Very Large Scale Integration (VLSI) technology has opened the door to the implementation of powerful digital circuits at low cost. It has become possible to build chips with more than a million transistors, as exemplified by state-of-the-art microprocessors. Such chips are realized using the full-custom approach, where all parts of a VLSI circuit are carefully tailored to meet a set of specific requirements. Semi-custom approaches such as Standard Cells and Mask-Programmed Gate Arrays (MPGAs) have provided an easier way of designing and manufacturing Application-Specific Integrated Circuits (ASICs).