1. A method for performing an arithmetic operation in a data processing unit, the method comprising: the data processing unit iteratively computing an approximate result of the arithmetic operation; concurrently with the iteratively computing, the data processing unit computing at least two supplementary values of the approximate result of the arithmetic operation; and the data processing unit selecting a final result of the arithmetic operation from among a set including the approximate result and the at least two supplementary values depending on a result of a last iteration of the iteratively computing.