mirror of
https://github.com/RaySollium99/picodrive.git
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131 lines
4 KiB
C
131 lines
4 KiB
C
#include "../PicoInt.h"
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#include "pcm.h"
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static unsigned int g_rate = 0; // 18.14 fixed point
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void pcm_write(unsigned int a, unsigned int d)
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{
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//printf("pcm_write(%i, %02x)\n", a, d);
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if (a < 7)
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{
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Pico_mcd->pcm.ch[Pico_mcd->pcm.cur_ch].regs[a] = d;
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}
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else if (a == 7) // control register
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{
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if (d & 0x40) Pico_mcd->pcm.cur_ch = d & 7;
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else Pico_mcd->pcm.bank = d & 0xf;
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Pico_mcd->pcm.control = d;
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// dprintf("pcm control=%02x", Pico_mcd->pcm.control);
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}
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else if (a == 8) // sound on/off
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{
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if (!(Pico_mcd->pcm.enabled & 0x01)) Pico_mcd->pcm.ch[0].addr =
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Pico_mcd->pcm.ch[0].regs[6] << (PCM_STEP_SHIFT + 8);
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if (!(Pico_mcd->pcm.enabled & 0x02)) Pico_mcd->pcm.ch[1].addr =
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Pico_mcd->pcm.ch[1].regs[6] << (PCM_STEP_SHIFT + 8);
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if (!(Pico_mcd->pcm.enabled & 0x04)) Pico_mcd->pcm.ch[2].addr =
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Pico_mcd->pcm.ch[2].regs[6] << (PCM_STEP_SHIFT + 8);
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if (!(Pico_mcd->pcm.enabled & 0x08)) Pico_mcd->pcm.ch[3].addr =
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Pico_mcd->pcm.ch[3].regs[6] << (PCM_STEP_SHIFT + 8);
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if (!(Pico_mcd->pcm.enabled & 0x10)) Pico_mcd->pcm.ch[4].addr =
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Pico_mcd->pcm.ch[4].regs[6] << (PCM_STEP_SHIFT + 8);
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if (!(Pico_mcd->pcm.enabled & 0x20)) Pico_mcd->pcm.ch[5].addr =
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Pico_mcd->pcm.ch[5].regs[6] << (PCM_STEP_SHIFT + 8);
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if (!(Pico_mcd->pcm.enabled & 0x40)) Pico_mcd->pcm.ch[6].addr =
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Pico_mcd->pcm.ch[6].regs[6] << (PCM_STEP_SHIFT + 8);
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if (!(Pico_mcd->pcm.enabled & 0x80)) Pico_mcd->pcm.ch[7].addr =
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Pico_mcd->pcm.ch[7].regs[6] << (PCM_STEP_SHIFT + 8);
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// printf("addr %x %x %x %x %x %x %x %x\n", Pico_mcd->pcm.ch[0].addr, Pico_mcd->pcm.ch[1].addr
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// , Pico_mcd->pcm.ch[2].addr, Pico_mcd->pcm.ch[3].addr, Pico_mcd->pcm.ch[4].addr, Pico_mcd->pcm.ch[5].addr
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// , Pico_mcd->pcm.ch[6].addr, Pico_mcd->pcm.ch[7].addr);
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Pico_mcd->pcm.enabled = ~d;
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//printf("enabled=%02x\n", Pico_mcd->pcm.enabled);
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}
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}
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void pcm_set_rate(int rate)
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{
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float step = 31.8 * 1024.0 / (float) rate; // max <4 @ 8000Hz
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step *= 256*256/4;
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g_rate = (unsigned int) step;
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if (step - (float) g_rate >= 0.5) g_rate++;
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printf("g_rate: %f %08x\n", (double)step, g_rate);
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}
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// TODO: make use of the fact that max_length == 3
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void pcm_update(int *buffer, int length, int stereo)
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{
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struct pcm_chan *ch;
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unsigned int step, addr;
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int mul_l, mul_r, smp;
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int i, j, k;
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int *out;
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// PCM disabled or all channels off (to be checked by caller)
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//if (!(Pico_mcd->pcm.control & 0x80) || !Pico_mcd->pcm.enabled) return;
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//printf("-- upd %i\n", length);
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for (i = 0; i < 8; i++)
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{
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if (!(Pico_mcd->pcm.enabled & (1 << i))) continue; // channel disabled
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out = buffer;
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ch = &Pico_mcd->pcm.ch[i];
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addr = ch->addr; // >> PCM_STEP_SHIFT;
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mul_l = ((int)ch->regs[0] * (ch->regs[1] & 0xf)) >> (5+1); // (env * pan) >> 5
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mul_r = ((int)ch->regs[0] * (ch->regs[1] >> 4)) >> (5+1);
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step = ((unsigned int)(*(unsigned short *)&ch->regs[2]) * g_rate) >> 14; // freq step
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// fprintf(stderr, "step=%i, cstep=%i, mul_l=%i, mul_r=%i, ch=%i, addr=%x, en=%02x\n",
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// *(unsigned short *)&ch->regs[2], step, mul_l, mul_r, i, addr, Pico_mcd->pcm.enabled);
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if (!stereo && mul_l < mul_r) mul_l = mul_r;
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for (j = 0; j < length; j++)
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{
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// printf("addr=%08x\n", addr);
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smp = Pico_mcd->pcm_ram[addr >> PCM_STEP_SHIFT];
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// test for loop signal
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if (smp == 0xff)
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{
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addr = *(unsigned short *)&ch->regs[4]; // loop_addr
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smp = Pico_mcd->pcm_ram[addr];
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addr <<= PCM_STEP_SHIFT;
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if (smp == 0xff) break;
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}
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if (smp & 0x80) smp = -(smp & 0x7f);
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*out++ += smp * mul_l; // max 128 * 119 = 15232
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if(stereo)
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*out++ += smp * mul_r;
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// update address register
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k = (addr >> PCM_STEP_SHIFT) + 1;
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addr = (addr + step) & 0x7FFFFFF;
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for(; k < (addr >> PCM_STEP_SHIFT); k++)
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{
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if (Pico_mcd->pcm_ram[k] == 0xff)
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{
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addr = (unsigned int)(*(unsigned short *)&ch->regs[4]) << PCM_STEP_SHIFT; // loop_addr
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break;
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}
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}
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}
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if (Pico_mcd->pcm_ram[addr >> PCM_STEP_SHIFT] == 0xff)
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addr = (unsigned int)(*(unsigned short *)&ch->regs[4]) << PCM_STEP_SHIFT; // loop_addr
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ch->addr = addr;
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}
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}
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