1/*
2 * *****************************************************************************
3 *
4 * SPDX-License-Identifier: BSD-2-Clause
5 *
6 * Copyright (c) 2018-2021 Gavin D. Howard and contributors.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions are met:
10 *
11 * * Redistributions of source code must retain the above copyright notice, this
12 *   list of conditions and the following disclaimer.
13 *
14 * * Redistributions in binary form must reproduce the above copyright notice,
15 *   this list of conditions and the following disclaimer in the documentation
16 *   and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
19 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
22 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28 * POSSIBILITY OF SUCH DAMAGE.
29 *
30 * *****************************************************************************
31 *
32 * Code for the number type.
33 *
34 */
35
36#include <assert.h>
37#include <ctype.h>
38#include <stdbool.h>
39#include <stdlib.h>
40#include <string.h>
41#include <setjmp.h>
42#include <limits.h>
43
44#include <num.h>
45#include <rand.h>
46#include <vm.h>
47
48static void bc_num_m(BcNum *a, BcNum *b, BcNum *restrict c, size_t scale);
49
50static inline ssize_t bc_num_neg(size_t n, bool neg) {
51	return (((ssize_t) n) ^ -((ssize_t) neg)) + neg;
52}
53
54ssize_t bc_num_cmpZero(const BcNum *n) {
55	return bc_num_neg((n)->len != 0, BC_NUM_NEG(n));
56}
57
58static inline size_t bc_num_int(const BcNum *n) {
59	return n->len ? n->len - BC_NUM_RDX_VAL(n) : 0;
60}
61
62static void bc_num_expand(BcNum *restrict n, size_t req) {
63
64	assert(n != NULL);
65
66	req = req >= BC_NUM_DEF_SIZE ? req : BC_NUM_DEF_SIZE;
67
68	if (req > n->cap) {
69
70		BC_SIG_LOCK;
71
72		n->num = bc_vm_realloc(n->num, BC_NUM_SIZE(req));
73		n->cap = req;
74
75		BC_SIG_UNLOCK;
76	}
77}
78
79static void bc_num_setToZero(BcNum *restrict n, size_t scale) {
80	assert(n != NULL);
81	n->scale = scale;
82	n->len = n->rdx = 0;
83}
84
85void bc_num_zero(BcNum *restrict n) {
86	bc_num_setToZero(n, 0);
87}
88
89void bc_num_one(BcNum *restrict n) {
90	bc_num_zero(n);
91	n->len = 1;
92	n->num[0] = 1;
93}
94
95static void bc_num_clean(BcNum *restrict n) {
96
97	while (BC_NUM_NONZERO(n) && !n->num[n->len - 1]) n->len -= 1;
98
99	if (BC_NUM_ZERO(n)) n->rdx = 0;
100	else {
101		size_t rdx = BC_NUM_RDX_VAL(n);
102		if (n->len < rdx) n->len = rdx;
103	}
104}
105
106static size_t bc_num_log10(size_t i) {
107	size_t len;
108	for (len = 1; i; i /= BC_BASE, ++len);
109	assert(len - 1 <= BC_BASE_DIGS + 1);
110	return len - 1;
111}
112
113static inline size_t bc_num_zeroDigits(const BcDig *n) {
114	assert(*n >= 0);
115	assert(((size_t) *n) < BC_BASE_POW);
116	return BC_BASE_DIGS - bc_num_log10((size_t) *n);
117}
118
119static size_t bc_num_intDigits(const BcNum *n) {
120	size_t digits = bc_num_int(n) * BC_BASE_DIGS;
121	if (digits > 0) digits -= bc_num_zeroDigits(n->num + n->len - 1);
122	return digits;
123}
124
125static size_t bc_num_nonzeroLen(const BcNum *restrict n) {
126	size_t i, len = n->len;
127	assert(len == BC_NUM_RDX_VAL(n));
128	for (i = len - 1; i < len && !n->num[i]; --i);
129	assert(i + 1 > 0);
130	return i + 1;
131}
132
133static BcDig bc_num_addDigits(BcDig a, BcDig b, bool *carry) {
134
135	assert(((BcBigDig) BC_BASE_POW) * 2 == ((BcDig) BC_BASE_POW) * 2);
136	assert(a < BC_BASE_POW);
137	assert(b < BC_BASE_POW);
138
139	a += b + *carry;
140	*carry = (a >= BC_BASE_POW);
141	if (*carry) a -= BC_BASE_POW;
142
143	assert(a >= 0);
144	assert(a < BC_BASE_POW);
145
146	return a;
147}
148
149static BcDig bc_num_subDigits(BcDig a, BcDig b, bool *carry) {
150
151	assert(a < BC_BASE_POW);
152	assert(b < BC_BASE_POW);
153
154	b += *carry;
155	*carry = (a < b);
156	if (*carry) a += BC_BASE_POW;
157
158	assert(a - b >= 0);
159	assert(a - b < BC_BASE_POW);
160
161	return a - b;
162}
163
164static void bc_num_addArrays(BcDig *restrict a, const BcDig *restrict b,
165                             size_t len)
166{
167	size_t i;
168	bool carry = false;
169
170	for (i = 0; i < len; ++i) a[i] = bc_num_addDigits(a[i], b[i], &carry);
