Mesen-SX/Core/Cpu.cpp
2020-10-11 13:57:01 +03:00

161 lines
3.3 KiB
C++

#include "stdafx.h"
#include "../Utilities/Serializer.h"
#include "CpuTypes.h"
#include "Cpu.h"
#include "Console.h"
#include "MemoryManager.h"
#include "DmaController.h"
#include "EventType.h"
#include "Cpu.Instructions.h"
#include "Cpu.Shared.h"
#ifndef DUMMYCPU
Cpu::Cpu(Console *console)
{
_console = console;
_memoryManager = console->GetMemoryManager().get();
_dmaController = console->GetDmaController().get();
}
#endif
Cpu::~Cpu()
{
}
void Cpu::Exec()
{
_immediateMode = false;
switch(_state.StopState) {
case CpuStopState::Running: RunOp(); break;
case CpuStopState::Stopped:
//STP was executed, CPU no longer executes any code
#ifndef DUMMYCPU
_memoryManager->IncMasterClock4();
#endif
return;
case CpuStopState::WaitingForIrq:
//WAI
Idle();
if(_state.IrqSource || _state.NeedNmi) {
Idle();
Idle();
_state.StopState = CpuStopState::Running;
}
break;
}
#ifndef DUMMYCPU
//Use the state of the IRQ/NMI flags on the previous cycle to determine if an IRQ is processed or not
if(_state.PrevNeedNmi) {
_state.NeedNmi = false;
uint32_t originalPc = GetProgramAddress(_state.PC);
ProcessInterrupt(_state.EmulationMode ? Cpu::LegacyNmiVector : Cpu::NmiVector, true);
_console->ProcessInterrupt<CpuType::Cpu>(originalPc, GetProgramAddress(_state.PC), true);
} else if(_state.PrevIrqSource) {
uint32_t originalPc = GetProgramAddress(_state.PC);
ProcessInterrupt(_state.EmulationMode ? Cpu::LegacyIrqVector : Cpu::IrqVector, true);
_console->ProcessInterrupt<CpuType::Cpu>(originalPc, GetProgramAddress(_state.PC), false);
}
#endif
}
void Cpu::Idle()
{
#ifndef DUMMYCPU
_memoryManager->SetCpuSpeed(6);
ProcessCpuCycle();
_memoryManager->IncMasterClock6();
UpdateIrqNmiFlags();
#endif
}
void Cpu::IdleEndJump()
{
//Used by SA1
}
void Cpu::IdleTakeBranch()
{
//Used by SA1
}
void Cpu::ProcessCpuCycle()
{
_state.CycleCount++;
DetectNmiSignalEdge();
_state.IrqLock = _dmaController->ProcessPendingTransfers();
}
uint16_t Cpu::ReadVector(uint16_t vector)
{
//Overridden in SA-1 to return the correct value directly, rather than loading from ROM
return ReadDataWord(vector);
}
uint16_t Cpu::GetResetVector()
{
return _memoryManager->PeekWord(Cpu::ResetVector);
}
#ifndef DUMMYCPU
uint8_t Cpu::Read(uint32_t addr, MemoryOperationType type)
{
_memoryManager->SetCpuSpeed(_memoryManager->GetCpuSpeed(addr));
ProcessCpuCycle();
uint8_t value = _memoryManager->Read(addr, type);
UpdateIrqNmiFlags();
return value;
}
void Cpu::Write(uint32_t addr, uint8_t value, MemoryOperationType type)
{
_memoryManager->SetCpuSpeed(_memoryManager->GetCpuSpeed(addr));
ProcessCpuCycle();
_memoryManager->Write(addr, value, type);
UpdateIrqNmiFlags();
}
#endif
void Cpu::SetReg(CpuRegister reg, uint16_t value)
{
switch (reg) {
case CpuRegister::CpuRegA:
{
_state.A = value;
} break;
case CpuRegister::CpuRegX:
{
_state.X = value;
} break;
case CpuRegister::CpuRegY:
{
_state.Y = value;
} break;
case CpuRegister::CpuRegSP:
{
_state.SP = value;
} break;
case CpuRegister::CpuRegD:
{
_state.D = value;
} break;
case CpuRegister::CpuRegPC:
{
_state.PC = value;
} break;
case CpuRegister::CpuRegK:
{
_state.K = value & 0xFF;
} break;
case CpuRegister::CpuRegDBR:
{
_state.DBR = value & 0xFF;
} break;
case CpuRegister::CpuRegPS:
{
_state.PS = value & 0xFF;
} break;
}
}