sysdeps/sparc/sparc64/soft-fp/qp_util.c

   1 /* Software floating-point emulation.
   2    Helper routine for _Qp_* routines.
   3    Simulate exceptions using double arithmetics.
   4    Copyright (C) 1999 Free Software Foundation, Inc.
   5    This file is part of the GNU C Library.
   6    Contributed by Jakub Jelinek (jj@ultra.linux.cz).
   7
   8    The GNU C Library is free software; you can redistribute it and/or
   9    modify it under the terms of the GNU Lesser General Public
  10    License as published by the Free Software Foundation; either
  11    version 2.1 of the License, or (at your option) any later version.
  12
  13    The GNU C Library is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16    Lesser General Public License for more details.
  17
  18    You should have received a copy of the GNU Lesser General Public
  19    License along with the GNU C Library; if not, see
  20    <http://www.gnu.org/licenses/>.  */
  21
  22 #include "soft-fp.h"
  23
  24 static unsigned long numbers [] = {
  25 0x7fef000000000000UL, /* A huge double number */
  26 0x0010100000000000UL, /* Very tiny number */
  27 0x0010000000000000UL, /* Minimum normalized number */
  28 0x0000000000000000UL, /* Zero */
  29 };
  30
  31 double __Qp_handle_exceptions(int exceptions)
  32 {
  33   double d, *p = (double *)numbers;
  34   if (exceptions & FP_EX_INVALID)
  35     d = p[3]/p[3];
  36   if (exceptions & FP_EX_OVERFLOW)
  37     {
  38       d = p[0] + p[0];
  39       exceptions &= ~FP_EX_INEXACT;
  40     }
  41   if (exceptions & FP_EX_UNDERFLOW)
  42     {
  43       if (exceptions & FP_EX_INEXACT)
  44         {
  45           d = p[2] * p[2];
  46           exceptions &= ~FP_EX_INEXACT;
  47         }
  48       else
  49         d = p[1] - p[2];
  50     }
  51   if (exceptions & FP_EX_DIVZERO)
  52     d = 1.0/p[3];
  53   if (exceptions & FP_EX_INEXACT)
  54     d = p[0] - p[2];
  55   return d;
  56 }