public override void Out(uint port, ushort value)
{
UpdateCh0();
if ((port & 0xFFF8) == 0)
{
// DMA controller: channel setup
Channel chan = channels[(port >> 1) & 3];
int x = 0;
int y = 0;
if ((port & 1) == 0)
{
// base/current address
x = chan.BaseAddress;
y = chan.CurrentAddress;
}
else
{
x = chan.BaseCount;
y = chan.CurrentCount;
}
bool p = msbFlipFlop;
msbFlipFlop = !p;
if (p)
{
x = (int)((x & 0xFF) | ((value << 8) & 0xFF00));
y = (int)((y & 0xFF) | ((value << 8) & 0xFF00));
}
else
{
x = (int)((x & 0xFF00) | (value & 0xFF));
y = (int)((y & 0xFF00) | (value & 0xFF));
}
if ((port & 1) == 0)
{
chan.BaseAddress = x;
chan.CurrentAddress = y;
}
else
{
chan.BaseCount = x;
chan.CurrentCount = y;
}
}
else if ((port & 0xFFF8) == 0x8)
{
// DMA controller: operation registers
if ((port & 0xF) == ((uint)8)) // write command register
{
cmdReg = value;
if ((value & 0x10) == 0)
{
prioChannel = 0; // enable fixed priority
}
if ((value & 1) == 1)
{
cpu.RaiseException("DMA8237: memory-to-memory transfer not implemented");
}
} // set/reset request register
else if ((port & 0xF) == ((uint)9))
{
if ((value & 4) == 0)
{
//reqReg = reqReg & (!(1 << (value & 3))); // reset request bit
reqReg &= ~(1 << (value & 3));
}
else
{
reqReg = reqReg | (1 << (value & 3)); // set request bit
if ((value & 7) == 4)
{
cpu.RaiseException("DMA8237: software request on channel 0 not implemented");
}
}
} // set/reset mask register
else if ((port & 0xF) == ((uint)10))
{
if ((value & 4) == 0)
{
//MaskReg = MaskReg & (!(1 << (value & 3))); // reset mask bit
MaskReg &= ~(1 << (value & 3));
}
else
{
MaskReg = MaskReg | (1 << (value & 3)); // set mask bit
}
channels[value & 3].Masked = (int)((value >> 2) & 1);
} // write mode register
else if ((port & 0xF) == ((uint)11))
{
channels[value & 3].Mode = value;
channels[value & 3].Direction = (int)((value >> 5) & 1);
channels[value & 3].AutoInit = (int)((value >> 4) & 1);
channels[value & 3].WriteMode = (int)((value >> 2) & 1);
if ((value & 3) == 0 && (value & 0xDC) != 0x58)
{
cpu.RaiseException("DMA8237: unsupported mode on channel 0");
}
} // clear msb flipflop
else if ((port & 0xF) == ((uint)12))
{
msbFlipFlop = false;
} // master clear
else if ((port & 0xF) == ((uint)13))
{
msbFlipFlop = false;
cmdReg = 0;
statusReg = 0;
reqReg = 0;
tempReg = 0;
MaskReg = 0xF;
} // clear mask register
else if ((port & 0xF) == ((uint)14))
{
MaskReg = 0;
} // write mask register
else if ((port & 0xF) == ((uint)15))
{
MaskReg = value;
}
TryHandleRequest();
}
else if ((port & 0xFFF8) == 0x80)
{
// DMA page registers
if (port == ((uint)(0x81)))
{
channels[2].Page = value;
}
else if (port == ((uint)(0x82)))
{
channels[3].Page = value;
}
else if (port == ((uint)(0x83)))
{
channels[1].Page = value;
}
else if (port == ((uint)(0x87)))
{
channels[0].Page = value;
}
}
}
private void Run()
{
ArrayList cleanInputBuf = new ArrayList();
ArrayList inputBuf = new ArrayList();
Task tsk = null;
ExternalInputEvent evt = default(ExternalInputEvent);
while (true)
{
// Detect the end of the simulation run
if (nextTime == STOPPING)
{
nextTime = pq.MinPriority();
break;
}
if (pendingInput.Count > 0)
{
// Fetch pending input events
inputBuf = pendingInput;
pendingInput = cleanInputBuf;
}
else if (nextTime <= mCurrentTime)
{
// Fetch the next pending task
tsk = NextTask();
if (ReferenceEquals(tsk, null))
{
continue; // This task was canceled, go round again
}
inputBuf.Clear();
}
else
{
tsk = null;
}
if (inputBuf.Count > 0)
{
// Process pending input events
for (int i = 0; i <= inputBuf.Count - 1; i++)
{
evt = (ExternalInputEvent)(inputBuf[i]);
evt.TimeStamp = mCurrentTime;
evt.Handler.HandleInput(evt);
}
inputBuf.Clear();
cleanInputBuf = inputBuf;
}
else if (tsk != null)
{
// Run the first pending task
tsk.Start();
}
else
{
// Run the CPU simulation for a bit (maxRunCycl)
try
{
mCPU.RunEmulation();
}
catch (Exception ex)
{
X8086.Notify("Shit happens at {0}:{1}: {2}", X8086.NotificationReasons.Fck, mCPU.Registers.CS.ToString("X4"), mCPU.Registers.IP.ToString("X4"), ex.Message);
mCPU.RaiseException($"Scheduler Main Loop Error: {ex.Message}");
}
if (mCPU.IsHalted)
{
SkipToNextEvent(); // The CPU is halted, skip immediately to the next event
}
}
}
}