1.20 release
[picodrive.git] / Pico / cd / pcm.c
1 #include "../PicoInt.h"
2 #include "pcm.h"
3
4 static unsigned int g_rate = 0; // 18.14 fixed point
5
6 void pcm_write(unsigned int a, unsigned int d)
7 {
8 //printf("pcm_write(%i, %02x)\n", a, d);
9
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
43                 Pico_mcd->pcm.enabled = ~d;
44 //printf("enabled=%02x\n", Pico_mcd->pcm.enabled);
45         }
46 }
47
48
49 void pcm_set_rate(int rate)
50 {
51         float step = 31.8 * 1024.0 / (float) rate; // max <4 @ 8000Hz
52         step *= 256*256/4;
53         g_rate = (unsigned int) step;
54         if (step - (float) g_rate >= 0.5) g_rate++;
55         printf("g_rate: %f %08x\n", (double)step, g_rate);
56 }
57
58
59 // TODO: make use of the fact that max_length == 3
60
61 void pcm_update(int *buffer, int length, int stereo)
62 {
63         struct pcm_chan *ch;
64         unsigned int step, addr;
65         int mul_l, mul_r, smp;
66         int i, j, k;
67         int *out;
68
69
70         // PCM disabled or all channels off (to be checked by caller)
71         //if (!(Pico_mcd->pcm.control & 0x80) || !Pico_mcd->pcm.enabled) return;
72
73 //printf("-- upd %i\n", length);
74
75         for (i = 0; i < 8; i++)
76         {
77                 if (!(Pico_mcd->pcm.enabled & (1 << i))) continue; // channel disabled
78
79                 out = buffer;
80                 ch = &Pico_mcd->pcm.ch[i];
81
82                 addr = ch->addr; // >> PCM_STEP_SHIFT;
83                 mul_l = ((int)ch->regs[0] * (ch->regs[1] & 0xf)) >> (5+1); // (env * pan) >> 5
84                 mul_r = ((int)ch->regs[0] * (ch->regs[1] >>  4)) >> (5+1);
85                 step  = ((unsigned int)(*(unsigned short *)&ch->regs[2]) * g_rate) >> 14; // freq step
86 //              fprintf(stderr, "step=%i, cstep=%i, mul_l=%i, mul_r=%i, ch=%i, addr=%x, en=%02x\n",
87 //                      *(unsigned short *)&ch->regs[2], step, mul_l, mul_r, i, addr, Pico_mcd->pcm.enabled);
88
89                 if (!stereo && mul_l < mul_r) mul_l = mul_r;
90
91                 for (j = 0; j < length; j++)
92                 {
93 //                      printf("addr=%08x\n", addr);
94                         smp = Pico_mcd->pcm_ram[addr >> PCM_STEP_SHIFT];
95
96                         // test for loop signal
97                         if (smp == 0xff)
98                         {
99                                 addr = *(unsigned short *)&ch->regs[4]; // loop_addr
100                                 smp = Pico_mcd->pcm_ram[addr];
101                                 addr <<= PCM_STEP_SHIFT;
102                                 if (smp == 0xff) break;
103                         }
104
105                         if (smp & 0x80) smp = -(smp & 0x7f);
106
107                         *out++ += smp * mul_l; // max 128 * 119 = 15232
108                         if(stereo)
109                                 *out++ += smp * mul_r;
110
111                         // update address register
112                         k = (addr >> PCM_STEP_SHIFT) + 1;
113                         addr = (addr + step) & 0x7FFFFFF;
114
115                         for(; k < (addr >> PCM_STEP_SHIFT); k++)
116                         {
117                                 if (Pico_mcd->pcm_ram[k] == 0xff)
118                                 {
119                                         addr = (unsigned int)(*(unsigned short *)&ch->regs[4]) << PCM_STEP_SHIFT; // loop_addr
120                                         break;
121                                 }
122                         }
123                 }
124
125                 if (Pico_mcd->pcm_ram[addr >> PCM_STEP_SHIFT] == 0xff)
126                         addr = (unsigned int)(*(unsigned short *)&ch->regs[4]) << PCM_STEP_SHIFT; // loop_addr
127
128                 ch->addr = addr;
129         }
130 }
131