source: trunk/cscrypt/bn_mul.c@ 1

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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#include "openssl_mods.h"
63
64#ifdef BN_RECURSION
65/* Karatsuba recursive multiplication algorithm
66 * (cf. Knuth, The Art of Computer Programming, Vol. 2) */
67
68/* r is 2*n2 words in size,
69 * a and b are both n2 words in size.
70 * n2 must be a power of 2.
71 * We multiply and return the result.
72 * t must be 2*n2 words in size
73 * We calculate
74 * a[0]*b[0]
75 * a[0]*b[0]+a[1]*b[1]+(a[0]-a[1])*(b[1]-b[0])
76 * a[1]*b[1]
77 */
78void bn_mul_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n2,
79 BN_ULONG *t)
80 {
81 int n=n2/2,c1,c2;
82 unsigned int neg,zero;
83 BN_ULONG ln,lo,*p;
84
85# ifdef BN_COUNT
86 printf(" bn_mul_recursive %d * %d\n",n2,n2);
87# endif
88# ifdef BN_MUL_COMBA
89# if 0
90 if (n2 == 4)
91 {
92 bn_mul_comba4(r,a,b);
93 return;
94 }
95# endif
96 if (n2 == 8)
97 {
98 bn_mul_comba8(r,a,b);
99 return;
100 }
101# endif /* BN_MUL_COMBA */
102 if (n2 < BN_MUL_RECURSIVE_SIZE_NORMAL)
103 {
104 /* This should not happen */
105 bn_mul_normal(r,a,n2,b,n2);
106 return;
107 }
108 /* r=(a[0]-a[1])*(b[1]-b[0]) */
109 c1=bn_cmp_words(a,&(a[n]),n);
110 c2=bn_cmp_words(&(b[n]),b,n);
111 zero=neg=0;
112 switch (c1*3+c2)
113 {
114 case -4:
115 bn_sub_words(t, &(a[n]),a, n); /* - */
116 bn_sub_words(&(t[n]),b, &(b[n]),n); /* - */
117 break;
118 case -3:
119 zero=1;
120 break;
121 case -2:
122 bn_sub_words(t, &(a[n]),a, n); /* - */
123 bn_sub_words(&(t[n]),&(b[n]),b, n); /* + */
124 neg=1;
125 break;
126 case -1:
127 case 0:
128 case 1:
129 zero=1;
130 break;
131 case 2:
132 bn_sub_words(t, a, &(a[n]),n); /* + */
133 bn_sub_words(&(t[n]),b, &(b[n]),n); /* - */
134 neg=1;
135 break;
136 case 3:
137 zero=1;
138 break;
139 case 4:
140 bn_sub_words(t, a, &(a[n]),n);
141 bn_sub_words(&(t[n]),&(b[n]),b, n);
142 break;
143 }
144
145# ifdef BN_MUL_COMBA
146 if (n == 4)
147 {
148 if (!zero)
149 bn_mul_comba4(&(t[n2]),t,&(t[n]));
150 else
151 memset(&(t[n2]),0,8*sizeof(BN_ULONG));
152
153 bn_mul_comba4(r,a,b);
154 bn_mul_comba4(&(r[n2]),&(a[n]),&(b[n]));
155 }
156 else if (n == 8)
157 {
158 if (!zero)
159 bn_mul_comba8(&(t[n2]),t,&(t[n]));
160 else
161 memset(&(t[n2]),0,16*sizeof(BN_ULONG));
162
163 bn_mul_comba8(r,a,b);
164 bn_mul_comba8(&(r[n2]),&(a[n]),&(b[n]));
165 }
166 else
167# endif /* BN_MUL_COMBA */
168 {
169 p= &(t[n2*2]);
170 if (!zero)
171 bn_mul_recursive(&(t[n2]),t,&(t[n]),n,p);
172 else
173 memset(&(t[n2]),0,n2*sizeof(BN_ULONG));
174 bn_mul_recursive(r,a,b,n,p);
175 bn_mul_recursive(&(r[n2]),&(a[n]),&(b[n]),n,p);
176 }
177
178 /* t[32] holds (a[0]-a[1])*(b[1]-b[0]), c1 is the sign
179 * r[10] holds (a[0]*b[0])
