void IClockSink.OnPowerUp()
{
_nextOpCodeStatus = OpCodeStatus.None;
_nextMicroCode = MicroCode.None;
// see also: https://wiki.nesdev.com/w/index.php/CPU_power_up_state
Status.Value = 0x34;
Registers.A = 0;
Registers.X = 0;
Registers.Y = 0;
Registers.S = 0xFD;
// _masterClient.Value = 0;
// _masterClient.Write(0x4017); // frame irq enabled
// _masterClient.Write(0x4015); // all channels disabled
// $4000 -$400F = $00
// for (ushort i = 0x4000; i <= 0x400F; i++)
// _masterClient.Write(i);
// TODO:
// All 15 bits of noise channel LFSR = $0000[3].The first time the LFSR is clocked from the all-0s state, it will shift in a 1.
Interrupt(InterruptType.Reset);
}
protected override void dispose(bool disposeManagedResources)
{
if (!IsDisposed)
{
if (disposeManagedResources)
{
// have to call this here reather than in Resource destructor
// since calling virtual methods in base destructors causes crash
if (IsLoaded)
{
unload();
MicroCode.SafeDispose();
this.constTable.SafeDispose();
}
else
{
UnloadHighLevel();
}
}
// There are no unmanaged resources to release, but
// if we add them, they need to be released here.
}
// If it is available, make the call to the
// base class's Dispose(Boolean) method
base.dispose(disposeManagedResources);
}
protected override void UnloadHighLevelImpl()
{
MicroCode.SafeDispose();
MicroCode = null;
this.constTable.SafeDispose();
this.constTable = null;
}
private MicroCode ExecuteMicroCode(MicroCode code)
{
switch (code)
{
case MicroCode.Nop:
return(MicroCode.None);
case MicroCode.Addressing:
DispatchAddressing();
return(MicroCode.None);
case MicroCode.Immediate:
_addressState.MemoryAddress = Registers.PC++;
DispatchAddressing();
return(MicroCode.None);
case MicroCode.Relative:
_masterClient.Read(Registers.PC++);
_addressState.MemoryAddress = (ushort)(Registers.PC + (sbyte)_masterClient.Value);
DispatchAddressing();
return(MicroCode.None);
case MicroCode.Absolute_1:
_masterClient.Read(Registers.PC++);
_addressState.MemoryAddress = _masterClient.Value;
return(MicroCode.Absolute_2);
case MicroCode.Absolute_2:
_masterClient.Read(Registers.PC++);
_addressState.MemoryAddress |= (ushort)(_masterClient.Value << 8);
return(MicroCode.Absolute_3);
case MicroCode.Absolute_3:
DispatchAddressing();
return(MicroCode.None);
case MicroCode.ZeroPage_1:
_masterClient.Read(Registers.PC++);
_addressState.MemoryAddress = _masterClient.Value;
return(MicroCode.ZeroPage_2);
case MicroCode.ZeroPage_2:
DispatchAddressing();
return(MicroCode.None);
case MicroCode.ZeroPageX_1:
_masterClient.Read(Registers.PC++);
_addressState.MemoryAddress = _masterClient.Value;
return(MicroCode.ZeroPageX_2);
case MicroCode.ZeroPageX_2:
_addressState.MemoryAddress = (byte)(_addressState.MemoryAddress + Registers.X);
return(MicroCode.ZeroPageX_3);
case MicroCode.ZeroPageX_3:
DispatchAddressing();
return(MicroCode.None);
case MicroCode.AbsoluteX_1:
_masterClient.Read(Registers.PC++);
_addressState.MemoryAddress = _masterClient.Value;
return(MicroCode.AbsoluteX_2);
case MicroCode.AbsoluteX_2:
_masterClient.Read(Registers.PC++);
_addressState.MemoryAddress |= (ushort)(_masterClient.Value << 8);
return(MicroCode.AbsoluteX_3);
case MicroCode.AbsoluteX_3:
_addressState.MemoryAddress += Registers.X;
DispatchAddressing();
return(MicroCode.None);
case MicroCode.AbsoluteY_1:
_masterClient.Read(Registers.PC++);
_addressState.MemoryAddress = _masterClient.Value;
return(MicroCode.AbsoluteX_2);
case MicroCode.AbsoluteY_2:
_masterClient.Read(Registers.PC++);
_addressState.MemoryAddress |= (ushort)(_masterClient.Value << 8);
return(MicroCode.AbsoluteX_3);
