Let t 1 and t 2 be cycles of machine DLX Π , and let t 1 2 . Suppose external interrupts i and j are both enabled, interrupt i becomes active in cycle t 1 , interrupt j becomes active in cycle t 2 ,...

Let t₁
and t₂
be cycles of machine DLX_Π, and let t_1
2. Suppose external interrupts i and j are both enabled, interrupt i becomes active in cycle t₁, interrupt j becomes active in cycle t₂, and no other interrupts are serviced or pending in cycle t₂.

1. Show that it is possible that interrupt j is serviced before interrupt i.

2. Why does this not constitute a counterexample for the correctness proof?