171
172	for (; carry; ++i) a[i] = bc_num_addDigits(a[i], 0, &carry);
173}
174
175static void bc_num_subArrays(BcDig *restrict a, const BcDig *restrict b,
176                             size_t len)
177{
178	size_t i;
179	bool carry = false;
180
181	for (i = 0; i < len; ++i) a[i] = bc_num_subDigits(a[i], b[i], &carry);
182
183	for (; carry; ++i) a[i] = bc_num_subDigits(a[i], 0, &carry);
184}
185
186static void bc_num_mulArray(const BcNum *restrict a, BcBigDig b,
187                            BcNum *restrict c)
188{
189	size_t i;
190	BcBigDig carry = 0;
191
192	assert(b <= BC_BASE_POW);
193
194	if (a->len + 1 > c->cap) bc_num_expand(c, a->len + 1);
195
196	memset(c->num, 0, BC_NUM_SIZE(c->cap));
197
198	for (i = 0; i < a->len; ++i) {
199		BcBigDig in = ((BcBigDig) a->num[i]) * b + carry;
200		c->num[i] = in % BC_BASE_POW;
201		carry = in / BC_BASE_POW;
202	}
203
204	assert(carry < BC_BASE_POW);
205	c->num[i] = (BcDig) carry;
206	c->len = a->len;
207	c->len += (carry != 0);
208
209	bc_num_clean(c);
210
211	assert(!BC_NUM_NEG(c) || BC_NUM_NONZERO(c));
212	assert(BC_NUM_RDX_VAL(c) <= c->len || !c->len);
213	assert(!c->len || c->num[c->len - 1] || BC_NUM_RDX_VAL(c) == c->len);
214}
215
216static void bc_num_divArray(const BcNum *restrict a, BcBigDig b,
217                            BcNum *restrict c, BcBigDig *rem)
218{
219	size_t i;
220	BcBigDig carry = 0;
221
222	assert(c->cap >= a->len);
223
224	for (i = a->len - 1; i < a->len; --i) {
225		BcBigDig in = ((BcBigDig) a->num[i]) + carry * BC_BASE_POW;
226		assert(in / b < BC_BASE_POW);
227		c->num[i] = (BcDig) (in / b);
228		carry = in % b;
229	}
230
231	c->len = a->len;
232	bc_num_clean(c);
233	*rem = carry;
234
235	assert(!BC_NUM_NEG(c) || BC_NUM_NONZERO(c));
236	assert(BC_NUM_RDX_VAL(c) <= c->len || !c->len);
237	assert(!c->len || c->num[c->len - 1] || BC_NUM_RDX_VAL(c) == c->len);
238}
239
240static ssize_t bc_num_compare(const BcDig *restrict a, const BcDig *restrict b,
241                              size_t len)
242{
243	size_t i;
244	BcDig c = 0;
245	for (i = len - 1; i < len && !(c = a[i] - b[i]); --i);
246	return bc_num_neg(i + 1, c < 0);
247}
248
249ssize_t bc_num_cmp(const BcNum *a, const BcNum *b) {
250
251	size_t i, min, a_int, b_int, diff, ardx, brdx;
252	BcDig *max_num, *min_num;
253	bool a_max, neg = false;
254	ssize_t cmp;
255
256	assert(a != NULL && b != NULL);
257
258	if (a == b) return 0;
259	if (BC_NUM_ZERO(a)) return bc_num_neg(b->len != 0, !BC_NUM_NEG(b));
260	if (BC_NUM_ZERO(b)) return bc_num_cmpZero(a);
261	if (BC_NUM_NEG(a)) {
262		if (BC_NUM_NEG(b)) neg = true;
263		else return -1;
264	}
265	else if (BC_NUM_NEG(b)) return 1;
266
267	a_int = bc_num_int(a);
268	b_int = bc_num_int(b);
269	a_int -= b_int;
270
271	if (a_int) return neg ? -((ssize_t) a_int) : (ssize_t) a_int;
272
273	ardx = BC_NUM_RDX_VAL(a);
274	brdx = BC_NUM_RDX_VAL(b);
275	a_max = (ardx > brdx);
276
277	if (a_max) {
278		min = brdx;
279		diff = ardx - brdx;
280		max_num = a->num + diff;
281		min_num = b->num;
282	}
283	else {
284		min = ardx;
285		diff = brdx - ardx;
286		max_num = b->num + diff;
287		min_num = a->num;
288	}
289
290	cmp = bc_num_compare(max_num, min_num, b_int + min);
291
292	if (cmp) return bc_num_neg((size_t) cmp, !a_max == !neg);
293
294	for (max_num -= diff, i = diff - 1; i < diff; --i) {
295		if (max_num[i]) return bc_num_neg(1, !a_max == !neg);
296	}
297
298	return 0;
299}
300
301void bc_num_truncate(BcNum *restrict n, size_t places) {
302
303	size_t nrdx, places_rdx;
304
305	if (!places) return;
306
307	nrdx = BC_NUM_RDX_VAL(n);
308	places_rdx = nrdx ? nrdx - BC_NUM_RDX(n->scale - places) : 0;
309	assert(places <= n->scale && (BC_NUM_ZERO(n) || places_rdx <= n->len));
310
311	n->scale -= places;
312	BC_NUM_RDX_SET(n, nrdx - places_rdx);
313
314	if (BC_NUM_NONZERO(n)) {
315
316		size_t pow;
317
318		pow = n->scale % BC_BASE_DIGS;
319		pow = pow ? BC_BASE_DIGS - pow : 0;
320		pow = bc_num_pow10[pow];
321
322		n->len -= places_rdx;
323		memmove(n->num, n->num + places_rdx, BC_NUM_SIZE(n->len));
324
325		// Clear the lower part of the last digit.
