freebsd-skq/lib/libc/stdlib/div.c
pfg 872b698bd4 General further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 3-Clause license.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
2017-11-20 19:49:47 +00:00

82 lines
3.0 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* 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.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)div.c 8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <stdlib.h> /* div_t */
div_t
div(num, denom)
int num, denom;
{
div_t r;
r.quot = num / denom;
r.rem = num % denom;
#if !defined(__STDC_VERSION__) || (__STDC_VERSION__ < 199901L)
/*
* 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;
}
#endif
return (r);
}