public byte ReadFromPort(TwinBit portNumber)
{
valueWrittenToPort1 = null;
if (portNumber == 0)
{
if (expansionVramSelected)
{
return(0xFF);
}
var value = readAheadBuffer;
vramPointer = (vramPointer + 1) & vramAddressMask;
readAheadBuffer = Vram[vramPointer];
return(value);
}
if (statusRegisterNumberToRead == 0)
{
var value = statusRegisterValue;
statusRegisterValue &= 0x7F;
IntLineIsActive = false;
return(value);
}
else if (statusRegisterNumberToRead == 2)
{
var value = lastValueOfS2;
lastValueOfS2 ^= 0xE0;
return(value);
}
else
{
return(0);
}
}
private void WriteToSecondarySlotRegister(byte value)
{
var primarySlotNumber = visibleSlotNumbers[3].PrimarySlotNumber;
secondarySlotSelectionRegisterForEachPrimarySlot[primarySlotNumber] = value;
var tempValue = value;
for (int p = 0; p < 4; p++)
{
TwinBit page = p;
TwinBit subslotNumber = tempValue & 3;
secondarySlotsSelectedForEachPrimarySlot[primarySlotNumber][page] = subslotNumber;
if (visibleSlotNumbers[page].PrimarySlotNumber == primarySlotNumber)
{
var newSlotNumber = new SlotNumber(primarySlotNumber, subslotNumber);
SetVisibleSlot((int)page, newSlotNumber);
}
tempValue >>= 2;
}
if (SecondarySlotSelectionRegisterWritten != null)
{
SecondarySlotSelectionRegisterWritten(
this,
new SecondarySlotSelectionRegisterWrittenEventArgs(value, primarySlotNumber));
}
}
public void Slot_are_expanded_as_array_of_expanded_slot_numbers_passed()
{
var expandedSlots = new TwinBit[] { 1, 3 };
var sut = new SlotsSystem(expandedSlots);
Assert.False(sut.IsExpanded(0));
Assert.True(sut.IsExpanded(1));
Assert.False(sut.IsExpanded(2));
Assert.True(sut.IsExpanded(3));
}
public void Exception_is_thrown_if_content_for_non_existing_expanded_slot_is_passed()
{
var expandedSlots = new TwinBit[] { 1, 3 };
var contents = new Dictionary <SlotNumber, IMemory>
{
{ new SlotNumber(0, 1), AnyMemory() }
};
Assert.Throws <ArgumentException>(() => new SlotsSystem(contents, expandedSlots));
}
private void FillSecondarySlotsSelectedForEachPrimarySlotTable()
{
secondarySlotsSelectedForEachPrimarySlot = new Dictionary <TwinBit, TwinBit[]>();
for (int primarySlot = 0; primarySlot < 4; primarySlot++)
{
if (!IsExpanded(primarySlot))
{
continue;
}
secondarySlotsSelectedForEachPrimarySlot[primarySlot] = new TwinBit[] { 0, 0, 0, 0 };
}
}
public void Writing_subslot_selection_register_fires_event_if_expanded_slot()
{
var sut = new SlotsSystem(new TwinBit[] { 2 });
var subslotSelectorValue = Fixture.Create <byte>();
byte subslotSelectorValueInEvent = 0;
TwinBit primarySlotValueInEvent = 0;
var eventFired = false;
sut.SecondarySlotSelectionRegisterWritten += (sender, args) =>
{
eventFired = true;
subslotSelectorValueInEvent = args.Value;
primarySlotValueInEvent = args.PrimarySlotNumber;
};
sut.WriteToSlotSelectionRegister(SlotSelectionRegisterValue(0, 0, 0, 2));
sut[0xFFFF] = subslotSelectorValue;
Assert.True(eventFired);
Assert.AreEqual(subslotSelectorValue, subslotSelectorValueInEvent);
Assert.AreEqual(2, primarySlotValueInEvent);
}
public void WriteToPort(TwinBit portNumber, byte value)
{
var oldValueWrittenToPort1 = valueWrittenToPort1;
valueWrittenToPort1 = null;
if (portNumber == 0)
{
WriteVram(vramPointer, value);
vramPointer = (vramPointer + 1) & vramAddressMask;
readAheadBuffer = value;
return;
}
if (portNumber == 3)
{
if (registerNumberForIndirectAccess != 17)
{
WriteControlRegister(value, registerNumberForIndirectAccess);
}
if (autoIncrementRegisterNumberForIndirectAccess)
{
registerNumberForIndirectAccess = (byte)((registerNumberForIndirectAccess + 1) & 0x3F);
}
return;
}
if (portNumber == 2)
{
if (valueWrittenToPort2 == null)
{
valueWrittenToPort2 = value;
}
else
{
var r = (valueWrittenToPort2.Value >> 4) & 7;
var b = (valueWrittenToPort2.Value) & 7;
var g = value & 7;
var color = Color.FromArgb(r, g, b);
displayRenderer.SetPalette(paletteRegisterValue, color);
valueWrittenToPort2 = null;
paletteRegisterValue = (byte)((paletteRegisterValue + 1) & 0x0F);
}
return;
}
if (oldValueWrittenToPort1 == null)
{
valueWrittenToPort1 = value;
return;
}
if ((value & 0x80) == 0)
{
SetVramAccess(oldValueWrittenToPort1.Value, value, vramAddressThreeHighBits);
}
else
{
WriteControlRegister(oldValueWrittenToPort1.Value, value);
}
}
public bool IsExpanded(TwinBit primarySlotNumber)
{
return(isExpanded[primarySlotNumber]);
}
public SecondarySlotSelectionRegisterWrittenEventArgs(byte value, TwinBit primarySlotNumber)
{
this.Value = value;
this.PrimarySlotNumber = primarySlotNumber;
}