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ext-libressl-portable/crypto/bn/bn_mul.c
Steveice10 41de3f161a libressl: Update to 3.8.0
2023-06-04 17:13:21 -07:00

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/* $OpenBSD: bn_mul.c,v 1.37 2023/04/19 10:51:22 jsing Exp $ */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
* All rights reserved.
*
* This package is an SSL implementation written
* by Eric Young (eay@cryptsoft.com).
* The implementation was written so as to conform with Netscapes SSL.
*
* This library is free for commercial and non-commercial use as long as
* the following conditions are aheared to. The following conditions
* apply to all code found in this distribution, be it the RC4, RSA,
* lhash, DES, etc., code; not just the SSL code. The SSL documentation
* included with this distribution is covered by the same copyright terms
* except that the holder is Tim Hudson (tjh@cryptsoft.com).
*
* Copyright remains Eric Young's, and as such any Copyright notices in
* the code are not to be removed.
* If this package is used in a product, Eric Young should be given attribution
* as the author of the parts of the library used.
* This can be in the form of a textual message at program startup or
* in documentation (online or textual) provided with the package.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* "This product includes cryptographic software written by
* Eric Young (eay@cryptsoft.com)"
* The word 'cryptographic' can be left out if the rouines from the library
* being used are not cryptographic related :-).
* 4. If you include any Windows specific code (or a derivative thereof) from
* the apps directory (application code) you must include an acknowledgement:
* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
*
* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* The licence and distribution terms for any publically available version or
* derivative of this code cannot be changed. i.e. this code cannot simply be
* copied and put under another distribution licence
* [including the GNU Public Licence.]
*/
#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <openssl/opensslconf.h>
#include "bn_arch.h"
#include "bn_internal.h"
#include "bn_local.h"
/*
* bn_mul_comba4() computes r[] = a[] * b[] using Comba multiplication
* (https://everything2.com/title/Comba+multiplication), where a and b are both
* four word arrays, producing an eight word array result.
*/
#ifndef HAVE_BN_MUL_COMBA4
void
bn_mul_comba4(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b)
{
BN_ULONG c0, c1, c2;
bn_mulw_addtw(a[0], b[0], 0, 0, 0, &c2, &c1, &r[0]);
bn_mulw_addtw(a[0], b[1], 0, c2, c1, &c2, &c1, &c0);
bn_mulw_addtw(a[1], b[0], c2, c1, c0, &c2, &c1, &r[1]);
bn_mulw_addtw(a[2], b[0], 0, c2, c1, &c2, &c1, &c0);
bn_mulw_addtw(a[1], b[1], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[0], b[2], c2, c1, c0, &c2, &c1, &r[2]);
bn_mulw_addtw(a[0], b[3], 0, c2, c1, &c2, &c1, &c0);
bn_mulw_addtw(a[1], b[2], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[2], b[1], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[3], b[0], c2, c1, c0, &c2, &c1, &r[3]);
bn_mulw_addtw(a[3], b[1], 0, c2, c1, &c2, &c1, &c0);
bn_mulw_addtw(a[2], b[2], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[1], b[3], c2, c1, c0, &c2, &c1, &r[4]);
bn_mulw_addtw(a[2], b[3], 0, c2, c1, &c2, &c1, &c0);
bn_mulw_addtw(a[3], b[2], c2, c1, c0, &c2, &c1, &r[5]);
bn_mulw_addtw(a[3], b[3], 0, c2, c1, &c2, &r[7], &r[6]);
}
#endif
/*
* bn_mul_comba8() computes r[] = a[] * b[] using Comba multiplication
* (https://everything2.com/title/Comba+multiplication), where a and b are both
* eight word arrays, producing a 16 word array result.
