/// <summary>
/// Starts with the CPU execution.
/// </summary>
public void Execute()
{
CPUExecution executionContext = CPUExecution.MORE_INSTRUCTIONS_AVAILABLE;
string OutputPortC = string.Empty;
string OutputPortD = string.Empty;
while (executionContext == CPUExecution.MORE_INSTRUCTIONS_AVAILABLE)
{
executionContext = ExecuteNextInstruction(out OutputPortC, out OutputPortD);
}
}
public static void Main(string[] args)
{
CPUExecution context = CPUExecution.MORE_INSTRUCTIONS_AVAILABLE;
string outC, outD;
char keyPressed = ' ';
// Initialize the BIOS
bios = new BIOS(rootFolder + "VirtualDisk.img");
// Load the binary code and initialize the CPU
LoadBinaryCode();
while (context != CPUExecution.FINISHED)
{
// Execute the next instruction
context = cpu.SingleStep(out outC, out outD);
if (context == CPUExecution.IN_A)
{
// Pass the read character from the console into the CPU Input Port A...
cpu.XL.SetBits(Convert.ToByte(keyPressed));
}
if (context == CPUExecution.IN_B)
{
ConsoleKeyInfo key = Console.ReadKey(true);
keyPressed = key.KeyChar;
// Set the Ready Bit on Input Port B when we have read the character from the console
cpu.XL.SetBits(1);
}
if (context == CPUExecution.INTERRUPT)
{
// We have triggered a software based interrupt...
switch (cpu.XL.GetInt())
{
case 1:
{
// Interrupt 1 is used for accessing hard disks
HandleHardDiskInterrupt();
break;
}
default:
throw new ArgumentException("Invalid Interrupt Number!");
}
// After we have handled the interrupt, we continue program execution by incrementing the Program Counter...
cpu.ProgramCounter.Increment();
continue;
}
if (outC != string.Empty)
{
Console.Write(Convert.ToChar(Helper.GetByte(outC)));
}
}
Console.WriteLine();
Console.WriteLine("Done");
Console.ReadLine();
}
private void ExecuteNextAssemblyInstruction()
{
string OutputPortC = string.Empty;
string OutputPortD = string.Empty;
bool incrementIndex = true;
instructionsExecuted++;
if (lstAssembly.SelectedItems.Count == 0)
{
cpu.SingleStep(out OutputPortC, out OutputPortD);
UpdateUI(OutputPortC, OutputPortD);
lblCPUState.Text = "RUNNING...";
lblCPUState.ForeColor = Color.Green;
// Highlight the first assembly instruction in the ListView.
lstAssembly.FocusedItem = lstAssembly.Items[0];
lstAssembly.Items[0].Selected = true;
lstAssembly.Select();
lstAssembly.EnsureVisible(0);
lstAssembly.Items[lstAssembly.SelectedItems[0].Index].EnsureVisible();
}
else
{
CPUExecution executionContext = cpu.SingleStep(out OutputPortC, out OutputPortD);
UpdateUI(OutputPortC, OutputPortD);
if (executionContext == CPUExecution.MORE_INSTRUCTIONS_AVAILABLE)
{
if (txtInstruction.Text == "JMP" || txtInstruction.Text == "JZ" || txtInstruction.Text == "JNZ")
{
incrementIndex = false;
}
// Highlight the next assembly instruction in the ListView
if (highlightInstruction)
{
lstAssembly.Items[indexForNextInstruction].Selected = true;
lstAssembly.Select();
lstAssembly.EnsureVisible(0);
lstAssembly.Items[lstAssembly.SelectedItems[0].Index].EnsureVisible();
}
lblCPUState.Text = "RUNNING...";
lblCPUState.ForeColor = Color.Green;
}
else if (executionContext == CPUExecution.BREAKPOINT_HIT)
{
// Highlight the current assembly instruction in the ListView
if (highlightInstruction)
{
lstAssembly.Items[indexForNextInstruction].Selected = true;
lstAssembly.Select();
lstAssembly.EnsureVisible(0);
lstAssembly.Items[lstAssembly.SelectedItems[0].Index].EnsureVisible();
}
lblCPUState.Text = "BREAKPOINT HIT!";
lblCPUState.ForeColor = Color.Red;
// Disable automatic CPU execution
// if (executionTimer.Enabled)
// executionTimer.Enabled = false;
if (microTimer.Enabled)
{
microTimer.Enabled = false;
}
}
else if (executionContext == CPUExecution.IN_A)
{
// Highlight the current assembly instruction in the ListView
if (highlightInstruction)
{
lstAssembly.Items[indexForNextInstruction].Selected = true;
lstAssembly.Select();
lstAssembly.EnsureVisible(0);
lstAssembly.Items[lstAssembly.SelectedItems[0].Index].EnsureVisible();
}
lblCPUState.Text = "IN A!";
lblCPUState.ForeColor = Color.Red;
// Disable automatic CPU execution
// if (executionTimer.Enabled)
// executionTimer.Enabled = false;
if (microTimer.Enabled)
{
microTimer.Enabled = false;
}
}
else if (executionContext == CPUExecution.IN_B)
{
// Highlight the current assembly instruction in the ListView
if (highlightInstruction)
{
lstAssembly.Items[indexForNextInstruction].Selected = true;
lstAssembly.Select();
lstAssembly.EnsureVisible(0);
lstAssembly.Items[lstAssembly.SelectedItems[0].Index].EnsureVisible();
}
lblCPUState.Text = "IN B!";
lblCPUState.ForeColor = Color.Red;
// Disable automatic CPU execution
// if (executionTimer.Enabled)
// executionTimer.Enabled = false;
if (microTimer.Enabled)
{
microTimer.Enabled = false;
}
}
else if (executionContext == CPUExecution.FINISHED)
{
// Highlight the current assembly instruction in the ListView
if (highlightInstruction)
{
lstAssembly.Items[indexForNextInstruction].Selected = true;
lstAssembly.Select();
lstAssembly.EnsureVisible(0);
lstAssembly.Items[lstAssembly.SelectedItems[0].Index].EnsureVisible();
}
lblCPUState.Text = "FINISHED!";
lblCPUState.ForeColor = Color.Green;
cmdExecute.Enabled = cmdSingleStep.Enabled = false;
// Disable automatic CPU execution
// if (executionTimer.Enabled)
// executionTimer.Enabled = false;
if (microTimer.Enabled)
{
microTimer.Enabled = false;
}
}
}
if (incrementIndex)
{
indexForNextInstruction++;
}
else
{
// Find the correct line for highlighting based on the new Program Counter value.
// Used during jumps (conditional, unconditional).
indexForNextInstruction = 0;
foreach (ListViewItem item in lstAssembly.Items)
{
indexForNextInstruction++;
if (item.SubItems[0].Text == txtProgramCounter.Text)
{
break;
}
}
// Correct the index by 1
indexForNextInstruction--;
}
}
