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#include "genesis.h"
uint16_t read_sram_w(uint32_t address, m68k_context * context)
{
genesis_context * gen = context->system;
address &= gen->save_ram_mask;
switch(gen->save_type)
{
case RAM_FLAG_BOTH:
return gen->save_storage[address] << 8 | gen->save_storage[address+1];
case RAM_FLAG_EVEN:
return gen->save_storage[address >> 1] << 8 | 0xFF;
case RAM_FLAG_ODD:
return gen->save_storage[address >> 1] | 0xFF00;
}
return 0xFFFF;//We should never get here
}
uint8_t read_sram_b(uint32_t address, m68k_context * context)
{
genesis_context * gen = context->system;
address &= gen->save_ram_mask;
switch(gen->save_type)
{
case RAM_FLAG_BOTH:
return gen->save_storage[address];
case RAM_FLAG_EVEN:
if (address & 1) {
return 0xFF;
} else {
return gen->save_storage[address >> 1];
}
case RAM_FLAG_ODD:
if (address & 1) {
return gen->save_storage[address >> 1];
} else {
return 0xFF;
}
}
return 0xFF;//We should never get here
}
m68k_context * write_sram_area_w(uint32_t address, m68k_context * context, uint16_t value)
{
genesis_context * gen = context->system;
if ((gen->bank_regs[0] & 0x3) == 1) {
address &= gen->save_ram_mask;
switch(gen->save_type)
{
case RAM_FLAG_BOTH:
gen->save_storage[address] = value >> 8;
gen->save_storage[address+1] = value;
break;
case RAM_FLAG_EVEN:
gen->save_storage[address >> 1] = value >> 8;
break;
case RAM_FLAG_ODD:
gen->save_storage[address >> 1] = value;
break;
}
}
return context;
}
m68k_context * write_sram_area_b(uint32_t address, m68k_context * context, uint8_t value)
{
genesis_context * gen = context->system;
if ((gen->bank_regs[0] & 0x3) == 1) {
address &= gen->save_ram_mask;
switch(gen->save_type)
{
case RAM_FLAG_BOTH:
gen->save_storage[address] = value;
break;
case RAM_FLAG_EVEN:
if (!(address & 1)) {
gen->save_storage[address >> 1] = value;
}
break;
case RAM_FLAG_ODD:
if (address & 1) {
gen->save_storage[address >> 1] = value;
}
break;
}
}
return context;
}
m68k_context * write_bank_reg_w(uint32_t address, m68k_context * context, uint16_t value)
{
genesis_context * gen = context->system;
address &= 0xE;
address >>= 1;
gen->bank_regs[address] = value;
if (!address) {
if (value & 1) {
//Used for games that only use the mapper for SRAM
if (context->mem_pointers[gen->mapper_start_index]) {
gen->mapper_temp = context->mem_pointers[gen->mapper_start_index];
}
context->mem_pointers[gen->mapper_start_index] = NULL;
//For games that need more than 4MB
for (int i = 4; i < 8; i++)
{
context->mem_pointers[gen->mapper_start_index + i] = NULL;
}
} else {
//Used for games that only use the mapper for SRAM
if (!context->mem_pointers[gen->mapper_start_index]) {
context->mem_pointers[gen->mapper_start_index] = gen->mapper_temp;
}
//For games that need more than 4MB
for (int i = 4; i < 8; i++)
{
context->mem_pointers[gen->mapper_start_index + i] = gen->cart + 0x40000*gen->bank_regs[i];
}
}
} else if (gen->mapper_type == MAPPER_SEGA) {
void *new_ptr = gen->cart + 0x40000*value;
if (context->mem_pointers[gen->mapper_start_index + address] != new_ptr) {
m68k_invalidate_code_range(gen->m68k, address * 0x80000, (address + 1) * 0x80000);
context->mem_pointers[gen->mapper_start_index + address] = new_ptr;
}
}
return context;
}
m68k_context * write_bank_reg_b(uint32_t address, m68k_context * context, uint8_t value)
{
if (address & 1) {
write_bank_reg_w(address, context, value);
}
return context;
}
void sega_mapper_serialize(genesis_context *gen, serialize_buffer *buf)
{
save_buffer8(buf, gen->bank_regs, sizeof(gen->bank_regs));
}
void sega_mapper_deserialize(deserialize_buffer *buf, genesis_context *gen)
{
for (int i = 0; i < sizeof(gen->bank_regs); i++)
{
write_bank_reg_w(i * 2, gen->m68k, load_int8(buf));
}
}
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