mirror of
https://github.com/RaySollium99/picodrive.git
synced 2025-10-27 00:29:39 -04:00
305 lines
7.6 KiB
C
305 lines
7.6 KiB
C
/*
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* PicoDrive
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* (C) notaz, 2006-2010,2013
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*
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* This work is licensed under the terms of MAME license.
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* See COPYING file in the top-level directory.
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*/
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#include <string.h>
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#include "pico_int.h"
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#include "cd/cue.h"
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unsigned char media_id_header[0x100];
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static void strlwr_(char *string)
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{
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char *p;
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for (p = string; *p; p++)
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if ('A' <= *p && *p <= 'Z')
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*p += 'a' - 'A';
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}
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static void get_ext(const char *file, char *ext)
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{
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const char *p;
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p = file + strlen(file) - 4;
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if (p < file) p = file;
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strncpy(ext, p, 4);
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ext[4] = 0;
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strlwr_(ext);
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}
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static int detect_media(const char *fname)
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{
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static const short sms_offsets[] = { 0x7ff0, 0x3ff0, 0x1ff0 };
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static const char *sms_exts[] = { "sms", "gg", "sg" };
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static const char *md_exts[] = { "gen", "bin", "smd" };
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char buff0[32], buff[32];
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unsigned short *d16;
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pm_file *pmf;
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char ext[5];
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int i;
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get_ext(fname, ext);
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// detect wrong extensions
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if (!strcmp(ext, ".srm") || !strcmp(ext, "s.gz") || !strcmp(ext, ".mds")) // s.gz ~ .mds.gz
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return PM_BAD_DETECT;
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/* don't believe in extensions, except .cue */
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if (strcasecmp(ext, ".cue") == 0)
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return PM_CD;
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pmf = pm_open(fname);
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if (pmf == NULL)
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return PM_BAD_DETECT;
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if (pm_read(buff0, 32, pmf) != 32) {
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pm_close(pmf);
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return PM_BAD_DETECT;
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}
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if (strncasecmp("SEGADISCSYSTEM", buff0 + 0x00, 14) == 0 ||
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strncasecmp("SEGADISCSYSTEM", buff0 + 0x10, 14) == 0) {
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pm_close(pmf);
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return PM_CD;
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}
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/* check for SMD evil */
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if (pmf->size >= 0x4200 && (pmf->size & 0x3fff) == 0x200) {
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if (pm_seek(pmf, sms_offsets[0] + 0x200, SEEK_SET) == sms_offsets[0] + 0x200 &&
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pm_read(buff, 16, pmf) == 16 &&
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strncmp("TMR SEGA", buff, 8) == 0)
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goto looks_like_sms;
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/* could parse further but don't bother */
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goto extension_check;
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}
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/* MD header? Act as TMSS BIOS here */
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if (pm_seek(pmf, 0x100, SEEK_SET) == 0x100 && pm_read(buff, 16, pmf) == 16) {
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if (strncmp(buff, "SEGA", 4) == 0 || strncmp(buff, " SEG", 4) == 0)
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goto looks_like_md;
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}
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for (i = 0; i < ARRAY_SIZE(sms_offsets); i++) {
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if (pm_seek(pmf, sms_offsets[i], SEEK_SET) != sms_offsets[i])
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continue;
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if (pm_read(buff, 16, pmf) != 16)
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continue;
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if (strncmp("TMR SEGA", buff, 8) == 0)
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goto looks_like_sms;
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}
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extension_check:
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/* probably some headerless thing. Maybe check the extension after all. */
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for (i = 0; i < ARRAY_SIZE(md_exts); i++)
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if (strcasecmp(pmf->ext, md_exts[i]) == 0)
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goto looks_like_md;
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for (i = 0; i < ARRAY_SIZE(sms_exts); i++)
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if (strcasecmp(pmf->ext, sms_exts[i]) == 0)
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goto looks_like_sms;
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/* If everything else fails, make a guess on the reset vector */
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d16 = (unsigned short *)(buff0 + 4);
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if ((((d16[0] << 16) | d16[1]) & 0xffffff) >= pmf->size) {
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lprintf("bad MD reset vector, assuming SMS\n");
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goto looks_like_sms;
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}
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looks_like_md:
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pm_close(pmf);
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return PM_MD_CART;
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looks_like_sms:
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pm_close(pmf);
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return PM_MARK3;
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}
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/* checks if fname points to valid MegaCD image */
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int PicoCdCheck(const char *fname_in, int *pregion)
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{
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const char *fname = fname_in;
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unsigned char buf[32];
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pm_file *cd_f;
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int region = 4; // 1: Japan, 4: US, 8: Europe
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char ext[5];
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cue_track_type type = CT_UNKNOWN;
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cue_data_t *cue_data = NULL;
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get_ext(fname_in, ext);
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if (strcasecmp(ext, ".cue") == 0) {
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cue_data = cue_parse(fname_in);
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if (cue_data != NULL) {
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fname = cue_data->tracks[1].fname;
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type = cue_data->tracks[1].type;
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}
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else
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return -1;
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}
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cd_f = pm_open(fname);
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if (cue_data != NULL)
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cue_destroy(cue_data);
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if (cd_f == NULL) return 0; // let the upper level handle this
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if (pm_read(buf, 32, cd_f) != 32) {
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pm_close(cd_f);
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return -1;
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}
