Which of the following is not true about compare_and_swap instruction?
A) It is a hardware instruction
B) It is executed atomically
C) Returns the original value of passed parameter
D) Set the new value of passed parameter to "TRUE"
E) Set the variable "value" the value of the passed parameter "new_value" but only if "value" =="expected"

Question

Which of the following is not true about compare_and_swap instruction?
A) It is a hardware instruction
B) It is executed atomically 
C) Returns the original value of passed parameter
D) Set the new value of passed parameter to "TRUE"
E) Set the variable "value" the value of the passed parameter "new_value" but only if "value" =="expected"

Quizplus · Accepted Answer

The compare_and_swap instruction sets the variable "value" to the value of the passed parameter "new_value" but only if "value" == "expected". It returns the original value of the passed parameter and is executed atomically. However, it does not always set the new value of the passed parameter to "TRUE", as the new value may be any value that is passed as a parameter.

Which of the Following Is Not True About Compare_and_swap Instruction