MACHINE CYCLE

The central processing unit executes an instruction it takes a series of steps the computed series of step is called machine cycle. A machine cycle it self can be broken down into smaller cycles the instruction cycle and the execution cycle at the begnning of the machine cycle that is during the instruction cycle.

The central processing unit take two steps.

FETCHING:
             Before the central processing unit can execute an instruction the control unit must retrieve (fetch) a command or data from the computer memory.

DECODING:
             Before a command can be executed the control unit must break down (decode) the command instructions that correspond to those in the central processing unit5 instruction set.

At this point the central processing unit is ready to begin the execution cycle.

EXECUTING:-
              when the command is executed the central processing unit carries out the instructions in order by converting them into microcode.

STORING:-
            The central processing unit may be required to store the result of an instruction in memory but this condition is not always required.