1  /* Wrapper to implement llogb in terms of ilogb.
       2     Copyright (C) 2012-2023 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 <math.h>
      20  #include <errno.h>
      21  #include <limits.h>
      22  #include <math_private.h>
      23  #include <fenv.h>
      24  
      25  long int
      26  M_DECL_FUNC (__llogb) (FLOAT x)
      27  {
      28    int r = M_SUF (__ieee754_ilogb) (x);
      29    long int lr = r;
      30    if (__glibc_unlikely (r == FP_ILOGB0)
      31        || __glibc_unlikely (r == FP_ILOGBNAN)
      32        || __glibc_unlikely (r == INT_MAX))
      33      {
      34  #if LONG_MAX != INT_MAX
      35        if (r == FP_ILOGB0)
      36  	lr = FP_LLOGB0;
      37        else if (r == FP_ILOGBNAN)
      38  	lr = FP_LLOGBNAN;
      39        else
      40  	lr = LONG_MAX;
      41  #endif
      42        __set_errno (EDOM);
      43        __feraiseexcept (FE_INVALID);
      44      }
      45    return lr;
      46  }
      47  declare_mgen_alias (__llogb, llogb)