1 /*
2 * PicoDrive
3 * (C) notaz, 2006-2010,2013
4 *
5 * This work is licensed under the terms of MAME license.
6 * See COPYING file in the top-level directory.
7 */
8
9 #include <string.h>
10 #include "pico_int.h"
11 #include "cd/cue.h"
12
13 unsigned char media_id_header[0x100];
14
strlwr_(char * string)15 static void strlwr_(char *string)
16 {
17 char *p;
18 for (p = string; *p; p++)
19 if ('A' <= *p && *p <= 'Z')
20 *p += 'a' - 'A';
21 }
22
get_ext(const char * file,char * ext)23 static void get_ext(const char *file, char *ext)
24 {
25 const char *p;
26
27 p = file + strlen(file) - 4;
28 if (p < file) p = file;
29 strncpy(ext, p, 4);
30 ext[4] = 0;
31 strlwr_(ext);
32 }
33
detect_media(const char * fname)34 static int detect_media(const char *fname)
35 {
36 static const short sms_offsets[] = { 0x7ff0, 0x3ff0, 0x1ff0 };
37 static const char *sms_exts[] = { "sms", "gg", "sg" };
38 static const char *md_exts[] = { "gen", "bin", "smd" };
39 char buff0[32], buff[32];
40 unsigned short *d16;
41 pm_file *pmf;
42 char ext[5];
43 int i;
44
45 get_ext(fname, ext);
46
47 // detect wrong extensions
48 if (!strcmp(ext, ".srm") || !strcmp(ext, "s.gz") || !strcmp(ext, ".mds")) // s.gz ~ .mds.gz
49 return PM_BAD_DETECT;
50
51 /* don't believe in extensions, except .cue */
52 if (strcasecmp(ext, ".cue") == 0)
53 return PM_CD;
54
55 pmf = pm_open(fname);
56 if (pmf == NULL)
57 return PM_BAD_DETECT;
58
59 if (pm_read(buff0, 32, pmf) != 32) {
60 pm_close(pmf);
61 return PM_BAD_DETECT;
62 }
63
64 if (strncasecmp("SEGADISCSYSTEM", buff0 + 0x00, 14) == 0 ||
65 strncasecmp("SEGADISCSYSTEM", buff0 + 0x10, 14) == 0) {
66 pm_close(pmf);
67 return PM_CD;
68 }
69
70 /* check for SMD evil */
71 if (pmf->size >= 0x4200 && (pmf->size & 0x3fff) == 0x200) {
72 if (pm_seek(pmf, sms_offsets[0] + 0x200, SEEK_SET) == sms_offsets[0] + 0x200 &&
73 pm_read(buff, 16, pmf) == 16 &&
74 strncmp("TMR SEGA", buff, 8) == 0)
75 goto looks_like_sms;
76
77 /* could parse further but don't bother */
78 goto extension_check;
79 }
80
81 /* MD header? Act as TMSS BIOS here */
82 if (pm_seek(pmf, 0x100, SEEK_SET) == 0x100 && pm_read(buff, 16, pmf) == 16) {
83 if (strncmp(buff, "SEGA", 4) == 0 || strncmp(buff, " SEG", 4) == 0)
84 goto looks_like_md;
85 }
86
87 for (i = 0; i < ARRAY_SIZE(sms_offsets); i++) {
88 if (pm_seek(pmf, sms_offsets[i], SEEK_SET) != sms_offsets[i])
89 continue;
90
91 if (pm_read(buff, 16, pmf) != 16)
92 continue;
93
94 if (strncmp("TMR SEGA", buff, 8) == 0)
95 goto looks_like_sms;
96 }
97
98 extension_check:
99 /* probably some headerless thing. Maybe check the extension after all. */
100 for (i = 0; i < ARRAY_SIZE(md_exts); i++)
101 if (strcasecmp(pmf->ext, md_exts[i]) == 0)
102 goto looks_like_md;
103
104 for (i = 0; i < ARRAY_SIZE(sms_exts); i++)
105 if (strcasecmp(pmf->ext, sms_exts[i]) == 0)
106 goto looks_like_sms;
107
108 /* If everything else fails, make a guess on the reset vector */
109 d16 = (unsigned short *)(buff0 + 4);
110 if ((((d16[0] << 16) | d16[1]) & 0xffffff) >= pmf->size) {
111 lprintf("bad MD reset vector, assuming SMS\n");
112 goto looks_like_sms;
113 }
114
115 looks_like_md:
116 pm_close(pmf);
117 return PM_MD_CART;
118
119 looks_like_sms:
120 pm_close(pmf);
