rdesktop/crypto/bn_sqr.c

/* 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 "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, BIGNUM *a, BN_CTX *ctx)
        {
        int max,al;
        int ret = 0;
        BIGNUM *tmp,*rr;

#ifdef BN_COUNT
printf("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 (tmp == NULL) goto err;

        max=(al+al);
        if (bn_wexpand(rr,max+1) == NULL) goto err;

        r->neg=0;
        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(a,k*2) == NULL) goto err;
                                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->top=max;
        if ((max > 0) && (rr->d[max-1] == 0)) rr->top--;
        if (rr != r) BN_copy(r,rr);
        ret = 1;
 err:
        BN_CTX_end(ctx);
        return(ret);
        }

/* tmp must have 2*n words */
void bn_sqr_normal(BN_ULONG *r, BN_ULONG *a, int n, BN_ULONG *tmp)
        {
        int i,j,max;
        BN_ULONG *ap,*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, BN_ULONG *a, int n2, BN_ULONG *t)
        {
        int n=n2/2;
        int zero,c1;
        BN_ULONG ln,lo,*p;

#ifdef BN_COUNT
printf(" 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
1	matty	32	/* crypto/bn/bn_sqr.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 "bn_lcl.h"
61
62			/* r must not be a */
63			/* I've just gone over this and it is now %20 faster on x86 - eay - 27 Jun 96 */
64			int BN_sqr(BIGNUM r, BIGNUM a, BN_CTX *ctx)
65			{
66			int max,al;
67			int ret = 0;
68			BIGNUM tmp,rr;
69
70			#ifdef BN_COUNT
71			printf("BN_sqr %d * %d\n",a->top,a->top);
72			#endif
73			bn_check_top(a);
74
75			al=a->top;
76			if (al <= 0)
77			{
78			r->top=0;
79			return(1);
80			}
81
82			BN_CTX_start(ctx);
83			rr=(a != r) ? r : BN_CTX_get(ctx);
84			tmp=BN_CTX_get(ctx);
85			if (tmp == NULL) goto err;
86
87			max=(al+al);
88			if (bn_wexpand(rr,max+1) == NULL) goto err;
89
90			r->neg=0;
91			if (al == 4)
92			{
93			#ifndef BN_SQR_COMBA
94			BN_ULONG t[8];
95			bn_sqr_normal(rr->d,a->d,4,t);
96			#else
97			bn_sqr_comba4(rr->d,a->d);
98			#endif
99			}
100			else if (al == 8)
101			{
102			#ifndef BN_SQR_COMBA
103			BN_ULONG t[16];
104			bn_sqr_normal(rr->d,a->d,8,t);
105			#else
106			bn_sqr_comba8(rr->d,a->d);
107			#endif
108			}
109			else
110			{
111			#if defined(BN_RECURSION)
112			if (al < BN_SQR_RECURSIVE_SIZE_NORMAL)
113			{
114			BN_ULONG t[BN_SQR_RECURSIVE_SIZE_NORMAL*2];
115			bn_sqr_normal(rr->d,a->d,al,t);
116			}
117			else
118			{
119			int j,k;
120
121			j=BN_num_bits_word((BN_ULONG)al);
122			j=1<<(j-1);
123			k=j+j;
124			if (al == j)
125			{
126			if (bn_wexpand(a,k*2) == NULL) goto err;
127			if (bn_wexpand(tmp,k*2) == NULL) goto err;
128			bn_sqr_recursive(rr->d,a->d,al,tmp->d);
129			}
130			else
131			{
132			if (bn_wexpand(tmp,max) == NULL) goto err;
133			bn_sqr_normal(rr->d,a->d,al,tmp->d);
134			}
135			}
136			#else
137			if (bn_wexpand(tmp,max) == NULL) goto err;
138			bn_sqr_normal(rr->d,a->d,al,tmp->d);
139			#endif
140			}
141
142			rr->top=max;
143			if ((max > 0) && (rr->d[max-1] == 0)) rr->top--;
144			if (rr != r) BN_copy(r,rr);
145			ret = 1;
146			err:
