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