1 /* 2 * Copyright (c) 1992, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This software was developed by the Computer Systems Engineering group 6 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 7 * contributed to Berkeley. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #pragma ident "%Z%%M% %I% %E% SMI" 35 36 #include "quadint.h" 37 38 #pragma weak __ashrdi3 = ___ashrdi3 39 40 /* 41 * Shift a (signed) quad value right (arithmetic shift right). 42 */ 43 longlong_t 44 ___ashrdi3(longlong_t a, qshift_t shift) 45 { 46 union uu aa; 47 48 aa.q = a; 49 if (shift >= LONG_BITS) { 50 long s; 51 52 /* 53 * Smear bits rightward using the machine's right-shift 54 * method, whether that is sign extension or zero fill, 55 * to get the `sign word' s. Note that shifting by 56 * LONG_BITS is undefined, so we shift (LONG_BITS-1), 57 * then 1 more, to get our answer. 58 */ 59 s = (aa.sl[H] >> (LONG_BITS - 1)) >> 1; 60 aa.ul[L] = shift >= QUAD_BITS ? s : 61 aa.sl[H] >> (shift - LONG_BITS); 62 aa.ul[H] = s; 63 } else if (shift > 0) { 64 aa.ul[L] = (aa.ul[L] >> shift) | 65 (aa.ul[H] << (LONG_BITS - shift)); 66 aa.sl[H] >>= shift; 67 } 68 return (aa.q); 69 } 70