source/src/vm/pv1000/psg.cpp

   1 /*
   2         CASIO PV-1000 Emulator 'ePV-1000'
   3
   4         Author : Takeda.Toshiya
   5         Date   : 2006.11.16 -
   6
   7         [ psg ]
   8 */
   9
  10 #include <math.h>
  11 #include "./psg.h"
  12 #include "../../types/util_sound.h"
  13
  14 #define PSG_CLOCK
  15 #define PSG_VOLUME      8192
  16
  17 namespace PV1000 {
  18
  19 void PSG::reset()
  20 {
  21         touch_sound();
  22         memset(ch, 0, sizeof(ch));
  23 }
  24
  25 void PSG::write_io8(uint32_t addr, uint32_t data)
  26 {
  27         touch_sound();
  28         ch[addr & 3].period = 0x3f - (data & 0x3f);
  29 }
  30
  31 void PSG::initialize_sound(int rate)
  32 {
  33         diff = (int)(1.3 * (double)CPU_CLOCKS / (double)rate + 0.5);
  34 }
  35
  36 void PSG::mix(int32_t* buffer, int cnt)
  37 {
  38         // create sound buffer
  39         for(int i = 0; i < cnt; i++) {
  40                 int vol = 0;
  41                 for(int j = 0; j < 3; j++) {
  42                         if(!ch[j].period) {
  43                                 continue;
  44                         }
  45                         bool prev_signal = ch[j].signal;
  46                         int prev_count = ch[j].count;
  47                         ch[j].count -= diff;
  48                         if(ch[j].count < 0) {
  49                                 ch[j].count += ch[j].period << 8;
  50                                 ch[j].signal = !ch[j].signal;
  51                         }
  52                         int vol_tmp = (prev_signal != ch[j].signal && prev_count < diff) ? (PSG_VOLUME * (2 * prev_count - diff)) / diff : PSG_VOLUME;
  53                         vol += prev_signal ? vol_tmp : -vol_tmp;
  54                 }
  55                 *buffer++ += apply_volume(vol, volume_l); // L
  56                 *buffer++ += apply_volume(vol, volume_l); // R
  57         }
  58 }
  59
  60 void PSG::set_volume(int ch, int decibel_l, int decibel_r)
  61 {
  62         volume_l = decibel_to_volume(decibel_l);
  63         volume_r = decibel_to_volume(decibel_r);
  64 }
  65
  66 #define STATE_VERSION   1
  67
  68 bool PSG::process_state(FILEIO* state_fio, bool loading)
  69 {
  70         if(!state_fio->StateCheckUint32(STATE_VERSION)) {
  71                 return false;
  72         }
  73         if(!state_fio->StateCheckInt32(this_device_id)) {
  74                 return false;
  75         }
  76         for(int i = 0; i < 3; i++) {
  77                 state_fio->StateValue(ch[i].period);
  78         }
  79         return true;
  80 }
  81
  82 }