EN0-001 Online Practice Questions and Answers

An Advanced SIMD intrinsic has the prototype: int16x4_t vmul_n_s16(int16x4_t a, int16_t b); How many multiplications does this intrinsic compute?

A. 1 multiplication

B. 4 multiplications

C. 16 multiplications

D. 64 multiplications

In an ARMv7-A processor that includes the Advanced SIMD extension (NEON), where are the data values operated on by NEON instructions stored?

A. In system memory

B. In registers shared with the VFP register set

C. In registers shared with the integer register set

D. In dedicated registers not shared with other registers

Which one of the following statements is TRUE for software breakpoints?

A. Limited software breakpoints can be placed in code running from ROM

B. Each software breakpoint requires one watchpoint resource in the debug hardware

C. Each software breakpoint requires one breakpoint resource in the debug hardware

D. The number of available software breakpoints is not limited by the debug hardware

When using an Operating System, which of the following operations can NOT typically be done by user processes?

A. Reading the link register (R14)

B. Reading data from the user stack

C. Changing from ARM state to Thumb state

D. Changing the interrupt mask bits (A, I, F) in the CPSR

If a Generic Interrupt Controller (GIC) implements 64 priority levels, which priority field bits hold the priority value?

A. bits [5:0]

B. bits [7:2]

C. bits [15:10]

D. bits [31:26]

When should an ISB instruction be used?

A. When executing a long branch

B. When clearing the branch predictor caches

C. When reading a register from a coprocessor

D. When returning from an exception handler

A software profiling tool records the address held in the Program Counter (PC) every 1 ms. The software function that resides at each recorded address can be determined by the profiling tool. The percentage of time spent in each function is calculated from the percentage of recorded addresses where each function is resident.

Which one of the following statements is FALSE?

A. The tool shows an estimate of the percentage of time spent in each function

B. The tool identifies all functions executed by the application

C. The function with the highest percentage is a good candidate for optimization

D. The results will be more accurate on a processor running at 250 MHz. than one running at 2 GHz

If the performance of an application remains unchanged when the core clock speed of a Cortex-A9 processor is reduced, what can you deduce about the system?

A. The Clocks Per Instruction (CPI) of the processor has increased

B. The processor is NOT the limiting factor on performance

C. Instruction cache utilization has improved

D. The core has stopped carrying out speculative data memory accesses

What side-effect could using a debugger to read memory contents have?

A. The memory contents could be set to zero

B. Some memory contents could be rewritten

C. The processor MMU pagetables could be modified

D. The processor cache could be cleaned or/and invalidated

When using the ARM Compiler (armcc), which of the following possible keywords can be used to remove padding bytes from a structure?

A. __package

B. __packed

C. __compact

D. __compress