121 return PM_MARK3;
122 }
123
124 /* checks if fname points to valid MegaCD image */
PicoCdCheck(const char * fname_in,int * pregion)125 int PicoCdCheck(const char *fname_in, int *pregion)
126 {
127 const char *fname = fname_in;
128 unsigned char buf[32];
129 pm_file *cd_f;
130 int region = 4; // 1: Japan, 4: US, 8: Europe
131 char ext[5];
132 cue_track_type type = CT_UNKNOWN;
133 cue_data_t *cue_data = NULL;
134
135 // opens a cue, or searches for one
136 cue_data = cue_parse(fname_in);
137 if (cue_data != NULL) {
138 fname = cue_data->tracks[1].fname;
139 type = cue_data->tracks[1].type;
140 }
141 else {
142 get_ext(fname_in, ext);
143 if (strcasecmp(ext, ".cue") == 0)
144 return -1;
145 }
146
147 cd_f = pm_open(fname);
148 if (cue_data != NULL)
149 cue_destroy(cue_data);
150
151 if (cd_f == NULL) return 0; // let the upper level handle this
152
153 if (pm_read(buf, 32, cd_f) != 32) {
154 pm_close(cd_f);
155 return -1;
156 }
157
158 if (!strncasecmp("SEGADISCSYSTEM", (char *)buf+0x00, 14)) {
159 if (type && type != CT_ISO)
160 elprintf(EL_STATUS, ".cue has wrong type: %i", type);
161 type = CT_ISO; // Sega CD (ISO)
162 }
163 if (!strncasecmp("SEGADISCSYSTEM", (char *)buf+0x10, 14)) {
164 if (type && type != CT_BIN)
165 elprintf(EL_STATUS, ".cue has wrong type: %i", type);
166 type = CT_BIN; // Sega CD (BIN)
167 }
168
169 if (type == CT_UNKNOWN) {
170 pm_close(cd_f);
171 return 0;
172 }
173
174 pm_seek(cd_f, (type == CT_ISO) ? 0x100 : 0x110, SEEK_SET);
175 pm_read(media_id_header, sizeof(media_id_header), cd_f);
176
177 /* it seems we have a CD image here. Try to detect region now.. */
178 pm_seek(cd_f, (type == CT_ISO) ? 0x100+0x10B : 0x110+0x10B, SEEK_SET);
179 pm_read(buf, 1, cd_f);
180 pm_close(cd_f);
181
182 if (buf[0] == 0x64) region = 8; // EU
183 if (buf[0] == 0xa1) region = 1; // JAP
184
185 lprintf("detected %s Sega/Mega CD image with %s region\n",
186 type == CT_BIN ? "BIN" : "ISO", region != 4 ? (region == 8 ? "EU" : "JAP") : "USA");
187
188 if (pregion != NULL)
189 *pregion = region;
190
191 return type;
192 }
193
PicoLoadMedia(const char * filename,const char * carthw_cfg_fname,const char * (* get_bios_filename)(int * region,const char * cd_fname),void (* do_region_override)(const char * media_filename))194 enum media_type_e PicoLoadMedia(const char *filename,
195 const char *carthw_cfg_fname,
196 const char *(*get_bios_filename)(int *region, const char *cd_fname),
197 void (*do_region_override)(const char *media_filename))
198 {
199 const char *rom_fname = filename;
200 enum media_type_e media_type;
201 enum cd_img_type cd_img_type = CIT_NOT_CD;
202 unsigned char *rom_data = NULL;
203 unsigned int rom_size = 0;
204 pm_file *rom = NULL;
205 int cd_region = 0;
206 int ret;
207
208 media_type = detect_media(filename);
209 if (media_type == PM_BAD_DETECT)
210 goto out;
211
212 if ((PicoIn.AHW & PAHW_MCD) && Pico_mcd != NULL)
213 cdd_unload();
214 PicoCartUnload();
215 PicoIn.AHW = 0;
216 PicoIn.quirks = 0;
217
218 if (media_type == PM_CD)
219 {
220 // check for MegaCD image
221 cd_img_type = PicoCdCheck(filename, &cd_region);
222 if ((int)cd_img_type >= 0 && cd_img_type != CIT_NOT_CD)
223 {
224 // valid CD image, ask frontend for BIOS..
