The numbers given for the interrupt-transparent synchronization
indicate the best case: the while-clause of
enqueue() (Figure 4, lines 5–7) and the if-clause of
dequeue() (Figure 5, lines 5–12) are not executed. Only
the expressions of the corresponding conditions are evaluated.
In addition, the numbers of dequeue() in all
three cases are for a queue with exactly one stored element.
The numbers for the blocking case include instructions and
clock cycles needed for disabling/enabling interrupts.