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Constify the BIGNUM routines a bit more. The only trouble were the
[thirdparty/openssl.git] / crypto / bn / bn_mul.c
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 "cryptlib.h"
61 #include "bn_lcl.h"
62
63 #ifdef BN_RECURSION
64 /* Karatsuba recursive multiplication algorithm
65 * (cf. Knuth, The Art of Computer Programming, Vol. 2) */
66
67 /* r is 2*n2 words in size,
68 * a and b are both n2 words in size.
69 * n2 must be a power of 2.
70 * We multiply and return the result.
71 * t must be 2*n2 words in size
72 * We calculate
73 * a[0]*b[0]
74 * a[0]*b[0]+a[1]*b[1]+(a[0]-a[1])*(b[1]-b[0])
75 * a[1]*b[1]
76 */
77 void bn_mul_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n2,
78 BN_ULONG *t)
79 {
80 int n=n2/2,c1,c2;
81 unsigned int neg,zero;
82 BN_ULONG ln,lo,*p;
83
84 # ifdef BN_COUNT
85 printf(" bn_mul_recursive %d * %d\n",n2,n2);
86 # endif
87 # ifdef BN_MUL_COMBA
88 # if 0
89 if (n2 == 4)
90 {
91 bn_mul_comba4(r,a,b);
92 return;
93 }
94 # endif
95 if (n2 == 8)
96 {
97 bn_mul_comba8(r,a,b);
98 return;
99 }
100 # endif /* BN_MUL_COMBA */
101 if (n2 < BN_MUL_RECURSIVE_SIZE_NORMAL)
102 {
103 /* This should not happen */
104 bn_mul_normal(r,a,n2,b,n2);
105 return;
106 }
107 /* r=(a[0]-a[1])*(b[1]-b[0]) */
108 c1=bn_cmp_words(a,&(a[n]),n);
109 c2=bn_cmp_words(&(b[n]),b,n);
110 zero=neg=0;
111 switch (c1*3+c2)
112 {
113 case -4:
114 bn_sub_words(t, &(a[n]),a, n); /* - */
115 bn_sub_words(&(t[n]),b, &(b[n]),n); /* - */
116 break;
117 case -3:
118 zero=1;
119 break;
120 case -2:
121 bn_sub_words(t, &(a[n]),a, n); /* - */
122 bn_sub_words(&(t[n]),&(b[n]),b, n); /* + */
123 neg=1;
124 break;
125 case -1:
126 case 0:
127 case 1:
128 zero=1;
129 break;
130 case 2:
131 bn_sub_words(t, a, &(a[n]),n); /* + */
132 bn_sub_words(&(t[n]),b, &(b[n]),n); /* - */
133 neg=1;
134 break;
135 case 3:
136 zero=1;
137 break;
138 case 4:
139 bn_sub_words(t, a, &(a[n]),n);
140 bn_sub_words(&(t[n]),&(b[n]),b, n);
141 break;
142 }
143
144 # ifdef BN_MUL_COMBA
145 if (n == 4)
146 {
147 if (!zero)
148 bn_mul_comba4(&(t[n2]),t,&(t[n]));
149 else
150 memset(&(t[n2]),0,8*sizeof(BN_ULONG));
151
152 bn_mul_comba4(r,a,b);
153 bn_mul_comba4(&(r[n2]),&(a[n]),&(b[n]));
154 }
155 else if (n == 8)
156 {
157 if (!zero)
158 bn_mul_comba8(&(t[n2]),t,&(t[n]));
159 else
160 memset(&(t[n2]),0,16*sizeof(BN_ULONG));
161
162 bn_mul_comba8(r,a,b);
163 bn_mul_comba8(&(r[n2]),&(a[n]),&(b[n]));
164 }
165 else
