clarify PicoDrive's license
[picodrive.git] / pico / pico / pico.c
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CommitLineData
1/*
2 * PicoDrive
3 * (C) notaz, 2008
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
10// x: 0x03c - 0x19d
11// y: 0x1fc - 0x2f7
12// 0x2f8 - 0x3f3
13picohw_state PicoPicohw;
14
15static int prev_line_cnt_irq3 = 0, prev_line_cnt_irq5 = 0;
16static int fifo_bytes_line = (16000<<16)/60/262/2;
17
18static const int guessed_rates[] = { 8000, 14000, 12000, 14000, 16000, 18000, 16000, 16000 }; // ?
19
20#define PICOHW_FIFO_IRQ_THRESHOLD 12
21
22PICO_INTERNAL void PicoReratePico(void)
23{
24 int rate = guessed_rates[PicoPicohw.r12 & 7];
25 if (Pico.m.pal)
26 fifo_bytes_line = (rate<<16)/50/312/2;
27 else fifo_bytes_line = (rate<<16)/60/262/2;
28 PicoPicoPCMRerate(rate);
29}
30
31static void PicoLinePico(void)
32{
33 PicoPicohw.line_counter++;
34
35#if 1
36 if ((PicoPicohw.r12 & 0x4003) && PicoPicohw.line_counter - prev_line_cnt_irq3 > 200) {
37 prev_line_cnt_irq3 = PicoPicohw.line_counter;
38 // just a guess/hack, allows 101 Dalmantians to boot
39 elprintf(EL_PICOHW, "irq3");
40 SekInterrupt(3);
41 return;
42 }
43#endif
44
45 if (PicoPicohw.fifo_bytes > 0)
46 {
47 PicoPicohw.fifo_line_bytes += fifo_bytes_line;
48 if (PicoPicohw.fifo_line_bytes >= (1<<16)) {
49 PicoPicohw.fifo_bytes -= PicoPicohw.fifo_line_bytes >> 16;
50 PicoPicohw.fifo_line_bytes &= 0xffff;
51 if (PicoPicohw.fifo_bytes < 0)
52 PicoPicohw.fifo_bytes = 0;
53 }
54 }
55 else
56 PicoPicohw.fifo_line_bytes = 0;
57
58#if 1
59 if (PicoPicohw.fifo_bytes_prev >= PICOHW_FIFO_IRQ_THRESHOLD &&
60 PicoPicohw.fifo_bytes < PICOHW_FIFO_IRQ_THRESHOLD) {
61 prev_line_cnt_irq3 = PicoPicohw.line_counter; // ?
62 elprintf(EL_PICOHW, "irq3, fb=%i", PicoPicohw.fifo_bytes);
63 SekInterrupt(3);
64 }
65 PicoPicohw.fifo_bytes_prev = PicoPicohw.fifo_bytes;
66#endif
67
68#if 0
69 if (PicoPicohw.line_counter - prev_line_cnt_irq5 > 512) {
70 prev_line_cnt_irq5 = PicoPicohw.line_counter;
71 elprintf(EL_PICOHW, "irq5");
72 SekInterrupt(5);
73 }
74#endif
75}
76
77static void PicoResetPico(void)
78{
79 PicoPicoPCMReset();
80 PicoPicohw.xpcm_ptr = PicoPicohw.xpcm_buffer;
81}
82
83PICO_INTERNAL void PicoInitPico(void)
84{
85 elprintf(EL_STATUS, "Pico startup");
86 PicoLineHook = PicoLinePico;
87 PicoResetHook = PicoResetPico;
88
89 PicoAHW = PAHW_PICO;
90 memset(&PicoPicohw, 0, sizeof(PicoPicohw));
91 PicoPicohw.pen_pos[0] = 0x03c + 320/2;
92 PicoPicohw.pen_pos[1] = 0x200 + 240/2;
93 prev_line_cnt_irq3 = prev_line_cnt_irq5 = 0;
94
95 // map version register
96 PicoDetectRegion();
97 switch (Pico.m.hardware >> 6) {
98 case 0: PicoPicohw.r1 = 0x00; break;
99 case 1: PicoPicohw.r1 = 0x00; break;
100 case 2: PicoPicohw.r1 = 0x40; break;
101 case 3: PicoPicohw.r1 = 0x20; break;
102 }
103}
104