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implement some obscure DMA types

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This commit is contained in:
StapleButter
2017-03-20 22:18:35 +01:00
parent a56bf5c76c
commit 2150240cbd
7 changed files with 76 additions and 14 deletions
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20
src/DMA.cpp
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@ -20,7 +20,7 @@
#include "NDS.h"
#include "DMA.h"
#include "NDSCart.h"
#include "GPU3D.h"
#include "GPU.h"
// NOTES ON DMA SHIT
@ -153,8 +153,8 @@ void DMA::WriteCnt(u32 val)
else if (StartMode == 0x07)
GPU3D::CheckFIFODMA();
if (StartMode==0x04 || StartMode==0x06 || StartMode==0x13)
printf("UNIMPLEMENTED ARM%d DMA%d START MODE %02X\n", CPU?7:9, Num, StartMode);
if (StartMode==0x06 || StartMode==0x13)
printf("UNIMPLEMENTED ARM%d DMA%d START MODE %02X, %08X->%08X\n", CPU?7:9, Num, StartMode, SrcAddr, DstAddr);
}
}
@ -194,6 +194,20 @@ void DMA::Start()
return;
}
// special path for the display FIFO. another gross hack.
// the display FIFO seems to be more like a circular buffer that holds 16 pixels
// from which the display controller reads. DMA is triggered every 8 pixels to fill it
// as it is being read from. emulating it properly would be resource intensive.
// proper emulation would only matter if something is trying to feed the FIFO manually
// instead of using the DMA. which is probably never happening. the only thing I know of
// that even uses the display FIFO is the aging cart.
if (StartMode == 0x04)
{
GPU::GPU2D_A->FIFODMA(CurSrcAddr);
CurSrcAddr += 256*2;
return;
}
// TODO eventually: not stop if we're running code in ITCM
Running = true;