xref: /titanic_41/usr/src/lib/libc/port/gen/getisax.c (revision e4b86885570d77af552e9cf94f142f4d744fb8c8)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 #pragma weak _getisax = getisax
30 
31 #include "lint.h"
32 #include <sys/types.h>
33 #include <sys/auxv.h>
34 
35 extern long ___getauxval(int type);
36 
37 /*
38  * Return the 'hwcap' vector of bits in the AT_SUN_HWCAP aux vector entry.
39  *
40  * At this time, the worst-case implementation only uses 13 bits, but for
41  * future-proofing, we allow the interface to describe an arbitrary length
42  * array of 32-bit words.
43  *
44  * As a convenience, the routine returns the maximum number of array alements
45  * that may contain non-zero values.
46  */
47 uint_t
48 getisax(uint32_t *array, uint_t n)
49 {
50 	int i;
51 	static uint32_t auxv_hwcap;
52 
53 	if (auxv_hwcap == 0)
54 		auxv_hwcap = (uint32_t)___getauxval(AT_SUN_HWCAP);
55 
56 	if (n > 0) {
57 		if (n >= 1)
58 			array[0] = auxv_hwcap;
59 		for (i = 1; i < n; i++)
60 			array[i] = 0;
61 	}
62 	return (auxv_hwcap == 0 ? 0 : 1);
63 }
64