Data Acquisition

12 which is equivalent to: 1100–4 Subtrahend – 01008 Result 1000The two’s complement (as discussed earlier) is found by first complementing all thebits in the subtrahend and then adding 1 to the least significant bit.Complementing the number results in 0100 becoming: 1011Adding 1 to the least significant bit gives a two’s complement number of: 1100.Add 1100 2 to 1100 2 as follows:110011001000 carry 1(Drop the carry 1 to achieve the same result as above.)Exclusive–OR is a procedure very commonly used with binary numbers in the errordetection sequences of data communications. The result of an XOR operation on any twobinary digits is the same as the addition of two digits without the carry bit.Consequently, this operation is sometimes also called the Modulo–2 adder. The truthtable for XOR is shown below.Table F.8Exclusive OR truth table