/* Handle floating-point rounding mode within libc.

   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/>.  */

#ifndef _ROUNDING_MODE_H

#define _ROUNDING_MODE_H	1

#include <fenv.h>

#include <stdbool.h>

#include <stdlib.h>

/* Get the architecture-specific definition of how to determine the

   rounding mode in libc.  This header must also define the FE_*

   macros for any standard rounding modes the architecture does not

   have in <fenv.h>, to arbitrary distinct values.  */

#include <get-rounding-mode.h>

/* Return true if a number should be rounded away from zero in

   rounding mode MODE, false otherwise.  NEGATIVE is true if the

   number is negative, false otherwise.  LAST_DIGIT_ODD is true if the

   last digit of the truncated value (last bit for binary) is odd,

   false otherwise.  HALF_BIT is true if the number is at least half

   way from the truncated value to the next value with the

   least-significant digit in the same place, false otherwise.

   MORE_BITS is true if the number is not exactly equal to the

   truncated value or the half-way value, false otherwise.  */

static bool

round_away (bool negative, bool last_digit_odd, bool half_bit, bool more_bits,

	    int mode)

{

  switch (mode)

    {

    case FE_DOWNWARD:

      return negative && (half_bit || more_bits);

    case FE_TONEAREST:

      return half_bit && (last_digit_odd || more_bits);

    case FE_TOWARDZERO:

      return false;

    case FE_UPWARD:

      return !negative && (half_bit || more_bits);

    default:

      abort ();

    }

}

#endif /* rounding-mode.h */