Import OpenSSL-0.9.8f.
[dragonfly.git] / crypto / openssl-0.9 / crypto / bn / bn_div.c
CommitLineData
56276539
SS
1/* crypto/bn/bn_div.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 <openssl/bn.h>
61#include "cryptlib.h"
62#include "bn_lcl.h"
63
64
65/* The old slow way */
66#if 0
67int BN_div(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m, const BIGNUM *d,
68 BN_CTX *ctx)
69 {
70 int i,nm,nd;
71 int ret = 0;
72 BIGNUM *D;
73
74 bn_check_top(m);
75 bn_check_top(d);
76 if (BN_is_zero(d))
77 {
78 BNerr(BN_F_BN_DIV,BN_R_DIV_BY_ZERO);
79 return(0);
80 }
81
82 if (BN_ucmp(m,d) < 0)
83 {
84 if (rem != NULL)
85 { if (BN_copy(rem,m) == NULL) return(0); }
86 if (dv != NULL) BN_zero(dv);
87 return(1);
88 }
89
90 BN_CTX_start(ctx);
91 D = BN_CTX_get(ctx);
92 if (dv == NULL) dv = BN_CTX_get(ctx);
93 if (rem == NULL) rem = BN_CTX_get(ctx);
94 if (D == NULL || dv == NULL || rem == NULL)
95 goto end;
96
97 nd=BN_num_bits(d);
98 nm=BN_num_bits(m);
99 if (BN_copy(D,d) == NULL) goto end;
100 if (BN_copy(rem,m) == NULL) goto end;
101
102 /* The next 2 are needed so we can do a dv->d[0]|=1 later
103 * since BN_lshift1 will only work once there is a value :-) */
104 BN_zero(dv);
105 bn_wexpand(dv,1);
106 dv->top=1;
107
108 if (!BN_lshift(D,D,nm-nd)) goto end;
109 for (i=nm-nd; i>=0; i--)
110 {
111 if (!BN_lshift1(dv,dv)) goto end;
112 if (BN_ucmp(rem,D) >= 0)
113 {
114 dv->d[0]|=1;
115 if (!BN_usub(rem,rem,D)) goto end;
116 }
117/* CAN IMPROVE (and have now :=) */
118 if (!BN_rshift1(D,D)) goto end;
119 }
120 rem->neg=BN_is_zero(rem)?0:m->neg;
121 dv->neg=m->neg^d->neg;
122 ret = 1;
123 end:
124 BN_CTX_end(ctx);
125 return(ret);
126 }
127
128#else
129
130#if !defined(OPENSSL_NO_ASM) && !defined(OPENSSL_NO_INLINE_ASM) \
131 && !defined(PEDANTIC) && !defined(BN_DIV3W)
132# if defined(__GNUC__) && __GNUC__>=2
133# if defined(__i386) || defined (__i386__)
134 /*
135 * There were two reasons for implementing this template:
136 * - GNU C generates a call to a function (__udivdi3 to be exact)
137 * in reply to ((((BN_ULLONG)n0)<<BN_BITS2)|n1)/d0 (I fail to
138 * understand why...);
139 * - divl doesn't only calculate quotient, but also leaves
140 * remainder in %edx which we can definitely use here:-)
141 *
142 * <appro@fy.chalmers.se>
143 */
144# define bn_div_words(n0,n1,d0) \
145 ({ asm volatile ( \
146 "divl %4" \
147 : "=a"(q), "=d"(rem) \
148 : "a"(n1), "d"(n0), "g"(d0) \
149 : "cc"); \
150 q; \
151 })
152# define REMAINDER_IS_ALREADY_CALCULATED
153# elif defined(__x86_64) && defined(SIXTY_FOUR_BIT_LONG)
154 /*
155 * Same story here, but it's 128-bit by 64-bit division. Wow!
156 * <appro@fy.chalmers.se>
157 */
158# define bn_div_words(n0,n1,d0) \
159 ({ asm volatile ( \
160 "divq %4" \
161 : "=a"(q), "=d"(rem) \
162 : "a"(n1), "d"(n0), "g"(d0) \
163 : "cc"); \
164 q; \
165 })
166# define REMAINDER_IS_ALREADY_CALCULATED
167# endif /* __<cpu> */
168# endif /* __GNUC__ */
169#endif /* OPENSSL_NO_ASM */
170
171
e6bc27f5
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172/* BN_div[_no_branch] computes dv := num / divisor, rounding towards
173 * zero, and sets up rm such that dv*divisor + rm = num holds.
