mirror of https://github.com/bsnes-emu/bsnes.git
63 lines
1.3 KiB
C++
Executable File
63 lines
1.3 KiB
C++
Executable File
#ifdef CARTRIDGE_CPP
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uint8 Cartridge::MBC1::mmio_read(uint16 addr) {
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if(addr >= 0x0000 && addr <= 0x3fff) {
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return cartridge.rom_read(addr);
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}
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if(addr >= 0x4000 && addr <= 0x7fff) {
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return cartridge.rom_read(rom_bank | (addr & 0x3fff));
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}
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if(addr >= 0xa000 && addr <= 0xbfff) {
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if(ram_enable) return cartridge.ram_read(ram_bank | (addr & 0x1fff));
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return 0x00;
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}
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}
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void Cartridge::MBC1::mmio_write(uint16 addr, uint8 data) {
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if(addr >= 0x0000 && addr <= 0x1fff) {
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ram_enable = (data & 0x0f) == 0x0a;
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}
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if(addr >= 0x2000 && addr <= 0x3fff) {
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rom_select = data & 0x1f;
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if(rom_select == 0) rom_select = 1;
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}
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if(addr >= 0x4000 && addr <= 0x5fff) {
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ram_select = data & 0x03;
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}
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if(addr >= 0x6000 && addr <= 0x7fff) {
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mode_select = data & 0x01;
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}
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if(mode_select == 0) {
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rom_bank = (ram_select << 19) | (rom_select << 14);
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ram_bank = 0x00;
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} else {
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rom_bank = (rom_select << 14);
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ram_bank = (ram_select << 13);
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}
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if(addr >= 0xa000 && addr <= 0xbfff) {
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if(ram_enable) cartridge.ram_write(ram_bank | (addr & 0x1fff), data);
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}
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}
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void Cartridge::MBC1::power() {
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}
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void Cartridge::MBC1::reset() {
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ram_enable = false;
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rom_select = 0x01;
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ram_select = 0x00;
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mode_select = 0;
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rom_bank = 0x4000;
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ram_bank = 0x0000;
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}
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#endif
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