mirror of https://github.com/bsnes-emu/bsnes.git
37 lines
736 B
C++
37 lines
736 B
C++
auto VDP::dmaRun() -> void {
|
|
if(!io.dmaEnable) return;
|
|
if(io.command.bits(4,5) != 2) return;
|
|
|
|
if(io.dmaMode <= 1) return dmaLoad();
|
|
if(io.dmaMode == 2) return dmaFill();
|
|
if(io.dmaMode == 3) return dmaCopy();
|
|
}
|
|
|
|
auto VDP::dmaLoad() -> void {
|
|
cpu.wait |= Wait::VDP_DMA;
|
|
|
|
auto data = cpu.readWord(io.dmaSource);
|
|
writeDataPort(data);
|
|
|
|
io.dmaSource.bits(0,15) += 2;
|
|
if(--io.dmaLength == 0) {
|
|
io.command.bit(5) = 0;
|
|
cpu.wait &=~ Wait::VDP_DMA;
|
|
}
|
|
}
|
|
|
|
auto VDP::dmaFill() -> void {
|
|
if(io.dmaFillWait) return;
|
|
|
|
auto data = io.dmaFillWord;
|
|
writeDataPort(data);
|
|
|
|
io.dmaSource.bits(0,15) += 2;
|
|
if(--io.dmaLength == 0 || --io.dmaLength == 0) {
|
|
io.command.bit(5) = 0;
|
|
}
|
|
}
|
|
|
|
auto VDP::dmaCopy() -> void {
|
|
}
|