/* Compute 2^x.

   Copyright (C) 2012-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   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 <math-underflow.h>

#include <float.h>

FLOAT

M_DECL_FUNC (__ieee754_exp2) (FLOAT x)

{

  if (__glibc_likely (isless (x, (FLOAT) M_MAX_EXP)))

    {

      if (__builtin_expect (isgreaterequal (x, (FLOAT) (M_MIN_EXP - M_MANT_DIG

							- 1)), 1))

	{

	  int intx = (int) x;

	  FLOAT fractx = x - intx;

	  FLOAT result;

	  if (M_FABS (fractx) < M_EPSILON / 4)

	    result = M_SCALBN (1 + fractx, intx);

	  else

	    result = M_SCALBN (M_EXP (M_MLIT (M_LN2) * fractx), intx);

	  math_check_force_underflow_nonneg (result);

	  return result;

	}

      else

	{

	  /* Underflow or exact zero.  */

	  if (isinf (x))

	    return 0;

	  else

	    return M_MIN * M_MIN;

	}

    }

  else

    /* Infinity, NaN or overflow.  */

    return M_MAX * x;

}

declare_mgen_finite_alias (__ieee754_exp2, __exp2)