180 * r[32] holds (b[1]*b[1])
181 */
182
183 c1=(int)(bn_add_words(t,r,&(r[n2]),n2));
184
185 if (neg) /* if t[32] is negative */
186 {
187 c1-=(int)(bn_sub_words(&(t[n2]),t,&(t[n2]),n2));
188 }
189 else
190 {
191 /* Might have a carry */
192 c1+=(int)(bn_add_words(&(t[n2]),&(t[n2]),t,n2));
193 }
194
195 /* t[32] holds (a[0]-a[1])*(b[1]-b[0])+(a[0]*b[0])+(a[1]*b[1])
196 * r[10] holds (a[0]*b[0])
197 * r[32] holds (b[1]*b[1])
198 * c1 holds the carry bits
199 */
200 c1+=(int)(bn_add_words(&(r[n]),&(r[n]),&(t[n2]),n2));
201 if (c1)
202 {
203 p= &(r[n+n2]);
204 lo= *p;
205 ln=(lo+c1)&BN_MASK2;
206 *p=ln;
207
208 /* The overflow will stop before we over write
209 * words we should not overwrite */
210 if (ln < (BN_ULONG)c1)
211 {
212 do {
213 p++;
214 lo= *p;
215 ln=(lo+1)&BN_MASK2;
216 *p=ln;
217 } while (ln == 0);
218 }
219 }
220 }
221
222/* n+tn is the word length
223 * t needs to be n*4 is size, as does r */
224void bn_mul_part_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int tn,
225 int n, BN_ULONG *t)
226 {
227 int i,j,n2=n*2;
228 unsigned int c1,c2,neg,zero;
229 BN_ULONG ln,lo,*p;
230
231# ifdef BN_COUNT
232 printf(" bn_mul_part_recursive %d * %d\n",tn+n,tn+n);
233# endif
234 if (n < 8)
235 {
236 i=tn+n;
237 bn_mul_normal(r,a,i,b,i);
238 return;
239 }
240
241 /* r=(a[0]-a[1])*(b[1]-b[0]) */
242 c1=bn_cmp_words(a,&(a[n]),n);
243 c2=bn_cmp_words(&(b[n]),b,n);
244 zero=neg=0;
245 switch (c1*3+c2)
246 {
247 case -4:
248 bn_sub_words(t, &(a[n]),a, n); /* - */
249 bn_sub_words(&(t[n]),b, &(b[n]),n); /* - */
250 break;
251 case -3:
252 zero=1;
253 /* break; */
254 case -2:
255 bn_sub_words(t, &(a[n]),a, n); /* - */
256 bn_sub_words(&(t[n]),&(b[n]),b, n); /* + */
257 neg=1;
258 break;
259 case -1:
260 case 0:
261 case 1:
262 zero=1;
263 /* break; */
264 case 2:
265 bn_sub_words(t, a, &(a[n]),n); /* + */
266 bn_sub_words(&(t[n]),b, &(b[n]),n); /* - */
267 neg=1;
268 break;
269 case 3:
270 zero=1;
271 /* break; */
272 case 4:
273 bn_sub_words(t, a, &(a[n]),n);
274 bn_sub_words(&(t[n]),&(b[n]),b, n);
275 break;
276 }
277 /* The zero case isn't yet implemented here. The speedup
278 would probably be negligible. */
279# if 0
280 if (n == 4)
281 {
282 bn_mul_comba4(&(t[n2]),t,&(t[n]));
283 bn_mul_comba4(r,a,b);
284 bn_mul_normal(&(r[n2]),&(a[n]),tn,&(b[n]),tn);
285 memset(&(r[n2+tn*2]),0,sizeof(BN_ULONG)*(n2-tn*2));
286 }
287 else
288# endif
289 if (n == 8)
290 {
291 bn_mul_comba8(&(t[n2]),t,&(t[n]));
292 bn_mul_comba8(r,a,b);
293 bn_mul_normal(&(r[n2]),&(a[n]),tn,&(b[n]),tn);
294 memset(&(r[n2+tn*2]),0,sizeof(BN_ULONG)*(n2-tn*2));
295 }
296 else
297 {
298 p= &(t[n2*2]);
299 bn_mul_recursive(&(t[n2]),t,&(t[n]),n,p);
300 bn_mul_recursive(r,a,b,n,p);
301 i=n/2;