case MicroCode.AbsoluteY_3:
_addressState.MemoryAddress += Registers.Y;
DispatchAddressing();
return(MicroCode.None);
case MicroCode.IndirectY_1:
_masterClient.Read(Registers.PC++);
_addressState.MemoryAddress8 = _masterClient.Value;
return(MicroCode.IndirectY_2);
case MicroCode.IndirectY_2:
_masterClient.Read(_addressState.MemoryAddress8);
_addressState.MemoryAddress = _masterClient.Value;
return(MicroCode.IndirectY_3);
case MicroCode.IndirectY_3:
_masterClient.Read((byte)(_addressState.MemoryAddress8 + 1));
_addressState.MemoryAddress |= (ushort)(_masterClient.Value << 8);
return(MicroCode.IndirectY_4);
case MicroCode.IndirectY_4:
_addressState.MemoryAddress += Registers.Y;
DispatchAddressing();
return(MicroCode.None);
/*
* case MicroCode.ZeroPage_1:
* _masterClient.Read(Registers.PC++);
* _addressResult = _masterClient.Value;
* _nextMicroCode = MicroCode.ZeroPage_2;
* break;
* case MicroCode.ZeroPage_2:
* _masterClient.Read(_addressResult);
* _addressResult = _masterClient.Value;
* _nextMicroCode = MicroCode.None;
* break;
* case MicroCode.ZeroPageY_1:
* _masterClient.Read(Registers.PC++);
* _addressResult = _masterClient.Value;
* _nextMicroCode = MicroCode.ZeroPageY_2;
* break;
* case MicroCode.ZeroPageY_2:
* _addressResult += Registers.Y;
* _nextMicroCode = MicroCode.ZeroPageY_3;
* break;
* case MicroCode.ZeroPageY_3:
* _masterClient.Read(_addressResult);
* _addressResult = _masterClient.Value;
* _nextMicroCode = MicroCode.None;
* break;
* case MicroCode.Absolute_1:
* _masterClient.Read(Registers.PC++);
* _addressResult = _masterClient.Value;
* _nextMicroCode = MicroCode.Absolute_2;
* break;
* case MicroCode.Absolute_2:
* _masterClient.Read(Registers.PC++);
* _addressResult2 = _masterClient.Value;
* _nextMicroCode = MicroCode.Absolute_3;
* break;
* case MicroCode.Absolute_3:
* _masterClient.Read((ushort)(_addressResult | _addressResult2 << 8));
* _addressResult = _masterClient.Value;
* _nextMicroCode = MicroCode.None;
* break;
* case MicroCode.IndirectX_1:
* _masterClient.Read(Registers.PC++);
* _addressResult = _masterClient.Value;
* _nextMicroCode = MicroCode.IndirectX_2;
* break;
* case MicroCode.IndirectX_2:
* _addressResult = (byte)(_addressResult + Registers.X);
* _addressResult2 = (byte)(_addressResult + 1);
* _nextMicroCode = MicroCode.IndirectX_3;
* break;
* case MicroCode.IndirectX_3:
* _masterClient.Read(_addressResult);
* _addressResult = _masterClient.Value;
* _nextMicroCode = MicroCode.IndirectX_4;
* break;
* case MicroCode.IndirectX_4:
* _masterClient.Read(_addressResult2);
* _addressResult2 = _masterClient.Value;
* _nextMicroCode = MicroCode.IndirectX_5;
* break;
* case MicroCode.IndirectX_5:
* _masterClient.Read((ushort)(_addressResult | _addressResult2 << 8));
* _addressResult = _masterClient.Value;
* _nextMicroCode = MicroCode.None;
* break;
* case MicroCode.ADC:
* {
* var result = (ushort)(Registers.A + _addressResult + Status.C);
* UpdateCVN(Registers.A, _addressResult, result);
* Registers.A = (byte)result;
* _nextMicroCode = MicroCode.None;
* }
*
* break;
*/
case MicroCode.Push:
_masterClient.Value = _addressState.ResultA;
_masterClient.Write((ushort)(0x100u + Registers.S--));
return(MicroCode.None);
case MicroCode.Pop:
_masterClient.Read((ushort)(0x100u + ++Registers.S));
_addressState.ResultA = _masterClient.Value;
return(MicroCode.None);
case MicroCode.SEI:
Status.I = true;
return(MicroCode.None);
case MicroCode.CLC:
Status.C = false;
return(MicroCode.None);
case MicroCode.CLD:
Status.D = false;
return(MicroCode.None);
default:
throw new InvalidProgramException($"invalid micro code: 0x{code:X}.");
}
}