private byte ReadHardware(ushort addr)
{
addr &= 0xFF;
switch (addr)
{
case 0: // PORT_LINK
LinkPort.Update();
return((byte)((_romPageHighBit << 4) | (LinkState << 2) | LinkOutput));
case 1: // PORT_KEYBOARD:
////Console.WriteLine("read PORT_KEYBOARD");
return(ReadKeyboard());
case 2: // PORT_ROMPAGE
return((byte)_romPageLow3Bits);
case 3: // PORT_STATUS
{
// Console.WriteLine("read PORT_STATUS");
// Bits:
// 0 - Set if ON key Interrupt generated
// 1 - Update things (keyboard etc)
// 2 - Unknown, but used
// 3 - Set if ON key is up
// 4-7 - Unknown
return((byte)((_controller.IsPressed("ON") ? 0 : 8) |
(TIM_1_int ? 2 : 0) |
(ON_key_int ? 1 : 0)));
}
case 4: // PORT_INTCTRL
// returns mirror of link port
return((byte)((_romPageHighBit << 4) | (LinkState << 2) | LinkOutput));
case 16: // PORT_DISPCTRL
// Console.WriteLine("read DISPCTRL");
break;
case 17: // PORT_DISPDATA
return(ReadDispData());
}
return(0xFF);
}
private void WriteHardware(ushort addr, byte value)
{
switch (addr)
{
case 0: // PORT_LINK
_romPageHighBit = (value >> 4) & 1;
_linkOutput = value & 3;
if (LinkActive)
{
// Prevent rom calls from disturbing link port activity
if (LinkActive && _cpu.RegisterPC < 0x4000)
{
return;
}
LinkPort.Update();
}
break;
case 1: // PORT_KEYBOARD:
_lagged = false;
_keyboardMask = value;
////Console.WriteLine("write PORT_KEYBOARD {0:X2}",value);
break;
case 2: // PORT_ROMPAGE
_romPageLow3Bits = value & 0x7;
break;
case 3: // PORT_STATUS
_maskOn = (byte)(value & 1);
break;
case 16: // PORT_DISPCTRL
////Console.WriteLine("write PORT_DISPCTRL {0}",value);
WriteDispCtrl(value);
break;
case 17: // PORT_DISPDATA
////Console.WriteLine("write PORT_DISPDATA {0}",value);
WriteDispData(value);
break;
}
}
private byte ReadHardware(ushort addr)
{
switch (addr)
{
case 0: // PORT_LINK
LinkPort.Update();
return((byte)((_romPageHighBit << 4) | (LinkState << 2) | LinkOutput));
case 1: // PORT_KEYBOARD:
////Console.WriteLine("read PORT_KEYBOARD");
return(ReadKeyboard());
case 2: // PORT_ROMPAGE
return((byte)_romPageLow3Bits);
case 3: // PORT_STATUS
{
// Console.WriteLine("read PORT_STATUS");
// Bits:
// 0 - Set if ON key is down and ON key is trapped
// 1 - Update things (keyboard etc)
// 2 - Unknown, but used
// 3 - Set if ON key is up
// 4-7 - Unknown
////if (onPressed && maskOn) ret |= 1;
////if (!onPressed) ret |= 0x8;
return((byte)((_controller.IsPressed("ON") ? _maskOn : 8) | (LinkActive ? 0 : 2)));
}
case 4: // PORT_INTCTRL
////Console.WriteLine("read PORT_INTCTRL");
return(0xFF);
case 16: // PORT_DISPCTRL
////Console.WriteLine("read DISPCTRL");
break;
case 17: // PORT_DISPDATA
return(ReadDispData());
}
return(0xFF);
}
private void WriteHardware(ushort addr, byte value)
{
addr &= 0xFF;
switch (addr)
{
case 0: // PORT_LINK
_romPageHighBit = (value >> 4) & 1;
_linkOutput = value & 3;
if (LinkActive)
{
// Prevent rom calls from disturbing link port activity
if (LinkActive && _cpu.RegPC < 0x4000)
{
return;
}
LinkPort.Update();
}
break;
case 1: // PORT_KEYBOARD:
_lagged = false;
_keyboardMask = value;
////Console.WriteLine("write PORT_KEYBOARD {0:X2}",value);
break;
case 2: // PORT_ROMPAGE
_romPageLow3Bits = value & 0x7;
break;
case 3: // PORT_STATUS
// controls ON key interrupts
if ((value & 0x1) == 0)
{
ON_key_int = false;
ON_key_int_EN = false;
}
else
{
ON_key_int_EN = true;
}
// controls first timer interrupts
if ((value & 0x2) == 0)
{
TIM_1_int = false;
TIM_1_int_EN = false;
}
else
{
TIM_1_int_EN = true;
}
// controls second timer, not yet implemented and unclear how to differentiate
if ((value & 0x4) == 0)
{
}
else
{
}
// controls low power mode, not yet implemeneted
if ((value & 0x8) == 0)
{
}
else
{
}
break;
case 4: // PORT_INTCTRL
// controls ON key interrupts
TIM_frq = value & 6;
TIM_mult = ((value & 0x10) == 0x10) ? 1800 : 1620;
TIM_hit = (int)Math.Floor(6000000.0 / Math.Floor((double)TIM_mult / (2 * TIM_frq + 3)));
// Bit 0 is some form of memory mapping
// Bit 5 controls reset
// Bit 6-7 controls battery power compare (not implemented, will always return full power)
break;
case 16: // PORT_DISPCTRL
////Console.WriteLine("write PORT_DISPCTRL {0}",value);
WriteDispCtrl(value);
break;
case 17: // PORT_DISPDATA
////Console.WriteLine("write PORT_DISPDATA {0}",value);
WriteDispData(value);
break;
}
}