302 /* If there is only a bottom half to the number,
303 * just do it */
304 j=tn-i;
305 if (j == 0)
306 {
307 bn_mul_recursive(&(r[n2]),&(a[n]),&(b[n]),i,p);
308 memset(&(r[n2+i*2]),0,sizeof(BN_ULONG)*(n2-i*2));
309 }
310 else if (j > 0) /* eg, n == 16, i == 8 and tn == 11 */
311 {
312 bn_mul_part_recursive(&(r[n2]),&(a[n]),&(b[n]),
313 j,i,p);
314 memset(&(r[n2+tn*2]),0,
315 sizeof(BN_ULONG)*(n2-tn*2));
316 }
317 else /* (j < 0) eg, n == 16, i == 8 and tn == 5 */
318 {
319 memset(&(r[n2]),0,sizeof(BN_ULONG)*n2);
320 if (tn < BN_MUL_RECURSIVE_SIZE_NORMAL)
321 {
322 bn_mul_normal(&(r[n2]),&(a[n]),tn,&(b[n]),tn);
323 }
324 else
325 {
326 for (;;)
327 {
328 i/=2;
329 if (i < tn)
330 {
331 bn_mul_part_recursive(&(r[n2]),
332 &(a[n]),&(b[n]),
333 tn-i,i,p);
334 break;
335 }
336 else if (i == tn)
337 {
338 bn_mul_recursive(&(r[n2]),
339 &(a[n]),&(b[n]),
340 i,p);
341 break;
342 }
343 }
344 }
345 }
346 }
347
348 /* t[32] holds (a[0]-a[1])*(b[1]-b[0]), c1 is the sign
349 * r[10] holds (a[0]*b[0])
350 * r[32] holds (b[1]*b[1])
351 */
352
353 c1=(int)(bn_add_words(t,r,&(r[n2]),n2));
354
355 if (neg) /* if t[32] is negative */
356 {
357 c1-=(int)(bn_sub_words(&(t[n2]),t,&(t[n2]),n2));
358 }
359 else
360 {
361 /* Might have a carry */
362 c1+=(int)(bn_add_words(&(t[n2]),&(t[n2]),t,n2));
363 }
364
365 /* t[32] holds (a[0]-a[1])*(b[1]-b[0])+(a[0]*b[0])+(a[1]*b[1])
366 * r[10] holds (a[0]*b[0])
367 * r[32] holds (b[1]*b[1])
368 * c1 holds the carry bits
369 */
370 c1+=(int)(bn_add_words(&(r[n]),&(r[n]),&(t[n2]),n2));
371 if (c1)
372 {
373 p= &(r[n+n2]);
374 lo= *p;
375 ln=(lo+c1)&BN_MASK2;
376 *p=ln;
377
378 /* The overflow will stop before we over write
379 * words we should not overwrite */
380 if (ln < c1)
381 {
382 do {
383 p++;
384 lo= *p;
385 ln=(lo+1)&BN_MASK2;
386 *p=ln;
387 } while (ln == 0);
388 }
389 }
390 }
391
392/* a and b must be the same size, which is n2.
393 * r needs to be n2 words and t needs to be n2*2
394 */
395void bn_mul_low_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n2,
396 BN_ULONG *t)
397 {
398 int n=n2/2;
399
400# ifdef BN_COUNT
401 printf(" bn_mul_low_recursive %d * %d\n",n2,n2);
402# endif
403
404 bn_mul_recursive(r,a,b,n,&(t[0]));
405 if (n >= BN_MUL_LOW_RECURSIVE_SIZE_NORMAL)
406 {
407 bn_mul_low_recursive(&(t[0]),&(a[0]),&(b[n]),n,&(t[n2]));
408 bn_add_words(&(r[n]),&(r[n]),&(t[0]),n);
409 bn_mul_low_recursive(&(t[0]),&(a[n]),&(b[0]),n,&(t[n2]));
410 bn_add_words(&(r[n]),&(r[n]),&(t[0]),n);
411 }
412 else
413 {
414 bn_mul_low_normal(&(t[0]),&(a[0]),&(b[n]),n);
415 bn_mul_low_normal(&(t[n]),&(a[n]),&(b[0]),n);
416 bn_add_words(&(r[n]),&(r[n]),&(t[0]),n);
417 bn_add_words(&(r[n]),&(r[n]),&(t[n]),n);
418 }
419 }
420
421/* a and b must be the same size, which is n2.
