sysdeps/ieee754/k_standardl.c

   1 /* Implement __kernel_standard_l.
   2    Copyright (C) 2012-2015 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 <float.h>
  36 #include <errno.h>
  37
  38
  39 static double zero = 0.0;
  40
  41 /* Handle errors for a libm function as specified by TYPE (see
  42    comments in k_standard.c for details), with arguments X and Y,
  43    returning the appropriate return value for that function.  */
  44
  45 long double
  46 __kernel_standard_l (long double x, long double y, int type)
  47 {
  48   double dx, dy;
  49   struct exception exc;
  50
  51   if (isfinite (x))
  52     {
  53       long double ax = fabsl (x);
  54       if (ax > DBL_MAX)
  55         dx = __copysignl (DBL_MAX, x);
  56       else if (ax > 0 && ax < DBL_MIN)
  57         dx = __copysignl (DBL_MIN, x);
  58       else
  59         dx = x;
  60     }
  61   else
  62     dx = x;
  63   if (isfinite (y))
  64     {
  65       long double ay = fabsl (y);
  66       if (ay > DBL_MAX)
  67         dy = __copysignl (DBL_MAX, y);
  68       else if (ay > 0 && ay < DBL_MIN)
  69         dy = __copysignl (DBL_MIN, y);
  70       else
  71         dy = y;
  72     }
  73   else
  74     dy = y;
  75
  76   switch (type)
  77     {
  78     case 221:
  79       /* powl (x, y) overflow.  */
  80       exc.arg1 = dx;
  81       exc.arg2 = dy;
  82       exc.type = OVERFLOW;
  83       exc.name = (char *) "powl";
  84       if (_LIB_VERSION == _SVID_)
  85         {
  86           exc.retval = HUGE;
  87           y *= 0.5;
  88           if (x < zero && __rintl (y) != y)
  89             exc.retval = -HUGE;
  90         }
  91       else
  92         {
  93           exc.retval = HUGE_VAL;
  94           y *= 0.5;
  95           if (x < zero && __rintl (y) != y)
  96             exc.retval = -HUGE_VAL;
  97         }
  98       if (_LIB_VERSION == _POSIX_)
  99         __set_errno (ERANGE);
 100       else if (!matherr (&exc))
 101         __set_errno (ERANGE);
 102       return exc.retval;
 103
 104     case 222:
 105       /* powl (x, y) underflow.  */
 106       exc.arg1 = dx;
 107       exc.arg2 = dy;
 108       exc.type = UNDERFLOW;
 109       exc.name = (char *) "powl";
 110       exc.retval = zero;
 111       y *= 0.5;
 112       if (x < zero && __rintl (y) != y)
 113         exc.retval = -zero;
 114       if (_LIB_VERSION == _POSIX_)
 115         __set_errno (ERANGE);
 116       else if (!matherr (&exc))
 117         __set_errno (ERANGE);
 118       return exc.retval;
 119
 120     default:
 121       return __kernel_standard (dx, dy, type);
 122     }
 123 }