Patent ID: 6343306
Filing Date: 2002-01-29
Classification: G06F

Abstract:
A one's complement adder for adding a first addend and a second addend to determine a one's complement sum of the first and second addends, comprising:a first two's complement adder coupled to receive the first and second addends at addend inputs and adapted to output a first sum, wherein the first sum is the one's complement sum that would result if no carry occurred upon addition of the first and second addends; a second two's complement adder coupled to receive the first and second addends at addend inputs and adapted to output a second sum, wherein the second sum is the one's complement sum that would result if a carry occurred upon addition of the first and second addends; and a selector coupled to receive the first sum from the first two's complement adder and the second sum from the second two's complement adder and the selector coupled to receive an indication of whether the carry occurred or not, wherein the selector is adapted to output the first sum as the one's complement sum when the indication indicates that the carry did not occur and to output the second sum as the one's complement sum when the indication indicates that the carry did occur.