Mercurial > repos > blastem
view realtec.c @ 2274:bf1bb893f104
Properly ignore low bits of SP start address in disassembler
author | Michael Pavone <pavone@retrodev.com> |
---|---|
date | Thu, 29 Dec 2022 22:44:35 -0800 |
parents | adb62000d296 |
children |
line wrap: on
line source
#include <stdint.h> #include <stdlib.h> #include <string.h> #include "romdb.h" #include "genesis.h" #include "util.h" typedef struct { uint8_t rom_space[512*1024]; uint8_t regs[3]; } realtec; uint8_t realtec_detect(uint8_t *rom, uint32_t rom_size) { //All Realtec mapper games are 512KB total if (rom_size != 512*1024) { return 0; } return memcmp(rom + 0x7E100, "SEGA", 4) == 0; } static realtec *get_realtec(genesis_context *gen) { if (!gen->extra) { gen->extra = gen->m68k->mem_pointers[0]; } return gen->extra; } static void *realtec_write_b(uint32_t address, void *context, uint8_t value) { if (address & 1) { return context; } m68k_context *m68k = context; genesis_context *gen = m68k->system; realtec *r = get_realtec(gen); uint32_t offset = address >> 13; if (offset < 3 && r->regs[offset] != value) { r->regs[offset] = value; //other regs are only 3 bits, so assume 3 for this one too uint32_t size = (r->regs[1] & 0x7) << 17; uint32_t start = (r->regs[2] & 7) << 17 | (r->regs[0] & 6) << 19; if (!size || size > 512*1024) { size = 512*1024; } for(uint32_t cur = 0; cur < 512*1024; cur += size) { if (start + size > 512*1024) { memcpy(r->rom_space + cur, gen->cart + start/2, 512*1024-start); //assume it wraps memcpy(r->rom_space + cur + 512*1024-start, gen->cart, size - (512*1024-start)); } else { memcpy(r->rom_space + cur, gen->cart + start/2, size); } } m68k_invalidate_code_range(gen->m68k, 0, 0x400000); } return context; } static void *realtec_write_w(uint32_t address, void *context, uint16_t value) { return realtec_write_b(address, context, value >> 8); } void realtec_serialize(genesis_context *gen, serialize_buffer *buf) { realtec *r = get_realtec(gen); save_buffer8(buf, r->regs, sizeof(r->regs)); } void realtec_deserialize(deserialize_buffer *buf, genesis_context *gen) { realtec *r = get_realtec(gen); for (int i = 0; i < sizeof(r->regs); i++) { realtec_write_b(i << 13, gen->m68k, load_int8(buf)); } } rom_info realtec_configure_rom(uint8_t *rom, uint32_t rom_size, memmap_chunk const *base_map, uint32_t base_chunks) { rom_info info; realtec *r = calloc(sizeof(realtec), 1); for (uint32_t i = 0; i < 512*1024; i += 8*1024) { memcpy(r->rom_space + i, rom + 0x7E000, 8*1024); } byteswap_rom(512*1024, (uint16_t *)r->rom_space); uint8_t *name_start = NULL, *name_end = NULL; for (int i = 0x94; i < 0xE0; i++) { if (name_start) { if (rom[i] < ' ' || rom[i] > 0x80 || !memcmp(rom+i, "ARE", 3) || !memcmp(rom+i, "are", 3)) { name_end = rom+i; break; } } else if (rom[i] > ' ' && rom[i] < 0x80 && rom[i] != ':') { name_start = rom + i; } } if (name_start && !name_end) { name_end = rom + 0xE0; } if (name_end) { while (name_end > name_start && name_end[-1] == ' ') { name_end--; } info.name = malloc(name_end-name_start+1); memcpy(info.name, name_start, name_end-name_start); info.name[name_end-name_start] = 0; } else { info.name = strdup("Realtec Game"); } info.save_type = SAVE_NONE; info.save_size = 0; info.save_buffer = NULL; info.num_eeprom = 0; info.eeprom_map = NULL; info.rom = rom; info.rom_size = rom_size; info.mapper_type = MAPPER_REALTEC; info.is_save_lock_on = 0; info.port1_override = info.port2_override = info.ext_override = info.mouse_mode = NULL; info.map_chunks = base_chunks + 2; info.map = calloc(sizeof(memmap_chunk), info.map_chunks); info.map[0].mask = sizeof(r->rom_space)-1; info.map[0].flags = MMAP_READ|MMAP_CODE|MMAP_PTR_IDX; info.map[0].start = 0; info.map[0].end = 0x400000; info.map[0].buffer = r->rom_space; info.map[0].write_16 = NULL; info.map[0].read_16 = NULL; info.map[0].write_8 = NULL; info.map[0].read_8 = NULL; info.map[1].mask = 0x7FFF; info.map[1].flags = 0; info.map[1].start = 0x400000; info.map[1].end = 0x800000; info.map[1].write_16 = realtec_write_w; info.map[1].write_8 = realtec_write_b; info.map[1].read_16 = NULL; info.map[1].read_8 = NULL; memcpy(info.map + 2, base_map, base_chunks * sizeof(memmap_chunk)); return info; }