libstdc++-v3/libmath/signbitl.c

   1 /* Return nonzero value if number is negative. */
   2
   3 /* Copyright (C) 1997, 1998, 1999 Free Software Foundation, Inc.
   4
   5    This file is part of the GNU ISO C++ Library.  This library is free
   6    software; you can redistribute it and/or modify it under the
   7    terms of the GNU General Public License as published by the
   8    Free Software Foundation; either version 2, or (at your option)
   9    any later version.
  10
  11    This 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
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License along
  17    with this library; see the file COPYING.  If not, write to the Free
  18    Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  19    USA.
  20
  21    As a special exception, you may use this file as part of a free software
  22    library without restriction.  Specifically, if other files instantiate
  23    templates or use macros or inline functions from this file, or you compile
  24    this file and link it with other files to produce an executable, this
  25    file does not by itself cause the resulting executable to be covered by
  26    the GNU General Public License.  This exception does not however
  27    invalidate any other reasons why the executable file might be covered by
  28    the GNU General Public License.  */
  29
  30 #include <float.h>
  31 #include <math.h>
  32 #include "mathconf.h"
  33
  34 int
  35 __signbitl (long double x)
  36 {
  37 #if LDBL_MANT_DIG == 113
  38   Int64_t msw;
  39
  40   GET_LDOUBLE_MSW64 (msw, x);
  41   return msw < 0;
  42 #else
  43   Int32_t e;
  44
  45   GET_LDOUBLE_EXP (e, x);
  46   return e & 0x8000;
  47 #endif
  48 }