Patent ID: 6625632
Filing Date: 2003-09-23
Classification: G06F

Abstract:
A method for rapidly calculating a square root of a number using a computer processor having floating point arithmetic functionality and having an instruction set that includes an estimated reciprocal square root operation, the estimated reciprocal square root operation producing a calculation error, comprising the steps of:calling the reciprocal square root operation of the processor with a number to calculate an estimated reciprocal square root of the number; calculating a one half reciprocal square root from the estimated reciprocal square root; calculating a one half square root from the one half reciprocal square root; calculating an estimated square root of the number from the one half of the square root; calculating an estimated calculation error using the estimated square root and the one half reciprocal square root; and applying the estimated calculation error to the estimated square root to double the precision of the estimated square root.