| /* crypto/bn/bn_sqr.c */ |
| /* 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 <openssl/opensslconf.h> |
| #if !defined(OPENSSL_SYS_STARBOARD) |
| #include <stdio.h> |
| #endif // !defined(OPENSSL_SYS_STARBOARD) |
| #include "cryptlib.h" |
| #include "bn_lcl.h" |
| |
| /* r must not be a */ |
| /* |
| * I've just gone over this and it is now %20 faster on x86 - eay - 27 Jun 96 |
| */ |
| int BN_sqr(BIGNUM *r, const BIGNUM *a, BN_CTX *ctx) |
| { |
| int max, al; |
| int ret = 0; |
| BIGNUM *tmp, *rr; |
| |
| #ifdef BN_COUNT |
| OPENSSL_port_printferr("BN_sqr %d * %d\n", a->top, a->top); |
| #endif |
| bn_check_top(a); |
| |
| al = a->top; |
| if (al <= 0) { |
| r->top = 0; |
| r->neg = 0; |
| return 1; |
| } |
| |
| BN_CTX_start(ctx); |
| rr = (a != r) ? r : BN_CTX_get(ctx); |
| tmp = BN_CTX_get(ctx); |
| if (!rr || !tmp) |
| goto err; |
| |
| max = 2 * al; /* Non-zero (from above) */ |
| if (bn_wexpand(rr, max) == NULL) |
| goto err; |
| |
| if (al == 4) { |
| #ifndef BN_SQR_COMBA |
| BN_ULONG t[8]; |
| bn_sqr_normal(rr->d, a->d, 4, t); |
| #else |
| bn_sqr_comba4(rr->d, a->d); |
| #endif |
| } else if (al == 8) { |
| #ifndef BN_SQR_COMBA |
| BN_ULONG t[16]; |
| bn_sqr_normal(rr->d, a->d, 8, t); |
| #else |
| bn_sqr_comba8(rr->d, a->d); |
| #endif |
| } else { |
| #if defined(BN_RECURSION) |
| if (al < BN_SQR_RECURSIVE_SIZE_NORMAL) { |
| BN_ULONG t[BN_SQR_RECURSIVE_SIZE_NORMAL * 2]; |
| bn_sqr_normal(rr->d, a->d, al, t); |
| } else { |
| int j, k; |
| |
| j = BN_num_bits_word((BN_ULONG)al); |
| j = 1 << (j - 1); |
| k = j + j; |
| if (al == j) { |
| if (bn_wexpand(tmp, k * 2) == NULL) |
| goto err; |
| bn_sqr_recursive(rr->d, a->d, al, tmp->d); |
| } else { |
| if (bn_wexpand(tmp, max) == NULL) |
| goto err; |
| bn_sqr_normal(rr->d, a->d, al, tmp->d); |
| } |
| } |
| #else |
| if (bn_wexpand(tmp, max) == NULL) |
| goto err; |
| bn_sqr_normal(rr->d, a->d, al, tmp->d); |
| #endif |
| } |
| |
| rr->neg = 0; |
| /* |
| * If the most-significant half of the top word of 'a' is zero, then the |
| * square of 'a' will max-1 words. |
| */ |
| if (a->d[al - 1] == (a->d[al - 1] & BN_MASK2l)) |
| rr->top = max - 1; |
| else |
| rr->top = max; |
| if (rr != r) |
| BN_copy(r, rr); |
| ret = 1; |
| err: |
| bn_check_top(rr); |
| bn_check_top(tmp); |
| BN_CTX_end(ctx); |
| return (ret); |
| } |
| |
| /* tmp must have 2*n words */ |
| void bn_sqr_normal(BN_ULONG *r, const BN_ULONG *a, int n, BN_ULONG *tmp) |
| { |
| int i, j, max; |
| const BN_ULONG *ap; |
| BN_ULONG *rp; |
| |
| max = n * 2; |
| ap = a; |
| rp = r; |
| rp[0] = rp[max - 1] = 0; |
| rp++; |
| j = n; |
| |
| if (--j > 0) { |
| ap++; |
| rp[j] = bn_mul_words(rp, ap, j, ap[-1]); |
