Hi

If U Want To Delay In C, Its Not Recommend To Use The NOP It Is Recommend (By Me) To Use The TIMERS For Accurate Delay Function, Or Any Other Accurate Waiting Function.
Also This Way, U Dont Need To Change Your Program EveryTime
U Replace The Crystal.
If U Want Non-Accurate Delay/Waiting Function, U Can Use Loop Of x++.

Have Fun