port/fp/finite.c

	finite.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
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 * CDDL HEADER END
 */
/*
 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

/*  Copyright (c) 1988 AT&T */
/*    All Rights Reserved   */


/*  IEEE recommended functions */

#pragma weak finite = _finite
#pragma weak fpclass = _fpclass
#pragma weak unordered = _unordered

#include "synonyms.h"
#include <values.h>
#include "fpparts.h"

#define P754_NOFAULT 1      /* avoid generating extra code */
#include <ieeefp.h>

/*
 * FINITE(X)
 * finite(x) returns 1 if x > -inf and x < +inf and 0 otherwise
 * NaN returns 0
 */

int
finite(double x)
{
    return ((EXPONENT(x) != MAXEXP));
}

/*
 * UNORDERED(x,y)
 * unordered(x,y) returns 1 if x is unordered with y, otherwise
 * it returns 0; x is unordered with y if either x or y is NAN
 */

int
unordered(double x, double y)
{
    if ((EXPONENT(x) == MAXEXP) && (HIFRACTION(x) || LOFRACTION(x)))
        return (1);
    if ((EXPONENT(y) == MAXEXP) && (HIFRACTION(y) || LOFRACTION(y)))
        return (1);
    return (0);
}

/*
 * FPCLASS(X)
 * fpclass(x) returns the floating point class x belongs to
 */

fpclass_t
fpclass(double x)
{
    int sign, exp;

    exp = EXPONENT(x);
    sign = SIGNBIT(x);
    if (exp == 0) { /* de-normal or zero */
        if (HIFRACTION(x) || LOFRACTION(x)) /* de-normal */
            return (sign ? FP_NDENORM : FP_PDENORM);
        else
            return (sign ? FP_NZERO : FP_PZERO);
    }
    if (exp == MAXEXP) { /* infinity or NaN */
        if ((HIFRACTION(x) == 0) && (LOFRACTION(x) == 0)) /* infinity */
            return (sign ? FP_NINF : FP_PINF);
        else
            if (QNANBIT(x))
            /* hi-bit of mantissa set - quiet nan */
                return (FP_QNAN);
            else    return (FP_SNAN);
    }
    /* if we reach here we have non-zero normalized number */
    return (sign ? FP_NNORM : FP_PNORM);
}