[apple/xnu.git] / iokit / IOKit / i386 / IOSharedLockImp.h

/*
 * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code 
 * as defined in and that are subject to the Apple Public Source License 
 * Version 2.0 (the 'License'). You may not use this file except in 
 * compliance with the License.  The rights granted to you under the 
 * License may not be used to create, or enable the creation or 
 * redistribution of, unlawful or unlicensed copies of an Apple operating 
 * system, or to circumvent, violate, or enable the circumvention or 
 * violation of, any terms of an Apple operating system software license 
 * agreement.
 *
 * Please obtain a copy of the License at 
 * http://www.opensource.apple.com/apsl/ and read it before using this 
 * file.
 *
 * The Original Code and all software distributed under the License are 
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 
 * Please see the License for the specific language governing rights and 
 * limitations under the License.
 *
 * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
 */
/*
 * Copyright (c) 1998 Apple Computer, Inc.  All rights reserved. 
 *
 * HISTORY
 *
 */

/* 	Copyright (c) 1992 NeXT Computer, Inc.  All rights reserved. 
 *
 * EventShmemLock.h -	Shared memory area locks for use between the
 *			WindowServer and the Event Driver.
 *
 *
 * HISTORY
 * 29 April 1992    Mike Paquette at NeXT
 *      Created. 
 *
 * Multiprocessor locks used within the shared memory area between the
 * kernel and event system.  These must work in both user and kernel mode.
 * The locks are defined in an include file so they get exported to the local
 * include file area.
 *
 * This is basically a ripoff of the spin locks under the cthreads packages.
 */

#ifndef _IOKIT_IOSHAREDLOCKIMP_H
#define _IOKIT_IOSHAREDLOCKIMP_H

#include <architecture/i386/asm_help.h>

/* 
 * void
 * ev_lock(p)
 *	int *p;
 *
 * Lock the lock pointed to by p.  Spin (possibly forever) until the next
 * lock is available.
 */
	TEXT

#ifndef KERNEL
LEAF(_ev_lock, 0)
LEAF(_IOSpinLock, 0)
	movl		4(%esp), %ecx
0:
	xorl		%eax, %eax
	rep
	nop		/* pause for hyperthreaded CPU's */
	lock
	cmpxchgl	%ecx, (%ecx)
	jne		0b
	ret
END(_ev_lock)
#endif

/*
 * void
 * ev_unlock(p)
 *	int *p;
 *
 * Unlock the lock pointed to by p.
 */
LEAF(_ev_unlock, 0)
LEAF(_IOSpinUnlock, 0)
	movl		4(%esp), %ecx
	movl		$0, (%ecx)
	ret
END(_ev_unlock)


/*
 * int
 * ev_try_lock(p)
 *	int *p;
 *
 * Try to lock p.  Return zero if not successful.
 */

LEAF(_ev_try_lock, 0)
LEAF(_IOTrySpinLock, 0)
        movl            4(%esp), %ecx 
	xorl		%eax, %eax
        lock
        cmpxchgl        %ecx, (%ecx)
	jne	1f
	movl	$1, %eax		/* yes */
	ret
1:
	xorl	%eax, %eax		/* no */
END(_ev_try_lock)


#endif /* ! _IOKIT_IOSHAREDLOCKIMP_H */
Commit	Line	Data
1c79356b A	1	/*
	2	* Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
	3	*
8ad349bb	4	* @APPLE_LICENSE_OSREFERENCE_HEADER_START@
1c79356b	5	*
8ad349bb A	6	* This file contains Original Code and/or Modifications of Original Code
	7	* as defined in and that are subject to the Apple Public Source License
	8	* Version 2.0 (the 'License'). You may not use this file except in
	9	* compliance with the License. The rights granted to you under the
	10	* License may not be used to create, or enable the creation or
	11	* redistribution of, unlawful or unlicensed copies of an Apple operating
	12	* system, or to circumvent, violate, or enable the circumvention or
	13	* violation of, any terms of an Apple operating system software license
	14	* agreement.
	15	*
	16	* Please obtain a copy of the License at
	17	* http://www.opensource.apple.com/apsl/ and read it before using this
	18	* file.
	19	*
	20	* The Original Code and all software distributed under the License are
	21	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	22	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	23	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	24	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	25	* Please see the License for the specific language governing rights and
	26	* limitations under the License.
	27	*
	28	* @APPLE_LICENSE_OSREFERENCE_HEADER_END@
1c79356b A	29	*/
	30	/*
	31	* Copyright (c) 1998 Apple Computer, Inc. All rights reserved.
	32	*
	33	* HISTORY
	34	*
	35	*/
	36
	37	/* Copyright (c) 1992 NeXT Computer, Inc. All rights reserved.
	38	*
	39	* EventShmemLock.h - Shared memory area locks for use between the
	40	* WindowServer and the Event Driver.
	41	*
	42	*
	43	* HISTORY
	44	* 29 April 1992 Mike Paquette at NeXT
	45	* Created.
	46	*
	47	* Multiprocessor locks used within the shared memory area between the
	48	* kernel and event system. These must work in both user and kernel mode.
	49	* The locks are defined in an include file so they get exported to the local
	50	* include file area.
	51	*
	52	* This is basically a ripoff of the spin locks under the cthreads packages.
	53	*/
	54
	55	#ifndef _IOKIT_IOSHAREDLOCKIMP_H
	56	#define _IOKIT_IOSHAREDLOCKIMP_H
	57
	58	#include <architecture/i386/asm_help.h>
	59
1c79356b A	60	/*
	61	* void
	62	* ev_lock(p)
	63	* int *p;
	64	*
	65	* Lock the lock pointed to by p. Spin (possibly forever) until the next
	66	* lock is available.
	67	*/
	68	TEXT
	69
	70	#ifndef KERNEL
	71	LEAF(_ev_lock, 0)
	72	LEAF(_IOSpinLock, 0)
55e303ae A	73	movl 4(%esp), %ecx
	74	0:
	75	xorl %eax, %eax
	76	rep
	77	nop /* pause for hyperthreaded CPU's */
	78	lock
	79	cmpxchgl %ecx, (%ecx)
	80	jne 0b
	81	ret
1c79356b A	82	END(_ev_lock)
	83	#endif
	84
	85	/*
	86	* void
	87	* ev_unlock(p)
	88	* int *p;
	89	*
	90	* Unlock the lock pointed to by p.
	91	*/
	92	LEAF(_ev_unlock, 0)
	93	LEAF(_IOSpinUnlock, 0)
55e303ae A	94	movl 4(%esp), %ecx
55e303ae A	95	movl $0, (%ecx)
55e303ae	96	ret
1c79356b A	97	END(_ev_unlock)
	98
	99
	100
	101	/*
	102	* int
	103	* ev_try_lock(p)
	104	* int *p;
	105	*
	106	* Try to lock p. Return zero if not successful.
	107	*/
	108
	109	LEAF(_ev_try_lock, 0)
	110	LEAF(_IOTrySpinLock, 0)
55e303ae A	111	movl 4(%esp), %ecx
	112	xorl %eax, %eax
	113	lock
	114	cmpxchgl %ecx, (%ecx)
	115	jne 1f
1c79356b A	116	movl $1, %eax /* yes */
	117	ret
	118	1:
1c79356b A	119	xorl %eax, %eax /* no */
	120	END(_ev_try_lock)
	121
	122
	123	#endif /* ! _IOKIT_IOSHAREDLOCKIMP_H */