166 # endif /* BN_MUL_COMBA */
167 {
168 p= &(t[n2*2]);
169 if (!zero)
170 bn_mul_recursive(&(t[n2]),t,&(t[n]),n,p);
171 else
172 memset(&(t[n2]),0,n2*sizeof(BN_ULONG));
173 bn_mul_recursive(r,a,b,n,p);
174 bn_mul_recursive(&(r[n2]),&(a[n]),&(b[n]),n,p);
175 }
176
177 /* t[32] holds (a[0]-a[1])*(b[1]-b[0]), c1 is the sign
178 * r[10] holds (a[0]*b[0])
179 * r[32] holds (b[1]*b[1])
180 */
181
182 c1=(int)(bn_add_words(t,r,&(r[n2]),n2));
183
184 if (neg) /* if t[32] is negative */
185 {
186 c1-=(int)(bn_sub_words(&(t[n2]),t,&(t[n2]),n2));
187 }
188 else
189 {
190 /* Might have a carry */
191 c1+=(int)(bn_add_words(&(t[n2]),&(t[n2]),t,n2));
192 }
193
194 /* t[32] holds (a[0]-a[1])*(b[1]-b[0])+(a[0]*b[0])+(a[1]*b[1])
195 * r[10] holds (a[0]*b[0])
196 * r[32] holds (b[1]*b[1])
197 * c1 holds the carry bits
198 */
199 c1+=(int)(bn_add_words(&(r[n]),&(r[n]),&(t[n2]),n2));
200 if (c1)
201 {
202 p= &(r[n+n2]);
203 lo= *p;
204 ln=(lo+c1)&BN_MASK2;
205 *p=ln;
206
207 /* The overflow will stop before we over write
208 * words we should not overwrite */
209 if (ln < (BN_ULONG)c1)
210 {
211 do {
212 p++;
213 lo= *p;
214 ln=(lo+1)&BN_MASK2;
215 *p=ln;
216 } while (ln == 0);
217 }
218 }
219 }
220
221 /* n+tn is the word length
222 * t needs to be n*4 is size, as does r */
223 void bn_mul_part_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int tn,
224 int n, BN_ULONG *t)
225 {
226 int i,j,n2=n*2;
227 unsigned int c1,c2,neg,zero;
228 BN_ULONG ln,lo,*p;
229
230 # ifdef BN_COUNT
231 printf(" bn_mul_part_recursive %d * %d\n",tn+n,tn+n);
232 # endif
233 if (n < 8)
234 {
235 i=tn+n;
236 bn_mul_normal(r,a,i,b,i);
237 return;
238 }
239
240 /* r=(a[0]-a[1])*(b[1]-b[0]) */
241 c1=bn_cmp_words(a,&(a[n]),n);
242 c2=bn_cmp_words(&(b[n]),b,n);
243 zero=neg=0;
244 switch (c1*3+c2)
245 {
246 case -4:
247 bn_sub_words(t, &(a[n]),a, n); /* - */
248 bn_sub_words(&(t[n]),b, &(b[n]),n); /* - */
249 break;
250 case -3:
251 zero=1;
252 /* break; */
253 case -2:
254 bn_sub_words(t, &(a[n]),a, n); /* - */
255 bn_sub_words(&(t[n]),&(b[n]),b, n); /* + */
256 neg=1;
257 break;
258 case -1:
259 case 0:
260 case 1:
261 zero=1;
262 /* break; */
263 case 2:
264 bn_sub_words(t, a, &(a[n]),n); /* + */
265 bn_sub_words(&(t[n]),b, &(b[n]),n); /* - */
266 neg=1;
267 break;
268 case 3:
269 zero=1;
270 /* break; */
271 case 4:
272 bn_sub_words(t, a, &(a[n]),n);
273 bn_sub_words(&(t[n]),&(b[n]),b, n);
274 break;
275 }
276 /* The zero case isn't yet implemented here. The speedup
