1/* crypto/bn/bn_mul.c */
2/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3 * All rights reserved.
4 *
5 * This package is an SSL implementation written
6 * by Eric Young (eay@cryptsoft.com).
7 * The implementation was written so as to conform with Netscapes SSL.
8 *
9 * This library is free for commercial and non-commercial use as long as
10 * the following conditions are aheared to.  The following conditions
11 * apply to all code found in this distribution, be it the RC4, RSA,
12 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
13 * included with this distribution is covered by the same copyright terms
14 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15 *
16 * Copyright remains Eric Young's, and as such any Copyright notices in
17 * the code are not to be removed.
18 * If this package is used in a product, Eric Young should be given attribution
19 * as the author of the parts of the library used.
20 * This can be in the form of a textual message at program startup or
21 * in documentation (online or textual) provided with the package.
22 *
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
25 * are met:
26 * 1. Redistributions of source code must retain the copyright
27 *    notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 *    notice, this list of conditions and the following disclaimer in the
30 *    documentation and/or other materials provided with the distribution.
31 * 3. All advertising materials mentioning features or use of this software
32 *    must display the following acknowledgement:
33 *    "This product includes cryptographic software written by
34 *     Eric Young (eay@cryptsoft.com)"
35 *    The word 'cryptographic' can be left out if the rouines from the library
36 *    being used are not cryptographic related :-).
37 * 4. If you include any Windows specific code (or a derivative thereof) from
38 *    the apps directory (application code) you must include an acknowledgement:
39 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40 *
41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51 * SUCH DAMAGE.
52 *
53 * The licence and distribution terms for any publically available version or
54 * derivative of this code cannot be changed.  i.e. this code cannot simply be
55 * copied and put under another distribution licence
56 * [including the GNU Public Licence.]
57 */
58
59#include <stdio.h>
60#include <string.h>
61#include "bn_lcl.h"
62
63int BN_mul(BIGNUM *r, BIGNUM *a, BIGNUM *b, BN_CTX *ctx)
64	{
65	int top,al,bl;
66	BIGNUM *rr;
67	int ret = 0;
68#if defined(BN_MUL_COMBA) || defined(BN_RECURSION)
69	int i;
70#endif
71
72#ifdef BN_COUNT
73	printf("BN_mul %d * %d\n",a->top,b->top);
74#endif
75
76	bn_check_top(a);
77	bn_check_top(b);
78	bn_check_top(r);
79
80	al=a->top;
81	bl=b->top;
82
83	if ((al == 0) || (bl == 0))
84		{
85		BN_zero(r);
86		return(1);
87		}
88	top=al+bl;
89
90	BN_CTX_start(ctx);
91	if ((r == a) || (r == b))
92		{
93		if ((rr = BN_CTX_get(ctx)) == NULL) goto err;
94		}
95	else
96		rr = r;
97	rr->neg=a->neg^b->neg;
98
99#if defined(BN_MUL_COMBA) || defined(BN_RECURSION)
100	i = al-bl;
101#endif
102#ifdef BN_MUL_COMBA
103	if (i == 0)
104		{
105# if 0
106		if (al == 4)
107			{
108			if (bn_wexpand(rr,8) == NULL) goto err;
109			rr->top=8;
110			bn_mul_comba4(rr->d,a->d,b->d);
111			goto end;
112			}
113# endif
114		if (al == 8)
115			{
116			if (bn_wexpand(rr,16) == NULL) goto err;
117			rr->top=16;
118			bn_mul_comba8(rr->d,a->d,b->d);
119			goto end;
120			}
121		}
122#endif /* BN_MUL_COMBA */
123	if (bn_wexpand(rr,top) == NULL) goto err;
124	rr->top=top;
125	bn_mul_normal(rr->d,a->d,al,b->d,bl);
126
127#if defined(BN_MUL_COMBA) || defined(BN_RECURSION)
128end:
129#endif
130	bn_fix_top(rr);
131	if (r != rr) BN_copy(r,rr);
132	ret=1;
133err:
134	BN_CTX_end(ctx);
135	return(ret);
136	}
137
138void bn_mul_normal(BN_ULONG *r, BN_ULONG *a, int na, BN_ULONG *b, int nb)
139	{
140	BN_ULONG *rr;
141
142#ifdef BN_COUNT
143	printf(" bn_mul_normal %d * %d\n",na,nb);
144#endif
145
146	if (na < nb)
147		{
148		int itmp;
149		BN_ULONG *ltmp;
150
151		itmp=na; na=nb; nb=itmp;
152		ltmp=a;   a=b;   b=ltmp;
153
154		}
155	rr= &(r[na]);
156	rr[0]=bn_mul_words(r,a,na,b[0]);
157
158	for (;;)
159		{
160		if (--nb <= 0) return;
161		rr[1]=bn_mul_add_words(&(r[1]),a,na,b[1]);
162		if (--nb <= 0) return;
163		rr[2]=bn_mul_add_words(&(r[2]),a,na,b[2]);
164		if (--nb <= 0) return;
165		rr[3]=bn_mul_add_words(&(r[3]),a,na,b[3]);
166		if (--nb <= 0) return;
167		rr[4]=bn_mul_add_words(&(r[4]),a,na,b[4]);
168		rr+=4;
169		r+=4;
170		b+=4;
171		}
172	}
173