Colony » Colony Scout » Colony Scout OS

/*

 * Copyright (c) 1990, 1993

 *        The Regents of the University of California.  All rights reserved.

 *

 * This code is derived from software contributed to Berkeley by

 * Chris Torek.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. Neither the name of the University nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 */

#include <stdlib.h>                /* div_t */

div_t

div(num, denom)

        int num, denom;

{

        div_t r;

        r.quot = num / denom;

        r.rem = num % denom;

        /*

         * The ANSI standard says that |r.quot| <= |n/d|, where

         * n/d is to be computed in infinite precision.  In other

         * words, we should always truncate the quotient towards

         * 0, never -infinity.

         *

         * Machine division and remainer may work either way when

         * one or both of n or d is negative.  If only one is

         * negative and r.quot has been truncated towards -inf,

         * r.rem will have the same sign as denom and the opposite

         * sign of num; if both are negative and r.quot has been

         * truncated towards -inf, r.rem will be positive (will

         * have the opposite sign of num).  These are considered

         * `wrong'.

         *

         * If both are num and denom are positive, r will always

         * be positive.

         *

         * This all boils down to:

         *        if num >= 0, but r.rem < 0, we got the wrong answer.

         * In that case, to get the right answer, add 1 to r.quot and

         * subtract denom from r.rem.

         */

        if (num >= 0 && r.rem < 0) {

                r.quot++;

                r.rem -= denom;

        }

        return (r);

}