xref: /freebsd/lib/msun/src/s_lrint.c (revision 4d846d260e2b9a3d4d0a701462568268cbfe7a5b)
110c9ffa4SDavid Schultz /*-
2*4d846d26SWarner Losh  * SPDX-License-Identifier: BSD-2-Clause
35e53a4f9SPedro F. Giffuni  *
410c9ffa4SDavid Schultz  * Copyright (c) 2005 David Schultz <das@FreeBSD.ORG>
510c9ffa4SDavid Schultz  * All rights reserved.
610c9ffa4SDavid Schultz  *
710c9ffa4SDavid Schultz  * Redistribution and use in source and binary forms, with or without
810c9ffa4SDavid Schultz  * modification, are permitted provided that the following conditions
910c9ffa4SDavid Schultz  * are met:
1010c9ffa4SDavid Schultz  * 1. Redistributions of source code must retain the above copyright
1110c9ffa4SDavid Schultz  *    notice, this list of conditions and the following disclaimer.
1210c9ffa4SDavid Schultz  * 2. Redistributions in binary form must reproduce the above copyright
1310c9ffa4SDavid Schultz  *    notice, this list of conditions and the following disclaimer in the
1410c9ffa4SDavid Schultz  *    documentation and/or other materials provided with the distribution.
1510c9ffa4SDavid Schultz  *
1610c9ffa4SDavid Schultz  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
1710c9ffa4SDavid Schultz  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
1810c9ffa4SDavid Schultz  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
1910c9ffa4SDavid Schultz  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
2010c9ffa4SDavid Schultz  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
2110c9ffa4SDavid Schultz  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
2210c9ffa4SDavid Schultz  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
2310c9ffa4SDavid Schultz  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
2410c9ffa4SDavid Schultz  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
2510c9ffa4SDavid Schultz  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
2610c9ffa4SDavid Schultz  * SUCH DAMAGE.
2710c9ffa4SDavid Schultz  */
2810c9ffa4SDavid Schultz 
2910c9ffa4SDavid Schultz #include <sys/cdefs.h>
3010c9ffa4SDavid Schultz #include <fenv.h>
3110c9ffa4SDavid Schultz #include <math.h>
3210c9ffa4SDavid Schultz 
3310c9ffa4SDavid Schultz #ifndef type
3410c9ffa4SDavid Schultz __FBSDID("$FreeBSD$");
3510c9ffa4SDavid Schultz #define type		double
3610c9ffa4SDavid Schultz #define	roundit		rint
3710c9ffa4SDavid Schultz #define dtype		long
3810c9ffa4SDavid Schultz #define	fn		lrint
3910c9ffa4SDavid Schultz #endif
4010c9ffa4SDavid Schultz 
4110c9ffa4SDavid Schultz /*
4210c9ffa4SDavid Schultz  * C99 says we should not raise a spurious inexact exception when an
4310c9ffa4SDavid Schultz  * invalid exception is raised.  Unfortunately, the set of inputs
4410c9ffa4SDavid Schultz  * that overflows depends on the rounding mode when 'dtype' has more
4510c9ffa4SDavid Schultz  * significant bits than 'type'.  Hence, we bend over backwards for the
4610c9ffa4SDavid Schultz  * sake of correctness; an MD implementation could be more efficient.
4710c9ffa4SDavid Schultz  */
4810c9ffa4SDavid Schultz dtype
4910c9ffa4SDavid Schultz fn(type x)
5010c9ffa4SDavid Schultz {
5110c9ffa4SDavid Schultz 	fenv_t env;
5210c9ffa4SDavid Schultz 	dtype d;
5310c9ffa4SDavid Schultz 
5410c9ffa4SDavid Schultz 	feholdexcept(&env);
5510c9ffa4SDavid Schultz 	d = (dtype)roundit(x);
5610c9ffa4SDavid Schultz 	if (fetestexcept(FE_INVALID))
5710c9ffa4SDavid Schultz 		feclearexcept(FE_INEXACT);
5810c9ffa4SDavid Schultz 	feupdateenv(&env);
5910c9ffa4SDavid Schultz 	return (d);
6010c9ffa4SDavid Schultz }
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