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

/*
 * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This 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 OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_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>

// 'Till we're building in kernel
.macro DISABLE_PREEMPTION
#ifdef KERNEL
#endif
.endmacro
.macro ENABLE_PREEMPTION
#ifdef KERNEL
#endif
.endmacro

/* 
 * 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)
	push 	%eax
	push	%ecx
	movl	$1, %ecx
	movl	12(%esp), %eax	
_spin:
	xchgl	%ecx,0(%eax)
	cmp	$0, %ecx
	jne	_spin
	pop	%ecx
	pop	%eax
END(_ev_lock)
#endif

/*
 * void
 * ev_unlock(p)
 *	int *p;
 *
 * Unlock the lock pointed to by p.
 */
LEAF(_ev_unlock, 0)
LEAF(_IOSpinUnlock, 0)
	push	%eax
	movl	8(%esp),%eax
	movl	$0,0(%eax)
	ENABLE_PREEMPTION()
	pop	%eax
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)
        DISABLE_PREEMPTION()
	movl	4(%esp), %eax
   lock;bts	$0, 0(%eax)
	jb	1f
	movl	$1, %eax		/* yes */
	ret
1:
	ENABLE_PREEMPTION()
	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	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
	6	* The contents of this file constitute Original Code as defined in and
	7	* are subject to the Apple Public Source License Version 1.1 (the
	8	* "License"). You may not use this file except in compliance with the
	9	* License. Please obtain a copy of the License at
	10	* http://www.apple.com/publicsource and read it before using this file.
	11	*
	12	* This Original Code and all software distributed under the License are
	13	* distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	14	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	15	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	16	* FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
	17	* License for the specific language governing rights and limitations
	18	* under the License.
	19	*
	20	* @APPLE_LICENSE_HEADER_END@
	21	*/
	22	/*
	23	* Copyright (c) 1998 Apple Computer, Inc. All rights reserved.
	24	*
	25	* HISTORY
	26	*
	27	*/
	28
	29	/* Copyright (c) 1992 NeXT Computer, Inc. All rights reserved.
	30	*
	31	* EventShmemLock.h - Shared memory area locks for use between the
	32	* WindowServer and the Event Driver.
	33	*
	34	*
	35	* HISTORY
	36	* 29 April 1992 Mike Paquette at NeXT
	37	* Created.
	38	*
	39	* Multiprocessor locks used within the shared memory area between the
	40	* kernel and event system. These must work in both user and kernel mode.
	41	* The locks are defined in an include file so they get exported to the local
	42	* include file area.
	43	*
	44	* This is basically a ripoff of the spin locks under the cthreads packages.
	45	*/
	46
	47	#ifndef _IOKIT_IOSHAREDLOCKIMP_H
	48	#define _IOKIT_IOSHAREDLOCKIMP_H
	49
	50	#include <architecture/i386/asm_help.h>
	51
	52	// 'Till we're building in kernel
	53	.macro DISABLE_PREEMPTION
	54	#ifdef KERNEL
	55	#endif
	56	.endmacro
	57	.macro ENABLE_PREEMPTION
	58	#ifdef KERNEL
	59	#endif
	60	.endmacro
	61
	62	/*
	63	* void
	64	* ev_lock(p)
65	* int *p;
66	*
67	* Lock the lock pointed to by p. Spin (possibly forever) until the next
68	* lock is available.
69	*/
70	TEXT
71
72	#ifndef KERNEL
73	LEAF(_ev_lock, 0)
74	LEAF(_IOSpinLock, 0)
75	push %eax
76	push %ecx
77	movl $1, %ecx
78	movl 12(%esp), %eax
79	_spin:
80	xchgl %ecx,0(%eax)
81	cmp $0, %ecx
82	jne _spin
83	pop %ecx
84	pop %eax
85	END(_ev_lock)
86	#endif
87
88	/*
89	* void
90	* ev_unlock(p)
91	* int *p;
92	*
93	* Unlock the lock pointed to by p.
94	*/
95	LEAF(_ev_unlock, 0)
96	LEAF(_IOSpinUnlock, 0)
97	push %eax
98	movl 8(%esp),%eax
99	movl $0,0(%eax)
100	ENABLE_PREEMPTION()
101	pop %eax
102	END(_ev_unlock)
103
104
105
106	/*
107	* int
108	* ev_try_lock(p)
109	* int *p;
110	*
111	* Try to lock p. Return zero if not successful.
112	*/
113
114	LEAF(_ev_try_lock, 0)
115	LEAF(_IOTrySpinLock, 0)
116	DISABLE_PREEMPTION()
117	movl 4(%esp), %eax
118	lock;bts $0, 0(%eax)
119	jb 1f
120	movl $1, %eax /* yes */
121	ret
122	1:
123	ENABLE_PREEMPTION()
124	xorl %eax, %eax /* no */
125	END(_ev_try_lock)
126
127
128	#endif /* ! _IOKIT_IOSHAREDLOCKIMP_H */