277 would probably be negligible. */
278 # if 0
279 if (n == 4)
280 {
281 bn_mul_comba4(&(t[n2]),t,&(t[n]));
282 bn_mul_comba4(r,a,b);
283 bn_mul_normal(&(r[n2]),&(a[n]),tn,&(b[n]),tn);
284 memset(&(r[n2+tn*2]),0,sizeof(BN_ULONG)*(n2-tn*2));
285 }
286 else
287 # endif
288 if (n == 8)
289 {
290 bn_mul_comba8(&(t[n2]),t,&(t[n]));
291 bn_mul_comba8(r,a,b);
292 bn_mul_normal(&(r[n2]),&(a[n]),tn,&(b[n]),tn);
293 memset(&(r[n2+tn*2]),0,sizeof(BN_ULONG)*(n2-tn*2));
294 }
295 else
296 {
297 p= &(t[n2*2]);
298 bn_mul_recursive(&(t[n2]),t,&(t[n]),n,p);
299 bn_mul_recursive(r,a,b,n,p);
300 i=n/2;
301 /* If there is only a bottom half to the number,
302 * just do it */
303 j=tn-i;
304 if (j == 0)
305 {
306 bn_mul_recursive(&(r[n2]),&(a[n]),&(b[n]),i,p);
307 memset(&(r[n2+i*2]),0,sizeof(BN_ULONG)*(n2-i*2));
308 }
309 else if (j > 0) /* eg, n == 16, i == 8 and tn == 11 */
310 {
311 bn_mul_part_recursive(&(r[n2]),&(a[n]),&(b[n]),
312 j,i,p);
313 memset(&(r[n2+tn*2]),0,
314 sizeof(BN_ULONG)*(n2-tn*2));
315 }
316 else /* (j < 0) eg, n == 16, i == 8 and tn == 5 */
317 {
318 memset(&(r[n2]),0,sizeof(BN_ULONG)*n2);
319 if (tn < BN_MUL_RECURSIVE_SIZE_NORMAL)
320 {
321 bn_mul_normal(&(r[n2]),&(a[n]),tn,&(b[n]),tn);
322 }
323 else
324 {
325 for (;;)
326 {
327 i/=2;
328 if (i < tn)
329 {
330 bn_mul_part_recursive(&(r[n2]),
331 &(a[n]),&(b[n]),
332 tn-i,i,p);
333 break;
334 }
335 else if (i == tn)
336 {
337 bn_mul_recursive(&(r[n2]),
338 &(a[n]),&(b[n]),
339 i,p);
340 break;
341 }
342 }
343 }
344 }
345 }
346
347 /* t[32] holds (a[0]-a[1])*(b[1]-b[0]), c1 is the sign
348 * r[10] holds (a[0]*b[0])
349 * r[32] holds (b[1]*b[1])
350 */
351
352 c1=(int)(bn_add_words(t,r,&(r[n2]),n2));
353
354 if (neg) /* if t[32] is negative */
355 {
356 c1-=(int)(bn_sub_words(&(t[n2]),t,&(t[n2]),n2));
357 }
358 else
359 {
360 /* Might have a carry */
361 c1+=(int)(bn_add_words(&(t[n2]),&(t[n2]),t,n2));
362 }
363
364 /* t[32] holds (a[0]-a[1])*(b[1]-b[0])+(a[0]*b[0])+(a[1]*b[1])
365 * r[10] holds (a[0]*b[0])
366 * r[32] holds (b[1]*b[1])
367 * c1 holds the carry bits
368 */
369 c1+=(int)(bn_add_words(&(r[n]),&(r[n]),&(t[n2]),n2));
370 if (c1)
371 {
372 p= &(r[n+n2]);
373 lo= *p;
374 ln=(lo+c1)&BN_MASK2;
375 *p=ln;
376
377 /* The overflow will stop before we over write
378 * words we should not overwrite */
379 if (ln < c1)
380 {
381 do {
382 p++;
383 lo= *p;
384 ln=(lo+1)&BN_MASK2;
385 *p=ln;
386 } while (ln == 0);
387 }
388 }
389 }
390
391 /* a and b must be the same size, which is n2.
