When silicon chips are fabricated, defects in materials (e.g., silicon) and manufacturing errors can result in defective circuits. A very common defect is for one wire to aff ect the signal in another. Th is is called a cross-talk fault. A special class of cross-talk faults is when a signal is connected to a wire that has a constant logical value (e.g., a power supply wire). In this case we have a stuck-at-0 or a stuck-at-1 fault, and the aff ected signal always has a logical value of 0 or 1, respectively. Th e following problems refer to bit 0 of the Write Register input on the register fi le in