math/w_pow_compat.c

   1 /* Copyright (C) 2011-2022 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 <math.h>
  19 #include <math_private.h>
  20 #include <math-svid-compat.h>
  21 #include <libm-alias-double.h>
  22
  23
  24 #if LIBM_SVID_COMPAT && (SHLIB_COMPAT (libm, GLIBC_2_0, GLIBC_2_29) \
  25                          || defined NO_LONG_DOUBLE \
  26                          || defined LONG_DOUBLE_COMPAT)
  27 /* wrapper pow */
  28 double
  29 __pow_compat (double x, double y)
  30 {
  31   double z = __ieee754_pow (x, y);
  32   if (__glibc_unlikely (!isfinite (z)))
  33     {
  34       if (_LIB_VERSION != _IEEE_)
  35         {
  36           if (isfinite (x) && isfinite (y))
  37             {
  38               if (isnan (z))
  39                 /* pow neg**non-int */
  40                 return __kernel_standard (x, y, 24);
  41               else if (x == 0.0 && y < 0.0)
  42                 {
  43                   if (signbit (x) && signbit (z))
  44                     /* pow(-0.0,negative) */
  45                     return __kernel_standard (x, y, 23);
  46                   else
  47                     /* pow(+0.0,negative) */
  48                     return __kernel_standard (x, y, 43);
  49                 }
  50               else
  51                 /* pow overflow */
  52                 return __kernel_standard (x, y, 21);
  53             }
  54         }
  55     }
  56   else if (__builtin_expect (z == 0.0, 0)
  57            && isfinite (x) && x != 0 && isfinite (y)
  58            && _LIB_VERSION != _IEEE_)
  59     /* pow underflow */
  60     return __kernel_standard (x, y, 22);
  61
  62   return z;
  63 }
  64 # if SHLIB_COMPAT (libm, GLIBC_2_0, GLIBC_2_29)
  65 compat_symbol (libm, __pow_compat, pow, GLIBC_2_0);
  66 # endif
  67 # ifdef NO_LONG_DOUBLE
  68 weak_alias (__pow_compat, powl)
  69 # endif
  70 # ifdef LONG_DOUBLE_COMPAT
  71 /* Work around gas bug "multiple versions for symbol".  */
  72 weak_alias (__pow_compat, __pow_compat_alias)
  73
  74 LONG_DOUBLE_COMPAT_CHOOSE_libm_powl (
  75   compat_symbol (libm, __pow_compat_alias, powl, FIRST_VERSION_libm_powl), );
  76 # endif
  77 #endif