bsnes/higan/fc/cartridge/board/nes-nrom.cpp

42 lines
1.0 KiB
C++

//NES-NROM-128
//NES-NROM-256
struct NES_NROM : Board {
NES_NROM(Markup::Node& document) : Board(document) {
settings.mirror = document["board/mirror/mode"].text() == "vertical" ? 1 : 0;
}
auto readPRG(uint addr) -> uint8 {
if(addr & 0x8000) return prgrom.read(addr);
return cpu.mdr();
}
auto writePRG(uint addr, uint8 data) -> void {
}
auto readCHR(uint addr) -> uint8 {
if(addr & 0x2000) {
if(settings.mirror == 0) addr = ((addr & 0x0800) >> 1) | (addr & 0x03ff);
return ppu.readCIRAM(addr & 0x07ff);
}
if(chrram.size) return chrram.read(addr);
return chrrom.read(addr);
}
auto writeCHR(uint addr, uint8 data) -> void {
if(addr & 0x2000) {
if(settings.mirror == 0) addr = ((addr & 0x0800) >> 1) | (addr & 0x03ff);
return ppu.writeCIRAM(addr & 0x07ff, data);
}
if(chrram.size) return chrram.write(addr, data);
}
auto serialize(serializer& s) -> void {
Board::serialize(s);
}
struct Settings {
bool mirror; //0 = horizontal, 1 = vertical
} settings;
};