+#include "../PicoInt.h"
+#include "pcm.h"
+
+static unsigned int g_rate = 0; // 18.14 fixed point
+
+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);
+ }
+}
+
+
+void pcm_set_rate(int rate)
+{
+ double step = 31.8 * 1024.0 / (double) rate; // max <4 @ 8000Hz
+ step *= 256*256/4;
+ g_rate = (unsigned int) step;
+ printf("g_rate: %08x\n", g_rate);
+}
+
+
+// TODO: make use of the fact that max_length == 3
+
+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
+// printf("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;
+ }
+}
+