Chapter 7: Exception

7-1. Introduction

7-1-1. What is exception

• Handle exceptional/undefined situation
  • Can't load insturction from memory
  • Unknown instruction
  • Access to unacessable memory
• When exception occur, processor automatically change PC to exception handler address

7-1-2. Exception in Architecture

• When exception occur, then processor switch to specific mode
  • Update register with exception situation's information
  • Branch to specific address
• in ARM official document: Exception is a source that change processor's execution flow. When exception occur, processor branch program counter to designated address specified by exception type

7-1-3. Excpetion in Software

• Memory Abort Type Exception: Crash, Critical Error, Core dump
• Interrupt: External device's signal
• System Call(Trap)