xref: /openbsd-src/sys/lib/libkern/lshrdi3.c (revision b725ae7711052a2233e31a66fefb8a752c388d7a)
1 /*	$OpenBSD: lshrdi3.c,v 1.3 2003/06/02 23:28:08 millert Exp $	*/
2 /*	$NetBSD: lshrdi3.c,v 1.5 1995/10/07 09:26:30 mycroft Exp $	*/
3 
4 /*-
5  * Copyright (c) 1992, 1993
6  *	The Regents of the University of California.  All rights reserved.
7  *
8  * This software was developed by the Computer Systems Engineering group
9  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
10  * contributed to Berkeley.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  * 3. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  */
36 
37 #if defined(LIBC_SCCS) && !defined(lint)
38 #if 0
39 static char sccsid[] = "@(#)lshrdi3.c	8.1 (Berkeley) 6/4/93";
40 #else
41 static char rcsid[] = "$OpenBSD: lshrdi3.c,v 1.3 2003/06/02 23:28:08 millert Exp $";
42 #endif
43 #endif /* LIBC_SCCS and not lint */
44 
45 #include "quad.h"
46 
47 /*
48  * Shift an (unsigned) quad value right (logical shift right).
49  */
50 quad_t
51 __lshrdi3(a, shift)
52 	quad_t a;
53 	qshift_t shift;
54 {
55 	union uu aa;
56 
57 	aa.q = a;
58 	if (shift >= LONG_BITS) {
59 		aa.ul[L] = shift >= QUAD_BITS ? 0 :
60 		    aa.ul[H] >> (shift - LONG_BITS);
61 		aa.ul[H] = 0;
62 	} else if (shift > 0) {
63 		aa.ul[L] = (aa.ul[L] >> shift) |
64 		    (aa.ul[H] << (LONG_BITS - shift));
65 		aa.ul[H] >>= shift;
66 	}
67 	return (aa.q);
68 }
69