common/Q/rndintl.c

	rndintl.c revision ddc0e0b53c661f6e439e3b7072b3ef353eadb4af
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (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]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
 */
/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * aintl(x) return x chopped to integral value
 * anintl(x)    return sign(x)*(|x|+0.5) chopped to integral value
 * irintl(x)    return rint(x) in integer format
 * nintl(x) return anint(x) in integer format
 *
 * NOTE: aintl(x), anintl(x), ceill(x), floorl(x), and rintl(x) return result
 * with the same sign as x's,  including 0.0.
 */

#include "libm.h"
#include "longdouble.h"

extern enum fp_direction_type __swapRD(enum fp_direction_type);

static const long double qone = 1.0L, qhalf = 0.5L, qmhalf = -0.5L;

long double
aintl(long double x) {
    long double t, w;

    if (!finitel(x))
        return (x + x);
    w = fabsl(x);
    t = rintl(w);
    if (t <= w)
        return (copysignl(t, x));   /* NaN or already aint(|x|) */
    else    /* |t|>|x| case */
        return (copysignl(t - qone, x));    /* |t-1|*sign(x) */
}

long double
anintl(long double x) {
    long double t, w, z;

    if (!finitel(x))
        return (x + x);
    w = fabsl(x);
    t = rintl(w);
    if (t == w)
        return (copysignl(t, x));
    z = t - w;
    if (z > qhalf)
        t = t - qone;
    else if (z <= qmhalf)
        t = t + qone;
    return (copysignl(t, x));
}

int
irintl(long double x) {
    enum fp_direction_type rd;

    rd = __swapRD(fp_nearest);
    (void) __swapRD(rd);    /* restore Rounding Direction */
    switch (rd) {
    case fp_nearest:
        if (x < 2147483647.5L && x >= -2147483648.5L)
            return ((int)rintl(x));
        break;
    case fp_tozero:
        if (x < 2147483648.0L && x > -2147483649.0L)
            return ((int)rintl(x));
        break;
    case fp_positive:
        if (x <= 2147483647.0L && x > -2147483649.0L)
            return ((int)rintl(x));
        break;
    case fp_negative:
        if (x < 2147483648.0L && x >= -2147483648.0L)
            return ((int)rintl(x));
        break;
    }
    return ((int)copysignl(1.0e100L, x));
}

int
nintl(long double x) {
    if ((x < 2147483647.5L) && (x > -2147483648.5L))
        return ((int)anintl(x));
    else
        return ((int)copysignl(1.0e100L, x));
}