mirror of https://github.com/bsnes-emu/bsnes.git
44 lines
993 B
C++
44 lines
993 B
C++
//NES-NROM-128
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//NES-NROM-256
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struct NES_NROM : 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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uint8 prg_read(unsigned addr) {
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if(addr & 0x8000) return prgrom.read(addr);
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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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}
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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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if(chrram.size) return chrram.read(addr);
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return chrrom.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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if(chrram.size) return chrram.write(addr, data);
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}
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void serialize(serializer& s) {
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Board::serialize(s);
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}
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NES_NROM(Markup::Node& document) : Board(document) {
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settings.mirror = document["cartridge"]["mirror"]["mode"].data == "vertical" ? 1 : 0;
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}
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};
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