/* Round double to integer away from zero.
   Copyright (C) 2011-2019 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 2011.

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

/* Based on a version which carries the following copyright:  */

/*
 * ====================================================
 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
 *
 * Developed at SunPro, a Sun Microsystems, Inc. business.
 * Permission to use, copy, modify, and distribute this
 * software is freely granted, provided that this notice
 * is preserved.
 * ====================================================
 */

#include <math.h>
#include <math_private.h>
#include <stdint.h>
#include <libm-alias-double.h>
#include <math-use-builtins.h>

/*
 * floor(x)
 * Return x rounded toward -inf to integral value
 * Method:
 *	Bit twiddling.
 */

double
__floor (double x)
{
#if USE_FLOOR_BUILTIN
  return __builtin_floor (x);
#else
  /* Use generic implementation.  */
  int64_t i0;
  EXTRACT_WORDS64 (i0, x);
  int32_t j0 = ((i0 >> 52) & 0x7ff) - 0x3ff;
  if (__glibc_likely (j0 < 52))
    {
      if (j0 < 0)
	{
	  /* return 0 * sign (x) if |x| < 1  */
	  if (i0 >= 0)
	    i0 = 0;
	  else if ((i0 & 0x7fffffffffffffffl) != 0)
	    i0 = 0xbff0000000000000l;
	}
      else
	{
	  uint64_t i = 0x000fffffffffffffl >> j0;
	  if ((i0 & i) == 0)
	    return x;			 /* x is integral */
	  if (i0 < 0)
	    i0 += 0x0010000000000000l >> j0;
	  i0 &= ~i;
	}
      INSERT_WORDS64 (x, i0);
    }
  else if (j0 == 0x400)
    return x + x;			/* inf or NaN */
  return x;
#endif /* ! USE_FLOOR_BUILTIN  */
}
#ifndef __floor
libm_alias_double (__floor, floor)
#endif