326		if (BC_NUM_NONZERO(n)) n->num[0] -= n->num[0] % (BcDig) pow;
327
328		bc_num_clean(n);
329	}
330}
331
332void bc_num_extend(BcNum *restrict n, size_t places) {
333
334	size_t nrdx, places_rdx;
335
336	if (!places) return;
337	if (BC_NUM_ZERO(n)) {
338		n->scale += places;
339		return;
340	}
341
342	nrdx = BC_NUM_RDX_VAL(n);
343	places_rdx = BC_NUM_RDX(places + n->scale) - nrdx;
344
345	if (places_rdx) {
346		bc_num_expand(n, bc_vm_growSize(n->len, places_rdx));
347		memmove(n->num + places_rdx, n->num, BC_NUM_SIZE(n->len));
348		memset(n->num, 0, BC_NUM_SIZE(places_rdx));
349	}
350
351	BC_NUM_RDX_SET(n, nrdx + places_rdx);
352	n->scale += places;
353	n->len += places_rdx;
354
355	assert(BC_NUM_RDX_VAL(n) == BC_NUM_RDX(n->scale));
356}
357
358static void bc_num_retireMul(BcNum *restrict n, size_t scale,
359                             bool neg1, bool neg2)
360{
361	if (n->scale < scale) bc_num_extend(n, scale - n->scale);
362	else bc_num_truncate(n, n->scale - scale);
363
364	bc_num_clean(n);
365	if (BC_NUM_NONZERO(n)) n->rdx = BC_NUM_NEG_VAL(n, !neg1 != !neg2);
366}
367
368static void bc_num_split(const BcNum *restrict n, size_t idx,
369                         BcNum *restrict a, BcNum *restrict b)
370{
371	assert(BC_NUM_ZERO(a));
372	assert(BC_NUM_ZERO(b));
373
374	if (idx < n->len) {
375
376		b->len = n->len - idx;
377		a->len = idx;
378		a->scale = b->scale = 0;
379		BC_NUM_RDX_SET(a, 0);
380		BC_NUM_RDX_SET(b, 0);
381
382		assert(a->cap >= a->len);
383		assert(b->cap >= b->len);
384
385		memcpy(b->num, n->num + idx, BC_NUM_SIZE(b->len));
386		memcpy(a->num, n->num, BC_NUM_SIZE(idx));
387
388		bc_num_clean(b);
389	}
390	else bc_num_copy(a, n);
391
392	bc_num_clean(a);
393}
394
395static size_t bc_num_shiftZero(BcNum *restrict n) {
396
397	size_t i;
398
399	assert(!BC_NUM_RDX_VAL(n) || BC_NUM_ZERO(n));
400
401	for (i = 0; i < n->len && !n->num[i]; ++i);
402
403	n->len -= i;
404	n->num += i;
405
406	return i;
407}
408
409static void bc_num_unshiftZero(BcNum *restrict n, size_t places_rdx) {
410	n->len += places_rdx;
411	n->num -= places_rdx;
412}
413
414static void bc_num_shift(BcNum *restrict n, BcBigDig dig) {
415
416	size_t i, len = n->len;
417	BcBigDig carry = 0, pow;
418	BcDig *ptr = n->num;
419
420	assert(dig < BC_BASE_DIGS);
421
422	pow = bc_num_pow10[dig];
423	dig = bc_num_pow10[BC_BASE_DIGS - dig];
424
425	for (i = len - 1; i < len; --i) {
426		BcBigDig in, temp;
427		in = ((BcBigDig) ptr[i]);
428		temp = carry * dig;
429		carry = in % pow;
430		ptr[i] = ((BcDig) (in / pow)) + (BcDig) temp;
431	}
432
433	assert(!carry);
434}
435
436static void bc_num_shiftLeft(BcNum *restrict n, size_t places) {
437
438	BcBigDig dig;
439	size_t places_rdx;
440	bool shift;
441
442	if (!places) return;
443	if (places > n->scale) {
444		size_t size = bc_vm_growSize(BC_NUM_RDX(places - n->scale), n->len);
445		if (size > SIZE_MAX - 1) bc_vm_err(BC_ERR_MATH_OVERFLOW);
446	}
447	if (BC_NUM_ZERO(n)) {
448		if (n->scale >= places) n->scale -= places;
449		else n->scale = 0;
450		return;
451	}
452
453	dig = (BcBigDig) (places % BC_BASE_DIGS);
454	shift = (dig != 0);
455	places_rdx = BC_NUM_RDX(places);
456
