20 ARM Processor Interview Questions and Answers

ARM Processors are used in a wide range of devices, from phones to tablets to wearables. They are known for their low power consumption and high performance. If you are interviewing for a position that uses ARM Processors, it is important to be prepared to answer questions about them. In this article, we will review some of the most common ARM Processor interview questions and how you should answer them.

ARM Processor Interview Questions and Answers

Here are 20 commonly asked ARM Processor interview questions and answers to prepare you for your interview:

1. What do you understand about ARM processors?

ARM processors are a type of microprocessor that is used in many small devices, such as cell phones and PDAs. They are known for their low power consumption and high performance.

2. Can you give me some examples of companies that use and sell ARM processors?

Some of the most popular companies that use ARM processors include Apple, Samsung, and Qualcomm. These companies all manufacture devices that use ARM processors, and they also sell these processors to other companies who then use them in their own devices.

3. What are the primary reasons for using an ARM processor over other types of processors such as Intel x86 or IBM PowerPC?

The main reasons for using an ARM processor are its low power consumption, small size, and low cost. ARM processors are used in a wide variety of devices including cell phones, PDAs, and digital cameras.

4. How does ARM compare with Intel in terms of instruction sets, performance, power consumption, cost, memory, and cache support?

ARM and Intel processors are both popular choices for embedded systems and mobile devices. ARM processors are typically more power-efficient than Intel processors, but they may not offer the same level of performance. In terms of instruction sets, both ARM and Intel processors support a wide variety of instructions, but ARM processors typically have a smaller instruction set than Intel processors. In terms of performance, ARM processors are typically slower than Intel processors, but they consume less power, which can be important in mobile devices. In terms of cost, ARM processors are typically less expensive than Intel processors. In terms of memory, both ARM and Intel processors support a wide variety of memory types, but ARM processors typically have less cache memory than Intel processors.

5. What is your understanding of the instruction set architecture used by ARM processors?

The instruction set architecture used by ARM processors is a RISC (Reduced Instruction Set Computer) architecture. This means that the instruction set is designed to be simple, and that the processor can execute instructions quickly. The trade-off is that RISC architectures generally have fewer features than CISC (Complex Instruction Set Computer) architectures.

6. What’s the difference between a register bank and a co-processor?

A register bank is a set of registers that are all used for the same purpose, such as storing data or holding address values. A co-processor is a separate processor that is used to perform specific tasks, such as floating point calculations.

7. What are the five basic stages involved in the execution of an ARM instruction?

The five basic stages involved in the execution of an ARM instruction are: fetch, decode, execute, memory, and writeback.

8. What are the key differences between TMS320C55x DSPs and ARM Processors?

The main difference between TMS320C55x DSPs and ARM processors is that the former are designed specifically for digital signal processing applications while the latter are more general purpose microprocessors. This means that TMS320C55x DSPs have features that are optimized for DSP applications such as a single-cycle MAC unit for fast multiply-accumulate operations. ARM processors, on the other hand, have a more traditional architecture and thus are more suited for general purpose applications.

9. What are the three main families of ARM microcontrollers?

The three main families of ARM microcontrollers are the Cortex-M series, the Cortex-R series, and the Cortex-A series.

10. Can you explain what bit sizes mean in the context of ARM processors?

The bit size of an ARM processor refers to the width of the data bus. A 32-bit data bus can transfer 4 bytes of data at a time, while a 64-bit data bus can transfer 8 bytes of data. The bit size also determines the maximum addressable memory, so a 32-bit processor can address 4 GB of memory, while a 64-bit processor can address 16 GB of memory.

11. What are the different ARM architectures available?

The different ARM architectures available are:

– ARMv5
– ARMv6
– ARMv7
– ARMv8

12. In an ARM processor, what is the difference between the CPSR and SPSR registers?

The CPSR register holds the current processor status, while the SPSR register holds the saved processor status. The SPSR register is used when an exception occurs, and the processor needs to save the current state before switching to a new state.

13. What type of interrupts can be handled by an ARM processor?

An ARM processor can handle both hardware and software interrupts.

14. What is the purpose of the Link Register (LR) in an ARM processor?

The Link Register is used to store the address of the instruction following the current instruction. This allows the processor to return to the correct location after a subroutine has been executed.

15. When should we use a branch instruction instead of a load/store instruction?

A branch instruction should be used when you want to change the order of execution of your program. A load/store instruction should be used when you want to load data from memory or store data to memory.

16. What’s the significance of mode switching in ARM processors?

Mode switching is used to change the state of the processor in order to run different types of code. For example, you might have a processor that is in user mode most of the time, but when it needs to run a privileged instruction, it will switch to supervisor mode. This allows the processor to maintain security by only allowing certain types of code to run in privileged mode.

17. What is the MMU present in ARM processors?

The Memory Management Unit is a hardware component present in ARM processors that is responsible for managing memory and providing memory protection. The MMU allows the processor to map virtual memory addresses to physical memory addresses, and it also enforces memory protection by preventing access to memory that is not supposed to be accessible.

18. What is the purpose of the Program Status Register (PSR) in ARM processors?

The PSR is a register that holds status information for the processor. This information includes things like the current processor mode, the condition code flags, and whether interrupts are enabled or disabled.

19. What is the purpose of the floating point coprocessor in ARM processors?

The floating point coprocessor in an ARM processor is responsible for executing all floating point instructions. This includes operations such as addition, subtraction, multiplication, and division. Without this coprocessor, these operations would need to be performed by the main processor, which would be much slower.

20. What is the purpose of the Thumb instruction set in ARM processors?

The Thumb instruction set is designed to provide more efficient code for certain types of operations. It is especially useful for code that is frequently executed or that is time-critical.