A quantum-dot cellular automata processor design

This paper describes the complete implementation of a robust SUBNEG (subtract and branch if negative) processor using quantum-dot cellular automata (QCA) technology. A processor is the basic unit in computer systems which is responsable for performing the basic arithmetic, logic, and input/output operations. QCA is a promising nanotechnology where components have nano size, ultra-low power consumption and could have a clock rate on terahertz rate. The architecture of our processor was inspired by the one used on the first carbon nanotube computer. We used this work as reference because both nanotechnology (the carbon nanotube and QCA) are promising and able to overcome the limits of current CMOS technology. Our work is the first implementation of a SUBNEG processor in QCA technology and, moreover, satisfies all constraints in order to make it robust. In a bottom-up approach, we first describe the building blocks that compose the QCA SUBNEG processor such as the ALU and the data and instruction memories. Next, we present the processor architecture. Lastly, we describe tests and performance evaluation of the QCA SUBNEG processor.