LXR uboot/lib/ldiv.c

   1// SPDX-License-Identifier: GPL-2.0+
   2/* Copyright (C) 1992, 1997 Free Software Foundation, Inc.
   3   This file is part of the GNU C Library.
   4 */
   5
   6typedef struct {
   7        long    quot;
   8        long    rem;
   9} ldiv_t;
  10/* Return the `ldiv_t' representation of NUMER over DENOM.  */
  11ldiv_t
  12ldiv (long int numer, long int denom)
  13{
  14  ldiv_t result;
  15
  16  result.quot = numer / denom;
  17  result.rem = numer % denom;
  18
  19  /* The ANSI standard says that |QUOT| <= |NUMER / DENOM|, where
  20     NUMER / DENOM is to be computed in infinite precision.  In
  21     other words, we should always truncate the quotient towards
  22     zero, never -infinity.  Machine division and remainer may
  23     work either way when one or both of NUMER or DENOM is
  24     negative.  If only one is negative and QUOT has been
  25     truncated towards -infinity, REM will have the same sign as
  26     DENOM and the opposite sign of NUMER; if both are negative
  27     and QUOT has been truncated towards -infinity, REM will be
  28     positive (will have the opposite sign of NUMER).  These are
  29     considered `wrong'.  If both are NUM and DENOM are positive,
  30     RESULT will always be positive.  This all boils down to: if
  31     NUMER >= 0, but REM < 0, we got the wrong answer.  In that
  32     case, to get the right answer, add 1 to QUOT and subtract
  33     DENOM from REM.  */
  34
  35  if (numer >= 0 && result.rem < 0)
  36    {
  37      ++result.quot;
  38      result.rem -= denom;
  39    }
  40
  41  return result;
  42}
  43