mirror of https://github.com/bsnes-emu/bsnes.git
37 lines
751 B
C++
37 lines
751 B
C++
auto VDP::dmaRun() -> void {
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if(!io.dmaEnable) return;
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if(!io.command.bit(5)) return;
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if(io.dmaMode <= 1) return dmaLoad();
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if(io.dmaMode == 2) return dmaFill();
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if(io.dmaMode == 3) return dmaCopy();
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}
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auto VDP::dmaLoad() -> void {
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cpu.wait |= Wait::VDP_DMA;
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auto data = busCPU.readWord(io.dmaMode.bit(0) << 23 | io.dmaSource << 1);
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writeDataPort(data);
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io.dmaSource.bits(0,15)++;
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if(--io.dmaLength == 0) {
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io.command.bit(5) = 0;
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cpu.wait &=~ Wait::VDP_DMA;
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}
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}
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auto VDP::dmaFill() -> void {
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if(io.dmaFillWait) return;
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auto data = io.dmaFillByte;
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writeDataPort(data << 8 | data << 0);
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io.dmaSource.bits(0,15)++;
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if(--io.dmaLength == 0) {
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io.command.bit(5) = 0;
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}
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}
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auto VDP::dmaCopy() -> void {
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}
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