1/*
2 * Copyright (c) 1992, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This software was developed by the Computer Systems Engineering group
6 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
7 * contributed to Berkeley.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#pragma ident	"%Z%%M%	%I%	%E% SMI"
35
36#include "quadint.h"
37
38#pragma weak __ashrdi3 = ___ashrdi3
39
40/*
41 * Shift a (signed) quad value right (arithmetic shift right).
42 */
43longlong_t
44___ashrdi3(longlong_t a, qshift_t shift)
45{
46	union uu aa;
47
48	aa.q = a;
49	if (shift >= LONG_BITS) {
50		long s;
51
52		/*
53		 * Smear bits rightward using the machine's right-shift
54		 * method, whether that is sign extension or zero fill,
55		 * to get the `sign word' s.  Note that shifting by
56		 * LONG_BITS is undefined, so we shift (LONG_BITS-1),
57		 * then 1 more, to get our answer.
58		 */
59		s = (aa.sl[H] >> (LONG_BITS - 1)) >> 1;
60		aa.ul[L] = shift >= QUAD_BITS ? s :
61		    aa.sl[H] >> (shift - LONG_BITS);
62		aa.ul[H] = s;
63	} else if (shift > 0) {
64		aa.ul[L] = (aa.ul[L] >> shift) |
65		    (aa.ul[H] << (LONG_BITS - shift));
66		aa.sl[H] >>= shift;
67	}
68	return (aa.q);
69}
70