*/
#ifndef HAVE_BN_MUL_COMBA8
void
bn_mul_comba8(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b)
{
BN_ULONG c0, c1, c2;
bn_mulw_addtw(a[0], b[0], 0, 0, 0, &c2, &c1, &r[0]);
bn_mulw_addtw(a[0], b[1], 0, c2, c1, &c2, &c1, &c0);
bn_mulw_addtw(a[1], b[0], c2, c1, c0, &c2, &c1, &r[1]);
bn_mulw_addtw(a[2], b[0], 0, c2, c1, &c2, &c1, &c0);
bn_mulw_addtw(a[1], b[1], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[0], b[2], c2, c1, c0, &c2, &c1, &r[2]);
bn_mulw_addtw(a[0], b[3], 0, c2, c1, &c2, &c1, &c0);
bn_mulw_addtw(a[1], b[2], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[2], b[1], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[3], b[0], c2, c1, c0, &c2, &c1, &r[3]);
bn_mulw_addtw(a[4], b[0], 0, c2, c1, &c2, &c1, &c0);
bn_mulw_addtw(a[3], b[1], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[2], b[2], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[1], b[3], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[0], b[4], c2, c1, c0, &c2, &c1, &r[4]);
bn_mulw_addtw(a[0], b[5], 0, c2, c1, &c2, &c1, &c0);
bn_mulw_addtw(a[1], b[4], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[2], b[3], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[3], b[2], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[4], b[1], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[5], b[0], c2, c1, c0, &c2, &c1, &r[5]);
bn_mulw_addtw(a[6], b[0], 0, c2, c1, &c2, &c1, &c0);
bn_mulw_addtw(a[5], b[1], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[4], b[2], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[3], b[3], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[2], b[4], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[1], b[5], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[0], b[6], c2, c1, c0, &c2, &c1, &r[6]);
bn_mulw_addtw(a[0], b[7], 0, c2, c1, &c2, &c1, &c0);
bn_mulw_addtw(a[1], b[6], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[2], b[5], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[3], b[4], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[4], b[3], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[5], b[2], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[6], b[1], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[7], b[0], c2, c1, c0, &c2, &c1, &r[7]);
bn_mulw_addtw(a[7], b[1], 0, c2, c1, &c2, &c1, &c0);
bn_mulw_addtw(a[6], b[2], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[5], b[3], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[4], b[4], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[3], b[5], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[2], b[6], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[1], b[7], c2, c1, c0, &c2, &c1, &r[8]);
bn_mulw_addtw(a[2], b[7], 0, c2, c1, &c2, &c1, &c0);
bn_mulw_addtw(a[3], b[6], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[4], b[5], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[5], b[4], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[6], b[3], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[7], b[2], c2, c1, c0, &c2, &c1, &r[9]);
bn_mulw_addtw(a[7], b[3], 0, c2, c1, &c2, &c1, &c0);
bn_mulw_addtw(a[6], b[4], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[5], b[5], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[4], b[6], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[3], b[7], c2, c1, c0, &c2, &c1, &r[10]);
bn_mulw_addtw(a[4], b[7], 0, c2, c1, &c2, &c1, &c0);
bn_mulw_addtw(a[5], b[6], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[6], b[5], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[7], b[4], c2, c1, c0, &c2, &c1, &r[11]);
bn_mulw_addtw(a[7], b[5], 0, c2, c1, &c2, &c1, &c0);
bn_mulw_addtw(a[6], b[6], c2, c1, c0, &c2, &c1, &c0);
bn_mulw_addtw(a[5], b[7], c2, c1, c0, &c2, &c1, &r[12]);
bn_mulw_addtw(a[6], b[7], 0, c2, c1, &c2, &c1, &c0);
bn_mulw_addtw(a[7], b[6], c2, c1, c0, &c2, &c1, &r[13]);
bn_mulw_addtw(a[7], b[7], 0, c2, c1, &c2, &r[15], &r[14]);
}
#endif
/*
* bn_mul_words() computes (carry:r[i]) = a[i] * w + carry, where a is an array
* of words and w is a single word. This should really be called bn_mulw_words()
* since only one input is an array. This is used as a step in the multiplication
* of word arrays.
