/// <summary>
/// This function releases a thread from the semaphore
/// </summary>
/// <param name="thread"> a reference to the thread to release</param>
/// <returns>the number of free allocation slots available after releasing the thread</returns>
public int Up(ref SimulatorThread thread)
{
if (insideThreads.Contains(thread))
{
insideThreads.Remove(thread);
thread.OwnerProcess.AllocatedResources.Remove(resource);
thread.WaitingForSemaphore = false;
thread.OwnsSemaphore = false;
thread.PreviousState = thread.CurrentState;
thread.CurrentState = EnumThreadState.UNKNOWN;
slots++;
}
else if (waitingThreads.Contains(thread))
{
List <SimulatorThread> temp = waitingThreads.ToList();
temp.Remove(thread);
waitingThreads = new Queue <SimulatorThread>(temp);
thread.OwnerProcess.AllocatedResources.Remove(resource);
thread.WaitingForSemaphore = false;
thread.OwnsSemaphore = false;
thread.PreviousState = thread.CurrentState;
thread.CurrentState = EnumThreadState.UNKNOWN;
}
else
{
MessageBox.Show("Thread must be captured by the semaphore before being released");
return(int.MinValue);
}
CaptureNextThread();
return(slots);
}
/// <summary>
/// This function captures a thread inside the semaphore
/// </summary>
/// <param name="thread"> a reference to the thread to capture</param>
/// <returns> the number of free allocation slots available after capturing the thread</returns>
public int Down(ref SimulatorThread thread)
{
if (!insideThreads.Contains(thread) && !waitingThreads.Contains(thread))
{
if (slots > 0)
{
thread.OwnerProcess.AllocatedResources.Add(resource);
insideThreads.Add(thread);
thread.OwnsSemaphore = true;
thread.WaitingForSemaphore = false;
thread.PreviousState = thread.CurrentState;
thread.CurrentState = EnumThreadState.IN_SEMAPHORE;
slots--;
}
else
{
waitingThreads.Enqueue(thread);
thread.OwnerProcess.RequestedResources.Add(resource);
thread.OwnsSemaphore = false;
thread.WaitingForSemaphore = true;
thread.PreviousState = thread.CurrentState;
thread.CurrentState = EnumThreadState.WAITING_SEMAPHORE;
}
}
else
{
MessageBox.Show("Can not capture a thread that has already been captured by the semaphore");
return(int.MinValue);
}
return(slots);
}
public SpinLock(SimulatorThread thread, int timeout = int.MaxValue)
{
this.locked = false;
this.process = null;
this.thread = thread;
this.timeout = timeout;
}
public SpinLock(SimulatorProcess process, int timeout = int.MaxValue)
{
this.locked = false;
this.process = process;
this.thread = null;
this.timeout = timeout;
}
/// <summary>
/// Constructor for execution unit that starts executing from a specified location in the program
/// </summary>
/// <param name="thread"> the thread to execute </param>
/// <param name="currentIndex"> the index to start executing from</param>
/// <param name="clockSpeed"> the clock speed of the CPU </param>
public ThreadExecutionUnit(SimulatorThread thread, int clockSpeed, int currentIndex) : base(thread.OwnerProcess, clockSpeed, currentIndex)
{
}
/// <summary>
/// Constructor for execution unit that starts executing from the beginning of the program
/// </summary>
/// <param name="thread"> the thread to execute </param>
/// <param name="clockSpeed"> the clock speed of the CPU </param>
public ThreadExecutionUnit(SimulatorThread thread, int clockSpeed) : base(thread.OwnerProcess, clockSpeed)
{
}