Mercurial > repos > blastem
view system.c @ 1925:039553703c20
Don't apply address and cd register changes to the 'live' registers until pending flag is cleared, but do preserve the upper address bits in the latch. Fixes regression in Overdrive 2 while preserving fix to Mona in 344 bytes
author | Michael Pavone <pavone@retrodev.com> |
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date | Mon, 13 Apr 2020 20:43:25 -0700 |
parents | 7b62e6805e6a |
children | c3c62dbf1ceb |
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#include <string.h> #include "system.h" #include "genesis.h" #include "sms.h" uint8_t safe_cmp(char *str, long offset, uint8_t *buffer, long filesize) { long len = strlen(str); return filesize >= offset+len && !memcmp(str, buffer + offset, len); } system_type detect_system_type(system_media *media) { if (safe_cmp("SEGA", 0x100, media->buffer, media->size)) { //TODO: Differentiate between vanilla Genesis and Sega CD/32X games return SYSTEM_GENESIS; } if (safe_cmp("TMR SEGA", 0x1FF0, media->buffer, media->size) || safe_cmp("TMR SEGA", 0x3FF0, media->buffer, media->size) || safe_cmp("TMR SEGA", 0x7FF0, media->buffer, media->size) ) { return SYSTEM_SMS; } //TODO: Detect Jaguar ROMs here //Header based detection failed, examine filename for clues if (media->extension) { if (!strcmp("md", media->extension) || !strcmp("gen", media->extension)) { return SYSTEM_GENESIS; } if (!strcmp("sms", media->extension)) { return SYSTEM_SMS; } if (!strcmp("j64", media->extension)) { return SYSTEM_JAGUAR; } } //More certain checks failed, look for a valid 68K reset vector if (media->size >= 8) { char *rom = media->buffer; uint32_t reset = rom[5] << 16 | rom[6] << 8 | rom[7]; if (!(reset & 1) && reset < media->size) { //we have a valid looking reset vector, assume it's a Genesis ROM return SYSTEM_GENESIS; } } return SYSTEM_UNKNOWN; } system_header *alloc_config_system(system_type stype, system_media *media, uint32_t opts, uint8_t force_region) { void *lock_on = NULL; uint32_t lock_on_size = 0; if (media->chain) { lock_on = media->chain->buffer; lock_on_size = media->chain->size; } switch (stype) { case SYSTEM_GENESIS: return &(alloc_config_genesis(media->buffer, media->size, lock_on, lock_on_size, opts, force_region))->header; #ifndef NO_Z80 case SYSTEM_SMS: return &(alloc_configure_sms(media, opts, force_region))->header; #endif default: return NULL; } }