Exception Processing

When an exception occurs, the current instruction stream cannot continue. If you ignore the exception, the results of executing the instruction may become undefined. Further execution of the program may cause unpredictable results.

The kernel provides a default exception-handling mechanism by which an instruction stream (a process- or interrupt-level program) can specify what action is to be taken when an exception occurs. Exceptions are handled differently depending on whether they occurred while executing in kernel mode or user mode.