/* Truncate argument to nearest integral value not larger than the argument.

   Copyright (C) 1997-2018 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 Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 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

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <math.h>

#include <math_private.h>

#include <libm-alias-double.h>

#include <math-use-builtins.h>

double

__trunc (double x)

{

#if USE_TRUNC_BUILTIN

  return __builtin_trunc (x);

#else

  /* Use generic implementation.  */

  int64_t i0, j0;

  int64_t sx;

  EXTRACT_WORDS64 (i0, x);

  sx = i0 & UINT64_C (0x8000000000000000);

  j0 = ((i0 >> 52) & 0x7ff) - 0x3ff;

  if (j0 < 52)

    {

      if (j0 < 0)

	/* The magnitude of the number is < 1 so the result is +-0.  */

	INSERT_WORDS64 (x, sx);

      else

	INSERT_WORDS64 (x, sx | (i0 & ~(UINT64_C (0x000fffffffffffff) >> j0)));

    }

  else

    {

      if (j0 == 0x400)

	/* x is inf or NaN.  */

	return x + x;

    }

  return x;

#endif /* ! USE_TRUNC_BUILTIN  */

}

#ifndef __trunc

libm_alias_double (__trunc, trunc)

#endif