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Gather up another utility.
[u/mdw/catacomb] / mp-arith.c
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d3409d5e 1/* -*-c-*-
2 *
b817bfc6 3 * $Id: mp-arith.c,v 1.18 2004/04/08 01:36:15 mdw Exp $
d3409d5e 4 *
5 * Basic arithmetic on multiprecision integers
6 *
7 * (c) 1999 Straylight/Edgeware
8 */
9
10/*----- Licensing notice --------------------------------------------------*
11 *
12 * This file is part of Catacomb.
13 *
14 * Catacomb is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU Library General Public License as
16 * published by the Free Software Foundation; either version 2 of the
17 * License, or (at your option) any later version.
18 *
19 * Catacomb is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU Library General Public License for more details.
23 *
24 * You should have received a copy of the GNU Library General Public
25 * License along with Catacomb; if not, write to the Free
26 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
27 * MA 02111-1307, USA.
28 */
29
d3409d5e 30/*----- Header files ------------------------------------------------------*/
31
32#include "mp.h"
33
ef5f4810 34/*----- Macros ------------------------------------------------------------*/
35
36#define MAX(x, y) ((x) >= (y) ? (x) : (y))
37
d3409d5e 38/*----- Main code ---------------------------------------------------------*/
39
81578196 40/* --- @mp_lsl@, @mp_lslc@, @mp_lsr@ --- *
d3409d5e 41 *
f09e814a 42 * Arguments: @mp *d@ = destination
43 * @mp *a@ = source
44 * @size_t n@ = number of bits to move
d3409d5e 45 *
f09e814a 46 * Returns: Result, @a@ shifted left or right by @n@.
81578196 47 *
48 * Use: Bitwise shift operators. @mp_lslc@ fills the bits introduced
49 * on the right with ones instead of zeroes: it's used
50 * internally by @mp_lsl2c@, though it may be useful on its
51 * own.
d3409d5e 52 */
53
f09e814a 54mp *mp_lsl(mp *d, mp *a, size_t n)
d3409d5e 55{
f09e814a 56 MP_DEST(d, MP_LEN(a) + (n + MPW_BITS - 1) / MPW_BITS, a->f);
57 mpx_lsl(d->v, d->vl, a->v, a->vl, n);
58 d->f = a->f & (MP_NEG | MP_BURN);
59 MP_SHRINK(d);
60 return (d);
61}
d3409d5e 62
81578196 63mp *mp_lslc(mp *d, mp *a, size_t n)
64{
65 MP_DEST(d, MP_LEN(a) + (n + MPW_BITS - 1) / MPW_BITS, a->f);
66 mpx_lslc(d->v, d->vl, a->v, a->vl, n);
67 d->f = a->f & (MP_NEG | MP_BURN);
68 MP_SHRINK(d);
69 return (d);
70}
71
f09e814a 72mp *mp_lsr(mp *d, mp *a, size_t n)
73{
d34decd2 74 MP_DEST(d, MP_LEN(a), a->f);
f09e814a 75 mpx_lsr(d->v, d->vl, a->v, a->vl, n);
76 d->f = a->f & (MP_NEG | MP_BURN);
d3409d5e 77 MP_SHRINK(d);
78 return (d);
79}
80
f09e814a 81/* --- @mp_lsl2c@, @mp_lsr2c@ --- *
d3409d5e 82 *
83 * Arguments: @mp *d@ = destination
84 * @mp *a@ = source
f09e814a 85 * @size_t n@ = number of bits to move
d3409d5e 86 *
f09e814a 87 * Returns: Result, @a@ shifted left or right by @n@. Handles the
88 * pretence of sign-extension for negative numbers.
d3409d5e 89 */
90
f09e814a 91mp *mp_lsl2c(mp *d, mp *a, size_t n)
d3409d5e 92{
f09e814a 93 if (!(a->f & MP_NEG))
94 return (mp_lsl(d, a, n));
95 d = mp_not2c(d, a);
81578196 96 d = mp_lslc(d, d, n);
f09e814a 97 d = mp_not2c(d, d);
98 return (d);
99}
d3409d5e 100
f09e814a 101mp *mp_lsr2c(mp *d, mp *a, size_t n)
102{
103 if (!(a->f & MP_NEG))
104 return (mp_lsr(d, a, n));
105 d = mp_not2c(d, a);
106 d = mp_lsr(d, d, n);
107 d = mp_not2c(d, d);
108 return (d);
d3409d5e 109}
110
f09e814a 111/* --- @mp_testbit@ --- *
d3409d5e 112 *
f09e814a 113 * Arguments: @mp *x@ = a large integer
09d00c6b 114 * @unsigned long n@ = which bit to test
d3409d5e 115 *
f09e814a 116 * Returns: Nonzero if the bit is set, zero if not.
