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freebsd/contrib/libgmp/mpz/mul.c
Mark Murray aa9bc17601 Clean import of libgmp 2.0.2, with only the non-x86 bits removed.
BMakefiles and other bits will follow.

Requested by:	Andrey Chernov
Made world by:	Chuck Robey
1996-10-20 08:49:26 +00:00

128 lines
3.1 KiB
C

/* mpz_mul -- Multiply two integers.
Copyright (C) 1991, 1993, 1994, 1996 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 Library General Public License as published by
the Free Software Foundation; either version 2 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 Library General Public
License for more details.
You should have received a copy of the GNU Library General Public License
along with the GNU MP Library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA. */
#include "gmp.h"
#include "gmp-impl.h"
#ifndef BERKELEY_MP
void
#if __STDC__
mpz_mul (mpz_ptr w, mpz_srcptr u, mpz_srcptr v)
#else
mpz_mul (w, u, v)
mpz_ptr w;
mpz_srcptr u;
mpz_srcptr v;
#endif
#else /* BERKELEY_MP */
void
#if __STDC__
mult (mpz_srcptr u, mpz_srcptr v, mpz_ptr w)
#else
mult (u, v, w)
mpz_srcptr u;
mpz_srcptr v;
mpz_ptr w;
#endif
#endif /* BERKELEY_MP */
{
mp_size_t usize = u->_mp_size;
mp_size_t vsize = v->_mp_size;
mp_size_t wsize;
mp_size_t sign_product;
mp_ptr up, vp;
mp_ptr wp;
mp_ptr free_me = NULL;
size_t free_me_size;
mp_limb_t cy_limb;
TMP_DECL (marker);
TMP_MARK (marker);
sign_product = usize ^ vsize;
usize = ABS (usize);
vsize = ABS (vsize);
if (usize < vsize)
{
/* Swap U and V. */
{const __mpz_struct *t = u; u = v; v = t;}
{mp_size_t t = usize; usize = vsize; vsize = t;}
}
up = u->_mp_d;
vp = v->_mp_d;
wp = w->_mp_d;
/* Ensure W has space enough to store the result. */
wsize = usize + vsize;
if (w->_mp_alloc < wsize)
{
if (wp == up || wp == vp)
{
free_me = wp;
free_me_size = w->_mp_alloc;
}
else
(*_mp_free_func) (wp, w->_mp_alloc * BYTES_PER_MP_LIMB);
w->_mp_alloc = wsize;
wp = (mp_ptr) (*_mp_allocate_func) (wsize * BYTES_PER_MP_LIMB);
w->_mp_d = wp;
}
else
{
/* Make U and V not overlap with W. */
if (wp == up)
{
/* W and U are identical. Allocate temporary space for U. */
up = (mp_ptr) TMP_ALLOC (usize * BYTES_PER_MP_LIMB);
/* Is V identical too? Keep it identical with U. */
if (wp == vp)
vp = up;
/* Copy to the temporary space. */
MPN_COPY (up, wp, usize);
}
else if (wp == vp)
{
/* W and V are identical. Allocate temporary space for V. */
vp = (mp_ptr) TMP_ALLOC (vsize * BYTES_PER_MP_LIMB);
/* Copy to the temporary space. */
MPN_COPY (vp, wp, vsize);
}
}
if (vsize == 0)
{
wsize = 0;
}
else
{
cy_limb = mpn_mul (wp, up, usize, vp, vsize);
wsize = usize + vsize;
wsize -= cy_limb == 0;
}
w->_mp_size = sign_product < 0 ? -wsize : wsize;
if (free_me != NULL)
(*_mp_free_func) (free_me, free_me_size * BYTES_PER_MP_LIMB);
TMP_FREE (marker);
}