1. A system for a microelectronic device for reducing power consumption and heat dissipation requirements, said microelectronic device having at least two functional units controlled by a clock signal produced by a clock unit, said system comprising: (a) compiler means for compiling source code to machine code and for determining on a preselected cycle basis, the need to use each of the functional units to perform an operation in conjunction with executing the machine code instruction; (b) logic means, coupled to the functional units and to the clock unit and in communication with the machine code, for controlling the supplying of the clock signal so that the clock signal on said preselected cycle basis is supplied only to each of the functional units needed to perform an operation in conjunction with executing the machine code.