d3409d5e 117 */
118
09d00c6b 119int mp_testbit(mp *x, unsigned long n)
d3409d5e 120{
f09e814a 121 if (n > MPW_BITS * MP_LEN(x))
122 return (0);
09d00c6b 123 return ((x->v[n/MPW_BITS] >> n%MPW_BITS) & 1u);
d3409d5e 124}
125
f09e814a 126/* --- @mp_testbit2c@ --- *
d3409d5e 127 *
f09e814a 128 * Arguments: @mp *x@ = a large integer
09d00c6b 129 * @unsigned long n@ = which bit to test
d3409d5e 130 *
f09e814a 131 * Returns: Nonzero if the bit is set, zero if not. Fakes up two's
132 * complement representation.
d3409d5e 133 */
134
09d00c6b 135int mp_testbit2c(mp *x, unsigned long n)
d3409d5e 136{
f09e814a 137 int r;
09d00c6b 138 if (!(x->f & MP_NEG))
f09e814a 139 return (mp_testbit(x, n));
140 x = mp_not2c(MP_NEW, x);
141 r = !mp_testbit(x, n);
142 MP_DROP(x);
143 return (r);
d3409d5e 144}
145
09d00c6b 146/* --- @mp_setbit@, @mp_clearbit@ --- *
147 *
148 * Arguments: @mp *d@ = a destination
149 * @mp *x@ = a large integer
150 * @unsigned long n@ = which bit to modify
151 *
152 * Returns: The argument @x@, with the appropriate bit set or cleared.
153 */
154
155mp *mp_setbit(mp *d, mp *x, unsigned long n)
156{
157 size_t rq;
158
159 rq = n + MPW_BITS; rq -= rq % MPW_BITS;
160 if (d != x) {
161 if (d) MP_DROP(d);
162 d = MP_COPY(x);
163 }
164 MP_DEST(d, rq, x->f & (MP_NEG | MP_BURN));
165 d->v[n/MPW_BITS] |= 1 << n%MPW_BITS;
166 return (d);
167}
168
169mp *mp_clearbit(mp *d, mp *x, unsigned long n)
170{
171 size_t rq;
172
173 rq = n + MPW_BITS; rq -= rq % MPW_BITS;
174 if (d != x) {
175 if (d) MP_DROP(d);
176 d = MP_COPY(x);
177 }
178 MP_DEST(d, rq, x->f & (MP_NEG | MP_BURN));
179 d->v[n/MPW_BITS] &= ~(1 << n%MPW_BITS);
180 return (d);
181}
182
183/* --- @mp_setbit2c@, @mp_clearbit2c@ --- *
184 *
185 * Arguments: @mp *d@ = a destination
186 * @mp *x@ = a large integer
187 * @unsigned long n@ = which bit to modify
188 *
189 * Returns: The argument @x@, with the appropriate bit set or cleared.
190 * Fakes up two's complement representation.
191 */
192
193mp *mp_setbit2c(mp *d, mp *x, unsigned long n)
194{
195 if (!(x->f & MP_NEG))
196 return mp_setbit(d, x, n);
197 d = mp_not2c(d, x);
198 d = mp_clearbit(d, d, n);
199 d = mp_not2c(d, d);
200 return (d);
201}
202
203mp *mp_clearbit2c(mp *d, mp *x, unsigned long n)
204{
205 if (!(x->f & MP_NEG))
206 return mp_clearbit(d, x, n);
207 d = mp_not2c(d, x);
208 d = mp_setbit(d, d, n);
209 d = mp_not2c(d, d);
210 return (d);
211}
212
4b536f42 213/* --- @mp_eq@ --- *
214 *
215 * Arguments: @const mp *a, *b@ = two numbers
216 *
217 * Returns: Nonzero if the numbers are equal.
218 */
219
220int mp_eq(const mp *a, const mp *b) { return (MP_EQ(a, b)); }
221
d3409d5e 222/* --- @mp_cmp@ --- *
223 *
224 * Arguments: @const mp *a, *b@ = two numbers
225 *
226 * Returns: Less than, equal to or greater than zero, according to
227 * whether @a@ is less than, equal to or greater than @b@.
228 */
229
230int mp_cmp(const mp *a, const mp *b)
231{
232 if (!((a->f ^ b->f) & MP_NEG))
233 return (mpx_ucmp(a->v, a->vl, b->v, b->vl));
234 else if (a->f & MP_NEG)
235 return (-1);
236 else
237 return (+1);
238}
239
397041a9 240/* --- @mp_neg@ --- *
241 *
242 * Arguments: @mp *d@ = destination
243 * @mp *a@ = argument
244 *
245 * Returns: The negation of the argument.
246 *
247 * Use: Negates its argument.
