1 |
/* |
2 |
* Copyright (C) 2006-2007 Anders Gavare. All rights reserved. |
3 |
* |
4 |
* Redistribution and use in source and binary forms, with or without |
5 |
* modification, are permitted provided that the following conditions are met: |
6 |
* |
7 |
* 1. Redistributions of source code must retain the above copyright |
8 |
* notice, this list of conditions and the following disclaimer. |
9 |
* 2. Redistributions in binary form must reproduce the above copyright |
10 |
* notice, this list of conditions and the following disclaimer in the |
11 |
* documentation and/or other materials provided with the distribution. |
12 |
* 3. The name of the author may not be used to endorse or promote products |
13 |
* derived from this software without specific prior written permission. |
14 |
* |
15 |
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
16 |
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
17 |
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
18 |
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
19 |
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
20 |
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
21 |
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
22 |
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
23 |
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
24 |
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
25 |
* SUCH DAMAGE. |
26 |
* |
27 |
* |
28 |
* $Id: dreamcast.c,v 1.17 2007/06/17 23:32:20 debug Exp $ |
29 |
* |
30 |
* COMMENT: Dreamcast PROM emulation |
31 |
* |
32 |
* NOTE: This is basically just a dummy module, for now. |
33 |
* |
34 |
* See http://mc.pp.se/dc/syscalls.html for a description of what the |
35 |
* PROM syscalls do. (The symbolic names in this module are the same as on |
36 |
* that page.) |
37 |
*/ |
38 |
|
39 |
#include <stdio.h> |
40 |
#include <stdlib.h> |
41 |
#include <string.h> |
42 |
#include <sys/types.h> |
43 |
|
44 |
#include "cpu.h" |
45 |
#include "machine.h" |
46 |
#include "memory.h" |
47 |
#include "misc.h" |
48 |
|
49 |
|
50 |
/* The ROM FONT seems to be located just after 1MB, in a real Dreamcast: */ |
51 |
#define DREAMCAST_ROMFONT_BASE 0x80100020 |
52 |
|
53 |
static int booting_from_cdrom = 0; |
54 |
|
55 |
|
56 |
/* |
57 |
* dreamcast_romfont_init() |
58 |
* |
59 |
* Initialize the ROM font. |
60 |
*/ |
61 |
static void dreamcast_romfont_init(struct machine *machine) |
62 |
{ |
63 |
struct cpu *cpu = machine->cpus[0]; |
64 |
int i, y, v; |
65 |
uint64_t d = DREAMCAST_ROMFONT_BASE; |
66 |
|
67 |
/* TODO: A real font. */ |
68 |
|
69 |
/* 288 narrow glyphs (12 x 24 pixels): */ |
70 |
for (i=0; i<288; i++) { |
71 |
for (y=0; y<24; y+=2) { |
72 |
if (y <= 1 || y >= 22) |
73 |
v = 0; |
74 |
else |
75 |
v = random(); |
76 |
store_byte(cpu, d++, v & 0x3f); |
77 |
store_byte(cpu, d++, v & 0xc3); |
78 |
store_byte(cpu, d++, v & 0xfc); |
79 |
} |
80 |
} |
81 |
|
82 |
/* 7078 wide glyphs (24 x 24 pixels): */ |
83 |
for (i=0; i<7078; i++) { |
84 |
for (y=0; y<24; y++) { |
85 |
if (y <= 1 || y >= 22) |
86 |
v = 0; |
87 |
else |
88 |
v = random(); |
89 |
store_byte(cpu, d++, v & 0x3f); |
90 |
store_byte(cpu, d++, v); |
91 |
store_byte(cpu, d++, v & 0xfc); |
92 |
} |
93 |
} |
94 |
|
95 |
/* 129 VME icons (32 x 32 pixels): */ |
96 |
for (i=0; i<129; i++) { |
97 |
for (y=0; y<32; y++) { |
98 |
if (y <= 1 || y >= 30) |
99 |
v = 0; |
100 |
else |
101 |
v = random(); |
102 |
store_byte(cpu, d++, v & 0x3f); |
103 |
store_byte(cpu, d++, v); |
104 |
store_byte(cpu, d++, v); |
105 |
store_byte(cpu, d++, v & 0xfc); |
106 |
} |
107 |
} |
108 |
} |
109 |
|
110 |
|
111 |
/* |
112 |
* dreamcast_machine_setup(): |
113 |
* |
114 |
* Initializes pointers to Dreamcast PROM syscalls. |
115 |
*/ |
116 |
void dreamcast_machine_setup(struct machine *machine) |
117 |
{ |
118 |
int i; |
119 |
struct cpu *cpu = machine->cpus[0]; |
120 |
|
121 |
for (i=0; i<0x50; i+=sizeof(uint32_t)) { |
122 |
/* Store pointer to PROM routine... */ |
123 |
store_32bit_word(cpu, 0x8c0000b0 + i, 0x8c000040 + i); |
124 |
|
125 |
/* ... which contains only 1 instruction, a special |
