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 #include "quad.h" 37 38 /* 39 * Shift a (signed) quad value right (arithmetic shift right). 40 */ 41 quad_t 42 __ashrdi3(quad_t a, qshift_t shift) 43 { 44 union uu aa; 45 46 aa.q = a; 47 if (shift >= LONG_BITS) { 48 long s; 49 50 /* 51 * Smear bits rightward using the machine's right-shift 52 * method, whether that is sign extension or zero fill, 53 * to get the `sign word' s. Note that shifting by 54 * LONG_BITS is undefined, so we shift (LONG_BITS-1), 55 * then 1 more, to get our answer. 56 */ 57 s = (aa.sl[H] >> (LONG_BITS - 1)) >> 1; 58 aa.ul[L] = shift >= QUAD_BITS ? s : 59 aa.sl[H] >> (shift - LONG_BITS); 60 aa.ul[H] = s; 61 } else if (shift > 0) { 62 aa.ul[L] = (aa.ul[L] >> shift) | 63 (aa.ul[H] << (LONG_BITS - shift)); 64 aa.sl[H] >>= shift; 65 } 66 return (aa.q); 67 } 68