248 */
249
250mp *mp_neg(mp *d, mp *a)
251{
252 /* --- Surprising amounts of messing about required --- */
253
254 MP_SHRINK(a);
255 MP_COPY(a);
81578196 256 if (d)
257 MP_DROP(d);
258 if (a->v == a->vl)
397041a9 259 return (a);
397041a9 260 MP_DEST(a, MP_LEN(a), a->f);
261 a->f ^= MP_NEG;
262 return (a);
263}
264
f09e814a 265/* --- @mp_bitop@ --- *
0f32e0f8 266 *
267 * Arguments: @mp *d@ = destination
268 * @mp *a, *b@ = sources
269 *
f09e814a 270 * Returns: The result of the given bitwise operation. These functions
271 * don't handle negative numbers at all sensibly. For that, use
272 * the @...2c@ variants. The functions are named after the
273 * truth tables they generate:
274 *
275 * a: 0011
276 * b: 0101
277 * @mpx_bitXXXX@
0f32e0f8 278 */
279
f09e814a 280#define MP_BITBINOP(string) \
0f32e0f8 281 \
f09e814a 282mp *mp_bit##string(mp *d, mp *a, mp *b) \
0f32e0f8 283{ \
75263f25 284 MP_DEST(d, MAX(MP_LEN(a), MP_LEN(b)), (a->f | b->f) & ~MP_NEG); \
f09e814a 285 mpx_bit##string(d->v, d->vl, a->v, a->vl, b->v, b->vl); \
0f32e0f8 286 d->f = (a->f | b->f) & MP_BURN; \
287 MP_SHRINK(d); \
288 return (d); \
289}
290
f09e814a 291MPX_DOBIN(MP_BITBINOP)
292
293/* --- @mp_not@ --- *
294 *
295 * Arguments: @mp *d@ = destination
296 * @mp *a@ = source
297 *
298 * Returns: The bitwise complement of the source.
299 */
0f32e0f8 300
301mp *mp_not(mp *d, mp *a)
302{
303 MP_DEST(d, MP_LEN(a), a->f);
304 mpx_not(d->v, d->vl, a->v, a->vl);
305 d->f = a->f & MP_BURN;
306 MP_SHRINK(d);
307 return (d);
308}
309
f09e814a 310/* --- @mp_bitop2c@ --- *
311 *
312 * Arguments: @mp *d@ = destination
313 * @mp *a, *b@ = sources
314 *
315 * Returns: The result of the given bitwise operation. Negative numbers
316 * are treated as two's complement, sign-extended infinitely to
317 * the left. The functions are named after the truth tables
318 * they generate:
319 *
320 * a: 0011
321 * b: 0101
322 * @mpx_bitXXXX@
323 */
324
325/* --- How this actually works --- *
326 *
327 * The two arguments are inverted (with a sign-swap) if they're currently
328 * negative. This means that we end up using a different function (one which
329 * reinverts as we go) for the main operation. Also, if the sign would be
330 * negative at the end, we preinvert the output and then invert again with a
331 * sign-swap.
332 *
333 * Start with: wxyz WXYZ
334 * If @a@ negative: yzwx or YZWX
335 * If @b@ negative: xwzy XWZY
336 * If both negative: zyxw ZYXW
337 */
338
339#define MP_BIT2CBINOP(n, base, an, bn, abn, p_base, p_an, p_bn, p_abn) \
340 \
341mp *mp_bit##n##2c(mp *d, mp *a, mp *b) \
342{ \
343 if (!((a->f | b->f) & MP_NEG)) { /* Both positive */ \
344 d = mp_bit##base(d, a, b); \
345 p_base \
346 } else if (!(b->f & MP_NEG)) { /* Only @b@ positive */ \
347 MP_COPY(b); \
348 d = mp_not2c(d, a); \
349 d = mp_bit##an(d, d, b); \
350 MP_DROP(b); \
351 p_an \
352 } else if (!(a->f & MP_NEG)) { /* Only @a@ positive */ \
353 MP_COPY(a); \
354 d = mp_not2c(d, b); \
355 d = mp_bit##bn(d, a, d); \
356 MP_DROP(a); \
357 p_bn \
358 } else { /* Both negative */ \
359 mp *t = mp_not2c(MP_NEW, a); \
360 mp *d = mp_not2c(d, b); \
361 d = mp_bit##abn(d, t, d); \
362 MP_DROP(t); \
363 p_abn \
364 } \
365 return (d); \
366} \
367
368#define NEG d = mp_not2c(d, d);
369#define POS
