lib/libm/src/s_nearbyint.c

/*-
 * Copyright (c) 2004 David Schultz <das@FreeBSD.ORG>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $FreeBSD: head/lib/msun/src/s_nearbyint.c 251024 2013-05-27 08:50:10Z das $
 */

#include <fenv.h>
#include <math.h>

/*
 * We save and restore the floating-point environment to avoid raising
 * an inexact exception.  We can get away with using fesetenv()
 * instead of feclearexcept()/feupdateenv() to restore the environment
 * because the only exception defined for rint() is overflow, and
 * rounding can't overflow as long as emax >= p.
 *
 * The volatile keyword is needed below because clang incorrectly assumes
 * that rint won't raise any floating-point exceptions. Declaring ret volatile
 * is sufficient to trick the compiler into doing the right thing.
 */
#define	DECL(type, fn, rint)	\
type				\
fn(type x)			\
{				\
	volatile type ret;	\
	fenv_t env;		\
				\
	fegetenv(&env);		\
	ret = rint(x);		\
	fesetenv(&env);		\
	return (ret);		\
}

DECL(double, nearbyint, rint)
DECL(float, nearbyintf, rintf)
DECL(long double, nearbyintl, rintl)
Commit	Line	Data
	1	/*-
	2	* Copyright (c) 2004 David Schultz <das@FreeBSD.ORG>
	3	* All rights reserved.
	4	*
	5	* Redistribution and use in source and binary forms, with or without
	6	* modification, are permitted provided that the following conditions
	7	* are met:
	8	* 1. Redistributions of source code must retain the above copyright
	9	* notice, this list of conditions and the following disclaimer.
	10	* 2. Redistributions in binary form must reproduce the above copyright
	11	* notice, this list of conditions and the following disclaimer in the
	12	* documentation and/or other materials provided with the distribution.
	13	*
	14	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	15	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	16	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	17	* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	18	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	19	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	20	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	21	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	22	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	23	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	24	* SUCH DAMAGE.
	25	*
	26	* $FreeBSD: head/lib/msun/src/s_nearbyint.c 251024 2013-05-27 08:50:10Z das $
	27	*/
	28
	29	#include <fenv.h>
	30	#include <math.h>
	31
	32	/*
	33	* We save and restore the floating-point environment to avoid raising
	34	* an inexact exception. We can get away with using fesetenv()
	35	* instead of feclearexcept()/feupdateenv() to restore the environment
	36	* because the only exception defined for rint() is overflow, and
	37	* rounding can't overflow as long as emax >= p.
	38	*
	39	* The volatile keyword is needed below because clang incorrectly assumes
	40	* that rint won't raise any floating-point exceptions. Declaring ret volatile
	41	* is sufficient to trick the compiler into doing the right thing.
	42	*/
	43	#define DECL(type, fn, rint) \
	44	type \
	45	fn(type x) \
	46	{ \
	47	volatile type ret; \
	48	fenv_t env; \
	49	\
	50	fegetenv(&env); \
	51	ret = rint(x); \
	52	fesetenv(&env); \
	53	return (ret); \
	54	}
	55
	56	DECL(double, nearbyint, rint)
	57	DECL(float, nearbyintf, rintf)
	58	DECL(long double, nearbyintl, rintl)