mpir/mpbsd/sdiv.c

/* sdiv -- Divide a MINT by a short integer.  Produce a MINT quotient
   and a short remainder.

Copyright 1991, 1994, 1995, 2000, 2001 Free Software Foundation, Inc.

This file is part of the GNU MP Library.

The GNU MP Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or (at your
option) any later version.

The GNU MP 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 Lesser General Public
License for more details.

You should have received a copy of the GNU Lesser General Public License
along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
MA 02110-1301, USA. */

#include "mp.h"
#include "mpir.h"
#include "gmp-impl.h"
#include "longlong.h"

void
sdiv (const MINT *dividend, signed short int divisor_short, MINT *quot, short *rem_ptr)
{
  mp_size_t sign_dividend;
  signed long int sign_divisor;
  mp_size_t dividend_size, quot_size;
  mp_ptr dividend_ptr, quot_ptr;
  mp_limb_t divisor_limb;
  mp_limb_t remainder_limb;

  sign_dividend = dividend->_mp_size;
  dividend_size = ABS (dividend->_mp_size);

  if (dividend_size == 0)
    {
      quot->_mp_size = 0;
      *rem_ptr = 0;
      return;
    }

  sign_divisor = divisor_short;
  divisor_limb = (unsigned short) ABS (divisor_short);

  /* No need for temporary allocation and copying even if QUOT == DIVIDEND
     as the divisor is just one limb, and thus no intermediate remainders
     need to be stored.  */

  if (quot->_mp_alloc < dividend_size)
    _mp_realloc (quot, dividend_size);

  quot_ptr = quot->_mp_d;
  dividend_ptr = dividend->_mp_d;

  remainder_limb = mpn_divmod_1 (quot_ptr,
				 dividend_ptr, dividend_size, divisor_limb);

  *rem_ptr = sign_dividend >= 0 ? remainder_limb : -remainder_limb;
  /* The quotient is DIVIDEND_SIZE limbs, but the most significant
     might be zero.  Set QUOT_SIZE properly. */
  quot_size = dividend_size - (quot_ptr[dividend_size - 1] == 0);
  quot->_mp_size = (sign_divisor ^ sign_dividend) >= 0 ? quot_size : -quot_size;
}