225 rom_fname = NULL;
226 if (get_bios_filename != NULL)
227 rom_fname = get_bios_filename(&cd_region, filename);
228 if (rom_fname == NULL) {
229 media_type = PM_BAD_CD_NO_BIOS;
230 goto out;
231 }
232
233 PicoIn.AHW |= PAHW_MCD;
234 }
235 else {
236 media_type = PM_BAD_CD;
237 goto out;
238 }
239 }
240 else if (media_type == PM_MARK3) {
241 lprintf("detected SMS ROM\n");
242 PicoIn.AHW = PAHW_SMS;
243 }
244
245 rom = pm_open(rom_fname);
246 if (rom == NULL) {
247 lprintf("Failed to open ROM\n");
248 media_type = PM_ERROR;
249 goto out;
250 }
251
252 ret = PicoCartLoad(rom, &rom_data, &rom_size, (PicoIn.AHW & PAHW_SMS) ? 1 : 0);
253 pm_close(rom);
254 if (ret != 0) {
255 if (ret == 2) lprintf("Out of memory\n");
256 else if (ret == 3) lprintf("Read failed\n");
257 else lprintf("PicoCartLoad() failed.\n");
258 media_type = PM_ERROR;
259 goto out;
260 }
261
262 // detect wrong files
263 if (strncmp((char *)rom_data, "Pico", 4) == 0) {
264 lprintf("savestate selected?\n");
265 media_type = PM_BAD_DETECT;
266 goto out;
267 }
268
269 if (!(PicoIn.AHW & PAHW_SMS)) {
270 unsigned short *d = (unsigned short *)(rom_data + 4);
271 if ((((d[0] << 16) | d[1]) & 0xffffff) >= (int)rom_size) {
272 lprintf("bad reset vector\n");
273 media_type = PM_BAD_DETECT;
274 goto out;
275 }
276 }
277
278 // load config for this ROM (do this before insert to get correct region)
279 if (!(PicoIn.AHW & PAHW_MCD)) {
280 memcpy(media_id_header, rom_data + 0x100, sizeof(media_id_header));
281 if (do_region_override != NULL)
282 do_region_override(filename);
283 }
284
285 if (PicoCartInsert(rom_data, rom_size, carthw_cfg_fname)) {
286 media_type = PM_ERROR;
287 goto out;
288 }
289 rom_data = NULL; // now belongs to PicoCart
290 Pico.m.ncart_in = 0;
291
292 // insert CD if it was detected
293 if (cd_img_type != CIT_NOT_CD) {
294 ret = cdd_load(filename, cd_img_type);
295 if (ret != 0) {
296 PicoCartUnload();
297 media_type = PM_BAD_CD;
298 goto out;
299 }
300 Pico.m.ncart_in = 1;
301 }
302
303 if (PicoIn.quirks & PQUIRK_FORCE_6BTN)
304 PicoSetInputDevice(0, PICO_INPUT_PAD_6BTN);
305
306 out:
307 if (rom_data)
308 free(rom_data);
309 return media_type;
310 }
311
312 // vim:shiftwidth=2:ts=2:expandtab
313