NIST CFTT: Testing Disk Imaging Tools

A three input binary adder with only a single carry path. First adder circuits receive one bit of each of the three words of the same significance. Second cells which include a carry path are coupled to the first circuits such that one of the bits of lower significance from the first circuits is coupled to one of the cells and the other bit from the first circuit is coupled to the next of the cells along the carry path.