392 * r needs to be n2 words and t needs to be n2*2
393 */
394 void bn_mul_low_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n2,
395 BN_ULONG *t)
396 {
397 int n=n2/2;
398
399 # ifdef BN_COUNT
400 printf(" bn_mul_low_recursive %d * %d\n",n2,n2);
401 # endif
402
403 bn_mul_recursive(r,a,b,n,&(t[0]));
404 if (n >= BN_MUL_LOW_RECURSIVE_SIZE_NORMAL)
405 {
406 bn_mul_low_recursive(&(t[0]),&(a[0]),&(b[n]),n,&(t[n2]));
407 bn_add_words(&(r[n]),&(r[n]),&(t[0]),n);
408 bn_mul_low_recursive(&(t[0]),&(a[n]),&(b[0]),n,&(t[n2]));
409 bn_add_words(&(r[n]),&(r[n]),&(t[0]),n);
410 }
411 else
412 {
413 bn_mul_low_normal(&(t[0]),&(a[0]),&(b[n]),n);
414 bn_mul_low_normal(&(t[n]),&(a[n]),&(b[0]),n);
415 bn_add_words(&(r[n]),&(r[n]),&(t[0]),n);
416 bn_add_words(&(r[n]),&(r[n]),&(t[n]),n);
417 }
418 }
419
420 /* a and b must be the same size, which is n2.
421 * r needs to be n2 words and t needs to be n2*2
422 * l is the low words of the output.
423 * t needs to be n2*3
424 */
425 void bn_mul_high(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, BN_ULONG *l, int n2,
426 BN_ULONG *t)
427 {
428 int i,n;
429 int c1,c2;
430 int neg,oneg,zero;
431 BN_ULONG ll,lc,*lp,*mp;
432
433 # ifdef BN_COUNT
434 printf(" bn_mul_high %d * %d\n",n2,n2);
435 # endif
436 n=n2/2;
437
438 /* Calculate (al-ah)*(bh-bl) */
439 neg=zero=0;
440 c1=bn_cmp_words(&(a[0]),&(a[n]),n);
441 c2=bn_cmp_words(&(b[n]),&(b[0]),n);
442 switch (c1*3+c2)
443 {
444 case -4:
445 bn_sub_words(&(r[0]),&(a[n]),&(a[0]),n);
446 bn_sub_words(&(r[n]),&(b[0]),&(b[n]),n);
447 break;
448 case -3:
449 zero=1;
450 break;
451 case -2:
452 bn_sub_words(&(r[0]),&(a[n]),&(a[0]),n);
453 bn_sub_words(&(r[n]),&(b[n]),&(b[0]),n);
454 neg=1;
455 break;
456 case -1:
457 case 0:
458 case 1:
459 zero=1;
460 break;
461 case 2:
462 bn_sub_words(&(r[0]),&(a[0]),&(a[n]),n);
463 bn_sub_words(&(r[n]),&(b[0]),&(b[n]),n);
464 neg=1;
465 break;
466 case 3:
467 zero=1;
468 break;
469 case 4:
470 bn_sub_words(&(r[0]),&(a[0]),&(a[n]),n);
471 bn_sub_words(&(r[n]),&(b[n]),&(b[0]),n);
472 break;
473 }
474
475 oneg=neg;
476 /* t[10] = (a[0]-a[1])*(b[1]-b[0]) */
477 /* r[10] = (a[1]*b[1]) */
478 # ifdef BN_MUL_COMBA
479 if (n == 8)
480 {
481 bn_mul_comba8(&(t[0]),&(r[0]),&(r[n]));
482 bn_mul_comba8(r,&(a[n]),&(b[n]));
483 }
484 else
485 # endif
486 {
487 bn_mul_recursive(&(t[0]),&(r[0]),&(r[n]),n,&(t[n2]));
488 bn_mul_recursive(r,&(a[n]),&(b[n]),n,&(t[n2]));
489 }
490
491 /* s0 == low(al*bl)
492 * s1 == low(ah*bh)+low((al-ah)*(bh-bl))+low(al*bl)+high(al*bl)
493 * We know s0 and s1 so the only unknown is high(al*bl)
494 * high(al*bl) == s1 - low(ah*bh+s0+(al-ah)*(bh-bl))
495 * high(al*bl) == s1 - (r[0]+l[0]+t[0])
496 */
