/// <summary>
/// Reads a byte of data from a specified port address
/// </summary>
public override byte ReadPort(ushort port)
{
BitArray portBits = new BitArray(BitConverter.GetBytes(port));
byte portUpper = (byte)(port >> 8);
byte portLower = (byte)(port & 0xff);
int result = 0xff;
if (DecodeINPort(port) == PortDevice.GateArray)
{
GateArray.ReadPort(port, ref result);
}
else if (DecodeINPort(port) == PortDevice.CRCT)
{
CRCT.ReadPort(port, ref result);
}
else if (DecodeINPort(port) == PortDevice.ROMSelect)
{
}
else if (DecodeINPort(port) == PortDevice.Printer)
{
}
else if (DecodeINPort(port) == PortDevice.PPI)
{
PPI.ReadPort(port, ref result);
}
else if (DecodeINPort(port) == PortDevice.Expansion)
{
}
return((byte)result);
}
static public void WritePort(int port, int val)
{
if ((port & 0xC000) == 0x04000)
{
VGA.Write(val);
}
if ((port & 0x4000) == 0)
{
CRTC.Write(port, val);
}
if ((port & 0x2000) == 0)
{
VGA.WriteROM(val);
}
if ((port & 0x0800) == 0)
{
PPI.Write(port, val);
}
if ((port & 0x0480) == 0)
{
UPD.Write(port, val);
}
}
/// <summary>
/// Reads a byte of data from a specified port address
/// </summary>
/// <param name="port"></param>
/// <returns></returns>
public override byte ReadPort(ushort port)
{
BitArray portBits = new BitArray(BitConverter.GetBytes(port));
byte portUpper = (byte)(port >> 8);
byte portLower = (byte)(port & 0xff);
int result = 0xff;
if (DecodeINPort(port) == PortDevice.GateArray)
{
GateArray.ReadPort(port, ref result);
}
else if (DecodeINPort(port) == PortDevice.CRCT)
{
CRCT.ReadPort(port, ref result);
}
else if (DecodeINPort(port) == PortDevice.ROMSelect)
{
}
else if (DecodeINPort(port) == PortDevice.Printer)
{
}
else if (DecodeINPort(port) == PortDevice.PPI)
{
PPI.ReadPort(port, ref result);
}
else if (DecodeINPort(port) == PortDevice.Expansion)
{
if (!port.Bit(7))
{
// FDC
if (port.Bit(8) && !port.Bit(0))
{
// FDC status register
UPDDiskDevice.ReadStatus(ref result);
}
if (port.Bit(8) && port.Bit(0))
{
// FDC data register
UPDDiskDevice.ReadData(ref result);
}
}
}
return((byte)result);
}
static public int ReadPort(int port)
{
if ((port & 0x0480) == 0)
{
return(UPD.Read(port));
}
if ((port & 0x0800) == 0)
{
return(PPI.Read(port));
}
if ((port & 0x4000) == 0)
{
return(CRTC.Read(port));
}
return(0xFF);
}
/// <summary>
/// Writes a byte of data to a specified port address
/// Because of the port decoding, multiple devices can be written to
/// </summary>
public override void WritePort(ushort port, byte value)
{
BitArray portBits = new BitArray(BitConverter.GetBytes(port));
BitArray dataBits = new BitArray(BitConverter.GetBytes(value));
byte portUpper = (byte)(port >> 8);
byte portLower = (byte)(port & 0xff);
var devs = DecodeOUTPort(port);
foreach (var d in devs)
{
if (d == PortDevice.GateArray)
{
GateArray.WritePort(port, value);
}
else if (d == PortDevice.RAMManagement)
{
// not present in the unexpanded CPC464
}
else if (d == PortDevice.CRCT)
{
CRCT.WritePort(port, value);
}
else if (d == PortDevice.ROMSelect)
{
}
else if (d == PortDevice.Printer)
{
}
else if (d == PortDevice.PPI)
{
PPI.WritePort(port, value);
}
else if (d == PortDevice.Expansion)
{
}
}
return;
}
/// <summary>
/// Writes a byte of data to a specified port address
/// Because of the port decoding, multiple devices can be written to
/// </summary>
/// <param name="port"></param>
/// <param name="value"></param>
public override void WritePort(ushort port, byte value)
{
BitArray portBits = new BitArray(BitConverter.GetBytes(port));
BitArray dataBits = new BitArray(BitConverter.GetBytes(value));
byte portUpper = (byte)(port >> 8);
byte portLower = (byte)(port & 0xff);
var devs = DecodeOUTPort(port);
foreach (var d in devs)
{
if (d == PortDevice.GateArray)
{
GateArray.WritePort(port, value);
}
else if (d == PortDevice.RAMManagement)
{
if (value.Bit(7) && value.Bit(6))
{
RAMConfig = value & 0x07;
// additional 64K bank index
var b64 = value & 0x38;
}
}
else if (d == PortDevice.CRCT)
{
CRCT.WritePort(port, value);
}
else if (d == PortDevice.ROMSelect)
{
UpperROMPosition = value;
}
else if (d == PortDevice.Printer)
{
}
else if (d == PortDevice.PPI)
{
PPI.WritePort(port, value);
}
else if (d == PortDevice.Expansion)
{
if (!port.Bit(7))
{
// FDC
if (port.Bit(8) && !port.Bit(0) || port.Bit(8) && port.Bit(0))
{
// FDC data register
UPDDiskDevice.WriteData(value);
}
if ((!port.Bit(8) && !port.Bit(0)) || (!port.Bit(8) && port.Bit(0)))
{
// FDC motor
UPDDiskDevice.Motor(value);
}
}
}
}
return;
}
