if (AtomicSwap (bCriticalSectionBusy, true))
{
  // The critical section is busy, put
  // the process into the waiting queue
  oWaitingProcesses.Put (GetCurrentProcess ());
  // Wait until somebody wakes the process
  Sleep ();
}

// Code of critical section comes here
...

// See if any process is waiting in the queue
oWaitingProcess = oWaitingProcesses.Get ();

if (oWaitingProcess)
{
  // A process was waiting, let it enter the critical section
  Wake (oWaitingProcess);
}
else
{
  // No process was waiting, mark the critical section as free
  bCriticalSectionBusy = false;
}