| /* Handle floating-point rounding mode within libc. |
| Copyright (C) 2012-2014 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 */ |