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#include "nes/mapper.hh"
#include "nes/cartridge.hh"
#include <iostream>
namespace nes
{
mapper::mapper(cartridge& cartridge, read_func const read, write_func const write)
: cartridge_{ cartridge }
, read_{ read }
, write_{ write }
{
}
auto mapper::select(cartridge& cartridge) -> mapper
{
switch (cartridge.get_mapper_number())
{
case 0x00:
return mapper{ cartridge, &mapper::nrom_read, &mapper::nrom_write };
default:
std::cerr << "Mapper not implemented: " << std::hex << cartridge.get_mapper_number() << std::endl;
std::abort();
}
}
// NROM
auto mapper::nrom_read(address const addr) -> std::uint8_t
{
if (addr <= address{ 0x7FFF })
{
return cartridge_.get_ram()[addr.get_absolute() % 0x2000];
}
if (addr <= address{ 0xBFFF })
{
auto const rel = addr.get_absolute() - 0x8000;
if (rel >= cartridge_.get_prg_rom_length()) { return 0x0; }
return cartridge_.get_prg_rom()[rel];
}
if (addr <= address{ 0xFFFF })
{
auto rel = addr.get_absolute() - 0xC000;
if (cartridge_.get_prg_rom_length() > 0x4000) { rel += 0x4000; }
if (rel >= cartridge_.get_prg_rom_length()) { return 0x0; }
return cartridge_.get_prg_rom()[rel];
}
return 0x0;
}
auto mapper::nrom_write(address const addr, std::uint8_t const value) -> void
{
if (addr <= address{ 0x7FFF })
{
cartridge_.get_ram_mut()[addr.get_absolute() % 0x2000] = value;
}
}
} // namespace nes
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