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- // Emulation routines for the RF5C164 PCM chip.
- // Based on Gens code by Stéphane Dallongeville
- // (c) Copyright 2007, Grazvydas "notaz" Ignotas
- #include "../PicoInt.h"
- #include "pcm.h"
- static unsigned int g_rate = 0; // 18.14 fixed point
- PICO_INTERNAL_ASM void pcm_write(unsigned int a, unsigned int d)
- {
- //printf("pcm_write(%i, %02x)\n", a, d);
- if (a < 7)
- {
- Pico_mcd->pcm.ch[Pico_mcd->pcm.cur_ch].regs[a] = d;
- }
- else if (a == 7) // control register
- {
- if (d & 0x40) Pico_mcd->pcm.cur_ch = d & 7;
- else Pico_mcd->pcm.bank = d & 0xf;
- Pico_mcd->pcm.control = d;
- // dprintf("pcm control=%02x", Pico_mcd->pcm.control);
- }
- else if (a == 8) // sound on/off
- {
- if (!(Pico_mcd->pcm.enabled & 0x01)) Pico_mcd->pcm.ch[0].addr =
- Pico_mcd->pcm.ch[0].regs[6] << (PCM_STEP_SHIFT + 8);
- if (!(Pico_mcd->pcm.enabled & 0x02)) Pico_mcd->pcm.ch[1].addr =
- Pico_mcd->pcm.ch[1].regs[6] << (PCM_STEP_SHIFT + 8);
- if (!(Pico_mcd->pcm.enabled & 0x04)) Pico_mcd->pcm.ch[2].addr =
- Pico_mcd->pcm.ch[2].regs[6] << (PCM_STEP_SHIFT + 8);
- if (!(Pico_mcd->pcm.enabled & 0x08)) Pico_mcd->pcm.ch[3].addr =
- Pico_mcd->pcm.ch[3].regs[6] << (PCM_STEP_SHIFT + 8);
- if (!(Pico_mcd->pcm.enabled & 0x10)) Pico_mcd->pcm.ch[4].addr =
- Pico_mcd->pcm.ch[4].regs[6] << (PCM_STEP_SHIFT + 8);
- if (!(Pico_mcd->pcm.enabled & 0x20)) Pico_mcd->pcm.ch[5].addr =
- Pico_mcd->pcm.ch[5].regs[6] << (PCM_STEP_SHIFT + 8);
- if (!(Pico_mcd->pcm.enabled & 0x40)) Pico_mcd->pcm.ch[6].addr =
- Pico_mcd->pcm.ch[6].regs[6] << (PCM_STEP_SHIFT + 8);
- if (!(Pico_mcd->pcm.enabled & 0x80)) Pico_mcd->pcm.ch[7].addr =
- Pico_mcd->pcm.ch[7].regs[6] << (PCM_STEP_SHIFT + 8);
- // printf("addr %x %x %x %x %x %x %x %x\n", Pico_mcd->pcm.ch[0].addr, Pico_mcd->pcm.ch[1].addr
- // , Pico_mcd->pcm.ch[2].addr, Pico_mcd->pcm.ch[3].addr, Pico_mcd->pcm.ch[4].addr, Pico_mcd->pcm.ch[5].addr
- // , Pico_mcd->pcm.ch[6].addr, Pico_mcd->pcm.ch[7].addr);
- Pico_mcd->pcm.enabled = ~d;
- //printf("enabled=%02x\n", Pico_mcd->pcm.enabled);
- }
- }
- PICO_INTERNAL void pcm_set_rate(int rate)
- {
- float step = 31.8 * 1024.0 / (float) rate; // max <4 @ 8000Hz
- step *= 256*256/4;
- g_rate = (unsigned int) step;
- if (step - (float) g_rate >= 0.5) g_rate++;
- printf("g_rate: %f %08x\n", (double)step, g_rate);
- }
- PICO_INTERNAL void pcm_update(int *buffer, int length, int stereo)
- {
- struct pcm_chan *ch;
- unsigned int step, addr;
- int mul_l, mul_r, smp;
- int i, j, k;
- int *out;
- // PCM disabled or all channels off (to be checked by caller)
- //if (!(Pico_mcd->pcm.control & 0x80) || !Pico_mcd->pcm.enabled) return;
- //printf("-- upd %i\n", length);
- for (i = 0; i < 8; i++)
- {
- if (!(Pico_mcd->pcm.enabled & (1 << i))) continue; // channel disabled
- out = buffer;
- ch = &Pico_mcd->pcm.ch[i];
- addr = ch->addr; // >> PCM_STEP_SHIFT;
- mul_l = ((int)ch->regs[0] * (ch->regs[1] & 0xf)) >> (5+1); // (env * pan) >> 5
- mul_r = ((int)ch->regs[0] * (ch->regs[1] >> 4)) >> (5+1);
- step = ((unsigned int)(*(unsigned short *)&ch->regs[2]) * g_rate) >> 14; // freq step
- // fprintf(stderr, "step=%i, cstep=%i, mul_l=%i, mul_r=%i, ch=%i, addr=%x, en=%02x\n",
- // *(unsigned short *)&ch->regs[2], step, mul_l, mul_r, i, addr, Pico_mcd->pcm.enabled);
- if (!stereo && mul_l < mul_r) mul_l = mul_r;
- for (j = 0; j < length; j++)
- {
- // printf("addr=%08x\n", addr);
- smp = Pico_mcd->pcm_ram[addr >> PCM_STEP_SHIFT];
- // test for loop signal
- if (smp == 0xff)
- {
- addr = *(unsigned short *)&ch->regs[4]; // loop_addr
- smp = Pico_mcd->pcm_ram[addr];
- addr <<= PCM_STEP_SHIFT;
- if (smp == 0xff) break;
- }
- if (smp & 0x80) smp = -(smp & 0x7f);
- *out++ += smp * mul_l; // max 128 * 119 = 15232
- if(stereo)
- *out++ += smp * mul_r;
- // update address register
- k = (addr >> PCM_STEP_SHIFT) + 1;
- addr = (addr + step) & 0x7FFFFFF;
- for(; k < (addr >> PCM_STEP_SHIFT); k++)
- {
- if (Pico_mcd->pcm_ram[k] == 0xff)
- {
- addr = (unsigned int)(*(unsigned short *)&ch->regs[4]) << PCM_STEP_SHIFT; // loop_addr
- break;
- }
- }
- }
- if (Pico_mcd->pcm_ram[addr >> PCM_STEP_SHIFT] == 0xff)
- addr = (unsigned int)(*(unsigned short *)&ch->regs[4]) << PCM_STEP_SHIFT; // loop_addr
- ch->addr = addr;
- }
- }
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