14 - Exceptions

ucla | CS M151B | 2024-02-29 16:17

Table of Contents

Types of Errors

Interrupts

  • asynchronous
  • due to external reasons (user input)
  • usually does not affect too much, we can just stall
  • can be automatically handled by handler and just stall

    Exceptions

  • synchronous
  • due to internal reason (code)
  • needs to be handled
  • types:
    • arithmetic - overflow, undderflow, dividee by zero
    • faults - page fault, invalid opcode
    • traps - breakpoint
    • error - parity
  • needs to be handled -> resume or abort after

    Precise Exceptions

  • when ecxepted:
  • all prev instrs executed
  • all future instrs unmodified
  • faulting instr may or may not have been executed

    Handling Errors

  • OOO processors - if fault happens on speculative branch, it should never bee seen/committed bc we can just jump back to taken branch