mirror of https://github.com/bsnes-emu/bsnes.git
38 lines
880 B
C++
38 lines
880 B
C++
auto CPU::idle() -> void {
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status.clockCount = 6;
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dmaEdge();
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step(6);
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aluEdge();
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}
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auto CPU::read(uint24 addr) -> uint8 {
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status.clockCount = speed(addr);
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dmaEdge();
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step(status.clockCount - 4);
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auto data = bus.read(addr, r.mdr);
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step(4);
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aluEdge();
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//$00-3f,80-bf:4000-43ff reads are internal to CPU, and do not update the MDR
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if((addr & 0x40fc00) != 0x4000) r.mdr = data;
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return data;
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}
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auto CPU::write(uint24 addr, uint8 data) -> void {
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aluEdge();
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status.clockCount = speed(addr);
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dmaEdge();
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step(status.clockCount);
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bus.write(addr, r.mdr = data);
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}
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auto CPU::speed(uint24 addr) const -> uint {
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if(addr & 0x408000) return addr & 0x800000 ? io.romSpeed : 8;
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if(addr + 0x6000 & 0x4000) return 8;
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if(addr - 0x4000 & 0x7e00) return 6;
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return 12;
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}
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auto CPU::readDisassembler(uint24 addr) -> uint8 {
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return bus.read(addr, r.mdr);
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}
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