sysdeps/ieee754/ldbl-128/s_nextupl.c

   1 /* Return the least floating-point number greater than X.
   2    Copyright (C) 2016 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 #include <math_private.h>
  21
  22 /* Return the least floating-point number greater than X.  */
  23 long double
  24 __nextupl (long double x)
  25 {
  26   int64_t hx, ix;
  27   u_int64_t lx;
  28
  29   GET_LDOUBLE_WORDS64 (hx, lx, x);
  30   ix = hx & 0x7fffffffffffffffLL;
  31
  32   /* x is nan.  */
  33   if (((ix >= 0x7fff000000000000LL)
  34        && ((ix - 0x7fff000000000000LL) | lx) != 0))
  35     return x + x;
  36   if ((ix | lx) == 0)
  37     return LDBL_TRUE_MIN;
  38   if (hx >= 0)
  39     {                           /* x > 0.  */
  40       if (isinf (x))
  41         return x;
  42       lx++;
  43       if (lx == 0)
  44         hx++;
  45     }
  46   else
  47     {                           /* x < 0.  */
  48       if (lx == 0)
  49         hx--;
  50       lx--;
  51     }
  52   SET_LDOUBLE_WORDS64 (x, hx, lx);
  53   return x;
  54 }
  55
  56 weak_alias (__nextupl, nextupl)