glibc/sysdeps/libm-ieee754/s_truncf.c

/* Truncate argument to nearest integral value not larger than the argument.
   Copyright (C) 1997, 1998 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <math.h>

#include "math_private.h"


float
__truncf (float x)
{
  int32_t i0, j0;
  int sx;

  GET_FLOAT_WORD (i0, x);
  sx = i0 & 0x80000000;
  j0 = ((i0 >> 23) & 0xff) - 0x7f;
  if (j0 < 23)
    {
      if (j0 < 0)
	/* The magnitude of the number is < 1 so the result is +-0.  */
	SET_FLOAT_WORD (x, sx);
      else
	SET_FLOAT_WORD (x, sx | (i0 & ~(0x007fffff >> j0)));
    }
  else
    {
      if (j0 == 0x80)
	/* x is inf or NaN.  */
	return x + x;
    }

  return x;
}
weak_alias (__truncf, truncf)