sysdeps/powerpc/fpu/s_rint.c

   1 /* Round a 64-bit floating point value to the nearest integer.
   2    Copyright (C) 1997, 2000 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library 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 GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include "math.h"
  21
  22 double
  23 __rint (double x)
  24 {
  25   static const float TWO52 = 4503599627370496.0;
  26
  27   if (fabs (x) < TWO52)
  28     {
  29       if (x > 0.0)
  30         {
  31           x += TWO52;
  32           x -= TWO52;
  33         }
  34       else if (x < 0.0)
  35         {
  36           x = TWO52 - x;
  37           x = -(x - TWO52);
  38         }
  39     }
  40
  41   return x;
  42 }
  43 weak_alias (__rint, rint)
  44 #ifdef NO_LONG_DOUBLE
  45 strong_alias (__rint, __rintl)
  46 weak_alias (__rint, rintl)
  47 #endif