Interrupt enable and disable in ARM Architecture - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of enabling interrupts in ARM architecture?

Enabling interrupts allows the processor to respond to external or internal events by temporarily pausing the current task and running a special function called an interrupt handler.

beginner

How does disabling interrupts affect the processor's behavior?

Disabling interrupts prevents the processor from responding to interrupt requests, ensuring that the current code runs without interruption until interrupts are enabled again.

intermediate

Name the ARM processor register commonly used to enable or disable interrupts.

The CPSR (Current Program Status Register) contains bits that control interrupt enable and disable states, such as the I bit for IRQ and the F bit for FIQ interrupts.

intermediate

What is the difference between IRQ and FIQ interrupts in ARM?

IRQ (Interrupt Request) is a normal interrupt, while FIQ (Fast Interrupt Request) is a higher priority interrupt designed for faster response with dedicated registers.

beginner

Why might a programmer disable interrupts temporarily in an ARM system?

To protect critical sections of code from being interrupted, ensuring data integrity and preventing race conditions during sensitive operations.

Which register bit in ARM controls the enabling of IRQ interrupts?

A I bit in CPSR

B F bit in CPSR

C T bit in CPSR

D M bit in CPSR

The I bit in the CPSR register is used to enable or disable IRQ interrupts.

What happens when interrupts are disabled in an ARM processor?

A Processor speeds up execution

B Processor ignores interrupt requests

C Processor resets

D Processor enters low power mode

Disabling interrupts causes the processor to ignore interrupt requests until they are enabled again.

Which interrupt type in ARM has higher priority and faster response?

A FIQ

B NMI

C IRQ

D SWI

FIQ (Fast Interrupt Request) has higher priority and is designed for faster response than IRQ.

Why is it important to disable interrupts during critical code sections?

A To enable debugging

B To increase power consumption

C To slow down the processor

D To prevent data corruption

Disabling interrupts prevents other code from interrupting critical sections, avoiding data corruption.

Which of the following is NOT a reason to disable interrupts?

A Protect critical code

B Prevent race conditions

C Improve multitasking

D Ensure data integrity

Disabling interrupts actually reduces multitasking ability by preventing the processor from handling other tasks.

Explain how enabling and disabling interrupts affects the flow of program execution in ARM processors.

Think about what happens when an interrupt occurs and how the processor decides to pause or continue.

Describe the difference between IRQ and FIQ interrupts and why a system might use both.

Consider which interrupt is faster and how that helps in real-time systems.