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

/*
 * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_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_OSREFERENCE_LICENSE_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	*
8f6c56a5	4	* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
1c79356b	5	*
8f6c56a5 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 License
	10	* may not be used to create, or enable the creation or redistribution of,
	11	* unlawful or unlicensed copies of an Apple operating system, or to
	12	* circumvent, violate, or enable the circumvention or violation of, any
	13	* terms of an Apple operating system software license agreement.
	14	*
	15	* Please obtain a copy of the License at
	16	* http://www.opensource.apple.com/apsl/ and read it before using this file.
	17	*
	18	* The Original Code and all software distributed under the License are
	19	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	20	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	21	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	22	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	23	* Please see the License for the specific language governing rights and
8ad349bb	24	* limitations under the License.
8f6c56a5 A	25	*
8f6c56a5 A	26	* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
1c79356b A	27	*/
	28	/*
	29	* Copyright (c) 1998 Apple Computer, Inc. All rights reserved.
	30	*
	31	* HISTORY
	32	*
	33	*/
	34
	35	/* Copyright (c) 1992 NeXT Computer, Inc. All rights reserved.
	36	*
	37	* EventShmemLock.h - Shared memory area locks for use between the
	38	* WindowServer and the Event Driver.
	39	*
	40	*
	41	* HISTORY
	42	* 29 April 1992 Mike Paquette at NeXT
	43	* Created.
	44	*
	45	* Multiprocessor locks used within the shared memory area between the
	46	* kernel and event system. These must work in both user and kernel mode.
	47	* The locks are defined in an include file so they get exported to the local
	48	* include file area.
	49	*
	50	* This is basically a ripoff of the spin locks under the cthreads packages.
	51	*/
	52
	53	#ifndef _IOKIT_IOSHAREDLOCKIMP_H
	54	#define _IOKIT_IOSHAREDLOCKIMP_H
	55
	56	#include <architecture/i386/asm_help.h>
	57
1c79356b A	58	/*
	59	* void
	60	* ev_lock(p)
	61	* int *p;
	62	*
	63	* Lock the lock pointed to by p. Spin (possibly forever) until the next
	64	* lock is available.
	65	*/
	66	TEXT
	67
	68	#ifndef KERNEL
	69	LEAF(_ev_lock, 0)
	70	LEAF(_IOSpinLock, 0)
55e303ae A	71	movl 4(%esp), %ecx
	72	0:
	73	xorl %eax, %eax
	74	rep
	75	nop /* pause for hyperthreaded CPU's */
	76	lock
	77	cmpxchgl %ecx, (%ecx)
	78	jne 0b
	79	ret
1c79356b A	80	END(_ev_lock)
	81	#endif
	82
	83	/*
	84	* void
	85	* ev_unlock(p)
	86	* int *p;
	87	*
	88	* Unlock the lock pointed to by p.
	89	*/
	90	LEAF(_ev_unlock, 0)
	91	LEAF(_IOSpinUnlock, 0)
55e303ae A	92	movl 4(%esp), %ecx
55e303ae A	93	movl $0, (%ecx)
55e303ae	94	ret
1c79356b A	95	END(_ev_unlock)
	96
	97
	98
	99	/*
	100	* int
	101	* ev_try_lock(p)
	102	* int *p;
	103	*
	104	* Try to lock p. Return zero if not successful.
	105	*/
	106
	107	LEAF(_ev_try_lock, 0)
	108	LEAF(_IOTrySpinLock, 0)
55e303ae A	109	movl 4(%esp), %ecx
	110	xorl %eax, %eax
	111	lock
	112	cmpxchgl %ecx, (%ecx)
	113	jne 1f
1c79356b A	114	movl $1, %eax /* yes */
	115	ret
	116	1:
1c79356b A	117	xorl %eax, %eax /* no */
	118	END(_ev_try_lock)
	119
	120
	121	#endif /* ! _IOKIT_IOSHAREDLOCKIMP_H */