GATE | GATE-CS-2001 | Question 13
A CPU has two modes-privileged and non-privileged. In order to change the mode from privileged to non-privileged
(A) a hardware interrupt is needed
(B) a software interrupt is needed
(C) a privileged instruction (which does not generate an interrupt) is needed
(D) a non-privileged instruction (which does not generate an interrupt is needed
Explanation: For switching between privileged to non-privileged area, non-privileged instruction is used, without interrupt.
Software interrupts are usually used to invoke system calls.
Option (D) is correct.
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