common/m9x/scalblnl.c

25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis/*
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * CDDL HEADER START
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis *
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * The contents of this file are subject to the terms of the
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * Common Development and Distribution License (the "License").
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * You may not use this file except in compliance with the License.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis *
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * or http://www.opensolaris.org/os/licensing.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * See the License for the specific language governing permissions
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * and limitations under the License.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis *
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * When distributing Covered Code, include this CDDL HEADER in each
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * If applicable, add the following below this CDDL HEADER, with the
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * fields enclosed by brackets "[]" replaced with your own identifying
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * information: Portions Copyright [yyyy] [name of copyright owner]
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis *
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * CDDL HEADER END
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis/*
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis/*
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * Use is subject to license terms.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
ddc0e0b53c661f6e439e3b7072b3ef353eadb4afRichard Lowe#pragma weak __scalblnl = scalblnl
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#include "libm.h"
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#include <float.h>      /* LDBL_MAX, LDBL_MIN */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#if defined(__sparc)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#define XSET_EXP(k, x)  ((int *) &x)[0] = (((int *) &x)[0] & ~0x7fff0000) | \
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis                (k << 16)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#define ISINFNANL(k, x) (k == 0x7fff)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#define XTWOT_OFFSET    113
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtisstatic const long double xtwot = 10384593717069655257060992658440192.0L,
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis                                /* 2^113 */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis    twomtm1 = 4.814824860968089632639944856462318296E-35L;  /* 2^-114 */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#elif defined(__x86)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#define XSET_EXP(k, x)  ((int *) &x)[2] = (((int *) &x)[2] & ~0x7fff) | k
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#if defined(HANDLE_UNSUPPORTED)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#define      ISINFNANL(k, x) (k == 0x7fff || \
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis                        (k != 0 && (((int *) &x)[1] & 0x80000000) == 0))
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#else
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#define ISINFNANL(k, x) (k == 0x7fff)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#endif
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#define XTWOT_OFFSET    64
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtisstatic const long double xtwot = 18446744073709551616.0L,   /* 2^64 */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis    twomtm1 = 2.7105054312137610850186E-20L;        /* 2^-65 */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#endif
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtislong double
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtisscalblnl(long double x, long n) {
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis    int k = XBIASED_EXP(x);
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis    if (ISINFNANL(k, x))
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis        return (x + x);
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis    if (ISZEROL(x) || n == 0)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis        return (x);
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis    if (k == 0) {
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis        x *= xtwot;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis        k = XBIASED_EXP(x) - XTWOT_OFFSET;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis    }
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis    k += (int) n;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis    if (n > 50000 || k > 0x7ffe)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis        return (LDBL_MAX * copysignl(LDBL_MAX, x));
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis    if (n < -50000 || k <= -XTWOT_OFFSET - 1)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis        return (LDBL_MIN * copysignl(LDBL_MIN, x));
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis    if (k > 0) {
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis        XSET_EXP(k, x);
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis        return (x);
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis    }
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis    k += XTWOT_OFFSET + 1;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis    XSET_EXP(k, x);
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis    return (x * twomtm1);
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis}