1/*
2 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
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
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28/*
29 * @OSF_COPYRIGHT@
30 */
31/*
32 * HISTORY
33 *
34 * Revision 1.1.1.1  1998/09/22 21:05:33  wsanchez
35 * Import of Mac OS X kernel (~semeria)
36 *
37 * Revision 1.1.1.1  1998/03/07 02:25:55  wsanchez
38 * Import of OSF Mach kernel (~mburg)
39 *
40 * Revision 1.1.10.3  1995/03/15  17:21:19  bruel
41 * 	compile only if !__GNUC__.
42 * 	[95/03/09            bruel]
43 *
44 * Revision 1.1.10.2  1995/01/06  19:48:05  devrcs
45 * 	mk6 CR668 - 1.3b26 merge
46 * 	* Revision 1.1.3.5  1994/05/06  18:51:43  tmt
47 * 	Merge in DEC Alpha changes to osc1.3b19.
48 * 	Merge Alpha changes into osc1.312b source code.
49 * 	Remove ifdef sun around insque and remque.
50 * 	* End1.3merge
51 * 	[1994/11/04  09:29:15  dwm]
52 *
53 * Revision 1.1.10.1  1994/09/23  02:25:00  ezf
54 * 	change marker to not FREE
55 * 	[1994/09/22  21:35:34  ezf]
56 *
57 * Revision 1.1.3.3  1993/07/28  17:16:26  bernard
58 * 	CR9523 -- Prototypes.
59 * 	[1993/07/21  17:00:38  bernard]
60 *
61 * Revision 1.1.3.2  1993/06/02  23:39:41  jeffc
62 * 	Added to OSF/1 R1.3 from NMK15.0.
63 * 	[1993/06/02  21:13:58  jeffc]
64 *
65 * Revision 1.1  1992/09/30  02:09:52  robert
66 * 	Initial revision
67 *
68 * $EndLog$
69 */
70/* CMU_HIST */
71/*
72 * Revision 2.4  91/05/14  16:45:45  mrt
73 * 	Correcting copyright
74 *
75 * Revision 2.3  91/05/08  12:48:22  dbg
76 * 	Compile queue routines on vax.
77 * 	[91/03/26            dbg]
78 *
79 * Revision 2.2  91/02/05  17:28:38  mrt
80 * 	Changed to new Mach copyright
81 * 	[91/02/01  16:16:22  mrt]
82 *
83 * Revision 2.1  89/08/03  15:51:47  rwd
84 * Created.
85 *
86 * 17-Mar-87  David Golub (dbg) at Carnegie-Mellon University
87 *	Created from routines written by David L. Black.
88 *
89 */
90/* CMU_ENDHIST */
91/*
92 * Mach Operating System
93 * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
94 * All Rights Reserved.
95 *
96 * Permission to use, copy, modify and distribute this software and its
97 * documentation is hereby granted, provided that both the copyright
98 * notice and this permission notice appear in all copies of the
99 * software, derivative works or modified versions, and any portions
100 * thereof, and that both notices appear in supporting documentation.
101 *
102 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
103 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
104 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
105 *
106 * Carnegie Mellon requests users of this software to return to
107 *
108 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
109 *  School of Computer Science
110 *  Carnegie Mellon University
111 *  Pittsburgh PA 15213-3890
112 *
113 * any improvements or extensions that they make and grant Carnegie Mellon
114 * the rights to redistribute these changes.
115 */
116/*
117 */
118
119/*
120 *	Routines to implement queue package.
121 */
122
123#include <kern/queue.h>
124
125#if	!defined(__GNUC__)
126
127/*
128 *	Insert element at head of queue.
129 */
130void
131enqueue_head(
132	register queue_t	que,
133	register queue_entry_t	elt)
134{
135	elt->next = que->next;
136	elt->prev = que;
137	elt->next->prev = elt;
138	que->next = elt;
139}
140
141/*
142 *	Insert element at tail of queue.
143 */
144void
145enqueue_tail(
146	register queue_t	que,
147	register queue_entry_t	elt)
148{
149	elt->next = que;
150	elt->prev = que->prev;
151	elt->prev->next = elt;
152	que->prev = elt;
153}
154
155/*
156 *	Remove and return element at head of queue.
157 */
158queue_entry_t
159dequeue_head(
160	register queue_t	que)
161{
162	register queue_entry_t	elt;
163
164	if (que->next == que)
165		return((queue_entry_t)0);
166
167	elt = que->next;
168	elt->next->prev = que;
169	que->next = elt->next;
170	return(elt);
171}
172
173/*
174 *	Remove and return element at tail of queue.
175 */
176queue_entry_t
177dequeue_tail(
178	register queue_t	que)
179{
180	register queue_entry_t	elt;
181
182	if (que->prev == que)
183		return((queue_entry_t)0);
184
185	elt = que->prev;
186	elt->prev->next = que;
187	que->prev = elt->prev;
188	return(elt);
189}
190
191/*
192 *	Remove arbitrary element from queue.
193 *	Does not check whether element is on queue - the world
194 *	will go haywire if it isn't.
195 */
196
197/*ARGSUSED*/
198void
199remqueue(
200	queue_t			que,
201	register queue_entry_t	elt)
202{
203	elt->next->prev = elt->prev;
204	elt->prev->next = elt->next;
205}
206
207/*
208 *	Routines to directly imitate the VAX hardware queue
209 *	package.
210 */
211void
212insque(
213	register queue_entry_t	entry,
214	register queue_entry_t	pred)
215{
216	entry->next = pred->next;
217	entry->prev = pred;
218	(pred->next)->prev = entry;
219	pred->next = entry;
220}
221
222int
223remque(
224	register queue_entry_t elt)
225{
226	(elt->next)->prev = elt->prev;
227	(elt->prev)->next = elt->next;
228	return((int)elt);
229}
230
231#endif
232