while (true)
{
  // Indicate the intent to enter the critical section
  bIWantToEnter = true;
  // Enter the critical section if the other
  // process does not indicate the same intent
  if (!bHeWantsToEnter) break;
  // Back off to give the other process
  // a chance and continue the active
  // waiting cycle
  bIWantToEnter = false;
}

// Code of critical section comes here
...

bIWantToEnter = false;