/* Emulation for sqrtl. Contributed by Paolo Bonzini Copyright 2002, 2003, 2007 Free Software Foundation, Inc. This file is part of gnulib. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ #include /* Specification. */ #include #include #include "isnanl.h" /* A simple Newton-Raphson method. */ long double sqrtl(long double x) { long double delta, y; int exponent; /* Check for NaN */ if (isnanl (x)) return x; /* Check for negative numbers */ if (x < 0.0L) return (long double) sqrt(-1); /* Check for zero and infinites */ if (x + x == x) return x; frexpl (x, &exponent); y = ldexpl (x, -exponent / 2); do { delta = y; y = (y + x / y) * 0.5L; delta -= y; } while (delta != 0.0L); return y; }