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/*
* 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 scalbnl = __scalbnl
#endif
#include "libm.h"
#include <float.h> /* LDBL_MAX, LDBL_MIN */
#include <stdlib.h> /* abs */
#if defined(__sparc)
#define XSET_EXP(k, x) ((int *) &x)[0] = (((int *) &x)[0] & ~0x7fff0000) | \
(k << 16)
#define ISINFNANL(k, x) (k == 0x7fff)
#define XTWOT_OFFSET 113
static const long double xtwot = 10384593717069655257060992658440192.0L,
/* 2^113 */
twomtm1 = 4.814824860968089632639944856462318296E-35L; /* 2^-114 */
#elif defined(__x86)
#define XSET_EXP(k, x) ((int *) &x)[2] = (((int *) &x)[2] & ~0x7fff) | k
#if defined(HANDLE_UNSUPPORTED)
#define ISINFNANL(k, x) (k == 0x7fff || k != 0 && \
(((int *) &x)[1] & 0x80000000) == 0)
#else
#define ISINFNANL(k, x) (k == 0x7fff)
#endif
#define XTWOT_OFFSET 64
static const long double xtwot = 18446744073709551616.0L, /* 2^64 */
twomtm1 = 2.7105054312137610850186E-20L; /* 2^-65 */
#endif
long double
scalbnl(long double x, int n) {
int k = XBIASED_EXP(x);
if (ISINFNANL(k, x))
return (x + x);
if (ISZEROL(x) || n == 0)
return (x);
if (k == 0) {
x *= xtwot;
k = XBIASED_EXP(x) - XTWOT_OFFSET;
}
if ((unsigned) abs(n) >= 131072) /* cast to unsigned for -2^31 */
n >>= 1; /* avoid subsequent integer overflow */
k += n;
if (k > 0x7ffe)
return (LDBL_MAX * copysignl(LDBL_MAX, x));
if (k <= -XTWOT_OFFSET - 1)
return (LDBL_MIN * copysignl(LDBL_MIN, x));
if (k > 0) {
XSET_EXP(k, x);
return (x);
}
k += XTWOT_OFFSET + 1;
XSET_EXP(k, x);
return (x * twomtm1);
}
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