147			BN_CTX_end(ctx);
148			return(ret);
149			}
150
151			/* tmp must have 2n words /
152			void bn_sqr_normal(BN_ULONG r, BN_ULONG a, int n, BN_ULONG *tmp)
153			{
154			int i,j,max;
155			BN_ULONG ap,rp;
156
157			max=n*2;
158			ap=a;
159			rp=r;
160			rp[0]=rp[max-1]=0;
161			rp++;
162			j=n;
163
164			if (--j > 0)
165			{
166			ap++;
167			rp[j]=bn_mul_words(rp,ap,j,ap[-1]);
168			rp+=2;
169			}
170
171			for (i=n-2; i>0; i--)
172			{
173			j--;
174			ap++;
175			rp[j]=bn_mul_add_words(rp,ap,j,ap[-1]);
176			rp+=2;
177			}
178
179			bn_add_words(r,r,r,max);
180
181			/* There will not be a carry */
182
183			bn_sqr_words(tmp,a,n);
184
185			bn_add_words(r,r,tmp,max);
186			}
187
188			#ifdef BN_RECURSION
189			/* r is 2*n words in size,
190			* a and b are both n words in size. (There's not actually a 'b' here ...)
191			* n must be a power of 2.
192			* We multiply and return the result.
193			* t must be 2*n words in size
194			* We calculate
195			* a[0]*b[0]
196			* a[0]b[0]+a[1]b[1]+(a[0]-a[1])*(b[1]-b[0])
197			* a[1]*b[1]
198			*/
199			void bn_sqr_recursive(BN_ULONG r, BN_ULONG a, int n2, BN_ULONG *t)
200			{
201			int n=n2/2;
202			int zero,c1;
203			BN_ULONG ln,lo,*p;
204
205			#ifdef BN_COUNT
206			printf(" bn_sqr_recursive %d * %d\n",n2,n2);
207			#endif
208			if (n2 == 4)
209			{
210			#ifndef BN_SQR_COMBA
211			bn_sqr_normal(r,a,4,t);
212			#else
213			bn_sqr_comba4(r,a);
214			#endif
215			return;
216			}
217			else if (n2 == 8)
218			{
219			#ifndef BN_SQR_COMBA
220			bn_sqr_normal(r,a,8,t);
221			#else
222			bn_sqr_comba8(r,a);
223			#endif
224			return;
225			}
226			if (n2 < BN_SQR_RECURSIVE_SIZE_NORMAL)
227			{
228			bn_sqr_normal(r,a,n2,t);
229			return;
230			}
231			/* r=(a[0]-a[1])(a[1]-a[0]) /
232			c1=bn_cmp_words(a,&(a[n]),n);
233			zero=0;
234			if (c1 > 0)
235			bn_sub_words(t,a,&(a[n]),n);
236			else if (c1 < 0)
237			bn_sub_words(t,&(a[n]),a,n);
238			else
239			zero=1;
240
241			/* The result will always be negative unless it is zero */
242			p= &(t[n2*2]);
243
244			if (!zero)
245			bn_sqr_recursive(&(t[n2]),t,n,p);
246			else
247	matthewc	195	memset(&(t[n2]),0,n2*sizeof(BN_ULONG));
248	matty	32	bn_sqr_recursive(r,a,n,p);
249			bn_sqr_recursive(&(r[n2]),&(a[n]),n,p);
250
251			/* t[32] holds (a[0]-a[1])*(a[1]-a[0]), it is negative or zero
252			* r[10] holds (a[0]*b[0])
253			* r[32] holds (b[1]*b[1])
254			*/
255
256			c1=(int)(bn_add_words(t,r,&(r[n2]),n2));
257
258			/* t[32] is negative */
259			c1-=(int)(bn_sub_words(&(t[n2]),t,&(t[n2]),n2));
260
261			/* t[32] holds (a[0]-a[1])(a[1]-a[0])+(a[0]a[0])+(a[1]*a[1])
262			* r[10] holds (a[0]*a[0])
263			* r[32] holds (a[1]*a[1])
264			* c1 holds the carry bits
265			*/
266			c1+=(int)(bn_add_words(&(r[n]),&(r[n]),&(t[n2]),n2));
267			if (c1)
268			{
269			p= &(r[n+n2]);
270			lo= *p;
271			ln=(lo+c1)&BN_MASK2;
272			*p=ln;
273
274			/* The overflow will stop before we over write
275			* words we should not overwrite */
276			if (ln < (BN_ULONG)c1)
277			{
278			do {
279			p++;
280			lo= *p;
281			ln=(lo+1)&BN_MASK2;
282			*p=ln;
283			} while (ln == 0);
284			}
285			}
286			}
287			#endif