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if (!strncasecmp("SEGADISCSYSTEM", (char *)buf+0x00, 14)) {
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if (type && type != CT_ISO)
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elprintf(EL_STATUS, ".cue has wrong type: %i", type);
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type = CT_ISO; // Sega CD (ISO)
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}
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if (!strncasecmp("SEGADISCSYSTEM", (char *)buf+0x10, 14)) {
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if (type && type != CT_BIN)
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elprintf(EL_STATUS, ".cue has wrong type: %i", type);
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type = CT_BIN; // Sega CD (BIN)
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}
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if (type == CT_UNKNOWN) {
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pm_close(cd_f);
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return 0;
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}
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pm_seek(cd_f, (type == CT_ISO) ? 0x100 : 0x110, SEEK_SET);
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pm_read(media_id_header, sizeof(media_id_header), cd_f);
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/* it seems we have a CD image here. Try to detect region now.. */
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pm_seek(cd_f, (type == CT_ISO) ? 0x100+0x10B : 0x110+0x10B, SEEK_SET);
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pm_read(buf, 1, cd_f);
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pm_close(cd_f);
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if (buf[0] == 0x64) region = 8; // EU
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if (buf[0] == 0xa1) region = 1; // JAP
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lprintf("detected %s Sega/Mega CD image with %s region\n",
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type == CT_BIN ? "BIN" : "ISO", region != 4 ? (region == 8 ? "EU" : "JAP") : "USA");
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if (pregion != NULL)
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*pregion = region;
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return type;
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}
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enum media_type_e PicoLoadMedia(const char *filename,
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const char *carthw_cfg_fname,
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const char *(*get_bios_filename)(int *region, const char *cd_fname),
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void (*do_region_override)(const char *media_filename))
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{
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const char *rom_fname = filename;
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enum media_type_e media_type;
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cd_img_type cd_img_type = CIT_NOT_CD;
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unsigned char *rom_data = NULL;
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unsigned int rom_size = 0;
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pm_file *rom = NULL;
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int cd_region = 0;
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int ret;
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media_type = detect_media(filename);
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if (media_type == PM_BAD_DETECT)
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goto out;
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if ((PicoAHW & PAHW_MCD) && Pico_mcd != NULL)
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Stop_CD();
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PicoCartUnload();
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PicoAHW = 0;
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if (media_type == PM_CD)
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{
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// check for MegaCD image
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cd_img_type = PicoCdCheck(filename, &cd_region);
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if ((int)cd_img_type >= 0 && cd_img_type != CIT_NOT_CD)
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{
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// valid CD image, ask frontend for BIOS..
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rom_fname = NULL;
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if (get_bios_filename != NULL)
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rom_fname = get_bios_filename(&cd_region, filename);
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if (rom_fname == NULL) {
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media_type = PM_BAD_CD_NO_BIOS;
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goto out;
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}
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PicoAHW |= PAHW_MCD;
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}
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else {
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media_type = PM_BAD_CD;
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goto out;
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}
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}
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else if (media_type == PM_MARK3) {
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lprintf("detected SMS ROM\n");
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PicoAHW = PAHW_SMS;
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}
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rom = pm_open(rom_fname);
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if (rom == NULL) {
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lprintf("Failed to open ROM");
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media_type = PM_ERROR;
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goto out;
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}
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ret = PicoCartLoad(rom, &rom_data, &rom_size, (PicoAHW & PAHW_SMS) ? 1 : 0);
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pm_close(rom);
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if (ret != 0) {
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if (ret == 2) lprintf("Out of memory");
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else if (ret == 3) lprintf("Read failed");
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else lprintf("PicoCartLoad() failed.");
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media_type = PM_ERROR;
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goto out;
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}
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// detect wrong files
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if (strncmp((char *)rom_data, "Pico", 4) == 0) {
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lprintf("savestate selected?\n");
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media_type = PM_BAD_DETECT;
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goto out;
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}
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if (!(PicoAHW & PAHW_SMS)) {
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unsigned short *d = (unsigned short *)(rom_data + 4);
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if ((((d[0] << 16) | d[1]) & 0xffffff) >= (int)rom_size) {
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lprintf("bad reset vector\n");
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media_type = PM_BAD_DETECT;
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goto out;
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}
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}
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// load config for this ROM (do this before insert to get correct region)
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if (!(PicoAHW & PAHW_MCD)) {
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memcpy(media_id_header, rom_data + 0x100, sizeof(media_id_header));
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if (do_region_override != NULL)
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do_region_override(filename);
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}
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if (PicoCartInsert(rom_data, rom_size, carthw_cfg_fname)) {
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media_type = PM_ERROR;
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goto out;
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}
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rom_data = NULL; // now belongs to PicoCart
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// insert CD if it was detected
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if (cd_img_type != CIT_NOT_CD) {
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ret = Insert_CD(filename, cd_img_type);
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if (ret != 0) {
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PicoCartUnload();
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media_type = PM_BAD_CD;
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goto out;
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}
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}
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out:
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if (rom_data)
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free(rom_data);
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return media_type;
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}
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// vim:shiftwidth=2:ts=2:expandtab
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