stk/Mp/gmp-1.3.2/mpz_mul_ui.c

79 lines
1.9 KiB
C
Raw Normal View History

1996-09-27 06:29:02 -04:00
/* mpz_mul_ui(product, multiplier, small_multiplicand) -- Set
PRODUCT to MULTIPLICATOR times SMALL_MULTIPLICAND.
Copyright (C) 1991 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_mul_ui (MP_INT *prod, const MP_INT *mult,
unsigned long int small_mult)
#else
mpz_mul_ui (prod, mult, small_mult)
MP_INT *prod;
const MP_INT *mult;
unsigned long int small_mult;
#endif
{
mp_size mult_size = mult->size;
mp_size sign_product = mult_size;
mp_size i;
mp_limb cy;
mp_size prod_size;
mp_srcptr mult_ptr;
mp_ptr prod_ptr;
mult_size = ABS (mult_size);
if (mult_size == 0 || small_mult == 0)
{
prod->size = 0;
return;
}
prod_size = mult_size + 1;
if (prod->alloc < prod_size)
_mpz_realloc (prod, prod_size);
mult_ptr = mult->d;
prod_ptr = prod->d;
cy = 0;
for (i = 0; i < mult_size; i++)
{
mp_limb p1, p0;
umul_ppmm (p1, p0, small_mult, mult_ptr[i]);
p0 += cy;
cy = p1 + (p0 < cy);
prod_ptr[i] = p0;
}
prod_size = mult_size;
if (cy != 0)
{
prod_ptr[mult_size] = cy;
prod_size++;
}
prod->size = sign_product > 0 ? prod_size : -prod_size;
}