*/
#ifndef HAVE_BN_MUL_WORDS
BN_ULONG
bn_mul_words(BN_ULONG *r, const BN_ULONG *a, int num, BN_ULONG w)
{
BN_ULONG carry = 0;
assert(num >= 0);
if (num <= 0)
return 0;
#ifndef OPENSSL_SMALL_FOOTPRINT
while (num & ~3) {
bn_mulw_addw(a[0], w, carry, &carry, &r[0]);
bn_mulw_addw(a[1], w, carry, &carry, &r[1]);
bn_mulw_addw(a[2], w, carry, &carry, &r[2]);
bn_mulw_addw(a[3], w, carry, &carry, &r[3]);
a += 4;
r += 4;
num -= 4;
}
#endif
while (num) {
bn_mulw_addw(a[0], w, carry, &carry, &r[0]);
a++;
r++;
num--;
}
return carry;
}
#endif
/*
* bn_mul_add_words() computes (carry:r[i]) = a[i] * w + r[i] + carry, where
* a is an array of words and w is a single word. This should really be called
* bn_mulw_add_words() since only one input is an array. This is used as a step
* in the multiplication of word arrays.
*/
#ifndef HAVE_BN_MUL_ADD_WORDS
BN_ULONG
bn_mul_add_words(BN_ULONG *r, const BN_ULONG *a, int num, BN_ULONG w)
{
BN_ULONG carry = 0;
assert(num >= 0);
if (num <= 0)
return 0;
#ifndef OPENSSL_SMALL_FOOTPRINT
while (num & ~3) {
bn_mulw_addw_addw(a[0], w, r[0], carry, &carry, &r[0]);
bn_mulw_addw_addw(a[1], w, r[1], carry, &carry, &r[1]);
bn_mulw_addw_addw(a[2], w, r[2], carry, &carry, &r[2]);
bn_mulw_addw_addw(a[3], w, r[3], carry, &carry, &r[3]);
a += 4;
r += 4;
num -= 4;
}
#endif
while (num) {
bn_mulw_addw_addw(a[0], w, r[0], carry, &carry, &r[0]);
a++;
r++;
num--;
}
return carry;
}
#endif
void
bn_mul_normal(BN_ULONG *r, BN_ULONG *a, int na, BN_ULONG *b, int nb)
{
BN_ULONG *rr;
if (na < nb) {
int itmp;
BN_ULONG *ltmp;
itmp = na;
na = nb;
nb = itmp;
ltmp = a;
a = b;
b = ltmp;
}
rr = &(r[na]);
if (nb <= 0) {
(void)bn_mul_words(r, a, na, 0);
return;
} else
rr[0] = bn_mul_words(r, a, na, b[0]);
for (;;) {
if (--nb <= 0)
return;
rr[1] = bn_mul_add_words(&(r[1]), a, na, b[1]);
if (--nb <= 0)
return;
rr[2] = bn_mul_add_words(&(r[2]), a, na, b[2]);
if (--nb <= 0)
return;
rr[3] = bn_mul_add_words(&(r[3]), a, na, b[3]);
if (--nb <= 0)
return;
rr[4] = bn_mul_add_words(&(r[4]), a, na, b[4]);
rr += 4;
r += 4;
b += 4;
}
}
#ifndef HAVE_BN_MUL
int
bn_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, int rn, BN_CTX *ctx)
{
bn_mul_normal(r->d, a->d, a->top, b->d, b->top);
return 1;
}
#endif /* HAVE_BN_MUL */
int
BN_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
{
BIGNUM *rr;
int rn;
int ret = 0;
BN_CTX_start(ctx);
if (BN_is_zero(a) || BN_is_zero(b)) {
BN_zero(r);
goto done;
}
rr = r;
if (rr == a || rr == b)
rr = BN_CTX_get(ctx);
if (rr == NULL)
goto err;
rn = a->top + b->top;
if (rn < a->top)
goto err;
if (!bn_wexpand(rr, rn))
goto err;
if (a->top == 4 && b->top == 4) {
bn_mul_comba4(rr->d, a->d, b->d);
} else if (a->top == 8 && b->top == 8) {
bn_mul_comba8(rr->d, a->d, b->d);
} else {
if (!bn_mul(rr, a, b, rn, ctx))
goto err;
}
rr->top = rn;
bn_correct_top(rr);
BN_set_negative(rr, a->neg ^ b->neg);
if (!bn_copy(r, rr))
goto err;
done:
ret = 1;
err:
BN_CTX_end(ctx);
return ret;
}
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