sysdeps/ieee754/k_standardl.c

   1 /* Implement __kernel_standard_l.
   2    Copyright (C) 2012-2017 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    <http://www.gnu.org/licenses/>.
  18
  19    Parts based on k_standard.c from fdlibm: */
  20
  21 /* @(#)k_standard.c 5.1 93/09/24 */
  22 /*
  23  * ====================================================
  24  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
  25  *
  26  * Developed at SunPro, a Sun Microsystems, Inc. business.
  27  * Permission to use, copy, modify, and distribute this
  28  * software is freely granted, provided that this notice
  29  * is preserved.
  30  * ====================================================
  31  */
  32
  33 #include <math.h>
  34 #include <math_private.h>
  35 #include <math-svid-compat.h>
  36 #include <fenv.h>
  37 #include <float.h>
  38 #include <errno.h>
  39
  40
  41 static double zero = 0.0;
  42
  43 /* Handle errors for a libm function as specified by TYPE (see
  44    comments in k_standard.c for details), with arguments X and Y,
  45    returning the appropriate return value for that function.  */
  46
  47 long double
  48 __kernel_standard_l (long double x, long double y, int type)
  49 {
  50   double dx, dy;
  51   struct exception exc;
  52   fenv_t env;
  53
  54   feholdexcept (&env);
  55   dx = x;
  56   dy = y;
  57   math_force_eval (dx);
  58   math_force_eval (dy);
  59   fesetenv (&env);
  60
  61   switch (type)
  62     {
  63     case 221:
  64       /* powl (x, y) overflow.  */
  65       exc.arg1 = dx;
  66       exc.arg2 = dy;
  67       exc.type = OVERFLOW;
  68       exc.name = (char *) "powl";
  69       if (_LIB_VERSION == _SVID_)
  70         {
  71           exc.retval = HUGE;
  72           y *= 0.5;
  73           if (x < zero && __rintl (y) != y)
  74             exc.retval = -HUGE;
  75         }
  76       else
  77         {
  78           exc.retval = HUGE_VAL;
  79           y *= 0.5;
  80           if (x < zero && __rintl (y) != y)
  81             exc.retval = -HUGE_VAL;
  82         }
  83       if (_LIB_VERSION == _POSIX_)
  84         __set_errno (ERANGE);
  85       else if (!matherr (&exc))
  86         __set_errno (ERANGE);
  87       return exc.retval;
  88
  89     case 222:
  90       /* powl (x, y) underflow.  */
  91       exc.arg1 = dx;
  92       exc.arg2 = dy;
  93       exc.type = UNDERFLOW;
  94       exc.name = (char *) "powl";
  95       exc.retval = zero;
  96       y *= 0.5;
  97       if (x < zero && __rintl (y) != y)
  98         exc.retval = -zero;
  99       if (_LIB_VERSION == _POSIX_)
 100         __set_errno (ERANGE);
 101       else if (!matherr (&exc))
 102         __set_errno (ERANGE);
 103       return exc.retval;
 104
 105     default:
 106       return __kernel_standard (dx, dy, type);
 107     }
 108 }