xref: /titanic_51/usr/src/lib/libm/common/m9x/scalblnl.c (revision ddc0e0b53c661f6e439e3b7072b3ef353eadb4af)
125c28e83SPiotr Jasiukajtis /*
225c28e83SPiotr Jasiukajtis  * CDDL HEADER START
325c28e83SPiotr Jasiukajtis  *
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525c28e83SPiotr Jasiukajtis  * Common Development and Distribution License (the "License").
625c28e83SPiotr Jasiukajtis  * You may not use this file except in compliance with the License.
725c28e83SPiotr Jasiukajtis  *
825c28e83SPiotr Jasiukajtis  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
925c28e83SPiotr Jasiukajtis  * or http://www.opensolaris.org/os/licensing.
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2125c28e83SPiotr Jasiukajtis 
2225c28e83SPiotr Jasiukajtis /*
2325c28e83SPiotr Jasiukajtis  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
2425c28e83SPiotr Jasiukajtis  */
2525c28e83SPiotr Jasiukajtis /*
2625c28e83SPiotr Jasiukajtis  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
2725c28e83SPiotr Jasiukajtis  * Use is subject to license terms.
2825c28e83SPiotr Jasiukajtis  */
2925c28e83SPiotr Jasiukajtis 
30*ddc0e0b5SRichard Lowe #pragma weak __scalblnl = scalblnl
3125c28e83SPiotr Jasiukajtis 
3225c28e83SPiotr Jasiukajtis #include "libm.h"
3325c28e83SPiotr Jasiukajtis #include <float.h>		/* LDBL_MAX, LDBL_MIN */
3425c28e83SPiotr Jasiukajtis 
3525c28e83SPiotr Jasiukajtis #if defined(__sparc)
3625c28e83SPiotr Jasiukajtis #define	XSET_EXP(k, x)	((int *) &x)[0] = (((int *) &x)[0] & ~0x7fff0000) | \
3725c28e83SPiotr Jasiukajtis 				(k << 16)
3825c28e83SPiotr Jasiukajtis #define	ISINFNANL(k, x)	(k == 0x7fff)
3925c28e83SPiotr Jasiukajtis #define	XTWOT_OFFSET	113
4025c28e83SPiotr Jasiukajtis static const long double xtwot = 10384593717069655257060992658440192.0L,
4125c28e83SPiotr Jasiukajtis 								/* 2^113 */
4225c28e83SPiotr Jasiukajtis 	twomtm1 = 4.814824860968089632639944856462318296E-35L;	/* 2^-114 */
4325c28e83SPiotr Jasiukajtis #elif defined(__x86)
4425c28e83SPiotr Jasiukajtis #define	XSET_EXP(k, x)	((int *) &x)[2] = (((int *) &x)[2] & ~0x7fff) | k
4525c28e83SPiotr Jasiukajtis #if defined(HANDLE_UNSUPPORTED)
4625c28e83SPiotr Jasiukajtis #define      ISINFNANL(k, x) (k == 0x7fff || \
4725c28e83SPiotr Jasiukajtis                         (k != 0 && (((int *) &x)[1] & 0x80000000) == 0))
4825c28e83SPiotr Jasiukajtis #else
4925c28e83SPiotr Jasiukajtis #define	ISINFNANL(k, x)	(k == 0x7fff)
5025c28e83SPiotr Jasiukajtis #endif
5125c28e83SPiotr Jasiukajtis #define	XTWOT_OFFSET	64
5225c28e83SPiotr Jasiukajtis static const long double xtwot = 18446744073709551616.0L,	/* 2^64 */
5325c28e83SPiotr Jasiukajtis 	twomtm1 = 2.7105054312137610850186E-20L;		/* 2^-65 */
5425c28e83SPiotr Jasiukajtis #endif
5525c28e83SPiotr Jasiukajtis 
5625c28e83SPiotr Jasiukajtis long double
5725c28e83SPiotr Jasiukajtis scalblnl(long double x, long n) {
5825c28e83SPiotr Jasiukajtis 	int k = XBIASED_EXP(x);
5925c28e83SPiotr Jasiukajtis 
6025c28e83SPiotr Jasiukajtis 	if (ISINFNANL(k, x))
6125c28e83SPiotr Jasiukajtis 		return (x + x);
6225c28e83SPiotr Jasiukajtis 	if (ISZEROL(x) || n == 0)
6325c28e83SPiotr Jasiukajtis 		return (x);
6425c28e83SPiotr Jasiukajtis 	if (k == 0) {
6525c28e83SPiotr Jasiukajtis 		x *= xtwot;
6625c28e83SPiotr Jasiukajtis 		k = XBIASED_EXP(x) - XTWOT_OFFSET;
6725c28e83SPiotr Jasiukajtis 	}
6825c28e83SPiotr Jasiukajtis 	k += (int) n;
6925c28e83SPiotr Jasiukajtis 	if (n > 50000 || k > 0x7ffe)
7025c28e83SPiotr Jasiukajtis 		return (LDBL_MAX * copysignl(LDBL_MAX, x));
7125c28e83SPiotr Jasiukajtis 	if (n < -50000 || k <= -XTWOT_OFFSET - 1)
7225c28e83SPiotr Jasiukajtis 		return (LDBL_MIN * copysignl(LDBL_MIN, x));
7325c28e83SPiotr Jasiukajtis 	if (k > 0) {
7425c28e83SPiotr Jasiukajtis 		XSET_EXP(k, x);
7525c28e83SPiotr Jasiukajtis 		return (x);
7625c28e83SPiotr Jasiukajtis 	}
7725c28e83SPiotr Jasiukajtis 	k += XTWOT_OFFSET + 1;
7825c28e83SPiotr Jasiukajtis 	XSET_EXP(k, x);
7925c28e83SPiotr Jasiukajtis 	return (x * twomtm1);
8025c28e83SPiotr Jasiukajtis }
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