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 Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the 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    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  19    Boston, MA 02110-1301, USA.
  20 */
  21
  22 #include <precomp.h>
  23
  24 double _logb (double __x)
  25 {
  26   register double __val;
  27 #ifdef __GNUC__
  28   register double __junk;
  29   __asm __volatile__
  30     ("fxtract\n\t"
  31      : "=t" (__junk), "=u" (__val) : "0" (__x));
  32 #else
  33 #error REVIEW ME
  34   __asm fld [__x];
  35   __asm fxtract;
  36   __asm fstp st(0);
  37   __asm fstp [__val];
  38 #endif /*__GNUC__*/
  39   return __val;
  40 }