is large // enough to justify the cost of the multiplications. // The threshold is selected experimentally as a linear function of n. threshold := n / 4 // We calculate how many of the most-significant bits of the exponent we can // compute before crossing the threshold, and we do it with doublings. i := bits.UintSize for logR>>i <= threshold { i-- } for k := uint(0); k < logR>>i; k++ { rr.Add(rr, m) } // Then we process the remaining bits of the exponent with a // square-and-double chain. for i >...