sysdeps/i386/fpu/e_hypot.c

   1 /* Euclidean distance function.  Double/Binary64 i386 version.
   2    Copyright (C) 2021-2024 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 <math_private.h>
  21 #include <math-narrow-eval.h>
  22 #include <math-underflow.h>
  23 #include <math-svid-compat.h>
  24 #include <libm-alias-finite.h>
  25 #include <libm-alias-double.h>
  26 #include <errno.h>
  27
  28 /* The i386 allows to use the default excess of precision to optimize the
  29    hypot implementation, since internal multiplication and sqrt is carried
  30    with 80-bit FP type.  */
  31 double
  32 __hypot (double x, double y)
  33 {
  34   if (!isfinite (x) || !isfinite (y))
  35     {
  36       if ((isinf (x) || isinf (y))
  37           && !issignaling (x) && !issignaling (y))
  38         return INFINITY;
  39       return x + y;
  40     }
  41
  42   long double lx = x;
  43   long double ly = y;
  44   double r = math_narrow_eval ((double) sqrtl (lx * lx + ly * ly));
  45   math_check_force_underflow_nonneg (r);
  46   if (isinf (r))
  47     __set_errno (ERANGE);
  48   return r;
  49 }
  50 strong_alias (__hypot, __ieee754_hypot)
  51 #if LIBM_SVID_COMPAT
  52 versioned_symbol (libm, __hypot, hypot, GLIBC_2_35);
  53 libm_alias_finite (__ieee754_hypot, __hypot)
  54 libm_alias_double_other (__hypot, hypot)
  55 #else
  56 libm_alias_double (__hypot, hypot)
  57 #endif