The
third step is to move the contents of the MBR to the instruction register (IR).This
frees up the MBR for use during a possible indirect cycle.
Thus, the simple fetch cycle actually consists of three steps and four microoperations.
Each micro-operation involves the movement of data into or out of a
register. So long as these movements do not interfere with one another, several of
them can take place during one step, saving time. Symbolically, we can write this