1 /* $OpenBSD: adddi3.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 * Add two quads. This is trivial since a one-bit carry from a single 39 * u_int addition x+y occurs if and only if the sum x+y is less than 40 * either x or y (the choice to compare with x or y is arbitrary). 41 */ 42 quad_t 43 __adddi3(quad_t a, quad_t b) 44 { 45 union uu aa, bb, sum; 46 47 aa.q = a; 48 bb.q = b; 49 sum.ul[L] = aa.ul[L] + bb.ul[L]; 50 sum.ul[H] = aa.ul[H] + bb.ul[H] + (sum.ul[L] < bb.ul[L]); 51 return (sum.q); 52 } 53