370MP_BIT2CBINOP(0000, 0000, 0000, 0000, 0000, POS, POS, POS, POS)
371MP_BIT2CBINOP(0001, 0001, 0100, 0010, 0111, POS, POS, POS, NEG)
372MP_BIT2CBINOP(0010, 0010, 0111, 0001, 0100, POS, NEG, POS, POS)
373MP_BIT2CBINOP(0011, 0011, 0011, 0011, 0011, POS, NEG, POS, NEG)
374MP_BIT2CBINOP(0100, 0100, 0001, 0111, 0010, POS, POS, NEG, POS)
375MP_BIT2CBINOP(0101, 0101, 0101, 0101, 0101, POS, POS, NEG, NEG)
376MP_BIT2CBINOP(0110, 0110, 0110, 0110, 0110, POS, NEG, NEG, POS)
377MP_BIT2CBINOP(0111, 0111, 0010, 0100, 0001, POS, NEG, NEG, NEG)
378MP_BIT2CBINOP(1000, 0111, 0010, 0100, 0001, NEG, POS, POS, POS)
379MP_BIT2CBINOP(1001, 0110, 0110, 0110, 0110, NEG, POS, POS, NEG)
380MP_BIT2CBINOP(1010, 0101, 0101, 0101, 0101, NEG, NEG, POS, POS)
381MP_BIT2CBINOP(1011, 0100, 0001, 0111, 0010, NEG, NEG, POS, NEG)
382MP_BIT2CBINOP(1100, 0011, 0011, 0011, 0011, NEG, POS, NEG, POS)
383MP_BIT2CBINOP(1101, 0010, 0111, 0001, 0100, NEG, POS, NEG, NEG)
384MP_BIT2CBINOP(1110, 0001, 0100, 0010, 0111, NEG, NEG, NEG, POS)
385MP_BIT2CBINOP(1111, 0000, 0000, 0000, 0000, NEG, NEG, NEG, NEG)
386#undef NEG
387#undef POS
388
389/* --- @mp_not2c@ --- *
390 *
391 * Arguments: @mp *d@ = destination
392 * @mp *a@ = source
393 *
394 * Returns: The sign-extended complement of the argument.
395 */
396
397mp *mp_not2c(mp *d, mp *a)
398{
399 mpw one = 1;
400
401 MP_DEST(d, MP_LEN(a) + 1, a->f);
402 if (d == a) {
403 if (a->f & MP_NEG)
404 MPX_USUBN(d->v, d->vl, 1);
405 else
406 MPX_UADDN(d->v, d->vl, 1);
407 } else {
408 if (a->f & MP_NEG)
409 mpx_usub(d->v, d->vl, a->v, a->vl, &one, &one + 1);
410 else
411 mpx_uadd(d->v, d->vl, a->v, a->vl, &one, &one + 1);
412 }
413 d->f = (a->f & (MP_NEG | MP_BURN)) ^ MP_NEG;
414 MP_SHRINK(d);
415 return (d);
416}
417
d3409d5e 418/* --- @mp_add@ --- *
419 *
420 * Arguments: @mp *d@ = destination
ef5f4810 421 * @mp *a, *b@ = sources
d3409d5e 422 *
423 * Returns: Result, @a@ added to @b@.
424 */
425
ef5f4810 426mp *mp_add(mp *d, mp *a, mp *b)
d3409d5e 427{
d34decd2 428 MP_DEST(d, MAX(MP_LEN(a), MP_LEN(b)) + 1, a->f | b->f);
d3409d5e 429 if (!((a->f ^ b->f) & MP_NEG))
430 mpx_uadd(d->v, d->vl, a->v, a->vl, b->v, b->vl);
431 else {
432 if (MPX_UCMP(a->v, a->vl, <, b->v, b->vl)) {
ef5f4810 433 mp *t = a; a = b; b = t;
d3409d5e 434 }
435 mpx_usub(d->v, d->vl, a->v, a->vl, b->v, b->vl);
436 }
437 d->f = ((a->f | b->f) & MP_BURN) | (a->f & MP_NEG);
438 MP_SHRINK(d);
439 return (d);
440}
441
442/* --- @mp_sub@ --- *
443 *
444 * Arguments: @mp *d@ = destination
ef5f4810 445 * @mp *a, *b@ = sources
d3409d5e 446 *
447 * Returns: Result, @b@ subtracted from @a@.
448 */
449
ef5f4810 450mp *mp_sub(mp *d, mp *a, mp *b)
d3409d5e 451{
452 unsigned sgn = 0;
d34decd2 453 MP_DEST(d, MAX(MP_LEN(a), MP_LEN(b)) + 1, a->f | b->f);
d3409d5e 454 if ((a->f ^ b->f) & MP_NEG)
455 mpx_uadd(d->v, d->vl, a->v, a->vl, b->v, b->vl);
456 else {
457 if (MPX_UCMP(a->v, a->vl, <, b->v, b->vl)) {
ef5f4810 458 mp *t = a; a = b; b = t;
d3409d5e 459 sgn = MP_NEG;
460 }
461 mpx_usub(d->v, d->vl, a->v, a->vl, b->v, b->vl);
462 }
463 d->f = ((a->f | b->f) & MP_BURN) | ((a->f ^ sgn) & MP_NEG);
464 MP_SHRINK(d);
465 return (d);
466}
467
468/* --- @mp_mul@ --- *
469 *
470 * Arguments: @mp *d@ = destination
ef5f4810 471 * @mp *a, *b@ = sources
d3409d5e 472 *
473 * Returns: Result, @a@ multiplied by @b@.
