xref: /titanic_52/usr/src/lib/libm/common/C/significand.c (revision ddc0e0b53c661f6e439e3b7072b3ef353eadb4af)
125c28e83SPiotr Jasiukajtis /*
225c28e83SPiotr Jasiukajtis  * CDDL HEADER START
325c28e83SPiotr Jasiukajtis  *
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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.
1025c28e83SPiotr Jasiukajtis  * See the License for the specific language governing permissions
1125c28e83SPiotr Jasiukajtis  * and limitations under the License.
1225c28e83SPiotr Jasiukajtis  *
1325c28e83SPiotr Jasiukajtis  * When distributing Covered Code, include this CDDL HEADER in each
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1525c28e83SPiotr Jasiukajtis  * If applicable, add the following below this CDDL HEADER, with the
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1725c28e83SPiotr Jasiukajtis  * information: Portions Copyright [yyyy] [name of copyright owner]
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2025c28e83SPiotr Jasiukajtis  */
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 __significand = significand
3125c28e83SPiotr Jasiukajtis 
3225c28e83SPiotr Jasiukajtis #include "libm.h"
3325c28e83SPiotr Jasiukajtis 
3425c28e83SPiotr Jasiukajtis double
3525c28e83SPiotr Jasiukajtis significand(double x) {
3625c28e83SPiotr Jasiukajtis 	int ix = ((int *) &x)[HIWORD] & ~0x80000000;
3725c28e83SPiotr Jasiukajtis 
3825c28e83SPiotr Jasiukajtis 	/* weed out 0/+-Inf/NaN because C99 ilogb raises invalid on them */
3925c28e83SPiotr Jasiukajtis 	if ((ix | ((int *) &x)[LOWORD]) == 0 || ix >= 0x7ff00000)
4025c28e83SPiotr Jasiukajtis #if defined(FPADD_TRAPS_INCOMPLETE_ON_NAN)
4125c28e83SPiotr Jasiukajtis 		return ((ix & 0x80000) != 0 ? x : x + x);
4225c28e83SPiotr Jasiukajtis 		/* assumes sparc-like QNaN */
4325c28e83SPiotr Jasiukajtis #else
4425c28e83SPiotr Jasiukajtis 		return (x + x);
4525c28e83SPiotr Jasiukajtis #endif
4625c28e83SPiotr Jasiukajtis 	else
4725c28e83SPiotr Jasiukajtis 		return (scalbn(x, -ilogb(x)));
4825c28e83SPiotr Jasiukajtis }
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