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  long double
      26  __nextupl (long double x)
      27  {
      28    uint32_t hx, ix;
      29    uint32_t lx;
      30    int32_t esx;
      31  
      32    GET_LDOUBLE_WORDS (esx, hx, lx, x);
      33    ix = esx & 0x7fff;
      34  
      35    if (((ix == 0x7fff) && (((hx & 0x7fffffff) | lx) != 0)))  /* x is nan.  */
      36      return x + x;
      37    if ((ix | hx | lx) == 0)
      38      return LDBL_TRUE_MIN;
      39    if (esx >= 0)
      40      {				/* x > 0.  */
      41        if (isinf (x))
      42          return x;
      43        lx += 1;
      44        if (lx == 0)
      45          {
      46            hx += 1;
      47  #if LDBL_MIN_EXP == -16381
      48            if (hx == 0 || (esx == 0 && hx == 0x80000000))
      49  #else
      50            if (hx == 0)
      51  #endif
      52            {
      53              esx += 1;
      54              hx |= 0x80000000;
      55            }
      56          }
      57      }
      58    else
      59      {				/* x < 0.  */
      60        if (lx == 0)
      61          {
      62  #if LDBL_MIN_EXP == -16381
      63            if (hx <= 0x80000000 && esx != 0xffff8000)
      64              {
      65                esx -= 1;
      66                hx = hx - 1;
      67                if ((esx & 0x7fff) > 0)
      68                  hx |= 0x80000000;
      69              }
      70            else
      71              hx -= 1;
      72  #else
      73            if (ix != 0 && hx == 0x80000000)
      74              hx = 0;
      75            if (hx == 0)
      76              esx -= 1;
      77            hx -= 1;
      78  #endif
      79          }
      80        lx -= 1;
      81      }
      82    SET_LDOUBLE_WORDS (x, esx, hx, lx);
      83    return x;
      84  }
      85  
      86  libm_alias_ldouble (__nextup, nextup)