474 */
475
ef5f4810 476mp *mp_mul(mp *d, mp *a, mp *b)
d3409d5e 477{
ef5f4810 478 a = MP_COPY(a);
479 b = MP_COPY(b);
480
52cdaca9 481 if (MP_LEN(a) <= MPK_THRESH || MP_LEN(b) <= MPK_THRESH) {
d34decd2 482 MP_DEST(d, MP_LEN(a) + MP_LEN(b), a->f | b->f | MP_UNDEF);
ef5f4810 483 mpx_umul(d->v, d->vl, a->v, a->vl, b->v, b->vl);
8017495b 484 } else {
dd22938e 485 size_t m = MAX(MP_LEN(a), MP_LEN(b));
ef5f4810 486 mpw *s;
dd22938e 487 MP_DEST(d, 3 * m, a->f | b->f | MP_UNDEF);
488 s = mpalloc(d->a, 5 * m);
489 mpx_kmul(d->v, d->vl, a->v, a->vl, b->v, b->vl, s, s + 5 * m);
d34decd2 490 mpfree(d->a, s);
ef5f4810 491 }
492
d3409d5e 493 d->f = ((a->f | b->f) & MP_BURN) | ((a->f ^ b->f) & MP_NEG);
494 MP_SHRINK(d);
ef5f4810 495 MP_DROP(a);
496 MP_DROP(b);
d3409d5e 497 return (d);
498}
499
500/* --- @mp_sqr@ --- *
501 *
502 * Arguments: @mp *d@ = destination
ef5f4810 503 * @mp *a@ = source
d3409d5e 504 *
505 * Returns: Result, @a@ squared.
506 */
507
ef5f4810 508mp *mp_sqr(mp *d, mp *a)
d3409d5e 509{
ef5f4810 510 size_t m = MP_LEN(a);
511
512 a = MP_COPY(a);
52cdaca9 513 if (m > MPK_THRESH) {
ef5f4810 514 mpw *s;
dd22938e 515 MP_DEST(d, 3 * m, a->f | MP_UNDEF);
516 s = mpalloc(d->a, 5 * m);
517 mpx_ksqr(d->v, d->vl, a->v, a->vl, s, s + 5 * m);
d34decd2 518 mpfree(d->a, s);
dd22938e 519 } else {
520 MP_DEST(d, 2 * m + 2, a->f | MP_UNDEF);
ef5f4810 521 mpx_usqr(d->v, d->vl, a->v, a->vl);
dd22938e 522 }
d3409d5e 523 d->f = a->f & MP_BURN;
524 MP_SHRINK(d);
ef5f4810 525 MP_DROP(a);
d3409d5e 526 return (d);
527}
528
529/* --- @mp_div@ --- *
530 *
531 * Arguments: @mp **qq, **rr@ = destination, quotient and remainder
ef5f4810 532 * @mp *a, *b@ = sources
d3409d5e 533 *
534 * Use: Calculates the quotient and remainder when @a@ is divided by
535 * @b@. The destinations @*qq@ and @*rr@ must be distinct.
536 * Either of @qq@ or @rr@ may be null to indicate that the
537 * result is irrelevant. (Discarding both results is silly.)
538 * There is a performance advantage if @a == *rr@.
539 *
540 * The behaviour when @a@ and @b@ have the same sign is
541 * straightforward. When the signs differ, this implementation
542 * chooses @r@ to have the same sign as @b@, rather than the
543 * more normal choice that the remainder has the same sign as
544 * the dividend. This makes modular arithmetic a little more
545 * straightforward.
546 */
547
ef5f4810 548void mp_div(mp **qq, mp **rr, mp *a, mp *b)
d3409d5e 549 {
550 mp *r = rr ? *rr : MP_NEW;
551 mp *q = qq ? *qq : MP_NEW;
552 mpw *sv, *svl;
553
d3409d5e 554 /* --- Set the remainder up right --- *
555 *
556 * Just in case the divisor is larger, be able to cope with this. It's not
557 * important in @mpx_udiv@, but it is here because of the sign correction.
558 */
559
d34decd2 560 b = MP_COPY(b);
561 a = MP_COPY(a);
562 if (r)
563 MP_DROP(r);
564 r = a;
a9c8f3d6 565 MP_DEST(r, MAX(MP_LEN(a), MP_LEN(b)) + 2, a->f | b->f);
d3409d5e 566
567 /* --- Fix up the quotient too --- */
568
d34decd2 569 r = MP_COPY(r);
570 MP_DEST(q, MP_LEN(r), r->f | MP_UNDEF);
571 MP_DROP(r);
572
573 /* --- Set up some temporary workspace --- */
574
575 {
576 size_t rq = MP_LEN(b) + 1;
577 sv = mpalloc(r->a, rq);
578 svl = sv + rq;
579 }
d3409d5e 580
581 /* --- Perform the calculation --- */
582
583 mpx_udiv(q->v, q->vl, r->v, r->vl, b->v, b->vl, sv, svl);
584
585 /* --- Sort out the sign of the results --- *
586 *
587 * If the signs of the arguments differ, and the remainder is nonzero, I
588 * must add one to the absolute value of the quotient and subtract the
589 * remainder from @b@.
