stk/Mp/gmp-1.3.2/mpz_dm_ui.c

82 lines
2.4 KiB
C

/* mpz_divmod_ui(quot,rem,dividend,short_divisor) --
Set QUOT to DIVIDEND / SHORT_DIVISOR
and REM to DIVIDEND mod SHORT_DIVISOR.
Copyright (C) 1991, 1992 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 General Public License as published by
the Free Software Foundation; either version 2, 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with the GNU MP Library; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "gmp.h"
#include "gmp-impl.h"
#include "longlong.h"
void
#ifdef __STDC__
mpz_divmod_ui (MP_INT *quot, MP_INT *rem,
const MP_INT *dividend, unsigned long int divisor_limb)
#else
mpz_divmod_ui (quot, rem, dividend, divisor_limb)
MP_INT *quot;
MP_INT *rem;
const MP_INT *dividend;
unsigned long int divisor_limb;
#endif
{
mp_size sign_dividend;
mp_size dividend_size, quot_size;
mp_ptr dividend_ptr, quot_ptr;
mp_limb remainder_limb;
sign_dividend = dividend->size;
dividend_size = ABS (dividend->size);
if (dividend_size == 0)
{
quot->size = 0;
rem->size = 0;
return;
}
/* No need for temporary allocation and copying if QUOT == DIVIDEND as
the divisor is just one limb, and thus no intermediate remainders
need to be stored. */
if (quot->alloc < dividend_size)
_mpz_realloc (quot, dividend_size);
quot_ptr = quot->d;
dividend_ptr = dividend->d;
remainder_limb = mpn_divmod_1 (quot_ptr,
dividend_ptr, dividend_size, divisor_limb);
if (remainder_limb == 0)
rem->size = 0;
else
{
/* Store the single-limb remainder. We don't check if there's space
for just one limb, since no function ever makes zero space. */
rem->size = sign_dividend >= 0 ? 1 : -1;
rem->d[0] = 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->size = sign_dividend >= 0 ? quot_size : -quot_size;
}