422 * r needs to be n2 words and t needs to be n2*2
423 * l is the low words of the output.
424 * t needs to be n2*3
425 */
426void bn_mul_high(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, BN_ULONG *l, int n2,
427 BN_ULONG *t)
428 {
429 int i,n;
430 int c1,c2;
431 int neg,oneg,zero;
432 BN_ULONG ll,lc,*lp,*mp;
433
434# ifdef BN_COUNT
435 printf(" bn_mul_high %d * %d\n",n2,n2);
436# endif
437 n=n2/2;
438
439 /* Calculate (al-ah)*(bh-bl) */
440 neg=zero=0;
441 c1=bn_cmp_words(&(a[0]),&(a[n]),n);
442 c2=bn_cmp_words(&(b[n]),&(b[0]),n);
443 switch (c1*3+c2)
444 {
445 case -4:
446 bn_sub_words(&(r[0]),&(a[n]),&(a[0]),n);
447 bn_sub_words(&(r[n]),&(b[0]),&(b[n]),n);
448 break;
449 case -3:
450 zero=1;
451 break;
452 case -2:
453 bn_sub_words(&(r[0]),&(a[n]),&(a[0]),n);
454 bn_sub_words(&(r[n]),&(b[n]),&(b[0]),n);
455 neg=1;
456 break;
457 case -1:
458 case 0:
459 case 1:
460 zero=1;
461 break;
462 case 2:
463 bn_sub_words(&(r[0]),&(a[0]),&(a[n]),n);
464 bn_sub_words(&(r[n]),&(b[0]),&(b[n]),n);
465 neg=1;
466 break;
467 case 3:
468 zero=1;
469 break;
470 case 4:
471 bn_sub_words(&(r[0]),&(a[0]),&(a[n]),n);
472 bn_sub_words(&(r[n]),&(b[n]),&(b[0]),n);
473 break;
474 }
475
476 oneg=neg;
477 /* t[10] = (a[0]-a[1])*(b[1]-b[0]) */
478 /* r[10] = (a[1]*b[1]) */
479# ifdef BN_MUL_COMBA
480 if (n == 8)
481 {
482 bn_mul_comba8(&(t[0]),&(r[0]),&(r[n]));
483 bn_mul_comba8(r,&(a[n]),&(b[n]));
484 }
485 else
486# endif
487 {
488 bn_mul_recursive(&(t[0]),&(r[0]),&(r[n]),n,&(t[n2]));
489 bn_mul_recursive(r,&(a[n]),&(b[n]),n,&(t[n2]));
490 }
491
492 /* s0 == low(al*bl)
493 * s1 == low(ah*bh)+low((al-ah)*(bh-bl))+low(al*bl)+high(al*bl)
494 * We know s0 and s1 so the only unknown is high(al*bl)
495 * high(al*bl) == s1 - low(ah*bh+s0+(al-ah)*(bh-bl))
496 * high(al*bl) == s1 - (r[0]+l[0]+t[0])
497 */
498 if (l != NULL)
499 {
500 lp= &(t[n2+n]);
501 c1=(int)(bn_add_words(lp,&(r[0]),&(l[0]),n));
502 }
503 else
504 {
505 c1=0;
506 lp= &(r[0]);
507 }
508
509 if (neg)
510 neg=(int)(bn_sub_words(&(t[n2]),lp,&(t[0]),n));
511 else
512 {
513 bn_add_words(&(t[n2]),lp,&(t[0]),n);
514 neg=0;
515 }
516
517 if (l != NULL)
518 {
519 bn_sub_words(&(t[n2+n]),&(l[n]),&(t[n2]),n);
520 }
521 else
522 {
523 lp= &(t[n2+n]);
524 mp= &(t[n2]);
525 for (i=0; i<n; i++)
526 lp[i]=((~mp[i])+1)&BN_MASK2;
527 }
528
529 /* s[0] = low(al*bl)
530 * t[3] = high(al*bl)
531 * t[10] = (a[0]-a[1])*(b[1]-b[0]) neg is the sign
532 * r[10] = (a[1]*b[1])
533 */
534 /* R[10] = al*bl
535 * R[21] = al*bl + ah*bh + (a[0]-a[1])*(b[1]-b[0])
536 * R[32] = ah*bh
537 */
