projects / dragonfly.git / blame
| Commit | Line | Data |
|---|---|---|
| 90637938 SS |
1 | /* |
| 2 | * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>. | |
| 3 | * All rights reserved. | |
| 4 | * copyright Douglas Santry 1996 | |
| 5 | * | |
| 6 | * Redistribution and use in source and binary forms, with or without | |
| 7 | * modification, are permitted provided that the above copyright is retained | |
| 8 | * in the source form. | |
| 9 | * | |
| 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 | |
| 20 | * SUCH DAMAGE. | |
| 21 | * | |
| 22 | * $FreeBSD: src/lib/libc_r/arch/i386/_atomic_lock.S,v 1.3 1999/08/28 00:03:01 peter Exp $ | |
| 90637938 SS |
23 | */ |
| 24 | ||
| eb9f4715 | 25 | #include <machine/asm.h> |
| 90637938 SS |
26 | |
| 27 | /* | |
| 28 | * Atomicly lock a location with an identifier provided the location | |
| 29 | * is not currently locked. | |
| 30 | * | |
| 31 | * long _atomic_lock(long *); | |
| 32 | * rax will contain the return value (zero if lock obtained). | |
| 33 | */ | |
| 34 | ENTRY(_atomic_lock) | |
| 35 | movq $1,%rax | |
| 36 | xchgq %rax,(%rdi) | |
| 37 | ret | |
| 38 |