Thanks muks for your reply.
If I use one "tick count" outside the loop and second inside the loop, and then subtract their output through shift registers, Will this method be correct to calculate the execution time of the loop or there is some simple way to do this?
The loop time can depend on may unknown and complicated factors (CPU speed and type, number of cores, OS, code inside the loop, parallel code outside the loop, any other program or service running on the computer, etc.etc.), so it cannot be calculated without running the program, even if all that information is known. There are too many unknown factors!
The only way to determine the loop rate is to run the loop and actually measure the tick count increment (Which of course also involves some calculations). I am sure that's what you meant.