497 if (l != NULL)
498 {
499 lp= &(t[n2+n]);
500 c1=(int)(bn_add_words(lp,&(r[0]),&(l[0]),n));
501 }
502 else
503 {
504 c1=0;
505 lp= &(r[0]);
506 }
507
508 if (neg)
509 neg=(int)(bn_sub_words(&(t[n2]),lp,&(t[0]),n));
510 else
511 {
512 bn_add_words(&(t[n2]),lp,&(t[0]),n);
513 neg=0;
514 }
515
516 if (l != NULL)
517 {
518 bn_sub_words(&(t[n2+n]),&(l[n]),&(t[n2]),n);
519 }
520 else
521 {
522 lp= &(t[n2+n]);
523 mp= &(t[n2]);
524 for (i=0; i<n; i++)
525 lp[i]=((~mp[i])+1)&BN_MASK2;
526 }
527
528 /* s[0] = low(al*bl)
529 * t[3] = high(al*bl)
530 * t[10] = (a[0]-a[1])*(b[1]-b[0]) neg is the sign
531 * r[10] = (a[1]*b[1])
532 */
533 /* R[10] = al*bl
534 * R[21] = al*bl + ah*bh + (a[0]-a[1])*(b[1]-b[0])
535 * R[32] = ah*bh
536 */
537 /* R[1]=t[3]+l[0]+r[0](+-)t[0] (have carry/borrow)
538 * R[2]=r[0]+t[3]+r[1](+-)t[1] (have carry/borrow)
539 * R[3]=r[1]+(carry/borrow)
540 */
541 if (l != NULL)
542 {
543 lp= &(t[n2]);
544 c1= (int)(bn_add_words(lp,&(t[n2+n]),&(l[0]),n));
545 }
546 else
547 {
548 lp= &(t[n2+n]);
549 c1=0;
550 }
551 c1+=(int)(bn_add_words(&(t[n2]),lp, &(r[0]),n));
552 if (oneg)
553 c1-=(int)(bn_sub_words(&(t[n2]),&(t[n2]),&(t[0]),n));
554 else
555 c1+=(int)(bn_add_words(&(t[n2]),&(t[n2]),&(t[0]),n));
556
557 c2 =(int)(bn_add_words(&(r[0]),&(r[0]),&(t[n2+n]),n));
558 c2+=(int)(bn_add_words(&(r[0]),&(r[0]),&(r[n]),n));
559 if (oneg)
560 c2-=(int)(bn_sub_words(&(r[0]),&(r[0]),&(t[n]),n));
561 else
562 c2+=(int)(bn_add_words(&(r[0]),&(r[0]),&(t[n]),n));
563
564 if (c1 != 0) /* Add starting at r[0], could be +ve or -ve */
565 {
566 i=0;
567 if (c1 > 0)
568 {
569 lc=c1;
570 do {
571 ll=(r[i]+lc)&BN_MASK2;
572 r[i++]=ll;
573 lc=(lc > ll);
574 } while (lc);
575 }
576 else
577 {
578 lc= -c1;
579 do {
580 ll=r[i];
581 r[i++]=(ll-lc)&BN_MASK2;
582 lc=(lc > ll);
583 } while (lc);
584 }
585 }
586 if (c2 != 0) /* Add starting at r[1] */
587 {
588 i=n;
589 if (c2 > 0)
590 {
591 lc=c2;
592 do {
593 ll=(r[i]+lc)&BN_MASK2;
594 r[i++]=ll;
595 lc=(lc > ll);
596 } while (lc);
597 }
598 else
599 {
600 lc= -c2;
601 do {
602 ll=r[i];
603 r[i++]=(ll-lc)&BN_MASK2;
604 lc=(lc > ll);
605 } while (lc);
606 }
607 }
608 }
609 #endif /* BN_RECURSION */
610
611 int BN_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
612 {
613 int top,al,bl;
614 BIGNUM *rr;
615 int ret = 0;
616 #if defined(BN_MUL_COMBA) || defined(BN_RECURSION)
617 int i;
618 #endif
619 #ifdef BN_RECURSION
620 BIGNUM *t;
621 int j,k;
622 #endif
623 BIGNUM *free_a = NULL, *free_b = NULL;
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 BIGNUM *tmp_bn = free_b;
682 b = free_b = bn_dup_expand(b,al);
683 free_b->d[bl]=0;
684 bl++;
685 i--;
686 if (tmp_bn) BN_free(tmp_bn);
687 }
