newlib/libc/stdlib/ldiv.c

   1 /*
   2 FUNCTION
   3 <<ldiv>>---divide two long integers
   4
   5 INDEX
   6         ldiv
   7
   8 SYNOPSIS
   9         #include <stdlib.h>
  10         ldiv_t ldiv(long <[n]>, long <[d]>);
  11
  12 DESCRIPTION
  13 Divide
  14 @tex
  15 $n/d$,
  16 @end tex
  17 @ifnottex
  18 <[n]>/<[d]>,
  19 @end ifnottex
  20 returning quotient and remainder as two long integers in a structure <<ldiv_t>>.
  21
  22 RETURNS
  23 The result is represented with the structure
  24
  25 . typedef struct
  26 . {
  27 .  long quot;
  28 .  long rem;
  29 . } ldiv_t;
  30
  31 where the <<quot>> field represents the quotient, and <<rem>> the
  32 remainder.  For nonzero <[d]>, if `<<<[r]> = ldiv(<[n]>,<[d]>);>>' then
  33 <[n]> equals `<<<[r]>.rem + <[d]>*<[r]>.quot>>'.
  34
  35 To divide <<int>> rather than <<long>> values, use the similar
  36 function <<div>>.
  37
  38 PORTABILITY
  39 <<ldiv>> is ANSI.
  40
  41 No supporting OS subroutines are required.
  42 */
  43
  44
  45 /*
  46  * Copyright (c) 1990 Regents of the University of California.
  47  * All rights reserved.
  48  *
  49  * This code is derived from software contributed to Berkeley by
  50  * Chris Torek.
  51  *
  52  * Redistribution and use in source and binary forms, with or without
  53  * modification, are permitted provided that the following conditions
  54  * are met:
  55  * 1. Redistributions of source code must retain the above copyright
  56  *    notice, this list of conditions and the following disclaimer.
  57  * 2. Redistributions in binary form must reproduce the above copyright
  58  *    notice, this list of conditions and the following disclaimer in the
  59  *    documentation and/or other materials provided with the distribution.
  60  * 3. Neither the name of the University nor the names of its contributors
  61  *    may be used to endorse or promote products derived from this software
  62  *    without specific prior written permission.
  63  *
  64  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  65  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  66  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  67  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  68  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  69  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  70  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  71  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  72  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  73  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  74  * SUCH DAMAGE.
  75  */
  76
  77 #include <_ansi.h>
  78 #include <stdlib.h>             /* ldiv_t */
  79
  80 ldiv_t
  81 ldiv (long num,
  82         long denom)
  83 {
  84         ldiv_t r;
  85
  86         /* see div.c for comments */
  87
  88         r.quot = num / denom;
  89         r.rem = num % denom;
  90         if (num >= 0 && r.rem < 0) {
  91                 ++r.quot;
  92                 r.rem -= denom;
  93         }
  94         else if (num < 0 && r.rem > 0) {
  95                 --r.quot;
  96                 r.rem += denom;
  97         }
  98         return (r);
  99 }