MCQ IN COMPUTER SCIENCE & ENGINEERING

Detailed explanation-1: -There are seven processor modes in total: six privileged modes (abort, fast interrupt request, interrupt request, supervisor, system, and undefined) and one nonprivileged mode (user). The processor enters abort mode when there is a failed attempt to access memory.

Detailed explanation-2: -User mode is the usual ARM program execution state, and is used for executing most application programs. Fast Interrupt (FIQ) mode supports a data transfer or channel process. Interrupt (IRQ) mode is used for general-purpose interrupt handling. Supervisor mode is a protected mode for the operating system.

Detailed explanation-3: -User mode is an unprivileged mode, and has restricted access to system resources. All other modes have full access to system resources in the current security state, can change mode freely, and execute software as privileged.

Detailed explanation-4: -The ARM processor has a simple privilege model: all modes are privileged apart from User mode. Privilege is the ability to perform certain tasks that cannot be done from User mode. For example, changing the operating mode is a privileged operation.

Detailed explanation-5: -As introduced in About the Application level programmers’ model, within a security state, the ARMv7 architecture defines different levels of execution privilege: in Secure state, the privilege levels are PL1 and PL0. in Non-secure state, the privilege levels are PL2, PL1, and PL0.