457	if (n->scale) {
458
459		size_t nrdx = BC_NUM_RDX_VAL(n);
460
461		if (nrdx >= places_rdx) {
462
463			size_t mod = n->scale % BC_BASE_DIGS, revdig;
464
465			mod = mod ? mod : BC_BASE_DIGS;
466			revdig = dig ? BC_BASE_DIGS - dig : 0;
467
468			if (mod + revdig > BC_BASE_DIGS) places_rdx = 1;
469			else places_rdx = 0;
470		}
471		else places_rdx -= nrdx;
472	}
473
474	if (places_rdx) {
475		bc_num_expand(n, bc_vm_growSize(n->len, places_rdx));
476		memmove(n->num + places_rdx, n->num, BC_NUM_SIZE(n->len));
477		memset(n->num, 0, BC_NUM_SIZE(places_rdx));
478		n->len += places_rdx;
479	}
480
481	if (places > n->scale) {
482		n->scale = 0;
483		BC_NUM_RDX_SET(n, 0);
484	}
485	else {
486		n->scale -= places;
487		BC_NUM_RDX_SET(n, BC_NUM_RDX(n->scale));
488	}
489
490	if (shift) bc_num_shift(n, BC_BASE_DIGS - dig);
491
492	bc_num_clean(n);
493}
494
495void bc_num_shiftRight(BcNum *restrict n, size_t places) {
496
497	BcBigDig dig;
498	size_t places_rdx, scale, scale_mod, int_len, expand;
499	bool shift;
500
501	if (!places) return;
502	if (BC_NUM_ZERO(n)) {
503		n->scale += places;
504		bc_num_expand(n, BC_NUM_RDX(n->scale));
505		return;
506	}
507
508	dig = (BcBigDig) (places % BC_BASE_DIGS);
509	shift = (dig != 0);
510	scale = n->scale;
511	scale_mod = scale % BC_BASE_DIGS;
512	scale_mod = scale_mod ? scale_mod : BC_BASE_DIGS;
513	int_len = bc_num_int(n);
514	places_rdx = BC_NUM_RDX(places);
515
516	if (scale_mod + dig > BC_BASE_DIGS) {
517		expand = places_rdx - 1;
518		places_rdx = 1;
519	}
520	else {
521		expand = places_rdx;
522		places_rdx = 0;
523	}
524
525	if (expand > int_len) expand -= int_len;
526	else expand = 0;
527
528	bc_num_extend(n, places_rdx * BC_BASE_DIGS);
529	bc_num_expand(n, bc_vm_growSize(expand, n->len));
530	memset(n->num + n->len, 0, BC_NUM_SIZE(expand));
531	n->len += expand;
532	n->scale = 0;
533	BC_NUM_RDX_SET(n, 0);
534
535	if (shift) bc_num_shift(n, dig);
536
537	n->scale = scale + places;
538	BC_NUM_RDX_SET(n, BC_NUM_RDX(n->scale));
539
540	bc_num_clean(n);
541
542	assert(BC_NUM_RDX_VAL(n) <= n->len && n->len <= n->cap);
543	assert(BC_NUM_RDX_VAL(n) == BC_NUM_RDX(n->scale));
544}
545
546static void bc_num_inv(BcNum *a, BcNum *b, size_t scale) {
547
548	BcNum one;
549	BcDig num[2];
550
551	assert(BC_NUM_NONZERO(a));
552
553	bc_num_setup(&one, num, sizeof(num) / sizeof(BcDig));
554	bc_num_one(&one);
555
556	bc_num_div(&one, a, b, scale);
557}
558
559#if BC_ENABLE_EXTRA_MATH
560static void bc_num_intop(const BcNum *a, const BcNum *b, BcNum *restrict c,
561                         BcBigDig *v)
562{
563	if (BC_ERR(BC_NUM_RDX_VAL(b))) bc_vm_err(BC_ERR_MATH_NON_INTEGER);
564	bc_num_copy(c, a);
565	bc_num_bigdig(b, v);
566}
567#endif // BC_ENABLE_EXTRA_MATH
568
569static void bc_num_as(BcNum *a, BcNum *b, BcNum *restrict c, size_t sub) {
570
571	BcDig *ptr_c, *ptr_l, *ptr_r;
572	size_t i, min_rdx, max_rdx, diff, a_int, b_int, min_len, max_len, max_int;
573	size_t len_l, len_r, ardx, brdx;
574	bool b_neg, do_sub, do_rev_sub, carry, c_neg;
575
576	// Because this function doesn't need to use scale (per the bc spec),
577	// I am hijacking it to say whether it's doing an add or a subtract.
