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authorDuncan Wilkie <antigravityd@gmail.com>2023-11-18 06:11:09 -0600
committerDuncan Wilkie <antigravityd@gmail.com>2023-11-18 06:11:09 -0600
commit11da511c784eca003deb90c23570f0873954e0de (patch)
treee14fdd3d5d6345956d67e79ae771d0633d28362b /gmp-6.3.0/mpz/mul.c
Initial commit.
Diffstat (limited to 'gmp-6.3.0/mpz/mul.c')
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diff --git a/gmp-6.3.0/mpz/mul.c b/gmp-6.3.0/mpz/mul.c
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+/* mpz_mul -- Multiply two integers.
+
+Copyright 1991, 1993, 1994, 1996, 2000, 2001, 2005, 2009, 2011, 2012,
+2015 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 either:
+
+ * the GNU Lesser General Public License as published by the Free
+ Software Foundation; either version 3 of the License, or (at your
+ option) any later version.
+
+or
+
+ * the GNU General Public License as published by the Free Software
+ Foundation; either version 2 of the License, or (at your option) any
+ later version.
+
+or both in parallel, as here.
+
+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 copies of the GNU General Public License and the
+GNU Lesser General Public License along with the GNU MP Library. If not,
+see https://www.gnu.org/licenses/. */
+
+#include <stdio.h> /* for NULL */
+#include "gmp-impl.h"
+
+
+void
+mpz_mul (mpz_ptr w, mpz_srcptr u, mpz_srcptr v)
+{
+ mp_size_t usize;
+ mp_size_t vsize;
+ mp_size_t wsize;
+ mp_size_t sign_product;
+ mp_ptr up, vp;
+ mp_ptr wp;
+ mp_ptr free_me;
+ size_t free_me_size;
+ mp_limb_t cy_limb;
+ TMP_DECL;
+
+ usize = SIZ (u);
+ vsize = SIZ (v);
+ sign_product = usize ^ vsize;
+ usize = ABS (usize);
+ vsize = ABS (vsize);
+
+ if (usize < vsize)
+ {
+ MPZ_SRCPTR_SWAP (u, v);
+ MP_SIZE_T_SWAP (usize, vsize);
+ }
+
+ if (vsize == 0)
+ {
+ SIZ (w) = 0;
+ return;
+ }
+
+#if HAVE_NATIVE_mpn_mul_2
+ if (vsize <= 2)
+ {
+ wp = MPZ_REALLOC (w, usize+vsize);
+ if (vsize == 1)
+ cy_limb = mpn_mul_1 (wp, PTR (u), usize, PTR (v)[0]);
+ else
+ {
+ cy_limb = mpn_mul_2 (wp, PTR (u), usize, PTR (v));
+ usize++;
+ }
+ wp[usize] = cy_limb;
+ usize += (cy_limb != 0);
+ SIZ (w) = (sign_product >= 0 ? usize : -usize);
+ return;
+ }
+#else
+ if (vsize == 1)
+ {
+ wp = MPZ_REALLOC (w, usize+1);
+ cy_limb = mpn_mul_1 (wp, PTR (u), usize, PTR (v)[0]);
+ wp[usize] = cy_limb;
+ usize += (cy_limb != 0);
+ SIZ (w) = (sign_product >= 0 ? usize : -usize);
+ return;
+ }
+#endif
+
+ TMP_MARK;
+ free_me = NULL;
+ up = PTR (u);
+ vp = PTR (v);
+ wp = PTR (w);
+
+ /* Ensure W has space enough to store the result. */
+ wsize = usize + vsize;
+ if (ALLOC (w) < wsize)
+ {
+ if (ALLOC (w) != 0)
+ {
+ if (wp == up || wp == vp)
+ {
+ free_me = wp;
+ free_me_size = ALLOC (w);
+ }
+ else
+ (*__gmp_free_func) (wp, (size_t) ALLOC (w) * GMP_LIMB_BYTES);
+ }
+
+ ALLOC (w) = wsize;
+ wp = __GMP_ALLOCATE_FUNC_LIMBS (wsize);
+ PTR (w) = wp;
+ }
+ else
+ {
+ /* Make U and V not overlap with W. */
+ if (wp == up)
+ {
+ /* W and U are identical. Allocate temporary space for U. */
+ up = TMP_ALLOC_LIMBS (usize);
+ /* 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 = TMP_ALLOC_LIMBS (vsize);
+ /* Copy to the temporary space. */
+ MPN_COPY (vp, wp, vsize);
+ }
+ }
+
+ if (up == vp)
+ {
+ mpn_sqr (wp, up, usize);
+ cy_limb = wp[wsize - 1];
+ }
+ else
+ {
+ cy_limb = mpn_mul (wp, up, usize, vp, vsize);
+ }
+
+ wsize -= cy_limb == 0;
+
+ SIZ (w) = sign_product < 0 ? -wsize : wsize;
+ if (free_me != NULL)
+ (*__gmp_free_func) (free_me, free_me_size * GMP_LIMB_BYTES);
+ TMP_FREE;
+}