/// <summary>
/// Responds to the changes of memory slot registers ($50-$57)
/// </summary>
private void OnMemSlotRegisterValueSet(object sender, RegisterSetEventArgs registerSetEventArgs)
{
if (sender is MemorySlotRegister slotRegister)
{
_memoryDevice.PageIn(slotRegister.Id - 0x50, slotRegister.LastValue, false);
}
}
/// <summary>
/// Sets the active palette whenever the value of ULA Next
/// control register ($43) is written
/// </summary>
private void OnUlaNextControlRegisterValueSet(object sender, RegisterSetEventArgs e)
{
switch (e.Value >> 4)
{
case 1:
ActivePalette = Layer2FirstPalette;
break;
case 2:
ActivePalette = SpritesFirstPalette;
break;
case 4:
ActivePalette = UlaNextSecondPalette;
break;
case 5:
ActivePalette = Layer2SecondPalette;
break;
case 6:
ActivePalette = SpritesSecondPalette;
break;
default:
ActivePalette = UlaNextFirstPalette;
break;
}
}
/// <summary>
/// Sets the palette value (8 bit) when Register $41 is set
/// </summary>
private void OnPaletteValueRegisterSet(object sender, RegisterSetEventArgs e)
{
// --- Set the first 8 bits of palette color: RRRGGGBBX,
// --- where X is the bitwise or of the two B bits
var newValue = e.Value << 1
| ((e.Value & 0x03) == 0 ? 0x00 : 0x01);
ActivePalette[PaletteIndexRegister.LastValue] = newValue;
// --- Palette index is automatically incremented
PaletteIndexRegister.Set((byte)(PaletteIndexRegister.LastValue + 1));
}
/// <summary>
/// Sets the 8-bit + 1-bit extended palette value
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void OnUlaNextPaletteExtensionValueSet(object sender, RegisterSetEventArgs e)
{
if (UlaNextPaletteExtensionRegister.FirstByteSet)
{
// --- We receive the 9th bit of the palette value
var index = PaletteIndexRegister.LastValue;
ActivePalette[index] = (ActivePalette[index] & 0x1FE) | (e.Value & 0x01);
// --- Palette index is automatically incremented
PaletteIndexRegister.Set((byte)(PaletteIndexRegister.LastValue + 1));
UlaNextPaletteExtensionRegister.FirstByteSet = false;
}
else
{
// --- Set the first 8 bits of palette color: RRRGGGBBX,
// --- where X is the bitwise or of the two B bits
var newValue = e.Value << 1
| ((e.Value & 0x03) == 0 ? 0x00 : 0x01);
ActivePalette[PaletteIndexRegister.LastValue] = newValue;
UlaNextPaletteExtensionRegister.FirstByteSet = true;
}
}
/// <summary>
/// Signs the Register $44 will receive the first byte
/// </summary>
private void OnPaletteIndexRegisterSet(object sender, RegisterSetEventArgs e)
{
UlaNextPaletteExtensionRegister.FirstByteSet = false;
}