578	// Convert substraction to addition of negative second operand.
579
580	if (BC_NUM_ZERO(b)) {
581		bc_num_copy(c, a);
582		return;
583	}
584	if (BC_NUM_ZERO(a)) {
585		bc_num_copy(c, b);
586		c->rdx = BC_NUM_NEG_VAL(c, BC_NUM_NEG(b) != sub);
587		return;
588	}
589
590	// Invert sign of b if it is to be subtracted. This operation must
591	// preced the tests for any of the operands being zero.
592	b_neg = (BC_NUM_NEG(b) != sub);
593
594	// Actually add the numbers if their signs are equal, else subtract.
595	do_sub = (BC_NUM_NEG(a) != b_neg);
596
597	a_int = bc_num_int(a);
598	b_int = bc_num_int(b);
599	max_int = BC_MAX(a_int, b_int);
600
601	ardx = BC_NUM_RDX_VAL(a);
602	brdx = BC_NUM_RDX_VAL(b);
603	min_rdx = BC_MIN(ardx, brdx);
604	max_rdx = BC_MAX(ardx, brdx);
605	diff = max_rdx - min_rdx;
606
607	max_len = max_int + max_rdx;
608
609	if (do_sub) {
610
611		// Check whether b has to be subtracted from a or a from b.
612		if (a_int != b_int) do_rev_sub = (a_int < b_int);
613		else if (ardx > brdx)
614			do_rev_sub = (bc_num_compare(a->num + diff, b->num, b->len) < 0);
615		else
616			do_rev_sub = (bc_num_compare(a->num, b->num + diff, a->len) <= 0);
617	}
618	else {
619
620		// The result array of the addition might come out one element
621		// longer than the bigger of the operand arrays.
622		max_len += 1;
623		do_rev_sub = (a_int < b_int);
624	}
625
626	assert(max_len <= c->cap);
627
628	if (do_rev_sub) {
629		ptr_l = b->num;
630		ptr_r = a->num;
631		len_l = b->len;
632		len_r = a->len;
633	}
634	else {
635		ptr_l = a->num;
636		ptr_r = b->num;
637		len_l = a->len;
638		len_r = b->len;
639	}
640
641	ptr_c = c->num;
642	carry = false;
643
644	if (diff) {
645
646		// If the rdx values of the operands do not match, the result will
647		// have low end elements that are the positive or negative trailing
648		// elements of the operand with higher rdx value.
649		if ((ardx > brdx) != do_rev_sub) {
650
651			// !do_rev_sub && ardx > brdx || do_rev_sub && brdx > ardx
652			// The left operand has BcDig values that need to be copied,
653			// either from a or from b (in case of a reversed subtraction).
654			memcpy(ptr_c, ptr_l, BC_NUM_SIZE(diff));
655			ptr_l += diff;
656			len_l -= diff;
657		}
658		else {
659
660			// The right operand has BcDig values that need to be copied
661			// or subtracted from zero (in case of a subtraction).
662			if (do_sub) {
663
664				// do_sub (do_rev_sub && ardx > brdx ||
665				// !do_rev_sub && brdx > ardx)
666				for (i = 0; i < diff; i++)
667					ptr_c[i] = bc_num_subDigits(0, ptr_r[i], &carry);
668			}
669			else {
670
671				// !do_sub && brdx > ardx
672				memcpy(ptr_c, ptr_r, BC_NUM_SIZE(diff));
673			}
674
675			ptr_r += diff;
676			len_r -= diff;
677		}
678
679		ptr_c += diff;
680	}
681
682	min_len = BC_MIN(len_l, len_r);
683
684	// After dealing with possible low array elements that depend on only one
685	// operand, the actual add or subtract can be performed as if the rdx of
686	// both operands was the same.
687	// Inlining takes care of eliminating constant zero arguments to
688	// addDigit/subDigit (checked in disassembly of resulting bc binary
689	// compiled with gcc and clang).
