On the notion of control signals in digital designs

The concept of control signals is fundamental to digital design. It evokes the notion of one or more signals that influence computation on other signals in a system, and regulate the behavior of the system. A formal definition of control signals is presented. It is argued that knowledge of the control signals in a complex design such as a microprocessor or a computer is crucial to the comprehension and specification of the design and that knowledge of the control signals of a design leads to a more efficient hardware implementation. The identification of control signals in two microprocessors are presented as examples.<>