1 /* $OpenBSD: ashrdi3.c,v 1.6 2005/08/08 08:05:35 espie Exp $ */ 2 /*- 3 * Copyright (c) 1992, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This software was developed by the Computer Systems Engineering group 7 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 8 * contributed to Berkeley. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include "quad.h" 36 37 /* 38 * Shift a (signed) quad value right (arithmetic shift right). 39 */ 40 quad_t 41 __ashrdi3(quad_t a, qshift_t shift) 42 { 43 union uu aa; 44 45 if (shift == 0) 46 return(a); 47 aa.q = a; 48 if (shift >= INT_BITS) { 49 int s; 50 51 /* 52 * Smear bits rightward using the machine's right-shift 53 * method, whether that is sign extension or zero fill, 54 * to get the `sign word' s. Note that shifting by 55 * INT_BITS is undefined, so we shift (INT_BITS-1), 56 * then 1 more, to get our answer. 57 */ 58 /* LINTED inherits machine dependency */ 59 s = (aa.sl[H] >> (INT_BITS - 1)) >> 1; 60 /* LINTED inherits machine dependency*/ 61 aa.ul[L] = aa.sl[H] >> (shift - INT_BITS); 62 aa.ul[H] = s; 63 } else { 64 aa.ul[L] = (aa.ul[L] >> shift) | 65 (aa.ul[H] << (INT_BITS - shift)); 66 /* LINTED inherits machine dependency */ 67 aa.sl[H] >>= shift; 68 } 69 return (aa.q); 70 } 71