690	if (do_sub) {
691		for (i = 0; i < min_len; ++i)
692			ptr_c[i] = bc_num_subDigits(ptr_l[i], ptr_r[i], &carry);
693		for (; i < len_l; ++i) ptr_c[i] = bc_num_subDigits(ptr_l[i], 0, &carry);
694	}
695	else {
696		for (i = 0; i < min_len; ++i)
697			ptr_c[i] = bc_num_addDigits(ptr_l[i], ptr_r[i], &carry);
698		for (; i < len_l; ++i) ptr_c[i] = bc_num_addDigits(ptr_l[i], 0, &carry);
699		ptr_c[i] = bc_num_addDigits(0, 0, &carry);
700	}
701
702	assert(carry == false);
703
704	// The result has the same sign as a, unless the operation was a
705	// reverse subtraction (b - a).
706	c_neg = BC_NUM_NEG(a) != (do_sub && do_rev_sub);
707	BC_NUM_RDX_SET_NEG(c, max_rdx, c_neg);
708	c->len = max_len;
709	c->scale = BC_MAX(a->scale, b->scale);
710
711	bc_num_clean(c);
712}
713
714static void bc_num_m_simp(const BcNum *a, const BcNum *b, BcNum *restrict c)
715{
716	size_t i, alen = a->len, blen = b->len, clen;
717	BcDig *ptr_a = a->num, *ptr_b = b->num, *ptr_c;
718	BcBigDig sum = 0, carry = 0;
719
720	assert(sizeof(sum) >= sizeof(BcDig) * 2);
721	assert(!BC_NUM_RDX_VAL(a) && !BC_NUM_RDX_VAL(b));
722
723	clen = bc_vm_growSize(alen, blen);
724	bc_num_expand(c, bc_vm_growSize(clen, 1));
725
726	ptr_c = c->num;
727	memset(ptr_c, 0, BC_NUM_SIZE(c->cap));
728
729	for (i = 0; i < clen; ++i) {
730
731		ssize_t sidx = (ssize_t) (i - blen + 1);
732		size_t j = (size_t) BC_MAX(0, sidx), k = BC_MIN(i, blen - 1);
733
734		for (; j < alen && k < blen; ++j, --k) {
735
736			sum += ((BcBigDig) ptr_a[j]) * ((BcBigDig) ptr_b[k]);
737
738			if (sum >= ((BcBigDig) BC_BASE_POW) * BC_BASE_POW) {
739				carry += sum / BC_BASE_POW;
740				sum %= BC_BASE_POW;
741			}
742		}
743
744		if (sum >= BC_BASE_POW) {
745			carry += sum / BC_BASE_POW;
746			sum %= BC_BASE_POW;
747		}
748
749		ptr_c[i] = (BcDig) sum;
750		assert(ptr_c[i] < BC_BASE_POW);
751		sum = carry;
752		carry = 0;
753	}
754
755	// This should always be true because there should be no carry on the last
756	// digit; multiplication never goes above the sum of both lengths.
757	assert(!sum);
758
759	c->len = clen;
760}
761
762static void bc_num_shiftAddSub(BcNum *restrict n, const BcNum *restrict a,
763                               size_t shift, BcNumShiftAddOp op)
764{
765	assert(n->len >= shift + a->len);
766	assert(!BC_NUM_RDX_VAL(n) && !BC_NUM_RDX_VAL(a));
767	op(n->num + shift, a->num, a->len);
768}
769
770static void bc_num_k(BcNum *a, BcNum *b, BcNum *restrict c) {
771
772	size_t max, max2, total;
773	BcNum l1, h1, l2, h2, m2, m1, z0, z1, z2, temp;
774	BcDig *digs, *dig_ptr;
775	BcNumShiftAddOp op;
776	bool aone = BC_NUM_ONE(a);
777
778	assert(BC_NUM_ZERO(c));
779
780	if (BC_NUM_ZERO(a) || BC_NUM_ZERO(b)) return;
781	if (aone || BC_NUM_ONE(b)) {
782		bc_num_copy(c, aone ? b : a);
783		if ((aone && BC_NUM_NEG(a)) || BC_NUM_NEG(b)) BC_NUM_NEG_TGL(c);
784		return;
785	}
786	if (a->len < BC_NUM_KARATSUBA_LEN || b->len < BC_NUM_KARATSUBA_LEN) {
787		bc_num_m_simp(a, b, c);
788		return;
789	}
790
791	max = BC_MAX(a->len, b->len);
792	max = BC_MAX(max, BC_NUM_DEF_SIZE);
793	max2 = (max + 1) / 2;
794
795	total = bc_vm_arraySize(BC_NUM_KARATSUBA_ALLOCS, max);
796
797	BC_SIG_LOCK;
798
799	digs = dig_ptr = bc_vm_malloc(BC_NUM_SIZE(total));
800
801	bc_num_setup(&l1, dig_ptr, max);
802	dig_ptr += max;
803	bc_num_setup(&h1, dig_ptr, max);
804	dig_ptr += max;
805	bc_num_setup(&l2, dig_ptr, max);
806	dig_ptr += max;
807	bc_num_setup(&h2, dig_ptr, max);
808	dig_ptr += max;
809	bc_num_setup(&m1, dig_ptr, max);