56276539
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174 * Thus:
175 * dv->neg == num->neg ^ divisor->neg (unless the result is zero)
176 * rm->neg == num->neg (unless the remainder is zero)
177 * If 'dv' or 'rm' is NULL, the respective value is not returned.
178 */
e6bc27f5
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179static int BN_div_no_branch(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num,
180 const BIGNUM *divisor, BN_CTX *ctx);
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181int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor,
182 BN_CTX *ctx)
183 {
184 int norm_shift,i,loop;
185 BIGNUM *tmp,wnum,*snum,*sdiv,*res;
186 BN_ULONG *resp,*wnump;
187 BN_ULONG d0,d1;
188 int num_n,div_n;
189
e6bc27f5
PA
190 if ((BN_get_flags(num, BN_FLG_CONSTTIME) != 0) || (BN_get_flags(divisor, BN_FLG_CONSTTIME) != 0))
191 {
192 return BN_div_no_branch(dv, rm, num, divisor, ctx);
193 }
194
5bd86ce5
SS
195 bn_check_top(dv);
196 bn_check_top(rm);
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197 bn_check_top(num);
198 bn_check_top(divisor);
199
200 if (BN_is_zero(divisor))
201 {
202 BNerr(BN_F_BN_DIV,BN_R_DIV_BY_ZERO);
203 return(0);
204 }
205
206 if (BN_ucmp(num,divisor) < 0)
207 {
208 if (rm != NULL)
209 { if (BN_copy(rm,num) == NULL) return(0); }
210 if (dv != NULL) BN_zero(dv);
211 return(1);
212 }
213
214 BN_CTX_start(ctx);
215 tmp=BN_CTX_get(ctx);
216 snum=BN_CTX_get(ctx);
217 sdiv=BN_CTX_get(ctx);
218 if (dv == NULL)
219 res=BN_CTX_get(ctx);
220 else res=dv;
221 if (sdiv == NULL || res == NULL) goto err;
222
223 /* First we normalise the numbers */
224 norm_shift=BN_BITS2-((BN_num_bits(divisor))%BN_BITS2);
225 if (!(BN_lshift(sdiv,divisor,norm_shift))) goto err;
226 sdiv->neg=0;
227 norm_shift+=BN_BITS2;
228 if (!(BN_lshift(snum,num,norm_shift))) goto err;
229 snum->neg=0;
230 div_n=sdiv->top;
231 num_n=snum->top;
232 loop=num_n-div_n;
233 /* Lets setup a 'window' into snum
234 * This is the part that corresponds to the current
235 * 'area' being divided */
236 wnum.neg = 0;
237 wnum.d = &(snum->d[loop]);
238 wnum.top = div_n;
239 /* only needed when BN_ucmp messes up the values between top and max */
240 wnum.dmax = snum->dmax - loop; /* so we don't step out of bounds */
241
242 /* Get the top 2 words of sdiv */
243 /* div_n=sdiv->top; */
244 d0=sdiv->d[div_n-1];
245 d1=(div_n == 1)?0:sdiv->d[div_n-2];
246
247 /* pointer to the 'top' of snum */
248 wnump= &(snum->d[num_n-1]);
249
250 /* Setup to 'res' */
251 res->neg= (num->neg^divisor->neg);
252 if (!bn_wexpand(res,(loop+1))) goto err;
253 res->top=loop;
254 resp= &(res->d[loop-1]);
255
256 /* space for temp */
257 if (!bn_wexpand(tmp,(div_n+1))) goto err;
258
259 if (BN_ucmp(&wnum,sdiv) >= 0)
260 {
261 /* If BN_DEBUG_RAND is defined BN_ucmp changes (via
262 * bn_pollute) the const bignum arguments =>
263 * clean the values between top and max again */
264 bn_clear_top2max(&wnum);
265 bn_sub_words(wnum.d, wnum.d, sdiv->d, div_n);
266 *resp=1;
267 }
268 else
269 res->top--;
270 /* if res->top == 0 then clear the neg value otherwise decrease
271 * the resp pointer */
272 if (res->top == 0)
273 res->neg = 0;
274 else
275 resp--;
276
277 for (i=0; i<loop-1; i++, wnump--, resp--)
278 {
279 BN_ULONG q,l0;
280 /* the first part of the loop uses the top two words of
281 * snum and sdiv to calculate a BN_ULONG q such that
282 * | wnum - sdiv * q | < sdiv */
283#if defined(BN_DIV3W) && !defined(OPENSSL_NO_ASM)
284 BN_ULONG bn_div_3_words(BN_ULONG*,BN_ULONG,BN_ULONG);
285 q=bn_div_3_words(wnump,d1,d0);
286#else
287 BN_ULONG n0,n1,rem=0;
288
289 n0=wnump[0];
290 n1=wnump[-1];
291 if (n0 == d0)
292 q=BN_MASK2;
293 else /* n0 < d0 */
294 {
295#ifdef BN_LLONG
296 BN_ULLONG t2;
297
298#if defined(BN_LLONG) && defined(BN_DIV2W) && !defined(bn_div_words)
299 q=(BN_ULONG)(((((BN_ULLONG)n0)<<BN_BITS2)|n1)/d0);
300#else
301 q=bn_div_words(n0,n1,d0);
302#ifdef BN_DEBUG_LEVITTE
303 fprintf(stderr,"DEBUG: bn_div_words(0x%08X,0x%08X,0x%08\
304X) -> 0x%08X\n",
305 n0, n1, d0, q);
306#endif
307#endif
308
309#ifndef REMAINDER_IS_ALREADY_CALCULATED
310 /*
311 * rem doesn't have to be BN_ULLONG. The least we
312 * know it's less that d0, isn't it?
