reactos/lib/sdk/crt/float/i386/logb.c

   1 /* Math functions for i387.
   2    Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by John C. Bowman <bowman@ipp-garching.mpg.de>, 1995.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Library General Public License as
   8    published by the Free Software Foundation; either version 2 of the
   9    License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Library General Public License for more details.
  15
  16    You should have received a copy of the GNU Library General Public
  17    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  18    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #include <precomp.h>
  22
  23 double _logb (double __x)
  24 {
  25   register double __val;
  26 #ifdef __GNUC__
  27   register double __junk;
  28   __asm __volatile__
  29     ("fxtract\n\t"
  30      : "=t" (__junk), "=u" (__val) : "0" (__x));
  31 #else
  32   __asm fld [__x];
  33   __asm fxtract;
  34   __asm fstp st(0);
  35   __asm fstp [__val];
  36 #endif /*__GNUC__*/
  37   return __val;
  38 }