Each exception is in one of the following
states:
- Inactive: The exception is not
active and not pending.
- Pending: The exception is
waiting to be serviced by the processor. An interrupt request from a peripheral or from
software can change the state of the corresponding interrupt to pending.
- Active: An exception is being
serviced by the processor but has not completed. An exception handler can interrupt the
execution of another exception handler. In this case, both exceptions are in the active
state.
- Active and Pending: The
exception is being serviced by the processor, and there is a pending exception from the
same source