Patent ID: 7689642

Claim:
A computer-implemented method for efficiently performing an accuracy-check computation for Newton-Raphson divide and square-root operations, wherein the method comprises: in a computer system, performing Newton-Raphson iterations followed by a multiply for a divide or square-root operation to produce a result; and performing the accuracy-check computation to determine whether rounding the result to a desired precision produces the correct result; wherein the accuracy-check computation involves performing a single pass through a multiply-add pipeline to perform a multiply-add operation, and wherein during the single pass, a Booth encoding of an operand in a multiply portion of the multiply-add pipeline is modified, if necessary, to cause an additional term for the accuracy-check computation to be added to the result of the multiply-add operation; whereby the accuracy-check computation is completed without requiring an additional pass through the multiply-add pipeline, and without an additional partial-product row in the multiply-add pipeline.