sysdeps/alpha/fpu/s_rint.c

   1 /* Copyright (C) 2000, 2006, 2007 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Richard Henderson.
   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 #include <math_ldbl_opt.h>
  22
  23
  24 double
  25 __rint (double x)
  26 {
  27   double two52 = copysign (0x1.0p52, x);
  28   double r;
  29
  30   r = x + two52;
  31   r = r - two52;
  32
  33   /* rint(-0.1) == -0, and in general we'll always have the same sign
  34      as our input.  */
  35   return copysign (r, x);
  36 }
  37
  38 weak_alias (__rint, rint)
  39 #ifdef NO_LONG_DOUBLE
  40 strong_alias (__rint, __rintl)
  41 weak_alias (__rint, rintl)
  42 #endif
  43 #if LONG_DOUBLE_COMPAT(libm, GLIBC_2_0)
  44 compat_symbol (libm, __rint, rintl, GLIBC_2_0);
  45 #endif