freebsd-dev/lib/libc_r/arch/i386/_atomic_lock.S
John Birrell 7d24d0302f Delete the atomic unlock function since it is no longer required.
Simplify the atomic lock to just write a value of 1 to the lock instead
of taking the value passed by the caller (which just confused things).
1998-06-09 08:25:41 +00:00

46 lines
1.6 KiB
ArmAsm

/*
* Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>.
* All rights reserved.
* copyright Douglas Santry 1996
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the above copyright is retained
* in the source form.
*
* THIS SOFTWARE IS PROVIDED BY Douglas Santry AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL Douglas Santry OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: _atomic_lock.S,v 1.1 1998/04/29 09:36:03 jb Exp $
*
*/
#if defined(LIBC_RCS) && !defined(lint)
.text
.asciz "$Id: _atomic_lock.S,v 1.1 1998/04/29 09:36:03 jb Exp $"
#endif /* LIBC_RCS and not lint */
#include "DEFS.h"
/*
* Atomicly lock a location with an identifier provided the location
* is not currently locked.
*
* long _atomic_lock(long *);
* eax will contain the return value (zero if lock obtained).
*/
ENTRY(_atomic_lock)
movl 4(%esp), %ecx
movl $1, %eax
xchg %eax, (%ecx)
ret