1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1992, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This software was developed by the Computer Systems Engineering group 8 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 9 * contributed to Berkeley. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #if defined(LIBC_SCCS) && !defined(lint) 37 static char sccsid[] = "@(#)ashrdi3.c 8.1 (Berkeley) 6/4/93"; 38 #endif /* LIBC_SCCS and not lint */ 39 #include <sys/cdefs.h> 40 __FBSDID("$FreeBSD$"); 41 42 #include "quad.h" 43 44 /* 45 * Shift a (signed) quad value right (arithmetic shift right). 46 */ 47 quad_t 48 __ashrdi3(a, shift) 49 quad_t a; 50 qshift_t shift; 51 { 52 union uu aa; 53 54 aa.q = a; 55 if (shift >= LONG_BITS) { 56 long s; 57 58 /* 59 * Smear bits rightward using the machine's right-shift 60 * method, whether that is sign extension or zero fill, 61 * to get the `sign word' s. Note that shifting by 62 * LONG_BITS is undefined, so we shift (LONG_BITS-1), 63 * then 1 more, to get our answer. 64 */ 65 s = (aa.sl[H] >> (LONG_BITS - 1)) >> 1; 66 aa.ul[L] = shift >= QUAD_BITS ? s : 67 aa.sl[H] >> (shift - LONG_BITS); 68 aa.ul[H] = s; 69 } else if (shift > 0) { 70 aa.ul[L] = (aa.ul[L] >> shift) | 71 (aa.ul[H] << (LONG_BITS - shift)); 72 aa.sl[H] >>= shift; 73 } 74 return (aa.q); 75 } 76