Mercurial > repos > blastem

annotate lc8951.c @ 2059:6399a776e981 segacd

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Add basic support for BIN/CUE images
author Michael Pavone <pavone@retrodev.com>
date Fri, 21 Jan 2022 21:59:46 -0800
parents 70260f6051dd
children 07ed42bd7b4c
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
2058
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
1 #include "lc8951.h"
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
2
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
3 enum {
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
4 COMIN,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
5 IFSTAT,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
6 DBCL,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
7 DBCH,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
8 HEAD0,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
9 HEAD1,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
10 HEAD2,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
11 HEAD3,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
12 PTL,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
13 PTH,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
14 WAL,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
15 WAH,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
16 STAT0,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
17 STAT1,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
18 STAT2,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
19 STAT3,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
20
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
21 SBOUT = COMIN,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
22 IFCTRL = IFSTAT,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
23 DACL = HEAD0,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
24 DACH = HEAD1,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
25 DTTRG = HEAD2,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
26 DTACK = HEAD3,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
27 WAL_WRITE = PTL,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
28 WAH_WRITE = PTH,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
29 CTRL0 = WAL,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
30 CTRL1 = WAH,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
31 PTL_WRITE = STAT0,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
32 PTH_WRITE = STAT1,
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
33 RESET = STAT3
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
34 };
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
35
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
36 //IFCTRL
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
37 #define BIT_CMDIEN 0x80
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
38 #define BIT_DTEIEN 0x40
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
39 #define BIT_CECIEN 0x20
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
40 #define BIT_CMDBK 0x10
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
41 #define BIT_DTWAI 0x08
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
42 #define BIT_STWAI 0x04
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
43 #define BIT_DOUTEN 0x02
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
44 #define BIT_SOUTEN 0x01
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
45
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
46 //IFSTAT
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
47 #define BIT_CMDI 0x80
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
48 #define BIT_DTEI 0x40
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
49 #define BIT_DECI 0x20
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
50 #define BIT_DTBSY 0x08
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
51 #define BIT_STBSY 0x04
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
52 #define BIT_DTEN 0x02
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
53 #define BIT_STEN 0x01
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
54
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
55 //datasheet timing info
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
56 //3 cycles for memory operation
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
57 //6 cycles min for DMA-mode host transfer
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
58
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
59 void lc8951_init(lc8951 *context)
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
60 {
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
61 //This seems to vary somewhat between Sega CD models
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
62 //unclear if the difference is in the lc8951 or gate array
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
63 context->regs[IFSTAT] = 0xFF;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
64 context->ar_mask = 0x1F;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
65 }
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
66
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
67 void lc8951_reg_write(lc8951 *context, uint8_t value)
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
68 {
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
69 switch (context->ar)
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
70 {
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
71 case SBOUT:
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
72 context->regs[context->ar] = value;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
73 if (context->ifctrl & BIT_SOUTEN) {
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
74 context->regs[IFSTAT] &= ~BIT_STBSY;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
75 }
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
76 break;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
77 case IFCTRL:
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
78 context->ifctrl = value;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
79 if (!(value & BIT_SOUTEN)) {
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
80 context->regs[IFSTAT] |= BIT_STBSY;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
81 }
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
82 if (!(value & BIT_DOUTEN)) {
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
83 context->regs[IFSTAT] |= BIT_DTBSY;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
84 }
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
85 break;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
86 case DBCL:
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
87 context->regs[context->ar] = value;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
88 break;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
89 case DBCH:
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
90 context->regs[context->ar] = value & 0xF;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
91 break;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
92 case DACL:
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
93 context->dac &= 0xFF00;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
94 context->dac |= value;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
95 break;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
96 case DACH:
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
97 context->dac &= 0xFF;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
98 context->dac |= value << 8;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
99 break;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
100 case DTTRG:
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
101 if (value & BIT_DOUTEN) {
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
102 context->regs[IFSTAT] &= ~BIT_DTBSY;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
103 }
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
104 break;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
105 case DTACK:
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
106 context->regs[IFSTAT] |= BIT_DTEI;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
107 break;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
108 case WAL_WRITE:
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
109 context->regs[WAL] = value;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
110 break;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
111 case WAH_WRITE:
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
112 context->regs[WAH] = value;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
113 break;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
114 case PTL_WRITE:
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
115 context->regs[PTL] = value;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
116 break;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
117 case PTH_WRITE:
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
118 context->regs[PTH] = value;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
119 break;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
120 case RESET:
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
121 context->comin_count = 0;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
122 context->regs[IFSTAT] = 0xFF;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
123 break;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
124 default:
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
125 break;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
126 }
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
127 if (context->ar != SBOUT) {
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
128 context->ar++;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
129 context->ar &= context->ar_mask;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
130 }
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
131 }
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
132
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
133 uint8_t lc8951_reg_read(lc8951 *context)
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
134 {
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
135 uint8_t value;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
136 if (context->ar == COMIN) {
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
137 if (!context->comin_count) {
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
138 return 0xFF;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
139 }
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
140 value = context->comin[(context->comin_write - context->comin_count)&sizeof(context->comin)];
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
141 context->comin_count--;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
142 if (!context->comin_count) {
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
143 context->regs[IFSTAT] |= BIT_CMDI;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
144 }
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
145 return value;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
146 }
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
147 if (context->ar == STAT3) {
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
148 context->regs[IFSTAT] |= BIT_DECI;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
149 }
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
150 if (context->ar >= sizeof(context->regs)) {
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
151 value = 0xFF;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
152 } else {
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
153 value = context->regs[context->ar];
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
154 }
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
155 context->ar++;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
156 context->ar &= context->ar_mask;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
157 return value;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
158 }
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
159
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
160 void lc8951_ar_write(lc8951 *context, uint8_t value)
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
161 {
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
162 context->ar = value & context->ar_mask;
70260f6051dd Initial work on CDC emulation
Michael Pavone <pavone@retrodev.com>
parents:
diff changeset
163 }