810	dig_ptr += max;
811	bc_num_setup(&m2, dig_ptr, max);
812	max = bc_vm_growSize(max, 1);
813	bc_num_init(&z0, max);
814	bc_num_init(&z1, max);
815	bc_num_init(&z2, max);
816	max = bc_vm_growSize(max, max) + 1;
817	bc_num_init(&temp, max);
818
819	BC_SETJMP_LOCKED(err);
820
821	BC_SIG_UNLOCK;
822
823	bc_num_split(a, max2, &l1, &h1);
824	bc_num_split(b, max2, &l2, &h2);
825
826	bc_num_expand(c, max);
827	c->len = max;
828	memset(c->num, 0, BC_NUM_SIZE(c->len));
829
830	bc_num_sub(&h1, &l1, &m1, 0);
831	bc_num_sub(&l2, &h2, &m2, 0);
832
833	if (BC_NUM_NONZERO(&h1) && BC_NUM_NONZERO(&h2)) {
834
835		assert(BC_NUM_RDX_VALID_NP(h1));
836		assert(BC_NUM_RDX_VALID_NP(h2));
837
838		bc_num_m(&h1, &h2, &z2, 0);
839		bc_num_clean(&z2);
840
841		bc_num_shiftAddSub(c, &z2, max2 * 2, bc_num_addArrays);
842		bc_num_shiftAddSub(c, &z2, max2, bc_num_addArrays);
843	}
844
845	if (BC_NUM_NONZERO(&l1) && BC_NUM_NONZERO(&l2)) {
846
847		assert(BC_NUM_RDX_VALID_NP(l1));
848		assert(BC_NUM_RDX_VALID_NP(l2));
849
850		bc_num_m(&l1, &l2, &z0, 0);
851		bc_num_clean(&z0);
852
853		bc_num_shiftAddSub(c, &z0, max2, bc_num_addArrays);
854		bc_num_shiftAddSub(c, &z0, 0, bc_num_addArrays);
855	}
856
857	if (BC_NUM_NONZERO(&m1) && BC_NUM_NONZERO(&m2)) {
858
859		assert(BC_NUM_RDX_VALID_NP(m1));
860		assert(BC_NUM_RDX_VALID_NP(m1));
861
862		bc_num_m(&m1, &m2, &z1, 0);
863		bc_num_clean(&z1);
864
865		op = (BC_NUM_NEG_NP(m1) != BC_NUM_NEG_NP(m2)) ?
866		     bc_num_subArrays : bc_num_addArrays;
867		bc_num_shiftAddSub(c, &z1, max2, op);
868	}
869
870err:
871	BC_SIG_MAYLOCK;
872	free(digs);
873	bc_num_free(&temp);
874	bc_num_free(&z2);
875	bc_num_free(&z1);
876	bc_num_free(&z0);
877	BC_LONGJMP_CONT;
878}
879
880static void bc_num_m(BcNum *a, BcNum *b, BcNum *restrict c, size_t scale) {
881
882	BcNum cpa, cpb;
883	size_t ascale, bscale, ardx, brdx, azero = 0, bzero = 0, zero, len, rscale;
884
885	assert(BC_NUM_RDX_VALID(a));
886	assert(BC_NUM_RDX_VALID(b));
887
888	bc_num_zero(c);
889	ascale = a->scale;
890	bscale = b->scale;
891	scale = BC_MAX(scale, ascale);
892	scale = BC_MAX(scale, bscale);
893
894	rscale = ascale + bscale;
895	scale = BC_MIN(rscale, scale);
896
897	if ((a->len == 1 || b->len == 1) && !a->rdx && !b->rdx) {
898
899		BcNum *operand;
900		BcBigDig dig;
901
902		if (a->len == 1) {
903			dig = (BcBigDig) a->num[0];
904			operand = b;
905		}
906		else {
907			dig = (BcBigDig) b->num[0];
908			operand = a;
909		}
910
911		bc_num_mulArray(operand, dig, c);
912
913		if (BC_NUM_NONZERO(c))
914			c->rdx = BC_NUM_NEG_VAL(c, BC_NUM_NEG(a) != BC_NUM_NEG(b));
915
916		return;
917	}
918
919	assert(BC_NUM_RDX_VALID(a));
920	assert(BC_NUM_RDX_VALID(b));
921
922	BC_SIG_LOCK;
923
924	bc_num_init(&cpa, a->len + BC_NUM_RDX_VAL(a));
925	bc_num_init(&cpb, b->len + BC_NUM_RDX_VAL(b));
926
927	BC_SETJMP_LOCKED(err);
928
929	BC_SIG_UNLOCK;
930
931	bc_num_copy(&cpa, a);
932	bc_num_copy(&cpb, b);
933
934	assert(BC_NUM_RDX_VALID_NP(cpa));
935	assert(BC_NUM_RDX_VALID_NP(cpb));
936
937	BC_NUM_NEG_CLR_NP(cpa);
938	BC_NUM_NEG_CLR_NP(cpb);
939
940	assert(BC_NUM_RDX_VALID_NP(cpa));
941	assert(BC_NUM_RDX_VALID_NP(cpb));
942
943	ardx = BC_NUM_RDX_VAL_NP(cpa) * BC_BASE_DIGS;
944	bc_num_shiftLeft(&cpa, ardx);
945
946	brdx = BC_NUM_RDX_VAL_NP(cpb) * BC_BASE_DIGS;
947	bc_num_shiftLeft(&cpb, brdx);
948
949	// We need to reset the jump here because azero and bzero are used in the
950	// cleanup, and local variables are not guaranteed to be the same after a
951	// jump.