313 */
314 rem=(n1-q*d0)&BN_MASK2;
315#endif
316 t2=(BN_ULLONG)d1*q;
317
318 for (;;)
319 {
320 if (t2 <= ((((BN_ULLONG)rem)<<BN_BITS2)|wnump[-2]))
321 break;
322 q--;
323 rem += d0;
324 if (rem < d0) break; /* don't let rem overflow */
325 t2 -= d1;
326 }
327#else /* !BN_LLONG */
328 BN_ULONG t2l,t2h,ql,qh;
329
330 q=bn_div_words(n0,n1,d0);
331#ifdef BN_DEBUG_LEVITTE
332 fprintf(stderr,"DEBUG: bn_div_words(0x%08X,0x%08X,0x%08\
333X) -> 0x%08X\n",
334 n0, n1, d0, q);
335#endif
336#ifndef REMAINDER_IS_ALREADY_CALCULATED
337 rem=(n1-q*d0)&BN_MASK2;
338#endif
339
340#if defined(BN_UMULT_LOHI)
341 BN_UMULT_LOHI(t2l,t2h,d1,q);
342#elif defined(BN_UMULT_HIGH)
343 t2l = d1 * q;
344 t2h = BN_UMULT_HIGH(d1,q);
345#else
346 t2l=LBITS(d1); t2h=HBITS(d1);
347 ql =LBITS(q); qh =HBITS(q);
348 mul64(t2l,t2h,ql,qh); /* t2=(BN_ULLONG)d1*q; */
349#endif
350
351 for (;;)
352 {
353 if ((t2h < rem) ||
354 ((t2h == rem) && (t2l <= wnump[-2])))
355 break;
356 q--;
357 rem += d0;
358 if (rem < d0) break; /* don't let rem overflow */
359 if (t2l < d1) t2h--; t2l -= d1;
360 }
361#endif /* !BN_LLONG */
362 }
363#endif /* !BN_DIV3W */
364
365 l0=bn_mul_words(tmp->d,sdiv->d,div_n,q);
366 tmp->d[div_n]=l0;
367 wnum.d--;
368 /* ingore top values of the bignums just sub the two
369 * BN_ULONG arrays with bn_sub_words */
370 if (bn_sub_words(wnum.d, wnum.d, tmp->d, div_n+1))
371 {
372 /* Note: As we have considered only the leading
373 * two BN_ULONGs in the calculation of q, sdiv * q
374 * might be greater than wnum (but then (q-1) * sdiv
375 * is less or equal than wnum)
376 */
377 q--;
378 if (bn_add_words(wnum.d, wnum.d, sdiv->d, div_n))
379 /* we can't have an overflow here (assuming
380 * that q != 0, but if q == 0 then tmp is
381 * zero anyway) */
382 (*wnump)++;
383 }
384 /* store part of the result */
385 *resp = q;
386 }
387 bn_correct_top(snum);
388 if (rm != NULL)
389 {
390 /* Keep a copy of the neg flag in num because if rm==num
391 * BN_rshift() will overwrite it.
