sysdeps/libm-ieee754/s_truncf.c

   1 /* Truncate argument to nearest integral value not larger than the argument.
   2    Copyright (C) 1997, 1998 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
   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 <math.h>
  22
  23 #include "math_private.h"
  24
  25
  26 float
  27 __truncf (float x)
  28 {
  29   int32_t i0, j0;
  30   int sx;
  31
  32   GET_FLOAT_WORD (i0, x);
  33   sx = i0 & 0x80000000;
  34   j0 = ((i0 >> 23) & 0xff) - 0x7f;
  35   if (j0 < 23)
  36     {
  37       if (j0 < 0)
  38         /* The magnitude of the number is < 1 so the result is +-0.  */
  39         SET_FLOAT_WORD (x, sx);
  40       else
  41         SET_FLOAT_WORD (x, sx | (i0 & ~(0x007fffff >> j0)));
  42     }
  43   else
  44     {
  45       if (j0 == 0x80)
  46         /* x is inf or NaN.  */
  47         return x + x;
  48     }
  49
  50   return x;
  51 }
  52 weak_alias (__truncf, truncf)