common/m9x/truncl.c

	truncl.c revision 25c28e83beb90e7c80452a7c818c5e6f73a07dc8
/*
 * 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 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#if defined(ELFOBJ)
#pragma weak truncl = __truncl
#endif

#include "libm.h"

#if defined(__sparc)
long double
truncl(long double x) {
    union {
        unsigned i[4];
        long double q;
    } xx;
    unsigned hx, sx;
    int j;

    xx.q = x;
    sx = xx.i[0] & 0x80000000;
    hx = xx.i[0] & ~0x80000000;

    /* handle trivial cases */
    if (hx >= 0x406f0000) /* |x| >= 2^112 + ... or x is nan */
        return (hx >= 0x7fff0000 ? x + x : x);

    /* handle |x| < 1 */
    if (hx < 0x3fff0000)
        return (sx ? -0.0L : 0.0L);

    j = 0x406f - (hx >> 16);        /* 1 <= j <= 112 */
    xx.i[0] = hx;
    if (j >= 96) {              /* 96 <= j <= 112 */
        xx.i[0] &= ~((1 << (j - 96)) - 1);
        xx.i[1] = xx.i[2] = xx.i[3] = 0;
    } else if (j >= 64) {           /* 64 <= j <= 95 */
        xx.i[1] &= ~((1 << (j - 64)) - 1);
        xx.i[2] = xx.i[3] = 0;
    } else if (j >= 32) {           /* 32 <= j <= 63 */
        xx.i[2] &= ~((1 << (j - 32)) - 1);
        xx.i[3] = 0;
    } else                  /* 1 <= j <= 31 */
        xx.i[3] &= ~((1 << j) - 1);

    /* negate result if need be */
    if (sx)
        xx.i[0] |= 0x80000000;
    return (xx.q);
}
#elif defined(__x86)
long double
truncl(long double x) {
    union {
        unsigned i[3];
        long double e;
    } xx;
    int ex, sx, i;

    xx.e = x;
    ex = xx.i[2] & 0x7fff;
    sx = xx.i[2] & 0x8000;
    if (ex < 0x403e) {  /* |x| < 2^63 */
        if (ex < 0x3fff)    /* |x| < 1 */
            return (sx ? -0.0L : 0.0L);

        /* chop x at the integer bit */
        if (ex < 0x401e) {
            i = 1 << (0x401d - ex);
            xx.i[1] &= ~(i | (i - 1));
            xx.i[0] = 0;
        } else {
            i = 1 << (0x403d - ex);
            xx.i[0] &= ~(i | (i - 1));
        }
        return (xx.e);
    } else if (ex < 0x7fff) /* x is integral */
        return (x);
    else            /* inf or nan */
        return (x + x);
}
#else
#error Unknown architecture
#endif  /* defined(__sparc) || defined(__x86) */