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Diffstat (limited to 'openssl/crypto/bn/bn_sqr.c')
| -rw-r--r-- | openssl/crypto/bn/bn_sqr.c | 294 |
1 files changed, 294 insertions, 0 deletions
diff --git a/openssl/crypto/bn/bn_sqr.c b/openssl/crypto/bn/bn_sqr.c new file mode 100644 index 000000000..270d0cd34 --- /dev/null +++ b/openssl/crypto/bn/bn_sqr.c @@ -0,0 +1,294 @@ +/* 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 <stdio.h> +#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 + fprintf(stderr,"BN_sqr %d * %d\n",a->top,a->top); +#endif + bn_check_top(a); + + al=a->top; + if (al <= 0) + { + r->top=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 + fprintf(stderr," 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 + 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 |