/* @(#)s_ceil.c 5.1 93/09/24 */

/*

 * ====================================================

 * 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.

 * ====================================================

 */

/*

 * ceil(x)

 * Return x rounded toward -inf to integral value

 * Method:

 *	Bit twiddling.

 */

#include <math.h>

#include <math_private.h>

#include <libm-alias-double.h>

double

__ceil (double x)

{

  int32_t i0, i1, j0;

  uint32_t i, j;

  EXTRACT_WORDS (i0, i1, x);

  j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;

  if (j0 < 20)

    {

      if (j0 < 0)

	{

	  /* return 0*sign(x) if |x|<1 */

	  if (i0 < 0)

	    {

	      i0 = 0x80000000; i1 = 0;

	    }

	  else if ((i0 | i1) != 0)

	    {

	      i0 = 0x3ff00000; i1 = 0;

	    }

	}

      else

	{

	  i = (0x000fffff) >> j0;

	  if (((i0 & i) | i1) == 0)

	    return x;                        /* x is integral */

	  if (i0 > 0)

	    i0 += (0x00100000) >> j0;

	  i0 &= (~i); i1 = 0;

	}

    }

  else if (j0 > 51)

    {

      if (j0 == 0x400)

	return x + x;                   /* inf or NaN */

      else

	return x;                       /* x is integral */

    }

  else

    {

      i = ((uint32_t) (0xffffffff)) >> (j0 - 20);

      if ((i1 & i) == 0)

	return x;                       /* x is integral */

      if (i0 > 0)

	{

	  if (j0 == 20)

	    i0 += 1;

	  else

	    {

	      j = i1 + (1 << (52 - j0));

	      if (j < i1)

		i0 += 1;                /* got a carry */

	      i1 = j;

	    }

	}

      i1 &= (~i);

    }

  INSERT_WORDS (x, i0, i1);

  return x;

}

#ifndef __ceil

libm_alias_double (__ceil, ceil)

#endif