1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2004 David Schultz <das@FreeBSD.ORG>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD$");
31
32#include <fenv.h>
33#include <math.h>
34
35/*
36 * We save and restore the floating-point environment to avoid raising
37 * an inexact exception.  We can get away with using fesetenv()
38 * instead of feclearexcept()/feupdateenv() to restore the environment
39 * because the only exception defined for rint() is overflow, and
40 * rounding can't overflow as long as emax >= p.
41 *
42 * The volatile keyword is needed below because clang incorrectly assumes
43 * that rint won't raise any floating-point exceptions. Declaring ret volatile
44 * is sufficient to trick the compiler into doing the right thing.
45 */
46#define	DECL(type, fn, rint)	\
47type				\
48fn(type x)			\
49{				\
50	volatile type ret;	\
51	fenv_t env;		\
52				\
53	fegetenv(&env);		\
54	ret = rint(x);		\
55	fesetenv(&env);		\
56	return (ret);		\
57}
58
59DECL(double, nearbyint, rint)
60DECL(float, nearbyintf, rintf)
61DECL(long double, nearbyintl, rintl)
62