590 */
591
d34decd2 592 q->f = ((r->f | b->f) & MP_BURN) | ((r->f ^ b->f) & MP_NEG);
d3409d5e 593 if (q->f & MP_NEG) {
ef5f4810 594 mpw *v;
595 for (v = r->v; v < r->vl; v++) {
d3409d5e 596 if (*v) {
597 MPX_UADDN(q->v, q->vl, 1);
598 mpx_usub(r->v, r->vl, b->v, b->vl, r->v, r->vl);
599 break;
600 }
601 }
602 }
603
d34decd2 604 r->f = ((r->f | b->f) & MP_BURN) | (b->f & MP_NEG);
d3409d5e 605
606 /* --- Store the return values --- */
607
d34decd2 608 mpfree(r->a, sv);
609 MP_DROP(b);
610
d3409d5e 611 if (!qq)
612 MP_DROP(q);
613 else {
614 MP_SHRINK(q);
615 *qq = q;
616 }
617
618 if (!rr)
619 MP_DROP(r);
620 else {
621 MP_SHRINK(r);
622 *rr = r;
623 }
d3409d5e 624}
625
f1713c63 626/* --- @mp_odd@ --- *
627 *
628 * Arguments: @mp *d@ = pointer to destination integer
629 * @mp *m@ = pointer to source integer
630 * @size_t *s@ = where to store the power of 2
631 *
632 * Returns: An odd integer integer %$t$% such that %$m = 2^s t$%.
633 *
634 * Use: Computes a power of two and an odd integer which, when
635 * multiplied, give a specified result. This sort of thing is
636 * useful in number theory quite often.
637 */
638
639mp *mp_odd(mp *d, mp *m, size_t *s)
640{
641 size_t ss = 0;
642 const mpw *v, *vl;
643
644 v = m->v;
645 vl = m->vl;
646 for (; !*v && v < vl; v++)
647 ss += MPW_BITS;
648 if (v >= vl)
649 ss = 0;
650 else {
651 mpw x = *v;
652 mpw mask = MPW_MAX;
653 unsigned z = MPW_BITS / 2;
654
655 while (z) {
656 mask >>= z;
657 if (!(x & mask)) {
658 x >>= z;
659 ss += z;
660 }
661 z >>= 1;
662 }
663 }
664
665 *s = ss;
666 return (mp_lsr(d, m, ss));
667}
668
d3409d5e 669/*----- Test rig ----------------------------------------------------------*/
670
671#ifdef TEST_RIG
672
673static int verify(const char *op, mp *expect, mp *result, mp *a, mp *b)
674{
4b536f42 675 if (!MP_EQ(expect, result)) {
d3409d5e 676 fprintf(stderr, "\n*** %s failed", op);
677 fputs("\n*** a = ", stderr); mp_writefile(a, stderr, 10);
678 fputs("\n*** b = ", stderr); mp_writefile(b, stderr, 10);
679 fputs("\n*** result = ", stderr); mp_writefile(result, stderr, 10);
680 fputs("\n*** expect = ", stderr); mp_writefile(expect, stderr, 10);
681 fputc('\n', stderr);
682 return (0);
683 }
684 return (1);
685}
686
687#define RIG(name, op) \
ef5f4810 688 static int t##name(dstr *v) \
d3409d5e 689 { \
690 mp *a = *(mp **)v[0].buf; \
691 mpw n = *(int *)v[1].buf; \
692 mp b; \
693 mp *r = *(mp **)v[2].buf; \
694 mp *c = op(MP_NEW, a, n); \
695 int ok; \
696 mp_build(&b, &n, &n + 1); \
697 ok = verify(#name, r, c, a, &b); \
698 mp_drop(a); mp_drop(c); mp_drop(r); \
ef5f4810 699 assert(mparena_count(MPARENA_GLOBAL) == 0); \
d3409d5e 700 return (ok); \
701 }
702
703RIG(lsl, mp_lsl)
704RIG(lsr, mp_lsr)
f09e814a 705RIG(lsl2c, mp_lsl2c)
706RIG(lsr2c, mp_lsr2c)
d3409d5e 707
708#undef RIG
709
710#define RIG(name, op) \
ef5f4810 711 static int t##name(dstr *v) \
d3409d5e 712 { \
713 mp *a = *(mp **)v[0].buf; \
714 mp *b = *(mp **)v[1].buf; \
715 mp *r = *(mp **)v[2].buf; \
716 mp *c = op(MP_NEW, a, b); \
717 int ok = verify(#name, r, c, a, b); \
718 mp_drop(a); mp_drop(b); mp_drop(c); mp_drop(r); \