538 /* R[1]=t[3]+l[0]+r[0](+-)t[0] (have carry/borrow)
539 * R[2]=r[0]+t[3]+r[1](+-)t[1] (have carry/borrow)
540 * R[3]=r[1]+(carry/borrow)
541 */
542 if (l != NULL)
543 {
544 lp= &(t[n2]);
545 c1= (int)(bn_add_words(lp,&(t[n2+n]),&(l[0]),n));
546 }
547 else
548 {
549 lp= &(t[n2+n]);
550 c1=0;
551 }
552 c1+=(int)(bn_add_words(&(t[n2]),lp, &(r[0]),n));
553 if (oneg)
554 c1-=(int)(bn_sub_words(&(t[n2]),&(t[n2]),&(t[0]),n));
555 else
556 c1+=(int)(bn_add_words(&(t[n2]),&(t[n2]),&(t[0]),n));
557
558 c2 =(int)(bn_add_words(&(r[0]),&(r[0]),&(t[n2+n]),n));
559 c2+=(int)(bn_add_words(&(r[0]),&(r[0]),&(r[n]),n));
560 if (oneg)
561 c2-=(int)(bn_sub_words(&(r[0]),&(r[0]),&(t[n]),n));
562 else
563 c2+=(int)(bn_add_words(&(r[0]),&(r[0]),&(t[n]),n));
564
565 if (c1 != 0) /* Add starting at r[0], could be +ve or -ve */
566 {
567 i=0;
568 if (c1 > 0)
569 {
570 lc=c1;
571 do {
572 ll=(r[i]+lc)&BN_MASK2;
573 r[i++]=ll;
574 lc=(lc > ll);
575 } while (lc);
576 }
577 else
578 {
579 lc= -c1;
580 do {
581 ll=r[i];
582 r[i++]=(ll-lc)&BN_MASK2;
583 lc=(lc > ll);
584 } while (lc);
585 }
586 }
587 if (c2 != 0) /* Add starting at r[1] */
588 {
589 i=n;
590 if (c2 > 0)
591 {
592 lc=c2;
593 do {
594 ll=(r[i]+lc)&BN_MASK2;
595 r[i++]=ll;
596 lc=(lc > ll);
597 } while (lc);
598 }
599 else
600 {
601 lc= -c2;
602 do {
603 ll=r[i];
604 r[i++]=(ll-lc)&BN_MASK2;
605 lc=(lc > ll);
606 } while (lc);
607 }
608 }
609 }
610#endif /* BN_RECURSION */
611
612int BN_mul(BIGNUM *r, BIGNUM *a, BIGNUM *b, BN_CTX *ctx)
613 {
614 int top,al,bl;
615 BIGNUM *rr;
616 int ret = 0;
617#if defined(BN_MUL_COMBA) || defined(BN_RECURSION)
618 int i;
619#endif
620#ifdef BN_RECURSION
621 BIGNUM *t;
622 int j,k;
623#endif
624
625#ifdef BN_COUNT
626 printf("BN_mul %d * %d\n",a->top,b->top);
627#endif
628
629 bn_check_top(a);
630 bn_check_top(b);
631 bn_check_top(r);
632
633 al=a->top;
634 bl=b->top;
635
636 if ((al == 0) || (bl == 0))
637 {
638 BN_zero(r);
639 return(1);
640 }
641 top=al+bl;
642
643 BN_CTX_start(ctx);
644 if ((r == a) || (r == b))
645 {
646 if ((rr = BN_CTX_get(ctx)) == NULL) goto err;
647 }
648 else
649 rr = r;
650 rr->neg=a->neg^b->neg;
651
652#if defined(BN_MUL_COMBA) || defined(BN_RECURSION)
653 i = al-bl;
654#endif
655#ifdef BN_MUL_COMBA
656 if (i == 0)
657 {
658# if 0
659 if (al == 4)
660 {
661 if (bn_wexpand(rr,8) == NULL) goto err;
662 rr->top=8;
663 bn_mul_comba4(rr->d,a->d,b->d);
664 goto end;
665 }
666# endif
667 if (al == 8)
668 {
669 if (bn_wexpand(rr,16) == NULL) goto err;
670 rr->top=16;
671 bn_mul_comba8(rr->d,a->d,b->d);
672 goto end;
673 }
674 }
675#endif /* BN_MUL_COMBA */
