81 {
  82 #ifdef PCM_DUMP
  83         fclose(fp_left);
  84         fclose(fp_right);
  85 #endif
  86         fprintf(log_get(), "PCM: Done.\n");
  87 }
  88
  89 void pcm_update(void)
  90 {
  91 }
  92
  93 void pcm_render_left_dac(void)
  94 {
  95 #ifdef PCM_DUMP
  96         fwrite(pcm_left, 1, sample_rate * 2, fp_left);
  97 #endif
  98 }
  99
 100 void pcm_render_right_dac(void)
 101 {
 102 #ifdef PCM_DUMP
 103         fwrite(pcm_right, 1, sample_rate * 2, fp_right);
 104 #endif
 105 }
 106
 107 void pcm_byte_write(uint32 offset, uint8 data)
 108 {
 109 //      fprintf(log_get(),"pcm: writing 0x%.2x at 0x%.8x\n",data,offset);
 110 }
 111
 112 void pcm_word_write(uint32 offset, uint16 data)
 113 {
 114         if (offset == 2)
 115         {
 116                 pcm_left[pcm_left_pos % buffer_modulo] = data;
 117                 pcm_left_pos++;
 118                 if ((pcm_left_pos % buffer_modulo) == 0)
 119                         pcm_render_left_dac();
 120         }
 121         else
 122         if (offset == 6)
 123         {
 124                 pcm_right[pcm_right_pos % buffer_modulo] = data;
 125                 pcm_right_pos++;
 126                 if ((pcm_right_pos % buffer_modulo) == 0)
 127                         pcm_render_right_dac();
 128         }
 129 }
 130
 131 uint8 pcm_byte_read(uint32 offset)
 132 {
 133 //      fprintf(log_get(),"pcm: reading byte from 0x%.8x\n",offset);
 134         return 0xFF;
 135 }
 136
 137 uint16 pcm_word_read(uint32 offset)
 138 {
 139 //      fprintf(log_get(),"pcm: reading word from 0x%.8x\n",offset);
 140         return 0xFFFF;
 141 }