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File: [cvs.NetBSD.org] / src / lib / libm / src / s_rintl.c (download)

Revision 1.5, Wed Aug 21 13:04:44 2013 UTC (10 years, 6 months ago) by martin
Branch: MAIN
CVS Tags: yamt-pagecache-base9, triaxx-drm, tls-maxphys-base, tls-earlyentropy-base, tls-earlyentropy, riastradh-xf86-video-intel-2-7-1-pre-2-21-15, riastradh-drm2-base3, prg-localcount2-base3, prg-localcount2-base2, prg-localcount2-base1, prg-localcount2-base, prg-localcount2, phil-wifi-base, phil-wifi-20200421, phil-wifi-20200411, phil-wifi-20200406, phil-wifi-20191119, phil-wifi-20190609, phil-wifi, pgoyette-localcount-base, pgoyette-localcount-20170426, pgoyette-localcount-20170320, pgoyette-localcount-20170107, pgoyette-localcount-20161104, pgoyette-localcount-20160806, pgoyette-localcount-20160726, pgoyette-localcount, pgoyette-compat-merge-20190127, pgoyette-compat-base, pgoyette-compat-20190127, pgoyette-compat-20190118, pgoyette-compat-1226, pgoyette-compat-1126, pgoyette-compat-1020, pgoyette-compat-0930, pgoyette-compat-0906, pgoyette-compat-0728, pgoyette-compat-0625, pgoyette-compat-0521, pgoyette-compat-0502, pgoyette-compat-0422, pgoyette-compat-0415, pgoyette-compat-0407, pgoyette-compat-0330, pgoyette-compat-0322, pgoyette-compat-0315, pgoyette-compat, perseant-stdc-iso10646-base, perseant-stdc-iso10646, netbsd-9-base, netbsd-9-3-RELEASE, netbsd-9-2-RELEASE, netbsd-9-1-RELEASE, netbsd-9-0-RELEASE, netbsd-9-0-RC2, netbsd-9-0-RC1, netbsd-9, netbsd-8-base, netbsd-8-2-RELEASE, netbsd-8-1-RELEASE, netbsd-8-1-RC1, netbsd-8-0-RELEASE, netbsd-8-0-RC2, netbsd-8-0-RC1, netbsd-8, netbsd-7-nhusb-base-20170116, netbsd-7-nhusb-base, netbsd-7-nhusb, netbsd-7-base, netbsd-7-2-RELEASE, netbsd-7-1-RELEASE, netbsd-7-1-RC2, netbsd-7-1-RC1, netbsd-7-1-2-RELEASE, netbsd-7-1-1-RELEASE, netbsd-7-1, netbsd-7-0-RELEASE, netbsd-7-0-RC3, netbsd-7-0-RC2, netbsd-7-0-RC1, netbsd-7-0-2-RELEASE, netbsd-7-0-1-RELEASE, netbsd-7-0, netbsd-7, netbsd-10-base, netbsd-10-0-RC6, netbsd-10-0-RC5, netbsd-10-0-RC4, netbsd-10-0-RC3, netbsd-10-0-RC2, netbsd-10-0-RC1, netbsd-10, matt-nb8-mediatek-base, matt-nb8-mediatek, localcount-20160914, is-mlppp-base, is-mlppp, cjep_sun2x-base1, cjep_sun2x-base, cjep_sun2x, cjep_staticlib_x-base1, cjep_staticlib_x-base, cjep_staticlib_x, bouyer-socketcan-base1, bouyer-socketcan-base, bouyer-socketcan, HEAD
Branch point for: yamt-pagecache
Changes since 1.4: +4 -2 lines

Add support for the long double format used on sparc64

/*	$NetBSD: s_rintl.c,v 1.5 2013/08/21 13:04:44 martin Exp $	*/

/*-
 * Copyright (c) 2008 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.
 */

#include <sys/cdefs.h>
#if 0
__FBSDID("$FreeBSD: src/lib/msun/src/s_rintl.c,v 1.5 2008/02/22 11:59:05 bde Exp $");
#else
__RCSID("$NetBSD: s_rintl.c,v 1.5 2013/08/21 13:04:44 martin Exp $");
#endif

#include <float.h>
#include <machine/ieee.h>

#include "math.h"
#include "math_private.h"

#ifdef __HAVE_LONG_DOUBLE
static const float
shift[2] = {
#if EXT_FRACBITS == 64
	0x1.0p63, -0x1.0p63
#elif EXT_FRACBITS == 113
	0x1.0p112, -0x1.0p112
#elif EXT_FRACBITS == 112
	0x1.0p111, -0x1.0p111
#else
#error "Unsupported long double format"
#endif
};
static const float zero[2] = { 0.0, -0.0 };

long double
rintl(long double x)
{
	union ieee_ext_u u;
	uint32_t expsign;
	int ex, sign;

	u.extu_ld = x;
	u.extu_ext.ext_frach &= ~0x80000000;
	expsign = u.extu_ext.ext_sign;
	ex = expsign & 0x7fff;

	if (ex >= EXT_EXP_BIAS + EXT_FRACBITS - 1) {
		if (ex == EXT_EXP_BIAS + EXT_FRACBITS)
			return (x + x);	/* Inf, NaN, or unsupported format */
		return (x);		/* finite and already an integer */
	}
	sign = expsign >> 15;

	/*
	 * The following code assumes that intermediate results are
	 * evaluated in long double precision. If they are evaluated in
	 * greater precision, double rounding may occur, and if they are
	 * evaluated in less precision (as on i386), results will be
	 * wildly incorrect.
	 */
	x += shift[sign];
	x -= shift[sign];

	/*
	 * If the result is +-0, then it must have the same sign as x, but
	 * the above calculation doesn't always give this.  Fix up the sign.
	 */
	if (ex < EXT_EXP_BIAS && x == 0.0L)
		return (zero[sign]);

	return (x);
}
#endif