usr/src/lib/libc/amd64/gen/lock.s

   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  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26         .file   "lock.s"
  27
  28 #include "SYS.h"
  29
  30 /
  31 / _lock_try(lp)
  32 /       - returns non-zero on success.
  33 /
  34         ENTRY(_lock_try)
  35         movl    $1,%eax
  36         xchgb   %al, (%rdi)
  37         xorb    $1, %al
  38         ret
  39         SET_SIZE(_lock_try)
  40
  41 /
  42 / _lock_clear(lp)
  43 /       - clear lock and force it to appear unlocked in memory.
  44 /
  45         ENTRY(_lock_clear)
  46         movb    $0, (%rdi)
  47         ret
  48         SET_SIZE(_lock_clear)