| rp += 2; |
| } |
| |
| for (i = n - 2; i > 0; i--) { |
| j--; |
| ap++; |
| rp[j] = bn_mul_add_words(rp, ap, j, ap[-1]); |
| rp += 2; |
| } |
| |
| bn_add_words(r, r, r, max); |
| |
| /* There will not be a carry */ |
| |
| bn_sqr_words(tmp, a, n); |
| |
| bn_add_words(r, r, tmp, max); |
| } |
| |
| #ifdef BN_RECURSION |
| /*- |
| * r is 2*n words in size, |
| * a and b are both n words in size. (There's not actually a 'b' here ...) |
| * n must be a power of 2. |
| * We multiply and return the result. |
| * t must be 2*n words in size |
| * We calculate |
| * a[0]*b[0] |
| * a[0]*b[0]+a[1]*b[1]+(a[0]-a[1])*(b[1]-b[0]) |
| * a[1]*b[1] |
| */ |
| void bn_sqr_recursive(BN_ULONG *r, const BN_ULONG *a, int n2, BN_ULONG *t) |
| { |
| int n = n2 / 2; |
| int zero, c1; |
| BN_ULONG ln, lo, *p; |
| |
| # ifdef BN_COUNT |
| OPENSSL_port_printferr(" bn_sqr_recursive %d * %d\n", n2, n2); |
| # endif |
| if (n2 == 4) { |
| # ifndef BN_SQR_COMBA |
| bn_sqr_normal(r, a, 4, t); |
| # else |
| bn_sqr_comba4(r, a); |
| # endif |
| return; |
| } else if (n2 == 8) { |
| # ifndef BN_SQR_COMBA |
| bn_sqr_normal(r, a, 8, t); |
| # else |
| bn_sqr_comba8(r, a); |
| # endif |
| return; |
| } |
| if (n2 < BN_SQR_RECURSIVE_SIZE_NORMAL) { |
| bn_sqr_normal(r, a, n2, t); |
| return; |
| } |
| /* r=(a[0]-a[1])*(a[1]-a[0]) */ |
| c1 = bn_cmp_words(a, &(a[n]), n); |
| zero = 0; |
| if (c1 > 0) |
| bn_sub_words(t, a, &(a[n]), n); |
| else if (c1 < 0) |
| bn_sub_words(t, &(a[n]), a, n); |
| else |
| zero = 1; |
| |
| /* The result will always be negative unless it is zero */ |
| p = &(t[n2 * 2]); |
| |
| if (!zero) |
| bn_sqr_recursive(&(t[n2]), t, n, p); |
| else |
| OPENSSL_port_memset(&(t[n2]), 0, n2 * sizeof(BN_ULONG)); |
| bn_sqr_recursive(r, a, n, p); |
| bn_sqr_recursive(&(r[n2]), &(a[n]), n, p); |
| |
| /*- |
| * t[32] holds (a[0]-a[1])*(a[1]-a[0]), it is negative or zero |
| * r[10] holds (a[0]*b[0]) |
| * r[32] holds (b[1]*b[1]) |
| */ |
| |
| c1 = (int)(bn_add_words(t, r, &(r[n2]), n2)); |
| |
| /* t[32] is negative */ |
| c1 -= (int)(bn_sub_words(&(t[n2]), t, &(t[n2]), n2)); |
| |
| /*- |
| * t[32] holds (a[0]-a[1])*(a[1]-a[0])+(a[0]*a[0])+(a[1]*a[1]) |
| * r[10] holds (a[0]*a[0]) |
| * r[32] holds (a[1]*a[1]) |
| * c1 holds the carry bits |
| */ |
| c1 += (int)(bn_add_words(&(r[n]), &(r[n]), &(t[n2]), n2)); |
| if (c1) { |
| p = &(r[n + n2]); |
| lo = *p; |
| ln = (lo + c1) & BN_MASK2; |
| *p = ln; |
| |
| /* |
| * The overflow will stop before we over write words we should not |
| * overwrite |
| */ |
| if (ln < (BN_ULONG)c1) { |
| do { |
| p++; |
| lo = *p; |
| ln = (lo + 1) & BN_MASK2; |
| *p = ln; |
| } while (ln == 0); |
| } |
| } |
| } |
| #endif |