bsnes/fc/cartridge/board/nes-gxrom.cpp

60 lines
1.4 KiB
C++

//NES-GNROM
//NES-MHROM
struct NES_GxROM : Board {
NES_GxROM(Markup::Node& document) : Board(document) {
settings.mirror = document["cartridge/mirror/mode"].text() == "vertical" ? 1 : 0;
}
auto prg_read(uint addr) -> uint8 {
if(addr & 0x8000) return prgrom.read((prg_bank << 15) | (addr & 0x7fff));
return cpu.mdr();
}
auto prg_write(uint addr, uint8 data) -> void {
if(addr & 0x8000) {
prg_bank = (data & 0x30) >> 4;
chr_bank = (data & 0x03) >> 0;
}
}
auto chr_read(uint addr) -> uint8 {
if(addr & 0x2000) {
if(settings.mirror == 0) addr = ((addr & 0x0800) >> 1) | (addr & 0x03ff);
return ppu.ciram_read(addr & 0x07ff);
}
addr = (chr_bank * 0x2000) + (addr & 0x1fff);
return Board::chr_read(addr);
}
auto chr_write(uint addr, uint8 data) -> void {
if(addr & 0x2000) {
if(settings.mirror == 0) addr = ((addr & 0x0800) >> 1) | (addr & 0x03ff);
return ppu.ciram_write(addr & 0x07ff, data);
}
addr = (chr_bank * 0x2000) + (addr & 0x1fff);
Board::chr_write(addr, data);
}
auto power() -> void {
}
auto reset() -> void {
prg_bank = 0;
chr_bank = 0;
}
auto serialize(serializer& s) -> void {
Board::serialize(s);
s.integer(prg_bank);
s.integer(chr_bank);
}
struct Settings {
bool mirror; //0 = horizontal, 1 = vertical
} settings;
uint2 prg_bank;
uint2 chr_bank;
};