17c478bd9Sstevel@tonic-gate /*
2*7257d1b4Sraf * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
37c478bd9Sstevel@tonic-gate * Use is subject to license terms.
47c478bd9Sstevel@tonic-gate */
57c478bd9Sstevel@tonic-gate
67c478bd9Sstevel@tonic-gate /*
77c478bd9Sstevel@tonic-gate * Copyright (c) 1990, 1993
87c478bd9Sstevel@tonic-gate * The Regents of the University of California. All rights reserved.
97c478bd9Sstevel@tonic-gate *
107c478bd9Sstevel@tonic-gate * This code is derived from software contributed to Berkeley by
117c478bd9Sstevel@tonic-gate * Chris Torek.
127c478bd9Sstevel@tonic-gate *
137c478bd9Sstevel@tonic-gate * Redistribution and use in source and binary forms, with or without
147c478bd9Sstevel@tonic-gate * modification, are permitted provided that the following conditions
157c478bd9Sstevel@tonic-gate * are met:
167c478bd9Sstevel@tonic-gate * 1. Redistributions of source code must retain the above copyright
177c478bd9Sstevel@tonic-gate * notice, this list of conditions and the following disclaimer.
187c478bd9Sstevel@tonic-gate * 2. Redistributions in binary form must reproduce the above copyright
197c478bd9Sstevel@tonic-gate * notice, this list of conditions and the following disclaimer in the
207c478bd9Sstevel@tonic-gate * documentation and/or other materials provided with the distribution.
217c478bd9Sstevel@tonic-gate * 3. All advertising materials mentioning features or use of this software
227c478bd9Sstevel@tonic-gate * must display the following acknowledgement:
237c478bd9Sstevel@tonic-gate * This product includes software developed by the University of
247c478bd9Sstevel@tonic-gate * California, Berkeley and its contributors.
257c478bd9Sstevel@tonic-gate * 4. Neither the name of the University nor the names of its contributors
267c478bd9Sstevel@tonic-gate * may be used to endorse or promote products derived from this software
277c478bd9Sstevel@tonic-gate * without specific prior written permission.
287c478bd9Sstevel@tonic-gate *
297c478bd9Sstevel@tonic-gate * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
307c478bd9Sstevel@tonic-gate * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
317c478bd9Sstevel@tonic-gate * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
327c478bd9Sstevel@tonic-gate * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
337c478bd9Sstevel@tonic-gate * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
347c478bd9Sstevel@tonic-gate * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
357c478bd9Sstevel@tonic-gate * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
367c478bd9Sstevel@tonic-gate * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
377c478bd9Sstevel@tonic-gate * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
387c478bd9Sstevel@tonic-gate * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
397c478bd9Sstevel@tonic-gate * SUCH DAMAGE.
407c478bd9Sstevel@tonic-gate */
417c478bd9Sstevel@tonic-gate
42*7257d1b4Sraf #include "lint.h"
437c478bd9Sstevel@tonic-gate #include <sys/types.h>
447c478bd9Sstevel@tonic-gate #include <stdlib.h>
457c478bd9Sstevel@tonic-gate
467c478bd9Sstevel@tonic-gate div_t
div(num,denom)477c478bd9Sstevel@tonic-gate div(num, denom)
487c478bd9Sstevel@tonic-gate int num, denom;
497c478bd9Sstevel@tonic-gate {
507c478bd9Sstevel@tonic-gate div_t r;
517c478bd9Sstevel@tonic-gate
527c478bd9Sstevel@tonic-gate r.quot = num / denom;
537c478bd9Sstevel@tonic-gate r.rem = num % denom;
547c478bd9Sstevel@tonic-gate /*
557c478bd9Sstevel@tonic-gate * The ANSI standard says that |r.quot| <= |n/d|, where
567c478bd9Sstevel@tonic-gate * n/d is to be computed in infinite precision. In other
577c478bd9Sstevel@tonic-gate * words, we should always truncate the quotient towards
587c478bd9Sstevel@tonic-gate * 0, never -infinity.
597c478bd9Sstevel@tonic-gate *
607c478bd9Sstevel@tonic-gate * Machine division and remainer may work either way when
617c478bd9Sstevel@tonic-gate * one or both of n or d is negative. If only one is
627c478bd9Sstevel@tonic-gate * negative and r.quot has been truncated towards -inf,
637c478bd9Sstevel@tonic-gate * r.rem will have the same sign as denom and the opposite
647c478bd9Sstevel@tonic-gate * sign of num; if both are negative and r.quot has been
657c478bd9Sstevel@tonic-gate * truncated towards -inf, r.rem will be positive (will
667c478bd9Sstevel@tonic-gate * have the opposite sign of num). These are considered
677c478bd9Sstevel@tonic-gate * `wrong'.
687c478bd9Sstevel@tonic-gate *
697c478bd9Sstevel@tonic-gate * If both are num and denom are positive, r will always
707c478bd9Sstevel@tonic-gate * be positive.
717c478bd9Sstevel@tonic-gate *
727c478bd9Sstevel@tonic-gate * This all boils down to:
737c478bd9Sstevel@tonic-gate * if num >= 0, but r.rem < 0, we got the wrong answer.
747c478bd9Sstevel@tonic-gate * In that case, to get the right answer, add 1 to r.quot and
757c478bd9Sstevel@tonic-gate * subtract denom from r.rem.
767c478bd9Sstevel@tonic-gate */
777c478bd9Sstevel@tonic-gate if (num >= 0 && r.rem < 0) {
787c478bd9Sstevel@tonic-gate r.quot++;
797c478bd9Sstevel@tonic-gate r.rem -= denom;
807c478bd9Sstevel@tonic-gate }
817c478bd9Sstevel@tonic-gate return (r);
827c478bd9Sstevel@tonic-gate }
837c478bd9Sstevel@tonic-gate
847c478bd9Sstevel@tonic-gate ldiv_t
ldiv(num,denom)857c478bd9Sstevel@tonic-gate ldiv(num, denom)
867c478bd9Sstevel@tonic-gate long num, denom;
877c478bd9Sstevel@tonic-gate {
887c478bd9Sstevel@tonic-gate ldiv_t r;
897c478bd9Sstevel@tonic-gate
907c478bd9Sstevel@tonic-gate /* see div() for comments */
917c478bd9Sstevel@tonic-gate
927c478bd9Sstevel@tonic-gate r.quot = num / denom;
937c478bd9Sstevel@tonic-gate r.rem = num % denom;
947c478bd9Sstevel@tonic-gate if (num >= 0 && r.rem < 0) {
957c478bd9Sstevel@tonic-gate r.quot++;
967c478bd9Sstevel@tonic-gate r.rem -= denom;
977c478bd9Sstevel@tonic-gate }
987c478bd9Sstevel@tonic-gate return (r);
997c478bd9Sstevel@tonic-gate }
100