In ARM architecture, processor modes are crucial for managing different levels of privilege and functionality.
Here are the main processor modes in ARM:
Mode Description
User Mode For running user applications with limited access to system resources.
FIQ Mode Fast Interrupt Request mode for handling high-priority interrupts.
IRQ Mode Interrupt Request mode for handling standard interrupts.
Supervisor Mode For operating system tasks with higher privileges than user mode.
Abort Mode For handling memory access violations.
Undefined Mode For handling undefined instructions.
System Mode Similar to user mode but with full access to system resources.
Monitor Mode For security extensions, managing secure and non-secure states.
Detailed Descriptions
1. User Mode:
Purpose: Runs user applications.
Access: Limited access to memory and hardware.
Example: Running a mobile app.
2. FIQ Mode:
Purpose: Handles high-priority interrupts.
Access: Fast access to specific registers for quick response.
Example: Handling real-time data from sensors.
3. IRQ Mode:
Purpose: Handles standard interrupts.
Access: Access to interrupt handling routines.
Example: Managing keyboard or mouse inputs.
4. Supervisor Mode:
Purpose: Executes operating system tasks.
Access: Full access to system resources.
Example: Managing memory allocation.
5. Abort Mode:
Purpose: Handles memory access violations.
Access: Special routines to manage errors.
Example: Responding to illegal memory access.
6. Undefined Mode:
Purpose: Handles undefined instructions.
Access: Executes routines for undefined instructions.
Example: Catching and managing illegal instructions.
7. System Mode:
Purpose: Similar to user mode but with full system access.
Access: Full access to system resources.
Example: Running system-level applications.
8. Monitor Mode:
Purpose: Manages secure and non-secure states.
Access: Controls transitions between secure and non-secure operations.
Example: Handling secure boot processes.
If you have any specific questions about these modes or need further details, feel free to ask!
