Permalink
Cannot retrieve contributors at this time
Name already in use
A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?
glibc/include/rounding-mode.h
Go to fileThis commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
65 lines (52 sloc)
2.24 KB
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
/* Handle floating-point rounding mode within libc. | |
Copyright (C) 2012-2016 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 */ |