//////////////////////////////////////////////////////////////////////
//
//@return true / if instruction was NOP
//
//////////////////////////////////////////////////////////////////////
public bool RunOneInstruction(bool bDebugEnabled)
{
if (m_started || m_runOnce || m_runToStepOver)
{
bool bCanRun = bDebugEnabled ? DebugFunctions.Z80Form().CanStep() : true;
if (bCanRun && (m_curInstruction == null || m_curInstructionCurCycle >= m_curInstructionNbCycles))
{
if (m_interruptsMgr.Update())
{
return(true);
}
else
{
byte opcode = 0;
opcode = GameBoy.Ram.ReadByteAt(m_PC);
m_curInstruction = m_decoder.GetNextInstruction();
if (m_curInstruction == null)
{
ThrowNullInstructionException(opcode, m_PC, bDebugEnabled);
return(true);
}
if (m_runOnce)
{
m_runOnce = false;
m_curInstructionCurCycle = m_curInstructionNbCycles;
}
if (bDebugEnabled)
{
DebugFunctions.CallStackForm().AddToCallstack();
}
ushort oldPc = m_PC;
m_PC = m_curInstruction.Exec(m_PC);
m_curInstructionNbCycles = m_curInstruction.GetCurNbCycles(oldPc);
m_curInstructionCurCycle = 4;
GameBoy.Cpu.IncInstructionNumber();
if (m_runToStepOver && opcode == 0xC9)
{
m_runToStepOver = false;
Stop();
}
}
}
else
{
if (!m_halted)
{
//on avance 4 cycles par 4 cycles car le timer est a 1Mhz, donc x4 pour les 4Mhz de la GB
m_curInstructionCurCycle += 4;
}
}
return(true);
}
return(false);
}
//////////////////////////////////////////////////////////////////////
//
//////////////////////////////////////////////////////////////////////
private void ThrowNullInstructionException(byte opcode, ushort pc, bool bDebugEnabled)
{
GameBoy.Cpu.Stop();
if (bDebugEnabled)
{
DebugFunctions.CallStackForm().AddToCallstack();
}
string message = String.Format(" Wrong instruction, cannot be decoded (0x{0:x2}), PC = 0x{1:x4}", opcode, pc);
string caption = "Error";
MessageBoxButtons buttons = MessageBoxButtons.OK;
DialogResult result;
result = MessageBox.Show(message, caption, buttons);
}
//////////////////////////////////////////////////////////////////////
//
//////////////////////////////////////////////////////////////////////
public bool Update()
{
if (!m_interruptStarted)
{
if (GameBoy.Cpu.IMEStatus())
{
for (int i = 0; i < (int)e_interrupt.__max_interrupts__; i++)
{
if (IsEnabled((e_interrupt)i) && IsRequested((e_interrupt)i))
{
Reset_IF((e_interrupt)i);
Reset_IME();
//save current PC adress
GameBoy.Cpu.SP -= 0x02;
GameBoy.Ram.WriteUshortAt(GameBoy.Cpu.SP, GameBoy.Cpu.PC);
//jump to interrupt adress
GameBoy.Cpu.PC = e_interrupts_startAdr[i];
if (DebugFunctions.CallStackForm() != null)
{
DebugFunctions.CallStackForm().AddInterruptToCallstack(i);
}
if (GameBoy.Cpu.IsHalted())
{
GameBoy.Cpu.ResumeFromHalt();
}
m_interruptStarted = true;
m_interruptCurCycle = 4;
return(true);
}
}
}
}
else
{
m_interruptCurCycle += 4;
if (m_interruptCurCycle >= INTERRUPT_NB_CYCLES)
{
m_interruptStarted = false;
m_interruptCurCycle = 0;
return(true);
}
}
return(false);
}