688 else if (i == -1 && !BN_get_flags(a,BN_FLG_STATIC_DATA))
689 {
690 BIGNUM *tmp_bn = free_a;
691 a = free_a = bn_dup_expand(a,bl);
692 free_a->d[al]=0;
693 al++;
694 i++;
695 if (tmp_bn) BN_free(tmp_bn);
696 }
697 if (i == 0)
698 {
699 /* symmetric and > 4 */
700 /* 16 or larger */
701 j=BN_num_bits_word((BN_ULONG)al);
702 j=1<<(j-1);
703 k=j+j;
704 t = BN_CTX_get(ctx);
705 if (al == j) /* exact multiple */
706 {
707 bn_wexpand(t,k*2);
708 bn_wexpand(rr,k*2);
709 bn_mul_recursive(rr->d,a->d,b->d,al,t->d);
710 }
711 else
712 {
713 BIGNUM *tmp_a = free_a,*tmp_b = free_b;
714 a = free_a = bn_dup_expand(a,k);
715 b = free_b = bn_dup_expand(b,k);
716 if (tmp_a) BN_free(tmp_a);
717 if (tmp_b) BN_free(tmp_b);
718 bn_wexpand(t,k*4);
719 bn_wexpand(rr,k*4);
720 for (i=free_a->top; i<k; i++)
721 free_a->d[i]=0;
722 for (i=free_b->top; i<k; i++)
723 free_b->d[i]=0;
724 bn_mul_part_recursive(rr->d,a->d,b->d,al-j,j,t->d);
725 }
726 rr->top=top;
727 goto end;
728 }
729 }
730 #endif /* BN_RECURSION */
731 if (bn_wexpand(rr,top) == NULL) goto err;
732 rr->top=top;
733 bn_mul_normal(rr->d,a->d,al,b->d,bl);
734
735 #if defined(BN_MUL_COMBA) || defined(BN_RECURSION)
736 end:
737 #endif
738 bn_fix_top(rr);
739 if (r != rr) BN_copy(r,rr);
740 ret=1;
741 err:
742 if (free_a) BN_free(free_a);
743 if (free_b) BN_free(free_b);
744 BN_CTX_end(ctx);
745 return(ret);
746 }
747
748 void bn_mul_normal(BN_ULONG *r, BN_ULONG *a, int na, BN_ULONG *b, int nb)
749 {
750 BN_ULONG *rr;
751
752 #ifdef BN_COUNT
753 printf(" bn_mul_normal %d * %d\n",na,nb);
754 #endif
755
756 if (na < nb)
757 {
758 int itmp;
759 BN_ULONG *ltmp;
760
761 itmp=na; na=nb; nb=itmp;
762 ltmp=a; a=b; b=ltmp;
763
764 }
765 rr= &(r[na]);
766 rr[0]=bn_mul_words(r,a,na,b[0]);
767
768 for (;;)
769 {
770 if (--nb <= 0) return;
771 rr[1]=bn_mul_add_words(&(r[1]),a,na,b[1]);
772 if (--nb <= 0) return;
773 rr[2]=bn_mul_add_words(&(r[2]),a,na,b[2]);
774 if (--nb <= 0) return;
775 rr[3]=bn_mul_add_words(&(r[3]),a,na,b[3]);
776 if (--nb <= 0) return;
777 rr[4]=bn_mul_add_words(&(r[4]),a,na,b[4]);
778 rr+=4;
779 r+=4;
780 b+=4;
781 }
782 }
783
784 void bn_mul_low_normal(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n)
785 {
786 #ifdef BN_COUNT
787 printf(" bn_mul_low_normal %d * %d\n",n,n);
788 #endif
789 bn_mul_words(r,a,n,b[0]);
790
791 for (;;)
792 {
793 if (--n <= 0) return;
794 bn_mul_add_words(&(r[1]),a,n,b[1]);
795 if (--n <= 0) return;
796 bn_mul_add_words(&(r[2]),a,n,b[2]);
797 if (--n <= 0) return;
798 bn_mul_add_words(&(r[3]),a,n,b[3]);
799 if (--n <= 0) return;
800 bn_mul_add_words(&(r[4]),a,n,b[4]);
801 r+=4;
802 b+=4;
803 }
804 }
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