392 */
393 int neg = num->neg;
394 BN_rshift(rm,snum,norm_shift);
395 if (!BN_is_zero(rm))
396 rm->neg = neg;
397 bn_check_top(rm);
398 }
399 BN_CTX_end(ctx);
400 return(1);
401err:
5bd86ce5 402 bn_check_top(rm);
56276539
SS
403 BN_CTX_end(ctx);
404 return(0);
405 }
406
e6bc27f5
PA
407
408/* BN_div_no_branch is a special version of BN_div. It does not contain
409 * branches that may leak sensitive information.
410 */
411static int BN_div_no_branch(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num,
412 const BIGNUM *divisor, BN_CTX *ctx)
413 {
414 int norm_shift,i,loop;
415 BIGNUM *tmp,wnum,*snum,*sdiv,*res;
416 BN_ULONG *resp,*wnump;
417 BN_ULONG d0,d1;
418 int num_n,div_n;
419
420 bn_check_top(dv);
421 bn_check_top(rm);
422 bn_check_top(num);
423 bn_check_top(divisor);
424
425 if (BN_is_zero(divisor))
426 {
427 BNerr(BN_F_BN_DIV_NO_BRANCH,BN_R_DIV_BY_ZERO);
428 return(0);
429 }
430
431 BN_CTX_start(ctx);
432 tmp=BN_CTX_get(ctx);
433 snum=BN_CTX_get(ctx);
434 sdiv=BN_CTX_get(ctx);
435 if (dv == NULL)
436 res=BN_CTX_get(ctx);
437 else res=dv;
438 if (sdiv == NULL || res == NULL) goto err;
439
440 /* First we normalise the numbers */
441 norm_shift=BN_BITS2-((BN_num_bits(divisor))%BN_BITS2);
442 if (!(BN_lshift(sdiv,divisor,norm_shift))) goto err;
443 sdiv->neg=0;
444 norm_shift+=BN_BITS2;
445 if (!(BN_lshift(snum,num,norm_shift))) goto err;
446 snum->neg=0;
447
448 /* Since we don't know whether snum is larger than sdiv,
449 * we pad snum with enough zeroes without changing its
450 * value.
451 */
452 if (snum->top <= sdiv->top+1)
453 {
454 if (bn_wexpand(snum, sdiv->top + 2) == NULL) goto err;
455 for (i = snum->top; i < sdiv->top + 2; i++) snum->d[i] = 0;
456 snum->top = sdiv->top + 2;
457 }
458 else
459 {
460 if (bn_wexpand(snum, snum->top + 1) == NULL) goto err;
461 snum->d[snum->top] = 0;
462 snum->top ++;
463 }
464
465 div_n=sdiv->top;
466 num_n=snum->top;
467 loop=num_n-div_n;
468 /* Lets setup a 'window' into snum
469 * This is the part that corresponds to the current
470 * 'area' being divided */
471 wnum.neg = 0;
472 wnum.d = &(snum->d[loop]);
473 wnum.top = div_n;
474 /* only needed when BN_ucmp messes up the values between top and max */
475 wnum.dmax = snum->dmax - loop; /* so we don't step out of bounds */
476
477 /* Get the top 2 words of sdiv */
478 /* div_n=sdiv->top; */
479 d0=sdiv->d[div_n-1];
480 d1=(div_n == 1)?0:sdiv->d[div_n-2];
481
482 /* pointer to the 'top' of snum */
483 wnump= &(snum->d[num_n-1]);
484
485 /* Setup to 'res' */
486 res->neg= (num->neg^divisor->neg);
487 if (!bn_wexpand(res,(loop+1))) goto err;
488 res->top=loop-1;
489 resp= &(res->d[loop-1]);
490
491 /* space for temp */
492 if (!bn_wexpand(tmp,(div_n+1))) goto err;
493
494 /* if res->top == 0 then clear the neg value otherwise decrease
495 * the resp pointer */
496 if (res->top == 0)
497 res->neg = 0;
498 else
499 resp--;
500
501 for (i=0; i<loop-1; i++, wnump--, resp--)
502 {
503 BN_ULONG q,l0;
504 /* the first part of the loop uses the top two words of
505 * snum and sdiv to calculate a BN_ULONG q such that
506 * | wnum - sdiv * q | < sdiv */
507#if defined(BN_DIV3W) && !defined(OPENSSL_NO_ASM)
508 BN_ULONG bn_div_3_words(BN_ULONG*,BN_ULONG,BN_ULONG);
509 q=bn_div_3_words(wnump,d1,d0);
510#else
511 BN_ULONG n0,n1,rem=0;
512
513 n0=wnump[0];
514 n1=wnump[-1];
515 if (n0 == d0)
516 q=BN_MASK2;
517 else /* n0 < d0 */
518 {
519#ifdef BN_LLONG
520 BN_ULLONG t2;
521
522#if defined(BN_LLONG) && defined(BN_DIV2W) && !defined(bn_div_words)
523 q=(BN_ULONG)(((((BN_ULLONG)n0)<<BN_BITS2)|n1)/d0);
524#else
525 q=bn_div_words(n0,n1,d0);
526#ifdef BN_DEBUG_LEVITTE
527 fprintf(stderr,"DEBUG: bn_div_words(0x%08X,0x%08X,0x%08\
528X) -> 0x%08X\n",
529 n0, n1, d0, q);
530#endif
531#endif
532
533#ifndef REMAINDER_IS_ALREADY_CALCULATED
534 /*
535 * rem doesn't have to be BN_ULLONG. The least we
536 * know it's less that d0, isn't it?
