11541Srgrimes/*- 21541Srgrimes * Copyright (c) 1992, 1993 31541Srgrimes * The Regents of the University of California. All rights reserved. 41541Srgrimes * 51541Srgrimes * This software was developed by the Computer Systems Engineering group 61541Srgrimes * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 71541Srgrimes * contributed to Berkeley. 81541Srgrimes * 91541Srgrimes * Redistribution and use in source and binary forms, with or without 101541Srgrimes * modification, are permitted provided that the following conditions 111541Srgrimes * are met: 121541Srgrimes * 1. Redistributions of source code must retain the above copyright 131541Srgrimes * notice, this list of conditions and the following disclaimer. 141541Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 151541Srgrimes * notice, this list of conditions and the following disclaimer in the 161541Srgrimes * documentation and/or other materials provided with the distribution. 171541Srgrimes * 4. Neither the name of the University nor the names of its contributors 181541Srgrimes * may be used to endorse or promote products derived from this software 191541Srgrimes * without specific prior written permission. 201541Srgrimes * 211541Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 221541Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 231541Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 241541Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 251541Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 261541Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 271541Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 281541Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 291541Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 301541Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 311541Srgrimes * SUCH DAMAGE. 321541Srgrimes */ 331541Srgrimes 34116189Sobrien#include <sys/cdefs.h> 35116189Sobrien__FBSDID("$FreeBSD: releng/10.2/sys/libkern/ashrdi3.c 128019 2004-04-07 20:46:16Z imp $"); 36116189Sobrien 3770949Sbenno#include <libkern/quad.h> 381541Srgrimes 391541Srgrimes/* 401541Srgrimes * Shift a (signed) quad value right (arithmetic shift right). 411541Srgrimes */ 421541Srgrimesquad_t 431541Srgrimes__ashrdi3(a, shift) 441541Srgrimes quad_t a; 451541Srgrimes qshift_t shift; 461541Srgrimes{ 471541Srgrimes union uu aa; 481541Srgrimes 491541Srgrimes aa.q = a; 501541Srgrimes if (shift >= LONG_BITS) { 511541Srgrimes long s; 521541Srgrimes 531541Srgrimes /* 541541Srgrimes * Smear bits rightward using the machine's right-shift 551541Srgrimes * method, whether that is sign extension or zero fill, 561541Srgrimes * to get the `sign word' s. Note that shifting by 571541Srgrimes * LONG_BITS is undefined, so we shift (LONG_BITS-1), 581541Srgrimes * then 1 more, to get our answer. 591541Srgrimes */ 601541Srgrimes s = (aa.sl[H] >> (LONG_BITS - 1)) >> 1; 611541Srgrimes aa.ul[L] = shift >= QUAD_BITS ? s : 621541Srgrimes aa.sl[H] >> (shift - LONG_BITS); 631541Srgrimes aa.ul[H] = s; 641541Srgrimes } else if (shift > 0) { 651541Srgrimes aa.ul[L] = (aa.ul[L] >> shift) | 661541Srgrimes (aa.ul[H] << (LONG_BITS - shift)); 671541Srgrimes aa.sl[H] >>= shift; 681541Srgrimes } 691541Srgrimes return (aa.q); 701541Srgrimes} 71