public bool PpuRead(NameTableMirrorMode mirrorMode, ushort address, out byte data)
{
if (address >= 0x2000 && address <= 0x3eff)
{
data = 0;
address -= 0x2000;
if (mirrorMode == NameTableMirrorMode.Horizontal)
{
if (address >= 0x0000 && address <= 0x03ff) // First 1KiB maps to the first name table.
{
data = _tables[0][address & 0x03ff];
}
else if (address >= 0x0400 && address <= 0x07ff) // Second 1KiB maps back to the first name table.
{
data = _tables[0][address & 0x03ff];
}
else if (address >= 0x0800 && address <= 0x0bff) // Third 1KiB maps to the second name table.
{
data = _tables[1][address & 0x03ff];
}
else if (address >= 0x0c00 && address <= 0x0fff) // Fourth 1KiB maps back to the second name table.
{
data = _tables[1][address & 0x03ff];
}
}
else if (mirrorMode == NameTableMirrorMode.Vertical)
{
if (address >= 0x0000 && address <= 0x03ff) // First 1KiB maps to the first name table.
{
data = _tables[0][address & 0x03ff];
}
else if (address >= 0x0400 && address <= 0x07ff) // Second 1KiB maps to the second name table.
{
data = _tables[1][address & 0x03ff];
}
else if (address >= 0x0800 && address <= 0x0bff) // Third 1KiB maps back to the first name table.
{
data = _tables[0][address & 0x03ff];
}
else if (address >= 0x0c00 && address <= 0x0fff) // Fourth 1KiB maps back to the second name table.
{
data = _tables[1][address & 0x03ff];
}
}
return(true);
}
data = 0;
return(false);
}
public override bool GetMirrorMode(out NameTableMirrorMode mirrorMode)
{
switch (_controlRegister & 0x3)
{
case 0b10:
mirrorMode = NameTableMirrorMode.Vertical;
return(true);
case 0b11:
mirrorMode = NameTableMirrorMode.Horizontal;
return(true);
default: // TODO: Handle mirror modes 0b00 and 0b01.
mirrorMode = NameTableMirrorMode.Vertical;
return(true);
}
}
public virtual bool GetMirrorMode(out NameTableMirrorMode mirrorMode)
{
mirrorMode = NameTableMirrorMode.Horizontal;
return(false);
}
