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#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;
}
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