sysdeps/alpha/fpu/s_rint.c

   1 /* Copyright (C) 2000-2019 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, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #define NO_MATH_REDIRECT
  20 #include <math.h>
  21 #include <math_ldbl_opt.h>
  22 #include <libm-alias-double.h>
  23
  24
  25 double
  26 __rint (double x)
  27 {
  28   if (isnan (x))
  29     return x + x;
  30
  31   if (isless (fabs (x), 9007199254740992.0))    /* 1 << DBL_MANT_DIG */
  32     {
  33       double tmp1, new_x;
  34       __asm ("cvttq/svid %2,%1\n\t"
  35              "cvtqt/d %1,%0\n\t"
  36              : "=f"(new_x), "=&f"(tmp1)
  37              : "f"(x));
  38
  39       /* rint(-0.1) == -0, and in general we'll always have the same
  40          sign as our input.  */
  41       x = copysign(new_x, x);
  42     }
  43   return x;
  44 }
  45
  46 libm_alias_double (__rint, rint)