pcm.c 4.2 KB

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  1. /*
  2. * Emulation routines for the RF5C164 PCM chip
  3. * (C) notaz, 2007
  4. *
  5. * This work is licensed under the terms of MAME license.
  6. * See COPYING file in the top-level directory.
  7. */
  8. #include "../pico_int.h"
  9. #include "pcm.h"
  10. static unsigned int g_rate = 0; // 18.14 fixed point
  11. PICO_INTERNAL_ASM void pcm_write(unsigned int a, unsigned int d)
  12. {
  13. //printf("pcm_write(%i, %02x)\n", a, d);
  14. if (a < 7)
  15. {
  16. Pico_mcd->pcm.ch[Pico_mcd->pcm.cur_ch].regs[a] = d;
  17. }
  18. else if (a == 7) // control register
  19. {
  20. if (d & 0x40) Pico_mcd->pcm.cur_ch = d & 7;
  21. else Pico_mcd->pcm.bank = d & 0xf;
  22. Pico_mcd->pcm.control = d;
  23. // dprintf("pcm control=%02x", Pico_mcd->pcm.control);
  24. }
  25. else if (a == 8) // sound on/off
  26. {
  27. if (!(Pico_mcd->pcm.enabled & 0x01)) Pico_mcd->pcm.ch[0].addr =
  28. Pico_mcd->pcm.ch[0].regs[6] << (PCM_STEP_SHIFT + 8);
  29. if (!(Pico_mcd->pcm.enabled & 0x02)) Pico_mcd->pcm.ch[1].addr =
  30. Pico_mcd->pcm.ch[1].regs[6] << (PCM_STEP_SHIFT + 8);
  31. if (!(Pico_mcd->pcm.enabled & 0x04)) Pico_mcd->pcm.ch[2].addr =
  32. Pico_mcd->pcm.ch[2].regs[6] << (PCM_STEP_SHIFT + 8);
  33. if (!(Pico_mcd->pcm.enabled & 0x08)) Pico_mcd->pcm.ch[3].addr =
  34. Pico_mcd->pcm.ch[3].regs[6] << (PCM_STEP_SHIFT + 8);
  35. if (!(Pico_mcd->pcm.enabled & 0x10)) Pico_mcd->pcm.ch[4].addr =
  36. Pico_mcd->pcm.ch[4].regs[6] << (PCM_STEP_SHIFT + 8);
  37. if (!(Pico_mcd->pcm.enabled & 0x20)) Pico_mcd->pcm.ch[5].addr =
  38. Pico_mcd->pcm.ch[5].regs[6] << (PCM_STEP_SHIFT + 8);
  39. if (!(Pico_mcd->pcm.enabled & 0x40)) Pico_mcd->pcm.ch[6].addr =
  40. Pico_mcd->pcm.ch[6].regs[6] << (PCM_STEP_SHIFT + 8);
  41. if (!(Pico_mcd->pcm.enabled & 0x80)) Pico_mcd->pcm.ch[7].addr =
  42. Pico_mcd->pcm.ch[7].regs[6] << (PCM_STEP_SHIFT + 8);
  43. // printf("addr %x %x %x %x %x %x %x %x\n", Pico_mcd->pcm.ch[0].addr, Pico_mcd->pcm.ch[1].addr
  44. // , Pico_mcd->pcm.ch[2].addr, Pico_mcd->pcm.ch[3].addr, Pico_mcd->pcm.ch[4].addr, Pico_mcd->pcm.ch[5].addr
  45. // , Pico_mcd->pcm.ch[6].addr, Pico_mcd->pcm.ch[7].addr);
  46. Pico_mcd->pcm.enabled = ~d;
  47. //printf("enabled=%02x\n", Pico_mcd->pcm.enabled);
  48. }
  49. }
  50. PICO_INTERNAL void pcm_set_rate(int rate)
  51. {
  52. float step = 31.8 * 1024.0 / (float) rate; // max <4 @ 8000Hz
  53. step *= 256*256/4;
  54. g_rate = (unsigned int) step;
  55. if (step - (float) g_rate >= 0.5) g_rate++;
  56. elprintf(EL_STATUS, "g_rate: %f %08x\n", (double)step, g_rate);
  57. }
  58. PICO_INTERNAL void pcm_update(int *buffer, int length, int stereo)
  59. {
  60. struct pcm_chan *ch;
  61. unsigned int step, addr;
  62. int mul_l, mul_r, smp;
  63. int i, j, k;
  64. int *out;
  65. // PCM disabled or all channels off (to be checked by caller)
  66. //if (!(Pico_mcd->pcm.control & 0x80) || !Pico_mcd->pcm.enabled) return;
  67. //printf("-- upd %i\n", length);
  68. for (i = 0; i < 8; i++)
  69. {
  70. if (!(Pico_mcd->pcm.enabled & (1 << i))) continue; // channel disabled
  71. out = buffer;
  72. ch = &Pico_mcd->pcm.ch[i];
  73. addr = ch->addr; // >> PCM_STEP_SHIFT;
  74. mul_l = ((int)ch->regs[0] * (ch->regs[1] & 0xf)) >> (5+1); // (env * pan) >> 5
  75. mul_r = ((int)ch->regs[0] * (ch->regs[1] >> 4)) >> (5+1);
  76. step = ((unsigned int)(*(unsigned short *)&ch->regs[2]) * g_rate) >> 14; // freq step
  77. // fprintf(stderr, "step=%i, cstep=%i, mul_l=%i, mul_r=%i, ch=%i, addr=%x, en=%02x\n",
  78. // *(unsigned short *)&ch->regs[2], step, mul_l, mul_r, i, addr, Pico_mcd->pcm.enabled);
  79. if (!stereo && mul_l < mul_r) mul_l = mul_r;
  80. for (j = 0; j < length; j++)
  81. {
  82. // printf("addr=%08x\n", addr);
  83. smp = Pico_mcd->pcm_ram[addr >> PCM_STEP_SHIFT];
  84. // test for loop signal
  85. if (smp == 0xff)
  86. {
  87. addr = *(unsigned short *)&ch->regs[4]; // loop_addr
  88. smp = Pico_mcd->pcm_ram[addr];
  89. addr <<= PCM_STEP_SHIFT;
  90. if (smp == 0xff) break;
  91. }
  92. if (smp & 0x80) smp = -(smp & 0x7f);
  93. *out++ += smp * mul_l; // max 128 * 119 = 15232
  94. if(stereo)
  95. *out++ += smp * mul_r;
  96. // update address register
  97. k = (addr >> PCM_STEP_SHIFT) + 1;
  98. addr = (addr + step) & 0x7FFFFFF;
  99. for(; k < (addr >> PCM_STEP_SHIFT); k++)
  100. {
  101. if (Pico_mcd->pcm_ram[k] == 0xff)
  102. {
  103. addr = (unsigned int)(*(unsigned short *)&ch->regs[4]) << PCM_STEP_SHIFT; // loop_addr
  104. break;
  105. }
  106. }
  107. }
  108. if (Pico_mcd->pcm_ram[addr >> PCM_STEP_SHIFT] == 0xff)
  109. addr = (unsigned int)(*(unsigned short *)&ch->regs[4]) << PCM_STEP_SHIFT; // loop_addr
  110. ch->addr = addr;
  111. }
  112. }