2 * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>.
4 * copyright Douglas Santry 1996
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the above copyright is retained
10 * THIS SOFTWARE IS PROVIDED BY Douglas Santry AND CONTRIBUTORS ``AS IS'' AND
11 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
12 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
13 * ARE DISCLAIMED. IN NO EVENT SHALL Douglas Santry OR CONTRIBUTORS BE LIABLE
14 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
15 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
16 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
17 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
18 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
19 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
22 * $FreeBSD: src/lib/libc_r/arch/i386/_atomic_lock.S,v 1.3 1999/08/28 00:03:01 peter Exp $
25 #include <machine/asm.h>
28 * Atomicly lock a location with an identifier provided the location
29 * is not currently locked.
31 * long _atomic_lock(long *);
32 * rax will contain the return value (zero if lock obtained).