mirror of https://github.com/bsnes-emu/bsnes.git
65 lines
1.4 KiB
C++
65 lines
1.4 KiB
C++
auto CPU::op_read(uint16 addr) -> uint8 {
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if(status.oam_dma_pending) {
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status.oam_dma_pending = false;
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op_read(addr);
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oam_dma();
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}
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while(status.rdy_line == 0) {
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regs.mdr = bus.read(status.rdy_addr_valid ? status.rdy_addr_value : addr);
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add_clocks(12);
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}
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regs.mdr = bus.read(addr);
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add_clocks(12);
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return regs.mdr;
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}
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auto CPU::op_write(uint16 addr, uint8 data) -> void {
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bus.write(addr, regs.mdr = data);
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add_clocks(12);
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}
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auto CPU::last_cycle() -> void {
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status.interrupt_pending = ((status.irq_line | status.irq_apu_line) & ~regs.p.i) | status.nmi_pending;
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}
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auto CPU::nmi(uint16& vector) -> void {
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if(status.nmi_pending) {
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status.nmi_pending = false;
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vector = 0xfffa;
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}
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}
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auto CPU::oam_dma() -> void {
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for(uint n : range(256)) {
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uint8 data = op_read((status.oam_dma_page << 8) + n);
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op_write(0x2004, data);
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}
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}
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auto CPU::set_nmi_line(bool line) -> void {
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//edge-sensitive (0->1)
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if(!status.nmi_line && line) status.nmi_pending = true;
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status.nmi_line = line;
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}
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auto CPU::set_irq_line(bool line) -> void {
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//level-sensitive
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status.irq_line = line;
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}
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auto CPU::set_irq_apu_line(bool line) -> void {
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//level-sensitive
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status.irq_apu_line = line;
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}
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auto CPU::set_rdy_line(bool line) -> void {
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status.rdy_line = line;
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}
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auto CPU::set_rdy_addr(bool valid, uint16 value) -> void {
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status.rdy_addr_valid = valid;
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status.rdy_addr_value = value;
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}
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