US Patent 7191199 Method and device for computing an absolute difference

Computing an absolute difference includes receiving a first value and a second value. Propagate terms are determined according to the first value and the second value at one or more adders (24). The second value is subtracted from the first value using the propagate terms to yield a subtraction difference. It is determined at one or more correctors (26) whether the subtraction difference is negative. If the subtraction difference is negative, the subtraction difference is modified according to the propagate terms to compute an absolute difference between the first value and the second value. Otherwise, the subtraction difference is reported as the absolute difference between the first value and the second value.