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author | Roland McGrath <roland@gnu.org> | 1995-02-18 01:27:10 +0000 |
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committer | Roland McGrath <roland@gnu.org> | 1995-02-18 01:27:10 +0000 |
commit | 28f540f45bbacd939bfd07f213bcad2bf730b1bf (patch) | |
tree | 15f07c4c43d635959c6afee96bde71fb1b3614ee /stdlib/div.c | |
download | glibc-28f540f45bbacd939bfd07f213bcad2bf730b1bf.tar.gz glibc-28f540f45bbacd939bfd07f213bcad2bf730b1bf.tar.xz glibc-28f540f45bbacd939bfd07f213bcad2bf730b1bf.zip |
initial import
Diffstat (limited to 'stdlib/div.c')
-rw-r--r-- | stdlib/div.c | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/stdlib/div.c b/stdlib/div.c new file mode 100644 index 0000000000..5a0ee7da38 --- /dev/null +++ b/stdlib/div.c @@ -0,0 +1,92 @@ +/* Copyright (C) 1992 Free Software Foundation, Inc. +This file is part of the GNU C Library. + +The GNU C Library is free software; you can redistribute it and/or +modify it under the terms of the GNU Library General Public License as +published by the Free Software Foundation; either version 2 of the +License, or (at your option) any later version. + +The GNU C Library is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +Library General Public License for more details. + +You should have received a copy of the GNU Library General Public +License along with the GNU C Library; see the file COPYING.LIB. If +not, write to the Free Software Foundation, Inc., 675 Mass Ave, +Cambridge, MA 02139, USA. */ + +/* + * Copyright (c) 1990 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. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. 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 <ansidecl.h> +#include <stdlib.h> + + +/* Return the `div_t' representation of NUMER over DENOM. */ +__CONSTVALUE +div_t +DEFUN(div, (numer, denom), int numer AND int denom) +{ + div_t result; + + result.quot = numer / denom; + result.rem = numer % denom; + + /* The ANSI standard says that |QUOT| <= |NUMER / DENOM|, where + NUMER / DENOM is to be computed in infinite precision. In + other words, we should always truncate the quotient towards + zero, never -infinity. Machine division and remainer may + work either way when one or both of NUMER or DENOM is + negative. If only one is negative and QUOT has been + truncated towards -infinity, REM will have the same sign as + DENOM and the opposite sign of NUMER; if both are negative + and QUOT has been truncated towards -infinity, REM will be + positive (will have the opposite sign of NUMER). These are + considered `wrong'. If both are NUM and DENOM are positive, + RESULT will always be positive. This all boils down to: if + NUMER >= 0, but REM < 0, we got the wrong answer. In that + case, to get the right answer, add 1 to QUOT and subtract + DENOM from REM. */ + + if (numer >= 0 && result.rem < 0) + { + ++result.quot; + result.rem -= denom; + } + + return result; +} |