xref: /original-bsd/lib/libcompat/4.3/insque.c (revision 6f738a42)
1 /*
2  * Copyright (c) 1987 Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms are permitted
6  * provided that the above copyright notice and this paragraph are
7  * duplicated in all such forms and that any documentation,
8  * advertising materials, and other materials related to such
9  * distribution and use acknowledge that the software was developed
10  * by the University of California, Berkeley.  The name of the
11  * University may not be used to endorse or promote products derived
12  * from this software without specific prior written permission.
13  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
14  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
15  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
16  */
17 
18 #if defined(LIBC_SCCS) && !defined(lint)
19 static char sccsid[] = "@(#)insque.c	5.2 (Berkeley) 07/21/88";
20 #endif /* LIBC_SCCS and not lint */
21 
22 /*
23  * insque -- vax insque instruction
24  *
25  * NOTE: this implementation is non-atomic!!
26  */
27 
28 struct vaxque {		/* queue format expected by VAX queue instructions */
29 	struct vaxque	*vq_next;
30 	struct vaxque	*vq_prev;
31 };
32 
33 insque(e, prev)
34 	register struct vaxque *e, *prev;
35 {
36 	e->vq_prev = prev;
37 	e->vq_next = prev->vq_next;
38 	prev->vq_next->vq_prev = e;
39 	prev->vq_next = e;
40 }
41