xref: /freebsd/lib/msun/src/s_nearbyint.c (revision 0dd5a5603e7a33d976f8e6015620bbc79839c609)
19428e108SDavid Schultz /*-
2*4d846d26SWarner Losh  * SPDX-License-Identifier: BSD-2-Clause
35e53a4f9SPedro F. Giffuni  *
49428e108SDavid Schultz  * Copyright (c) 2004 David Schultz <das@FreeBSD.ORG>
59428e108SDavid Schultz  * All rights reserved.
69428e108SDavid Schultz  *
79428e108SDavid Schultz  * Redistribution and use in source and binary forms, with or without
89428e108SDavid Schultz  * modification, are permitted provided that the following conditions
99428e108SDavid Schultz  * are met:
109428e108SDavid Schultz  * 1. Redistributions of source code must retain the above copyright
119428e108SDavid Schultz  *    notice, this list of conditions and the following disclaimer.
129428e108SDavid Schultz  * 2. Redistributions in binary form must reproduce the above copyright
139428e108SDavid Schultz  *    notice, this list of conditions and the following disclaimer in the
149428e108SDavid Schultz  *    documentation and/or other materials provided with the distribution.
159428e108SDavid Schultz  *
169428e108SDavid Schultz  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
179428e108SDavid Schultz  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
189428e108SDavid Schultz  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
199428e108SDavid Schultz  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
209428e108SDavid Schultz  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
219428e108SDavid Schultz  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
229428e108SDavid Schultz  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
239428e108SDavid Schultz  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
249428e108SDavid Schultz  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
259428e108SDavid Schultz  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
269428e108SDavid Schultz  * SUCH DAMAGE.
279428e108SDavid Schultz  */
289428e108SDavid Schultz 
299428e108SDavid Schultz #include <fenv.h>
309428e108SDavid Schultz #include <math.h>
319428e108SDavid Schultz 
329428e108SDavid Schultz /*
339428e108SDavid Schultz  * We save and restore the floating-point environment to avoid raising
349428e108SDavid Schultz  * an inexact exception.  We can get away with using fesetenv()
359428e108SDavid Schultz  * instead of feclearexcept()/feupdateenv() to restore the environment
369428e108SDavid Schultz  * because the only exception defined for rint() is overflow, and
379428e108SDavid Schultz  * rounding can't overflow as long as emax >= p.
387dbbb6ddSDavid Schultz  *
397dbbb6ddSDavid Schultz  * The volatile keyword is needed below because clang incorrectly assumes
407dbbb6ddSDavid Schultz  * that rint won't raise any floating-point exceptions. Declaring ret volatile
417dbbb6ddSDavid Schultz  * is sufficient to trick the compiler into doing the right thing.
429428e108SDavid Schultz  */
439428e108SDavid Schultz #define	DECL(type, fn, rint)	\
449428e108SDavid Schultz type				\
459428e108SDavid Schultz fn(type x)			\
469428e108SDavid Schultz {				\
477dbbb6ddSDavid Schultz 	volatile type ret;	\
489428e108SDavid Schultz 	fenv_t env;		\
499428e108SDavid Schultz 				\
509428e108SDavid Schultz 	fegetenv(&env);		\
519428e108SDavid Schultz 	ret = rint(x);		\
529428e108SDavid Schultz 	fesetenv(&env);		\
539428e108SDavid Schultz 	return (ret);		\
549428e108SDavid Schultz }
559428e108SDavid Schultz 
569428e108SDavid Schultz DECL(double, nearbyint, rint)
579428e108SDavid Schultz DECL(float, nearbyintf, rintf)
58d3f9671aSDavid Schultz DECL(long double, nearbyintl, rintl)
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