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

Revision 1.4, Fri Aug 26 08:20:31 2016 UTC (7 years, 7 months ago) by christos
Branch: MAIN
CVS Tags: 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-20170426, pgoyette-localcount-20170320, pgoyette-localcount-20170107, pgoyette-localcount-20161104, 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-10-base, netbsd-10-0-RELEASE, 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
Changes since 1.3: +6 -2 lines 

fix sun2 build; only IEEE math platform (and coldfire) without fenv

/*	$NetBSD: s_ilogbl.c,v 1.4 2016/08/26 08:20:31 christos Exp $	*/

/*-
 * Copyright (c) 2011 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Joerg Sonnenberger.
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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>
__RCSID("$NetBSD: s_ilogbl.c,v 1.4 2016/08/26 08:20:31 christos Exp $");

#include "namespace.h"

#include <float.h>
#include <math.h>
#define __TEST_FENV
#include <fenv.h>
#ifndef __HAVE_FENV
#define feraiseexcept(a)
#endif
#include <machine/ieee.h>

#ifdef __HAVE_LONG_DOUBLE

#if LDBL_MANT_DIG == 64
#define	FROM_UNDERFLOW	0x1p65L
#elif LDBL_MANT_DIG == 113
#define	FROM_UNDERFLOW	0x1p114L
#else
#error Unsupported long double format
#endif

int
ilogbl(long double x)
{
	union ieee_ext_u u;

	if (x == 0.0L) {
		feraiseexcept(FE_INVALID);
		return FP_ILOGB0;	/* ilogbl(0) = 0x80000001 */
	}

	u.extu_ld = x;

	if (u.extu_ext.ext_exp == EXT_EXP_INFNAN) {
		feraiseexcept(FE_INVALID);
		return isnan(x) ? FP_ILOGBNAN : INT_MAX;
	}

	if (u.extu_ext.ext_exp == 0) {
		/*
		 * Scale denormalized numbers slightly,
		 * so that they are normal.
		 */
		u.extu_ld *= FROM_UNDERFLOW;
		return u.extu_ext.ext_exp - EXT_EXP_BIAS - LDBL_MANT_DIG - 1;
	}
	return u.extu_ext.ext_exp - EXT_EXP_BIAS;

}

#endif