sysdeps/ieee754/ldbl-128/s_nextupl.c

   1 /* Return the least floating-point number greater than X.
   2    Copyright (C) 2016-2024 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    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <float.h>
  20 #include <math.h>
  21 #include <math_private.h>
  22 #include <libm-alias-ldouble.h>
  23
  24 /* Return the least floating-point number greater than X.  */
  25 _Float128
  26 __nextupl (_Float128 x)
  27 {
  28   int64_t hx, ix;
  29   uint64_t lx;
  30
  31   GET_LDOUBLE_WORDS64 (hx, lx, x);
  32   ix = hx & 0x7fffffffffffffffLL;
  33
  34   /* x is nan.  */
  35   if (((ix >= 0x7fff000000000000LL)
  36        && ((ix - 0x7fff000000000000LL) | lx) != 0))
  37     return x + x;
  38   if ((ix | lx) == 0)
  39     return LDBL_TRUE_MIN;
  40   if (hx >= 0)
  41     {                           /* x > 0.  */
  42       if (isinf (x))
  43         return x;
  44       lx++;
  45       if (lx == 0)
  46         hx++;
  47     }
  48   else
  49     {                           /* x < 0.  */
  50       if (lx == 0)
  51         hx--;
  52       lx--;
  53     }
  54   SET_LDOUBLE_WORDS64 (x, hx, lx);
  55   return x;
  56 }
  57
  58 libm_alias_ldouble (__nextup, nextup)