So far we have dealt with the representation of nonnegative integers by binary strings. We also designed combinational circuits that perform addition for nonnegative numbers represented by binary strings. How are negative integers represented? Can we add and subtract negative integers?
We refer to integers that are either positive, zero, or negative as signed integers. In this chapter, we deal with the representation of signed integers by binary strings. We focus on a representation that is called two’s complement. We present combinational circuits for adding and subtracting signed numbers that are represented in two’s complement representation. Although the designs are obtained by very minor changes of a binary ...