126 |
opcode which triggers PROM emulation: */ |
127 |
store_16bit_word(cpu, 0x8c000040 + i, SH_INVALID_INSTR); |
128 |
} |
129 |
|
130 |
/* PROM reboot, in case someone jumps to 0xa0000000: */ |
131 |
store_16bit_word(cpu, 0xa0000000, SH_INVALID_INSTR); |
132 |
|
133 |
dreamcast_romfont_init(machine); |
134 |
} |
135 |
|
136 |
|
137 |
/* |
138 |
* dreamcast_emul(): |
139 |
*/ |
140 |
int dreamcast_emul(struct cpu *cpu) |
141 |
{ |
142 |
int addr = (cpu->pc & 0xff) - 0x40 + 0xb0; |
143 |
int r1 = cpu->cd.sh.r[1]; |
144 |
int r6 = cpu->cd.sh.r[6]; |
145 |
int r7 = cpu->cd.sh.r[7]; |
146 |
|
147 |
/* Special case: Reboot */ |
148 |
if ((uint32_t)cpu->pc == 0xa0000000) { |
149 |
fatal("[ dreamcast reboot ]\n"); |
150 |
cpu->running = 0; |
151 |
return 1; |
152 |
} |
153 |
|
154 |
switch (addr) { |
155 |
|
156 |
case 0xb0: |
157 |
/* SYSINFO */ |
158 |
switch (r7) { |
159 |
default:fatal("[ SYSINFO: Unimplemented r7=%i ]\n", r7); |
160 |
goto bad; |
161 |
} |
162 |
break; |
163 |
|
164 |
case 0xb4: |
165 |
/* ROMFONT */ |
166 |
switch (r1) { |
167 |
case 0: /* ROMFONT_ADDRESS */ |
168 |
cpu->cd.sh.r[0] = DREAMCAST_ROMFONT_BASE; |
169 |
break; |
170 |
default:fatal("[ ROMFONT: Unimplemented r1=%i ]\n", r1); |
171 |
goto bad; |
172 |
} |
173 |
break; |
174 |
|
175 |
case 0xb8: |
176 |
/* FLASHROM */ |
177 |
switch (r7) { |
178 |
case 0: /* FLASHROM_INFO */ |
179 |
/* TODO */ |
180 |
cpu->cd.sh.r[0] = (uint32_t) -1; |
181 |
break; |
182 |
default:fatal("[ FLASHROM: Unimplemented r7=%i ]\n", r7); |
183 |
goto bad; |
184 |
} |
185 |
break; |
186 |
|
187 |
case 0xbc: |
188 |
switch ((int32_t)r6) { |
189 |
case 0: /* GD-ROM emulation */ |
190 |
switch (r7) { |
191 |
case 0: /* GDROM_SEND_COMMAND */ |
192 |
/* TODO */ |
193 |
cpu->cd.sh.r[0] = (uint32_t) -1; |
194 |
break; |
195 |
case 1: /* GDROM_CHECK_COMMAND */ |
196 |
/* TODO */ |
197 |
cpu->cd.sh.r[0] = 0; |
198 |
break; |
199 |
case 2: /* GDROM_MAINLOOP */ |
200 |
/* TODO */ |
201 |
break; |
202 |
case 3: /* GDROM_INIT */ |
203 |
/* TODO: Do something here? */ |
204 |
break; |
205 |
case 4: /* GDROM_CHECK_DRIVE */ |
206 |
/* TODO: Return status words */ |
207 |
break; |
208 |
default:fatal("[ GDROM: Unimplemented r7=%i ]\n", r7); |
209 |
goto bad; |
210 |
} |
211 |
break; |
212 |
default:fatal("[ 0xbc: Unimplemented r6=0x%x ]\n", r6); |
213 |
goto bad; |
214 |
} |
215 |
break; |
216 |
|
217 |
case 0xe0: |
218 |
/* |
219 |
* This seems to have two uses: |
220 |
* |
221 |
* 1. KalistOS calls this from arch_menu(), i.e. to return |
222 |
* from a running program. |
223 |
* 2. The "licence code" in the IP.BIN code when booting from |
224 |
* a bootable CD image calls this once the license screen |
225 |
* has been displayed, and it wants the ROM to jump to |
226 |
* 0x8c00b800 ("Bootstrap 1"). |
227 |
* |
228 |
* The easiest way to support both is probably to keep track |
229 |
* of whether the IP.BIN code was started by the (software) |
230 |
* ROM emulation code, or not. |
231 |
*/ |
232 |
if (booting_from_cdrom) { |
233 |
fatal("[ dreamcast: Switching to bootstrap 1 ]\n"); |
234 |
booting_from_cdrom = 0; |
235 |
cpu->pc = 0x8c00b800; |
236 |
return 1; |
237 |
} else { |
238 |
fatal("[ dreamcast: Returning to main menu. ]\n"); |
239 |
cpu->running = 0; |
240 |
} |
241 |
break; |
242 |
|
243 |
case 0xf0: |
244 |
/* |
245 |
* GXemul hack: |
246 |
* |
247 |
* By jumping to this address (0x8c000080), a "boot from |
248 |
* CDROM" is simulated. Control is transfered to the license |
249 |
* code in the loaded IP.BIN file. |
250 |
*/ |
251 |
debug("[ dreamcast boot from CDROM ]\n"); |
252 |
booting_from_cdrom = 1; |
253 |
cpu->pc = 0x8c008300; |
254 |
return 1; |
255 |
|
256 |
default:goto bad; |
257 |
} |
258 |
|
259 |
/* Return from subroutine: */ |
260 |
cpu->pc = cpu->cd.sh.pr; |
261 |
|
262 |
return 1; |
263 |
|
264 |
bad: |
265 |
cpu_register_dump(cpu->machine, cpu, 1, 0); |
266 |
printf("\n"); |
267 |
fatal("[ dreamcast_emul(): unimplemented dreamcast PROM call, " |
268 |
"pc=0x%08"PRIx32" ]\n", (uint32_t)cpu->pc); |
269 |
cpu->running = 0; |
270 |
return 1; |
271 |
} |
272 |
|