sysdeps/vax/infnan.c

   1 /* Copyright (C) 1991, 1992, 1995 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 Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 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 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #ifndef __GNUC__
  20   #error This file uses GNU C extensions; you must compile with GCC.
  21 #else
  22
  23 #include <ansidecl.h>
  24 #include <errno.h>
  25 #include <math.h>
  26
  27 /* Deal with an infinite or NaN result.
  28    If ERROR is ERANGE, result is +Inf;
  29    if ERROR is - ERANGE, result is -Inf;
  30    otherwise result is NaN.
  31    This will set `errno' to either ERANGE or EDOM,
  32    and may return an infinity or NaN, or may do something else.  */
  33 double
  34 DEFUN(__infnan, (error), int error)
  35 {
  36   switch (error)
  37     {
  38     case ERANGE:
  39       errno = ERANGE;
  40       break;
  41
  42     case - ERANGE:
  43       errno = ERANGE;
  44       break;
  45
  46     default:
  47       errno = EDOM;
  48       break;
  49     }
  50
  51   /* Trigger a reserved operand fault.  */
  52   {
  53     double result;
  54     asm volatile("emodd %1, %1, %2, %0, %0" : "=r" (result) :
  55                  "i" (0), "i" (0x8000));
  56     return result;
  57   }
  58 }
  59
  60 #endif
  61
  62 weak_alias (__infnan, infnan)