Interrupts use the same exception handler table.

The same mode switch occurs when an interrupt occurs. However, instead of being caused by the trap instrucution, the interrupt is signal is sent by an external device to the processor (INTR line into the processor). The hardware processor then saves the currently executing thread's context in its TCB, acknowledges the interrupt and receives an integer value indicating which handler to use. This integer is then used in the same way as the 0x80 argument to lookup the handler and begin its execution.