pcm.c 4.1 KB

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  1. // Emulation routines for the RF5C164 PCM chip.
  2. // Based on Gens code by Stéphane Dallongeville
  3. // (c) Copyright 2007, Grazvydas "notaz" Ignotas
  4. #include "../PicoInt.h"
  5. #include "pcm.h"
  6. static unsigned int g_rate = 0; // 18.14 fixed point
  7. PICO_INTERNAL_ASM void pcm_write(unsigned int a, unsigned int d)
  8. {
  9. //printf("pcm_write(%i, %02x)\n", a, d);
  10. if (a < 7)
  11. {
  12. Pico_mcd->pcm.ch[Pico_mcd->pcm.cur_ch].regs[a] = d;
  13. }
  14. else if (a == 7) // control register
  15. {
  16. if (d & 0x40) Pico_mcd->pcm.cur_ch = d & 7;
  17. else Pico_mcd->pcm.bank = d & 0xf;
  18. Pico_mcd->pcm.control = d;
  19. // dprintf("pcm control=%02x", Pico_mcd->pcm.control);
  20. }
  21. else if (a == 8) // sound on/off
  22. {
  23. if (!(Pico_mcd->pcm.enabled & 0x01)) Pico_mcd->pcm.ch[0].addr =
  24. Pico_mcd->pcm.ch[0].regs[6] << (PCM_STEP_SHIFT + 8);
  25. if (!(Pico_mcd->pcm.enabled & 0x02)) Pico_mcd->pcm.ch[1].addr =
  26. Pico_mcd->pcm.ch[1].regs[6] << (PCM_STEP_SHIFT + 8);
  27. if (!(Pico_mcd->pcm.enabled & 0x04)) Pico_mcd->pcm.ch[2].addr =
  28. Pico_mcd->pcm.ch[2].regs[6] << (PCM_STEP_SHIFT + 8);
  29. if (!(Pico_mcd->pcm.enabled & 0x08)) Pico_mcd->pcm.ch[3].addr =
  30. Pico_mcd->pcm.ch[3].regs[6] << (PCM_STEP_SHIFT + 8);
  31. if (!(Pico_mcd->pcm.enabled & 0x10)) Pico_mcd->pcm.ch[4].addr =
  32. Pico_mcd->pcm.ch[4].regs[6] << (PCM_STEP_SHIFT + 8);
  33. if (!(Pico_mcd->pcm.enabled & 0x20)) Pico_mcd->pcm.ch[5].addr =
  34. Pico_mcd->pcm.ch[5].regs[6] << (PCM_STEP_SHIFT + 8);
  35. if (!(Pico_mcd->pcm.enabled & 0x40)) Pico_mcd->pcm.ch[6].addr =
  36. Pico_mcd->pcm.ch[6].regs[6] << (PCM_STEP_SHIFT + 8);
  37. if (!(Pico_mcd->pcm.enabled & 0x80)) Pico_mcd->pcm.ch[7].addr =
  38. Pico_mcd->pcm.ch[7].regs[6] << (PCM_STEP_SHIFT + 8);
  39. // printf("addr %x %x %x %x %x %x %x %x\n", Pico_mcd->pcm.ch[0].addr, Pico_mcd->pcm.ch[1].addr
  40. // , Pico_mcd->pcm.ch[2].addr, Pico_mcd->pcm.ch[3].addr, Pico_mcd->pcm.ch[4].addr, Pico_mcd->pcm.ch[5].addr
  41. // , Pico_mcd->pcm.ch[6].addr, Pico_mcd->pcm.ch[7].addr);
  42. Pico_mcd->pcm.enabled = ~d;
  43. //printf("enabled=%02x\n", Pico_mcd->pcm.enabled);
  44. }
  45. }
  46. PICO_INTERNAL void pcm_set_rate(int rate)
  47. {
  48. float step = 31.8 * 1024.0 / (float) rate; // max <4 @ 8000Hz
  49. step *= 256*256/4;
  50. g_rate = (unsigned int) step;
  51. if (step - (float) g_rate >= 0.5) g_rate++;
  52. printf("g_rate: %f %08x\n", (double)step, g_rate);
  53. }
  54. PICO_INTERNAL void pcm_update(int *buffer, int length, int stereo)
  55. {
  56. struct pcm_chan *ch;
  57. unsigned int step, addr;
  58. int mul_l, mul_r, smp;
  59. int i, j, k;
  60. int *out;
  61. // PCM disabled or all channels off (to be checked by caller)
  62. //if (!(Pico_mcd->pcm.control & 0x80) || !Pico_mcd->pcm.enabled) return;
  63. //printf("-- upd %i\n", length);
  64. for (i = 0; i < 8; i++)
  65. {
  66. if (!(Pico_mcd->pcm.enabled & (1 << i))) continue; // channel disabled
  67. out = buffer;
  68. ch = &Pico_mcd->pcm.ch[i];
  69. addr = ch->addr; // >> PCM_STEP_SHIFT;
  70. mul_l = ((int)ch->regs[0] * (ch->regs[1] & 0xf)) >> (5+1); // (env * pan) >> 5
  71. mul_r = ((int)ch->regs[0] * (ch->regs[1] >> 4)) >> (5+1);
  72. step = ((unsigned int)(*(unsigned short *)&ch->regs[2]) * g_rate) >> 14; // freq step
  73. // fprintf(stderr, "step=%i, cstep=%i, mul_l=%i, mul_r=%i, ch=%i, addr=%x, en=%02x\n",
  74. // *(unsigned short *)&ch->regs[2], step, mul_l, mul_r, i, addr, Pico_mcd->pcm.enabled);
  75. if (!stereo && mul_l < mul_r) mul_l = mul_r;
  76. for (j = 0; j < length; j++)
  77. {
  78. // printf("addr=%08x\n", addr);
  79. smp = Pico_mcd->pcm_ram[addr >> PCM_STEP_SHIFT];
  80. // test for loop signal
  81. if (smp == 0xff)
  82. {
  83. addr = *(unsigned short *)&ch->regs[4]; // loop_addr
  84. smp = Pico_mcd->pcm_ram[addr];
  85. addr <<= PCM_STEP_SHIFT;
  86. if (smp == 0xff) break;
  87. }
  88. if (smp & 0x80) smp = -(smp & 0x7f);
  89. *out++ += smp * mul_l; // max 128 * 119 = 15232
  90. if(stereo)
  91. *out++ += smp * mul_r;
  92. // update address register
  93. k = (addr >> PCM_STEP_SHIFT) + 1;
  94. addr = (addr + step) & 0x7FFFFFF;
  95. for(; k < (addr >> PCM_STEP_SHIFT); k++)
  96. {
  97. if (Pico_mcd->pcm_ram[k] == 0xff)
  98. {
  99. addr = (unsigned int)(*(unsigned short *)&ch->regs[4]) << PCM_STEP_SHIFT; // loop_addr
  100. break;
  101. }
  102. }
  103. }
  104. if (Pico_mcd->pcm_ram[addr >> PCM_STEP_SHIFT] == 0xff)
  105. addr = (unsigned int)(*(unsigned short *)&ch->regs[4]) << PCM_STEP_SHIFT; // loop_addr
  106. ch->addr = addr;
  107. }
  108. }