usr/src/lib/libc/port/gen/getisax.c

   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  * Copyright (c) 2012, Joyent, Inc.  All rights reserved.
  28  */
  29
  30 #pragma weak _getisax = getisax
  31
  32 #include "lint.h"
  33 #include <sys/types.h>
  34 #include <sys/auxv.h>
  35
  36 extern long ___getauxval(int type);
  37
  38 /*
  39  * Return the 'hwcap' vector of bits in the AT_SUN_HWCAP and AT_SUN_HWCAP2 aux
  40  * vector entries. Therefore there are two words of bits here.
  41  *
  42  * As a convenience, the routine returns the maximum number of array alements
  43  * that may contain non-zero values.
  44  */
  45 uint_t
  46 getisax(uint32_t *array, uint_t n)
  47 {
  48         int i;
  49         static uint32_t auxv_hwcap;
  50         static uint32_t auxv_hwcap_2;
  51
  52         if (auxv_hwcap == 0) {
  53                 auxv_hwcap = (uint32_t)___getauxval(AT_SUN_HWCAP);
  54                 auxv_hwcap_2 = (uint32_t)___getauxval(AT_SUN_HWCAP2);
  55         }
  56
  57         if (n > 0) {
  58                 if (n >= 1)
  59                         array[0] = auxv_hwcap;
  60                 if (n >= 2)
  61                         array[1] = auxv_hwcap_2;
  62                 for (i = 2; i < n; i++)
  63                         array[i] = 0;
  64         }
  65
  66         return (auxv_hwcap == 0 ? 0 : n >= 2 ? 2 : 1);
  67 }