ef5f4810 719 assert(mparena_count(MPARENA_GLOBAL) == 0); \
d3409d5e 720 return (ok); \
721 }
722
723RIG(add, mp_add)
724RIG(sub, mp_sub)
725RIG(mul, mp_mul)
726
727#undef RIG
728
729static int tdiv(dstr *v)
730{
731 mp *a = *(mp **)v[0].buf;
732 mp *b = *(mp **)v[1].buf;
733 mp *q = *(mp **)v[2].buf;
734 mp *r = *(mp **)v[3].buf;
735 mp *c = MP_NEW, *d = MP_NEW;
736 int ok = 1;
737 mp_div(&c, &d, a, b);
738 ok &= verify("div(quotient)", q, c, a, b);
739 ok &= verify("div(remainder)", r, d, a, b);
740 mp_drop(a); mp_drop(b); mp_drop(c); mp_drop(d); mp_drop(r); mp_drop(q);
ef5f4810 741 assert(mparena_count(MPARENA_GLOBAL) == 0);
d3409d5e 742 return (ok);
743}
744
f09e814a 745static int tbin(dstr *v)
746{
747 static mp *(*fn[])(mp *, mp *, mp *) = {
748#define DO(string) mp_bit##string##2c,
749MPX_DOBIN(DO)
750#undef DO
751 };
752 int ok = 1;
753 unsigned op = 0;
754 mp *a = *(mp **)v[1].buf;
755 mp *b = *(mp **)v[2].buf;
756 mp *r = *(mp **)v[3].buf;
757 mp *c;
758
759 if (strcmp(v[0].buf, "and") == 0) op = 1;
760 else if (strcmp(v[0].buf, "or") == 0) op = 7;
761 else if (strcmp(v[0].buf, "nand") == 0) op = 14;
762 else if (strcmp(v[0].buf, "nor") == 0) op = 8;
763 else if (strcmp(v[0].buf, "xor") == 0) op = 6;
764 else {
765 char *p = v[0].buf;
766 while (*p) {
767 op <<= 1;
768 if (*p++ == '1')
769 op |= 1;
770 }
771 }
772
773 c = fn[op](MP_NEW, a, b);
774 ok = verify(v[0].buf, r, c, a, b);
775 mp_drop(a); mp_drop(b); mp_drop(r); mp_drop(c);
776 assert(mparena_count(MPARENA_GLOBAL) == 0);
777 return (ok);
778}
779
09d00c6b 780static int tset(dstr *v)
781{
782 mp *a = *(mp **)v[0].buf;
783 unsigned long n = *(unsigned long *)v[1].buf;
784 mp *r = *(mp **)v[2].buf;
785 mp *c;
786 int ok = 1;
787
788 c = mp_setbit2c(MP_NEW, a, n);
789 if (!MP_EQ(c, r)) {
790 ok = 0;
791 fprintf(stderr, "\n***setbit (set) failed");
792 fputs("\n*** a = ", stderr); mp_writefile(a, stderr, 16);
793 fprintf(stderr, "\n*** n = %lu", n);
794 fputs("\n*** r = ", stderr); mp_writefile(r, stderr, 16);
795 fputs("\n*** c = ", stderr); mp_writefile(c, stderr, 16);
796 fputc('\n', stderr);
797 }
798 if (!mp_testbit2c(r, n)) {
799 ok = 0;
800 fprintf(stderr, "\n***setbit (test) failed");
801 fprintf(stderr, "\n*** n = %lu", n);
802 fputs("\n*** r = ", stderr); mp_writefile(r, stderr, 16);
803 fputc('\n', stderr);
804 }
805 mp_drop(a);
806 mp_drop(r);
807 mp_drop(c);
808 assert(mparena_count(MPARENA_GLOBAL) == 0);
809 return (ok);
810}
811
812static int tclr(dstr *v)
813{
814 mp *a = *(mp **)v[0].buf;
815 unsigned long n = *(unsigned long *)v[1].buf;
816 mp *r = *(mp **)v[2].buf;
817 mp *c;
818 int ok = 1;
819
820 c = mp_clearbit2c(MP_NEW, a, n);
821 if (!MP_EQ(c, r)) {
822 ok = 0;
823 fprintf(stderr, "\n***clrbit (set) failed");
824 fputs("\n*** a = ", stderr); mp_writefile(a, stderr, 16);
825 fprintf(stderr, "\n*** n = %lu", n);
826 fputs("\n*** r = ", stderr); mp_writefile(r, stderr, 16);
827 fputs("\n*** c = ", stderr); mp_writefile(c, stderr, 16);
828 fputc('\n', stderr);
829 }
830 if (mp_testbit2c(r, n)) {
831 ok = 0;
832 fprintf(stderr, "\n***clrbit (test) failed");
833 fprintf(stderr, "\n*** n = %lu", n);
