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DMA: Fixed (?) source bank for HDMA

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Sour 2019-02-22 18:40:39 -05:00
parent 02425d7453
commit b6b1620e00
1 changed files with 4 additions and 4 deletions
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8
Core/DmaController.cpp
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@ -153,18 +153,18 @@ void DmaController::ProcessHdmaChannels()
//5. If Line Counter is zero...
if((ch.HdmaLineCounterAndRepeat & 0x7F) == 0) {
//"a. Read the next byte from Address into $43xA (thus, into both Line Counter and Repeat)."
ch.HdmaLineCounterAndRepeat = _memoryManager->ReadDma(ch.HdmaTableAddress++);
ch.HdmaLineCounterAndRepeat = _memoryManager->ReadDma((ch.SrcBank << 16) | ch.HdmaTableAddress++);
//"b. If Addressing Mode is Indirect, read two bytes from Address into Indirect Address(and increment Address by two bytes)."
if(ch.HdmaIndirectAddressing) {
if(ch.HdmaLineCounterAndRepeat == 0) {
//"One oddity: if $43xA is 0 and this is the last active HDMA channel for this scanline, only load one byte for Address,
//and use the $00 for the low byte.So Address ends up incremented one less than otherwise expected, and one less CPU Cycle is used."
uint8_t msb = _memoryManager->ReadDma(ch.HdmaTableAddress++);
uint8_t msb = _memoryManager->ReadDma((ch.SrcBank << 16) | ch.HdmaTableAddress++);
ch.TransferSize = (msb << 8);
} else {
uint8_t lsb = _memoryManager->ReadDma(ch.HdmaTableAddress++);
uint8_t msb = _memoryManager->ReadDma(ch.HdmaTableAddress++);
uint8_t lsb = _memoryManager->ReadDma((ch.SrcBank << 16) | ch.HdmaTableAddress++);
uint8_t msb = _memoryManager->ReadDma((ch.SrcBank << 16) | ch.HdmaTableAddress++);
ch.TransferSize = (msb << 8) | lsb;
}