ashrdi3.c revision 256281 
10Sstevel@tonic-gate/*-
20Sstevel@tonic-gate * Copyright (c) 1992, 1993
30Sstevel@tonic-gate *	The Regents of the University of California.  All rights reserved.
40Sstevel@tonic-gate *
50Sstevel@tonic-gate * This software was developed by the Computer Systems Engineering group
60Sstevel@tonic-gate * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
70Sstevel@tonic-gate * contributed to Berkeley.
80Sstevel@tonic-gate *
90Sstevel@tonic-gate * Redistribution and use in source and binary forms, with or without
100Sstevel@tonic-gate * modification, are permitted provided that the following conditions
110Sstevel@tonic-gate * are met:
120Sstevel@tonic-gate * 1. Redistributions of source code must retain the above copyright
130Sstevel@tonic-gate *    notice, this list of conditions and the following disclaimer.
140Sstevel@tonic-gate * 2. Redistributions in binary form must reproduce the above copyright
150Sstevel@tonic-gate *    notice, this list of conditions and the following disclaimer in the
160Sstevel@tonic-gate *    documentation and/or other materials provided with the distribution.
170Sstevel@tonic-gate * 4. Neither the name of the University nor the names of its contributors
180Sstevel@tonic-gate *    may be used to endorse or promote products derived from this software
190Sstevel@tonic-gate *    without specific prior written permission.
200Sstevel@tonic-gate *
210Sstevel@tonic-gate * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
220Sstevel@tonic-gate * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
230Sstevel@tonic-gate * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
240Sstevel@tonic-gate * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
250Sstevel@tonic-gate * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
260Sstevel@tonic-gate * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
270Sstevel@tonic-gate * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
280Sstevel@tonic-gate * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
290Sstevel@tonic-gate * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
300Sstevel@tonic-gate * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
310Sstevel@tonic-gate * SUCH DAMAGE.
320Sstevel@tonic-gate */
330Sstevel@tonic-gate
340Sstevel@tonic-gate#if defined(LIBC_SCCS) && !defined(lint)
350Sstevel@tonic-gatestatic char sccsid[] = "@(#)ashrdi3.c	8.1 (Berkeley) 6/4/93";
360Sstevel@tonic-gate#endif /* LIBC_SCCS and not lint */
370Sstevel@tonic-gate#include <sys/cdefs.h>
380Sstevel@tonic-gate__FBSDID("$FreeBSD: stable/10/lib/libc/quad/ashrdi3.c 165903 2007-01-09 00:28:16Z imp $");
390Sstevel@tonic-gate
400Sstevel@tonic-gate#include "quad.h"
410Sstevel@tonic-gate
420Sstevel@tonic-gate/*
430Sstevel@tonic-gate * Shift a (signed) quad value right (arithmetic shift right).
440Sstevel@tonic-gate */
450Sstevel@tonic-gatequad_t
460Sstevel@tonic-gate__ashrdi3(a, shift)
47	quad_t a;
48	qshift_t shift;
49{
50	union uu aa;
51
52	aa.q = a;
53	if (shift >= LONG_BITS) {
54		long s;
55
56		/*
57		 * Smear bits rightward using the machine's right-shift
58		 * method, whether that is sign extension or zero fill,
59		 * to get the `sign word' s.  Note that shifting by
60		 * LONG_BITS is undefined, so we shift (LONG_BITS-1),
61		 * then 1 more, to get our answer.
62		 */
63		s = (aa.sl[H] >> (LONG_BITS - 1)) >> 1;
64		aa.ul[L] = shift >= QUAD_BITS ? s :
65		    aa.sl[H] >> (shift - LONG_BITS);
66		aa.ul[H] = s;
67	} else if (shift > 0) {
68		aa.ul[L] = (aa.ul[L] >> shift) |
69		    (aa.ul[H] << (LONG_BITS - shift));
70		aa.sl[H] >>= shift;
71	}
72	return (aa.q);
73}
74