EN0-001 Online Practice Questions and Answers

When setting the initial location of the stack pointer and the base address of the heap, the ARM EABI requires that the:

A. Base address of the heap must be the same as the initial stack pointer.

B. Stack pointer must be 8-byte aligned.

C. Heap must be in external RAM.

D. Initial stack pointer must be the lowest addressable memory location.

Which of the following processors includes a Generic Interrupt Controller as a standard component?

A. Cortex-A8

B. Cortex-M3

C. Cortex-R4F

D. Cortex-A9 MPCore

The following function is declared: float func(float fl, float f2);

The file file1 .c contains a call to func, and is compiled with hard floating point linkage. The file file2.c contains the definition of func, and is compiled with AACPS soft floating point linkage.

Assume that the two files are successfully linked using the ARM linker and an executable is generated. The generated executable:

A. Exhibits correct behavior, but suffers a performance penalty because the linker has to generate extra code.

B. Exhibits correct behavior, and suffers no performance penalty.

C. Will not execute.

D. Exhibits incorrect behavior.

In an ARMv7-A processor with Security Extensions, which of the following mechanisms best describes the way Secure memory is protected from access by software running in a Non-secure privileged mode?

A. The memory system has visibility of the security status of all accesses, and will reject all Non- secure accesses to Secure memory

B. Secure memory contents are encrypted, and cannot be decrypted by Non-secure software

C. The level 2 cache controller blocks all accesses to Secure memory when the SCR.NS bit of the processor is set

D. The MMU generates an abort on accesses to Secure memory performed by Non-secure software

Processors which implement the ARMv7-A architecture can be configured to allow unaligned memory access. Unaligned accesses have a number of advantages, disadvantages, and limitations.

Which TWO of the following statements are true? (Choose two)

A. Unaligned accesses may take more cycles to execute than aligned accesses

B. Unaligned loads and stores are necessary for accessing fields in packed structures

C. A program compiled using unaligned accesses can be safely executed on all ARMv7-A devices

D. If the relevant control register setting is enabled all loads and stores can function from unaligned addresses

E. Unaligned accesses can only be made to Normal memory

The Cortex-A9 MPCore processor contains a hardware block whose function is to maintain data cache coherency between cores. What is the name of this block?

A. Shareable Memory

B. Snoop Control Unit

C. Private Memory Region

D. Level 2 Cache Controller

The following pair of functions implement a simple mutex spinlock which might be used to protect a critical code section in a multi-threaded application. The address of the lock variable is in r0.

In order to minimize power while waiting for the lock to be available. SEV and WFE instructions can be used to place the processor in a low power state while waiting for the lock to become available. At which points should these instructions be placed?

A. WFENE at , SEV at

B. WFEEQ at SEV at

C. WFE at SEV at WFENE at

D. SEV at