1ab44f52202878cdf2bf22457aeae33ec24089556Elliott Hughes/* $NetBSD: div.c,v 1.8 2012/06/25 22:32:45 abs Exp $ */ 2ab44f52202878cdf2bf22457aeae33ec24089556Elliott Hughes 31dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* 4ab44f52202878cdf2bf22457aeae33ec24089556Elliott Hughes * Copyright (c) 1990, 1993 5ab44f52202878cdf2bf22457aeae33ec24089556Elliott Hughes * The Regents of the University of California. All rights reserved. 61dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 71dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * This code is derived from software contributed to Berkeley by 81dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Chris Torek. 91dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 101dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Redistribution and use in source and binary forms, with or without 111dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * modification, are permitted provided that the following conditions 121dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * are met: 131dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 1. Redistributions of source code must retain the above copyright 141dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * notice, this list of conditions and the following disclaimer. 151dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 2. Redistributions in binary form must reproduce the above copyright 161dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * notice, this list of conditions and the following disclaimer in the 171dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * documentation and/or other materials provided with the distribution. 181dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 3. Neither the name of the University nor the names of its contributors 191dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * may be used to endorse or promote products derived from this software 201dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * without specific prior written permission. 211dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 221dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 231dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 241dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 251dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 261dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 271dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 281dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 291dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 301dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 311dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 321dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * SUCH DAMAGE. 331dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 341dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 35ab44f52202878cdf2bf22457aeae33ec24089556Elliott Hughes#include <sys/cdefs.h> 36ab44f52202878cdf2bf22457aeae33ec24089556Elliott Hughes#if defined(LIBC_SCCS) && !defined(lint) 37ab44f52202878cdf2bf22457aeae33ec24089556Elliott Hughes#if 0 38ab44f52202878cdf2bf22457aeae33ec24089556Elliott Hughesstatic char sccsid[] = "@(#)div.c 8.1 (Berkeley) 6/4/93"; 39ab44f52202878cdf2bf22457aeae33ec24089556Elliott Hughes#else 40ab44f52202878cdf2bf22457aeae33ec24089556Elliott Hughes__RCSID("$NetBSD: div.c,v 1.8 2012/06/25 22:32:45 abs Exp $"); 41ab44f52202878cdf2bf22457aeae33ec24089556Elliott Hughes#endif 42ab44f52202878cdf2bf22457aeae33ec24089556Elliott Hughes#endif /* LIBC_SCCS and not lint */ 43ab44f52202878cdf2bf22457aeae33ec24089556Elliott Hughes 441dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#include <stdlib.h> /* div_t */ 451dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 461dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectdiv_t 471dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectdiv(int num, int denom) 481dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 491dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project div_t r; 501dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 511dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project r.quot = num / denom; 521dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project r.rem = num % denom; 531dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* 541dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * The ANSI standard says that |r.quot| <= |n/d|, where 551dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * n/d is to be computed in infinite precision. In other 561dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * words, we should always truncate the quotient towards 571dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 0, never -infinity. 581dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 591dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Machine division and remainer may work either way when 601dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * one or both of n or d is negative. If only one is 611dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * negative and r.quot has been truncated towards -inf, 621dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * r.rem will have the same sign as denom and the opposite 631dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * sign of num; if both are negative and r.quot has been 641dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * truncated towards -inf, r.rem will be positive (will 651dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * have the opposite sign of num). These are considered 661dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * `wrong'. 671dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 681dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * If both are num and denom are positive, r will always 691dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * be positive. 701dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 711dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * This all boils down to: 721dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * if num >= 0, but r.rem < 0, we got the wrong answer. 731dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * In that case, to get the right answer, add 1 to r.quot and 741dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * subtract denom from r.rem. 751dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 761dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (num >= 0 && r.rem < 0) { 771dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project r.quot++; 781dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project r.rem -= denom; 791dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 801dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return (r); 811dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 82