1  /* Return the least floating-point number greater than X.
       2     Copyright (C) 2016-2023 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)