93 lines
2.5 KiB
C++
93 lines
2.5 KiB
C++
#include "stdafx.h"
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#include "GbDmaController.h"
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#include "MessageManager.h"
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#include "CpuTypes.h"
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#include "GbMemoryManager.h"
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GbDmaController::GbDmaController(GbMemoryManager* memoryManager)
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{
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_memoryManager = memoryManager;
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_state = {};
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}
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void GbDmaController::Exec()
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{
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if(_state.DmaCounter > 0) {
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if(_state.DmaCounter <= 160) {
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_memoryManager->WriteDma(0xFE00 + (160 - _state.DmaCounter), _state.DmaReadBuffer);
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}
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_state.DmaCounter--;
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_state.DmaReadBuffer = _memoryManager->ReadDma((_state.OamDmaDest << 8) + (160 - _state.DmaCounter));
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}
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if(_state.DmaStartDelay > 0) {
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if(--_state.DmaStartDelay == 0) {
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_state.InternalDest = _state.OamDmaDest;
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_state.DmaCounter = 161;
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}
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}
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}
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bool GbDmaController::IsOamDmaRunning()
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{
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return _state.DmaCounter > 0 && _state.DmaCounter < 161;
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}
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uint8_t GbDmaController::Read()
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{
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return _state.OamDmaDest;
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}
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void GbDmaController::Write(uint8_t value)
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{
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_state.DmaStartDelay = 1;
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_state.OamDmaDest = value;
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}
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uint8_t GbDmaController::ReadCgb(uint16_t addr)
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{
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switch(addr) {
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case 0xFF51: return _state.CgbDmaSource >> 8;
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case 0xFF52: return _state.CgbDmaSource & 0xFF;
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case 0xFF53: return _state.CgbDmaDest >> 8;
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case 0xFF54: return _state.CgbDmaDest & 0xFF;
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case 0xFF55: return _state.CgbDmaLength | (_state.CgbHdmaMode ? 0x80 : 0);
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}
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return 0;
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}
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void GbDmaController::WriteCgb(uint16_t addr, uint8_t value)
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{
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switch(addr) {
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case 0xFF51: _state.CgbDmaSource = (_state.CgbDmaSource & 0xFF) | (value << 8); break;
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case 0xFF52: _state.CgbDmaSource = (_state.CgbDmaSource & 0xFF00) | value; break;
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case 0xFF53: _state.CgbDmaDest = (_state.CgbDmaDest & 0xFF) | (value << 8); break;
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case 0xFF54: _state.CgbDmaDest = (_state.CgbDmaDest & 0xFF00) | value; break;
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case 0xFF55:
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_state.CgbDmaLength = value & 0x7F;
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_state.CgbHdmaMode = (value & 0x80) != 0;
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if(!_state.CgbHdmaMode) {
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//TODO check invalid dma sources/etc.
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//TODO timing
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for(int i = 0; i < _state.CgbDmaLength * 16; i++) {
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uint16_t dst = 0x8000 | (((_state.CgbDmaDest & 0x1FF0) + i) & 0x1FFF);
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_memoryManager->Write(dst, _memoryManager->Read((_state.CgbDmaSource & 0xFFF0) + i, MemoryOperationType::DmaRead));
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}
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_state.CgbDmaLength = 0x7F;
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} else {
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MessageManager::Log("TODO HDMA");
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}
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break;
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}
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}
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void GbDmaController::Serialize(Serializer& s)
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{
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s.Stream(
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_state.OamDmaDest, _state.DmaStartDelay, _state.InternalDest, _state.DmaCounter, _state.DmaReadBuffer,
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_state.CgbDmaDest, _state.CgbDmaLength, _state.CgbDmaSource, _state.CgbHdmaMode
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);
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}
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