public void Clock()
{
if (!_read.IsComplete)
{
_read.Clock();
if (_read.IsComplete)
{
_write.AddressedValue = _targetRegister.GetValue(_cpu);
_targetRegister.SetValueOnProcessor(_cpu, _read.AddressedValue);
}
return;
}
if (_additionalReadCycles-- > 0)
{
// http://www.baltazarstudios.com/files/xx.html#E3 shows that the cpu read/write signals aren't affected by
// the extended cycles so we can just do nothing for these cycles
return;
}
if (!_write.IsComplete)
{
_write.Clock();
return;
}
_additionalWriteCycles--;
}
public void LoadRegisterToRegisterPointer()
{
// Arrange
WideRegister pointerRegister = WideRegister.BC;
Register source = Register.A;
byte opcode = 0x02;
byte loadValue = 0xe3;
ushort pointer = 0xdead;
pointerRegister.SetValueOnProcessor(_cpu, pointer);
source.SetValueOnProcessor(_cpu, loadValue);
_ram[0] = opcode;
// Act
RunUntil(2);
// Assert
Assert.That(_ram[pointer], Is.EqualTo(loadValue));
}
public void LoadRegisterPointerToRegister()
{
// Arrange
// Again these 3 can be parameterized
Register destination = Register.A;
WideRegister source = WideRegister.HL;
byte opcode = 0x7e;
byte value = 0x1f;
ushort pointer = 0x0bad;
source.SetValueOnProcessor(_cpu, pointer);
_ram[0] = opcode;
_ram[pointer] = value;
// Act
RunUntil(2);
// Assert
Assert.That(destination.GetValue(_cpu), Is.EqualTo(value));
}
public void LoadImmediateToIndexedPointer()
{
// Arrange
WideRegister indexRegister = WideRegister.IX;
byte instructionByte1 = 0xdd;
byte instructionByte2 = 0x36;
byte loadValue = 0x86;
ushort pointer = 0xb00b;
indexRegister.SetValueOnProcessor(_cpu, pointer);
_ram[0] = instructionByte1;
_ram[1] = instructionByte2;
_ram[2] = 0xf;
_ram[3] = loadValue;
// Act
RunUntil(5);
// Assert
Assert.That(_ram[pointer + 0xf], Is.EqualTo(loadValue));
}
public void LoadRegisterToIndexedPointer()
{
// Arrange
WideRegister indexRegister = WideRegister.IY;
Register source = Register.E;
byte instructionByte1 = 0xfd;
byte instructionByte2 = 0x73;
byte loadValue = 0x28;
ushort pointer = 0xdeaf;
indexRegister.SetValueOnProcessor(_cpu, pointer);
source.SetValueOnProcessor(_cpu, loadValue);
_ram[0] = instructionByte1;
_ram[1] = instructionByte2;
_ram[2] = 0x10;
// Act
RunUntil(4);
// Assert
Assert.That(_ram[pointer + 0x10], Is.EqualTo(loadValue));
}