reactos/lib/crtdll/old cruft/float/isnan.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 #include <msvcrt/math.h>
  20 #include <msvcrt/float.h>
  21 #include <msvcrt/internal/ieee.h>
  22
  23
  24 /*
  25  * @implemented
  26  */
  27 int _isnan(double __x)
  28 {
  29         double_t* x = (double_t*)&__x;
  30         return (x->exponent == 0x7ff  && (x->mantissah != 0 || x->mantissal != 0));
  31 }
  32
  33 int _isnanl(long double __x)
  34 {
  35         /* Intel's extended format has the normally implicit 1 explicit
  36            present.  Sigh!  */
  37
  38         long_double_t* x = (long_double_t*)&__x;
  39
  40
  41          /* IEEE 854 NaN's have the maximum possible
  42      exponent and a nonzero mantissa.  */
  43
  44         return (( x->exponent == 0x7fff)
  45           && ((x->mantissah & 0x80000000) != 0)
  46           && ((x->mantissah & (unsigned int)0x7fffffff) != 0 || x->mantissal != 0));
  47 }
  48
  49 int _isinf(double __x)
  50 {
  51         double_t* x = (double_t*)&__x;
  52         return (x->exponent == 0x7ff  && (x->mantissah == 0 && x->mantissal == 0));
  53 }
  54
  55 /*
  56  * @implemented
  57  */
  58 int _finite(double x)
  59 {
  60         return !_isinf(x);
  61 }
  62
  63 int _isinfl(long double __x)
  64 {
  65         /* Intel's extended format has the normally implicit 1 explicit
  66            present.  Sigh!  */
  67
  68         long_double_t* x = (long_double_t*)&__x;
  69
  70
  71          /* An IEEE 854 infinity has an exponent with the
  72      maximum possible value and a zero mantissa.  */
  73
  74
  75         if (x->exponent == 0x7fff && ((x->mantissah == 0x80000000) && x->mantissal == 0))
  76                 return x->sign ? -1 : 1;
  77         return 0;
  78 }