1  /* Copyright (C) 2011-2023 Free Software Foundation, Inc.
       2     This file is part of the GNU C Library.
       3  
       4     The GNU C Library is free software; you can redistribute it and/or
       5     modify it under the terms of the GNU Lesser General Public
       6     License as published by the Free Software Foundation; either
       7     version 2.1 of the License, or (at your option) any later version.
       8  
       9     The GNU C Library is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12     Lesser General Public License for more details.
      13  
      14     You should have received a copy of the GNU Lesser General Public
      15     License along with the GNU C Library; if not, see
      16     <https://www.gnu.org/licenses/>.  */
      17  
      18  #include <fenv.h>
      19  #include <math.h>
      20  #include <math_private.h>
      21  #include <math-svid-compat.h>
      22  #include <libm-alias-ldouble.h>
      23  
      24  
      25  #if LIBM_SVID_COMPAT
      26  /* wrapper log2l(x) */
      27  long double
      28  __log2l (long double x)
      29  {
      30    if (__builtin_expect (islessequal (x, 0.0L), 0) && _LIB_VERSION != _IEEE_)
      31      {
      32        if (x == 0.0L)
      33  	{
      34  	  feraiseexcept (FE_DIVBYZERO);
      35  	  return __kernel_standard_l (x, x, 248); /* log2(0) */
      36  	}
      37        else
      38  	{
      39  	  feraiseexcept (FE_INVALID);
      40  	  return __kernel_standard_l (x, x, 249); /* log2(x<0) */
      41  	}
      42      }
      43  
      44    return  __ieee754_log2l (x);
      45  }
      46  libm_alias_ldouble (__log2, log2)
      47  #endif