mirror of https://github.com/bsnes-emu/bsnes.git
40 lines
922 B
C++
40 lines
922 B
C++
auto VDC::DMA::step(uint clocks) -> void {
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while(clocks--) {
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if(vramActive) {
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uint16 data = vdc.vramRead(source);
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vdc.vramWrite(target, data);
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sourceIncrementMode == 0 ? source++ : source--;
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targetIncrementMode == 0 ? target++ : target--;
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if(!--length) {
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vramActive = false;
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vdc.irq.raise(VDC::IRQ::Line::TransferVRAM);
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}
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}
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if(satbActive) {
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uint16 data = vdc.vramRead(satbSource + satbOffset);
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vdc.satb[satbOffset] = data;
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if(++satbOffset == 256) {
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satbActive = false;
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satbOffset = 0;
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satbPending = satbRepeat;
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vdc.irq.raise(VDC::IRQ::Line::TransferSATB);
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}
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}
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}
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}
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auto VDC::DMA::vramStart() -> void {
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vramActive = true;
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}
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auto VDC::DMA::satbStart() -> void {
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if(!satbPending) return;
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satbActive = true;
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satbOffset = 0;
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}
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auto VDC::DMA::satbQueue() -> void {
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satbPending = true;
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}
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