1 /*
2 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
3 * Use is subject to license terms.
4 */
5
6 /*
7 * Copyright (c) 1990, 1993
8 * The Regents of the University of California. All rights reserved.
9 *
10 * This code is derived from software contributed to Berkeley by
11 * Chris Torek.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 * 3. All advertising materials mentioning features or use of this software
22 * must display the following acknowledgement:
23 * This product includes software developed by the University of
24 * California, Berkeley and its contributors.
25 * 4. Neither the name of the University nor the names of its contributors
26 * may be used to endorse or promote products derived from this software
27 * without specific prior written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
32 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39 * SUCH DAMAGE.
40 */
41
42 #pragma ident "%Z%%M% %I% %E% SMI"
43
44 #include "lint.h"
45 #include <sys/types.h>
46 #include <stdlib.h>
47
48 div_t
div(num,denom)49 div(num, denom)
50 int num, denom;
51 {
52 div_t r;
53
54 r.quot = num / denom;
55 r.rem = num % denom;
56 /*
57 * The ANSI standard says that |r.quot| <= |n/d|, where
58 * n/d is to be computed in infinite precision. In other
59 * words, we should always truncate the quotient towards
60 * 0, never -infinity.
61 *
62 * Machine division and remainer may work either way when
63 * one or both of n or d is negative. If only one is
64 * negative and r.quot has been truncated towards -inf,
65 * r.rem will have the same sign as denom and the opposite
66 * sign of num; if both are negative and r.quot has been
67 * truncated towards -inf, r.rem will be positive (will
68 * have the opposite sign of num). These are considered
69 * `wrong'.
70 *
71 * If both are num and denom are positive, r will always
72 * be positive.
73 *
74 * This all boils down to:
75 * if num >= 0, but r.rem < 0, we got the wrong answer.
76 * In that case, to get the right answer, add 1 to r.quot and
77 * subtract denom from r.rem.
78 */
79 if (num >= 0 && r.rem < 0) {
80 r.quot++;
81 r.rem -= denom;
82 }
83 return (r);
84 }
85
86 ldiv_t
ldiv(num,denom)87 ldiv(num, denom)
88 long num, denom;
89 {
90 ldiv_t r;
91
92 /* see div() for comments */
93
94 r.quot = num / denom;
95 r.rem = num % denom;
96 if (num >= 0 && r.rem < 0) {
97 r.quot++;
98 r.rem -= denom;
99 }
100 return (r);
101 }
102