537 */
538 rem=(n1-q*d0)&BN_MASK2;
539#endif
540 t2=(BN_ULLONG)d1*q;
541
542 for (;;)
543 {
544 if (t2 <= ((((BN_ULLONG)rem)<<BN_BITS2)|wnump[-2]))
545 break;
546 q--;
547 rem += d0;
548 if (rem < d0) break; /* don't let rem overflow */
549 t2 -= d1;
550 }
551#else /* !BN_LLONG */
552 BN_ULONG t2l,t2h,ql,qh;
553
554 q=bn_div_words(n0,n1,d0);
555#ifdef BN_DEBUG_LEVITTE
556 fprintf(stderr,"DEBUG: bn_div_words(0x%08X,0x%08X,0x%08\
557X) -> 0x%08X\n",
558 n0, n1, d0, q);
559#endif
560#ifndef REMAINDER_IS_ALREADY_CALCULATED
561 rem=(n1-q*d0)&BN_MASK2;
562#endif
563
564#if defined(BN_UMULT_LOHI)
565 BN_UMULT_LOHI(t2l,t2h,d1,q);
566#elif defined(BN_UMULT_HIGH)
567 t2l = d1 * q;
568 t2h = BN_UMULT_HIGH(d1,q);
569#else
570 t2l=LBITS(d1); t2h=HBITS(d1);
571 ql =LBITS(q); qh =HBITS(q);
572 mul64(t2l,t2h,ql,qh); /* t2=(BN_ULLONG)d1*q; */
573#endif
574
575 for (;;)
576 {
577 if ((t2h < rem) ||
578 ((t2h == rem) && (t2l <= wnump[-2])))
579 break;
580 q--;
581 rem += d0;
582 if (rem < d0) break; /* don't let rem overflow */
583 if (t2l < d1) t2h--; t2l -= d1;
584 }
585#endif /* !BN_LLONG */
586 }
587#endif /* !BN_DIV3W */
588
589 l0=bn_mul_words(tmp->d,sdiv->d,div_n,q);
590 tmp->d[div_n]=l0;
591 wnum.d--;
592 /* ingore top values of the bignums just sub the two
593 * BN_ULONG arrays with bn_sub_words */
594 if (bn_sub_words(wnum.d, wnum.d, tmp->d, div_n+1))
595 {
596 /* Note: As we have considered only the leading
597 * two BN_ULONGs in the calculation of q, sdiv * q
598 * might be greater than wnum (but then (q-1) * sdiv
599 * is less or equal than wnum)
600 */
601 q--;
602 if (bn_add_words(wnum.d, wnum.d, sdiv->d, div_n))
603 /* we can't have an overflow here (assuming
604 * that q != 0, but if q == 0 then tmp is
605 * zero anyway) */
606 (*wnump)++;
607 }
608 /* store part of the result */
609 *resp = q;
610 }
611 bn_correct_top(snum);
612 if (rm != NULL)
613 {
614 /* Keep a copy of the neg flag in num because if rm==num
615 * BN_rshift() will overwrite it.
616 */
617 int neg = num->neg;
618 BN_rshift(rm,snum,norm_shift);
619 if (!BN_is_zero(rm))
620 rm->neg = neg;
621 bn_check_top(rm);
622 }
623 bn_correct_top(res);
624 BN_CTX_end(ctx);
625 return(1);
626err:
627 bn_check_top(rm);
628 BN_CTX_end(ctx);
629 return(0);
630 }
631
56276539 632#endif