/// <summary>
/// Writes to Port C
/// </summary>
private void OUTPortC(int data)
{
// latch the data
Regs[PORT_C] = (byte)data;
if (DirPortCL == PortDirection.Output)
{
// lower Port C bits OUT
// keyboard line update
Keyboard.CurrentLine = Regs[PORT_C] & 0x0f;
}
if (DirPortCU == PortDirection.Output)
{
// upper Port C bits OUT
// write to PSG using latched data
PSG.SetFunction(data);
PSG.PortWrite(Regs[PORT_A]);
// cassete write data
//not implemeted
// cas motor control
Tape.TapeMotor = Regs[PORT_C].Bit(4);
}
}
/// <summary>
/// Writes to Port A
/// </summary>
private void OUTPortA(int data)
{
// latch the data
Regs[PORT_A] = (byte)data;
if (DirPortA == PortDirection.Output)
{
// PSG write
PSG.PortWrite(data);
}
}
/// <summary>
/// Writes to the control register
/// </summary>
/// <param name="data"></param>
private void OUTControl(int data)
{
if (data.Bit(7))
{
// update configuration
Regs[PORT_CONTROL] = (byte)data;
// Writing to PIO Control Register (with Bit7 set), automatically resets PIO Ports A,B,C to 00h each
Regs[PORT_A] = 0;
Regs[PORT_B] = 0;
Regs[PORT_C] = 0;
}
else
{
// register is used to set/reset a single bit in Port C
bool isSet = data.Bit(0);
// get the bit in PortC that we wish to change
var bit = (data >> 1) & 7;
// modify this bit
if (isSet)
{
Regs[PORT_C] = (byte)(Regs[PORT_C] | (bit * bit));
}
else
{
Regs[PORT_C] = (byte)(Regs[PORT_C] & ~(bit * bit));
}
// any other ouput business
if (DirPortCL == PortDirection.Output)
{
// update keyboard line
Keyboard.CurrentLine = Regs[PORT_C] & 0x0f;
}
if (DirPortCU == PortDirection.Output)
{
// write to PSG using latched data
PSG.SetFunction(data);
PSG.PortWrite(Regs[PORT_A]);
// cassete write data
//not implemeted
// cas motor control
Tape.TapeMotor = Regs[PORT_C].Bit(4);
}
}
}