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Commit	Line	Data
	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 */