sysdeps/powerpc/fpu/s_rint.c

   1 /* Round a 64-bit floating point value to the nearest integer.
   2    Copyright (C) 1997-2015 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, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <math.h>
  20
  21 double
  22 __rint (double x)
  23 {
  24   static const float TWO52 = 4503599627370496.0;
  25
  26   if (fabs (x) < TWO52)
  27     {
  28       if (x > 0.0)
  29         {
  30           x += TWO52;
  31           x -= TWO52;
  32         }
  33       else if (x < 0.0)
  34         {
  35           x = TWO52 - x;
  36           x = -(x - TWO52);
  37         }
  38     }
  39
  40   return x;
  41 }
  42 weak_alias (__rint, rint)
  43 #ifdef NO_LONG_DOUBLE
  44 strong_alias (__rint, __rintl)
  45 weak_alias (__rint, rintl)
  46 #endif