mirror of https://github.com/bsnes-emu/bsnes.git
53 lines
1.2 KiB
C++
53 lines
1.2 KiB
C++
//NES-CNROM
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struct NES_CNROM : Board {
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NES_CNROM(Markup::Node& document) : Board(document) {
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settings.mirror = document["board/mirror/mode"].text() == "vertical" ? 1 : 0;
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}
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auto readPRG(uint addr) -> uint8 {
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if(addr & 0x8000) return prgrom.read(addr & 0x7fff);
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return cpu.mdr();
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}
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auto writePRG(uint addr, uint8 data) -> void {
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if(addr & 0x8000) chrBank = data & 0x03;
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}
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auto readCHR(uint addr) -> uint8 {
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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.readCIRAM(addr & 0x07ff);
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}
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addr = (chrBank * 0x2000) + (addr & 0x1fff);
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return Board::readCHR(addr);
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}
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auto writeCHR(uint addr, uint8 data) -> void {
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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.writeCIRAM(addr & 0x07ff, data);
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}
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addr = (chrBank * 0x2000) + (addr & 0x1fff);
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Board::writeCHR(addr, data);
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}
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auto power() -> void {
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}
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auto reset() -> void {
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chrBank = 0;
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}
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auto serialize(serializer& s) -> void {
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Board::serialize(s);
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s.integer(chrBank);
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}
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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 chrBank;
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};
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