2 * (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
3 * See the copyright notice in the ACK home directory, in the file "Copyright".
5 * Author: Ceriel J.H. Jacobs
7 /* $Id: sqrt.c,v 1.4 1994/06/24 11:44:18 ceriel Exp $ */
26 if (x < 0) errno = EDOM;
30 if (x > DBL_MAX) return x; /* for infinity */
32 val = frexp(x, &exponent);
37 val = ldexp(val + 1.0, exponent/2 - 1);
38 /* was: val = (val + 1.0)/2.0; val = ldexp(val, exponent/2); */
39 for (exponent = NITER - 1; exponent >= 0; exponent--) {
40 val = (val + x / val) / 2.0;