148 lines
3.8 KiB
C
148 lines
3.8 KiB
C
/* mpz_mul -- Multiply two integers.
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Copyright 1991, 1993, 1994, 1996, 2000, 2001, 2005 Free Software Foundation,
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Inc.
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This file is part of the GNU MP Library.
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The GNU MP Library is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or (at your
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option) any later version.
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The GNU MP Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the GNU MP Library; see the file COPYING.LIB. If not, write to
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the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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MA 02110-1301, USA. */
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#include <stdio.h> /* for NULL */
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#include "gmp.h"
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#include "gmp-impl.h"
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#ifdef BERKELEY_MP
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#include "mp.h"
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#endif
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void
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#ifndef BERKELEY_MP
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mpz_mul (mpz_ptr w, mpz_srcptr u, mpz_srcptr v)
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#else /* BERKELEY_MP */
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mult (mpz_srcptr u, mpz_srcptr v, mpz_ptr w)
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#endif /* BERKELEY_MP */
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{
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mp_size_t usize = u->_mp_size;
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mp_size_t vsize = v->_mp_size;
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mp_size_t wsize;
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mp_size_t sign_product;
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mp_ptr up, vp;
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mp_ptr wp;
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mp_ptr free_me;
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size_t free_me_size;
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mp_limb_t cy_limb;
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TMP_DECL;
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sign_product = usize ^ vsize;
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usize = ABS (usize);
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vsize = ABS (vsize);
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if (usize < vsize)
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{
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MPZ_SRCPTR_SWAP (u, v);
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MP_SIZE_T_SWAP (usize, vsize);
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}
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if (vsize == 0)
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{
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SIZ(w) = 0;
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return;
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}
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#if HAVE_NATIVE_mpn_mul_2
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if (vsize <= 2)
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{
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MPZ_REALLOC (w, usize+vsize);
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wp = PTR(w);
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if (vsize == 1)
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cy_limb = mpn_mul_1 (wp, PTR(u), usize, PTR(v)[0]);
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else
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{
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cy_limb = mpn_mul_2 (wp, PTR(u), usize, PTR(v));
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usize++;
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}
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wp[usize] = cy_limb;
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usize += (cy_limb != 0);
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SIZ(w) = (sign_product >= 0 ? usize : -usize);
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return;
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}
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#else
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if (vsize == 1)
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{
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MPZ_REALLOC (w, usize+1);
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wp = PTR(w);
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cy_limb = mpn_mul_1 (wp, PTR(u), usize, PTR(v)[0]);
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wp[usize] = cy_limb;
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usize += (cy_limb != 0);
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SIZ(w) = (sign_product >= 0 ? usize : -usize);
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return;
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}
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#endif
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TMP_MARK;
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free_me = NULL;
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up = u->_mp_d;
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vp = v->_mp_d;
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wp = w->_mp_d;
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/* Ensure W has space enough to store the result. */
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wsize = usize + vsize;
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if (w->_mp_alloc < wsize)
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{
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if (wp == up || wp == vp)
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{
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free_me = wp;
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free_me_size = w->_mp_alloc;
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}
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else
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(*__gmp_free_func) (wp, w->_mp_alloc * BYTES_PER_MP_LIMB);
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w->_mp_alloc = wsize;
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wp = (mp_ptr) (*__gmp_allocate_func) (wsize * BYTES_PER_MP_LIMB);
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w->_mp_d = wp;
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}
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else
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{
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/* Make U and V not overlap with W. */
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if (wp == up)
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{
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/* W and U are identical. Allocate temporary space for U. */
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up = (mp_ptr) TMP_ALLOC (usize * BYTES_PER_MP_LIMB);
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/* Is V identical too? Keep it identical with U. */
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if (wp == vp)
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vp = up;
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/* Copy to the temporary space. */
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MPN_COPY (up, wp, usize);
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}
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else if (wp == vp)
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{
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/* W and V are identical. Allocate temporary space for V. */
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vp = (mp_ptr) TMP_ALLOC (vsize * BYTES_PER_MP_LIMB);
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/* Copy to the temporary space. */
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MPN_COPY (vp, wp, vsize);
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}
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}
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cy_limb = mpn_mul (wp, up, usize, vp, vsize);
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wsize = usize + vsize;
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wsize -= cy_limb == 0;
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w->_mp_size = sign_product < 0 ? -wsize : wsize;
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if (free_me != NULL)
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(*__gmp_free_func) (free_me, free_me_size * BYTES_PER_MP_LIMB);
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TMP_FREE;
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}
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