exceptions & interrupts

Concept

Exceptions

• might occur when executing machine level instructions
• arithmetic errors:
  • overflow, underflow, divide by zero
• memory errors:
  • illegal mem address, mis-aligned memory access
• synchronous, occurs due to program execution
• program is terminated and exception handler is executed automatically

Interrupts

• external events that interrupt the program execution
• e.g. timer, mouse movement, keyboard input
• program is suspended and interrupt handler is executed automatically

ctrl + c to interrupt programs in the terminal

Handlers

1. save register and CPU state
2. perform handler routine
3. restore register and CPU
4. return

• control is transferred to the handler automatically on exception/interrupt

Application

Program that cannot be interrupted by ctrl + c