libm/sqrt.c

   1 /*
   2  *  ZeX/OS
   3  *  Copyright (C) 2009  Tomas 'ZeXx86' Jedrzejek (zexx86@gmail.com)
   4  *
   5  *  This program is free software: you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation, either version 3 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19
  20 double sqrt (double arg)
  21 {
  22         /*double x, temp;
  23         int exp;
  24         int i;
  25
  26         if (arg <= 0.)
  27                 return (0.);
  28
  29         x = frexp (arg, &exp);
  30
  31         while (x < 0.5) {
  32                 x *= 2;
  33                 exp --;
  34         }
  35
  36         if (exp & 1) {
  37                 x *= 2;
  38                 exp--;
  39         }
  40
  41         temp = 0.5 * (1.0 + x);
  42
  43         while (exp > 60) {
  44                 temp *= (1L << 30);
  45                 exp -= 60;
  46         }
  47
  48         while (exp < -60) {
  49                 temp /= (1L << 30);
  50                 exp += 60;
  51         }
  52
  53         if (exp >= 0)
  54                 temp *= 1L << (exp/2);
  55         else
  56                 temp /= 1L << (-exp/2);
  57
  58         for (i = 0; i <= 4; i ++)
  59                 temp = 0.5 * (temp + arg / temp);*/
  60
  61         return __builtin_sqrt(arg);
  62 }