676#ifdef BN_RECURSION
677 if ((al >= BN_MULL_SIZE_NORMAL) && (bl >= BN_MULL_SIZE_NORMAL))
678 {
679 if (i == 1 && !BN_get_flags(b,BN_FLG_STATIC_DATA))
680 {
681 bn_wexpand(b,al);
682 b->d[bl]=0;
683 bl++;
684 i--;
685 }
686 else if (i == -1 && !BN_get_flags(a,BN_FLG_STATIC_DATA))
687 {
688 bn_wexpand(a,bl);
689 a->d[al]=0;
690 al++;
691 i++;
692 }
693 if (i == 0)
694 {
695 /* symmetric and > 4 */
696 /* 16 or larger */
697 j=BN_num_bits_word((BN_ULONG)al);
698 j=1<<(j-1);
699 k=j+j;
700 t = BN_CTX_get(ctx);
701 if (al == j) /* exact multiple */
702 {
703 bn_wexpand(t,k*2);
704 bn_wexpand(rr,k*2);
705 bn_mul_recursive(rr->d,a->d,b->d,al,t->d);
706 }
707 else
708 {
709 bn_wexpand(a,k);
710 bn_wexpand(b,k);
711 bn_wexpand(t,k*4);
712 bn_wexpand(rr,k*4);
713 for (i=a->top; i<k; i++)
714 a->d[i]=0;
715 for (i=b->top; i<k; i++)
716 b->d[i]=0;
717 bn_mul_part_recursive(rr->d,a->d,b->d,al-j,j,t->d);
718 }
719 rr->top=top;
720 goto end;
721 }
722 }
723#endif /* BN_RECURSION */
724 if (bn_wexpand(rr,top) == NULL) goto err;
725 rr->top=top;
726 bn_mul_normal(rr->d,a->d,al,b->d,bl);
727
728#if defined(BN_MUL_COMBA) || defined(BN_RECURSION)
729end:
730#endif
731 bn_fix_top(rr);
732 if (r != rr) BN_copy(r,rr);
733 ret=1;
734err:
735 BN_CTX_end(ctx);
736 return(ret);
737 }
738
739void bn_mul_normal(BN_ULONG *r, BN_ULONG *a, int na, BN_ULONG *b, int nb)
740 {
741 BN_ULONG *rr;
742
743#ifdef BN_COUNT
744 printf(" bn_mul_normal %d * %d\n",na,nb);
745#endif
746
747 if (na < nb)
748 {
749 int itmp;
750 BN_ULONG *ltmp;
751
752 itmp=na; na=nb; nb=itmp;
753 ltmp=a; a=b; b=ltmp;
754
755 }
756 rr= &(r[na]);
757 rr[0]=bn_mul_words(r,a,na,b[0]);
758
759 for (;;)
760 {
761 if (--nb <= 0) return;
762 rr[1]=bn_mul_add_words(&(r[1]),a,na,b[1]);
763 if (--nb <= 0) return;
764 rr[2]=bn_mul_add_words(&(r[2]),a,na,b[2]);
765 if (--nb <= 0) return;
766 rr[3]=bn_mul_add_words(&(r[3]),a,na,b[3]);
767 if (--nb <= 0) return;
768 rr[4]=bn_mul_add_words(&(r[4]),a,na,b[4]);
769 rr+=4;
770 r+=4;
771 b+=4;
772 }
773 }
774
775void bn_mul_low_normal(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n)
776 {
777#ifdef BN_COUNT
778 printf(" bn_mul_low_normal %d * %d\n",n,n);
779#endif
780 bn_mul_words(r,a,n,b[0]);
781
782 for (;;)
783 {
784 if (--n <= 0) return;
785 bn_mul_add_words(&(r[1]),a,n,b[1]);
786 if (--n <= 0) return;
787 bn_mul_add_words(&(r[2]),a,n,b[2]);
788 if (--n <= 0) return;
789 bn_mul_add_words(&(r[3]),a,n,b[3]);
790 if (--n <= 0) return;
791 bn_mul_add_words(&(r[4]),a,n,b[4]);
792 r+=4;
793 b+=4;
794 }
795 }
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