834 fputs("\n*** r = ", stderr); mp_writefile(r, stderr, 16);
835 fputc('\n', stderr);
836 }
837 mp_drop(a);
838 mp_drop(c);
839 mp_drop(r);
840 assert(mparena_count(MPARENA_GLOBAL) == 0);
841 return (ok);
842}
843
397041a9 844static int tneg(dstr *v)
845{
846 mp *a = *(mp **)v[0].buf;
847 mp *r = *(mp **)v[1].buf;
848 int ok = 1;
849 mp *n = mp_neg(MP_NEW, a);
850 if (!MP_EQ(r, n)) {
851 ok = 0;
852 fprintf(stderr, "\n*** neg failed\n");
853 fputs("\n*** a = ", stderr); mp_writefile(a, stderr, 10);
854 fputs("\n*** r = ", stderr); mp_writefile(r, stderr, 10);
855 fputs("\n*** n = ", stderr); mp_writefile(n, stderr, 10);
856 fputc('\n', stderr);
857 }
858 mp_drop(n);
859 n = mp_neg(a, a);
860 if (!MP_EQ(r, n)) {
861 ok = 0;
862 fprintf(stderr, "\n*** neg failed\n");
863 fputs("\n*** a* = ", stderr); mp_writefile(a, stderr, 10);
864 fputs("\n*** r = ", stderr); mp_writefile(r, stderr, 10);
865 fputs("\n*** n = ", stderr); mp_writefile(n, stderr, 10);
866 fputc('\n', stderr);
867 }
868 mp_drop(a);
869 mp_drop(r);
870 assert(mparena_count(MPARENA_GLOBAL) == 0);
871 return (ok);
872}
873
f1713c63 874static int todd(dstr *v)
875{
876 mp *a = *(mp **)v[0].buf;
877 size_t rs = *(uint32 *)v[1].buf;
878 mp *rt = *(mp **)v[2].buf;
879 int ok = 1;
880 mp *t;
881 size_t s;
882 t = mp_odd(MP_NEW, a, &s);
4b536f42 883 if (s != rs || !MP_EQ(t, rt)) {
f1713c63 884 ok = 0;
885 fprintf(stderr, "\n*** odd failed");
886 fputs("\n*** a = ", stderr); mp_writefile(a, stderr, 10);
887 fprintf(stderr, "\n*** s = %lu", (unsigned long)s);
888 fputs("\n*** t = ", stderr); mp_writefile(t, stderr, 10);
889 fprintf(stderr, "\n*** rs = %lu", (unsigned long)rs);
890 fputs("\n*** rt = ", stderr); mp_writefile(rt, stderr, 10);
891 fputc('\n', stderr);
892 }
893 mp_drop(a);
894 mp_drop(rt);
895 mp_drop(t);
09d00c6b 896 assert(mparena_count(MPARENA_GLOBAL) == 0);
f1713c63 897 return (ok);
898}
899
d3409d5e 900static test_chunk tests[] = {
f09e814a 901 { "lsl", tlsl, { &type_mp, &type_int, &type_mp, 0 } },
902 { "lsr", tlsr, { &type_mp, &type_int, &type_mp, 0 } },
903 { "lsl2c", tlsl2c, { &type_mp, &type_int, &type_mp, 0 } },
904 { "lsr2c", tlsr2c, { &type_mp, &type_int, &type_mp, 0 } },
09d00c6b 905 { "setbit", tset, { &type_mp, &type_ulong, &type_mp, 0 } },
906 { "clrbit", tclr, { &type_mp, &type_ulong, &type_mp, 0 } },
d3409d5e 907 { "add", tadd, { &type_mp, &type_mp, &type_mp, 0 } },
908 { "sub", tsub, { &type_mp, &type_mp, &type_mp, 0 } },
909 { "mul", tmul, { &type_mp, &type_mp, &type_mp, 0 } },
910 { "div", tdiv, { &type_mp, &type_mp, &type_mp, &type_mp, 0 } },
f09e814a 911 { "bin2c", tbin, { &type_string, &type_mp, &type_mp, &type_mp, 0 } },
f1713c63 912 { "odd", todd, { &type_mp, &type_uint32, &type_mp, 0 } },
397041a9 913 { "neg", tneg, { &type_mp, &type_mp, 0 } },
d3409d5e 914 { 0, 0, { 0 } },
915};
916
917int main(int argc, char *argv[])
918{
919 sub_init();
920 test_run(argc, argv, tests, SRCDIR "/tests/mp");
921 return (0);
922}
923
924#endif
925
926/*----- That's all, folks -------------------------------------------------*/
Catacomb cryptographic library (downstream of http://git.distorted.org.uk/~mdw/catacomb/)