952	BC_SIG_LOCK;
953
954	BC_UNSETJMP;
955
956	azero = bc_num_shiftZero(&cpa);
957	bzero = bc_num_shiftZero(&cpb);
958
959	BC_SETJMP_LOCKED(err);
960
961	BC_SIG_UNLOCK;
962
963	bc_num_clean(&cpa);
964	bc_num_clean(&cpb);
965
966	bc_num_k(&cpa, &cpb, c);
967
968	zero = bc_vm_growSize(azero, bzero);
969	len = bc_vm_growSize(c->len, zero);
970
971	bc_num_expand(c, len);
972	bc_num_shiftLeft(c, (len - c->len) * BC_BASE_DIGS);
973	bc_num_shiftRight(c, ardx + brdx);
974
975	bc_num_retireMul(c, scale, BC_NUM_NEG(a), BC_NUM_NEG(b));
976
977err:
978	BC_SIG_MAYLOCK;
979	bc_num_unshiftZero(&cpb, bzero);
980	bc_num_free(&cpb);
981	bc_num_unshiftZero(&cpa, azero);
982	bc_num_free(&cpa);
983	BC_LONGJMP_CONT;
984}
985
986static bool bc_num_nonZeroDig(BcDig *restrict a, size_t len) {
987	size_t i;
988	bool nonzero = false;
989	for (i = len - 1; !nonzero && i < len; --i) nonzero = (a[i] != 0);
990	return nonzero;
991}
992
993static ssize_t bc_num_divCmp(const BcDig *a, const BcNum *b, size_t len) {
994
995	ssize_t cmp;
996
997	if (b->len > len && a[len]) cmp = bc_num_compare(a, b->num, len + 1);
998	else if (b->len <= len) {
999		if (a[len]) cmp = 1;
1000		else cmp = bc_num_compare(a, b->num, len);
1001	}
1002	else cmp = -1;
1003
1004	return cmp;
1005}
1006
1007static void bc_num_divExtend(BcNum *restrict a, BcNum *restrict b,
1008                             BcBigDig divisor)
1009{
1010	size_t pow;
1011
1012	assert(divisor < BC_BASE_POW);
1013
1014	pow = BC_BASE_DIGS - bc_num_log10((size_t) divisor);
1015
1016	bc_num_shiftLeft(a, pow);
1017	bc_num_shiftLeft(b, pow);
1018}
1019
1020static void bc_num_d_long(BcNum *restrict a, BcNum *restrict b,
1021                          BcNum *restrict c, size_t scale)
1022{
1023	BcBigDig divisor;
1024	size_t len, end, i, rdx;
1025	BcNum cpb;
1026	bool nonzero = false;
1027
1028	assert(b->len < a->len);
1029	len = b->len;
1030	end = a->len - len;
1031	assert(len >= 1);
1032
1033	bc_num_expand(c, a->len);
1034	memset(c->num, 0, c->cap * sizeof(BcDig));
1035
1036	BC_NUM_RDX_SET(c, BC_NUM_RDX_VAL(a));
1037	c->scale = a->scale;
1038	c->len = a->len;
1039
1040	divisor = (BcBigDig) b->num[len - 1];
1041
1042	if (len > 1 && bc_num_nonZeroDig(b->num, len - 1)) {
1043
1044		nonzero = (divisor > 1 << ((10 * BC_BASE_DIGS) / 6 + 1));
1045
1046		if (!nonzero) {
1047
1048			bc_num_divExtend(a, b, divisor);
1049
1050			len = BC_MAX(a->len, b->len);
1051			bc_num_expand(a, len + 1);
1052
1053			if (len + 1 > a->len) a->len = len + 1;
1054
1055			len = b->len;
1056			end = a->len - len;
1057			divisor = (BcBigDig) b->num[len - 1];
1058
1059			nonzero = bc_num_nonZeroDig(b->num, len - 1);
1060		}
1061	}
1062
1063	divisor += nonzero;
1064
1065	bc_num_expand(c, a->len);
1066	memset(c->num, 0, BC_NUM_SIZE(c->cap));
1067
1068	assert(c->scale >= scale);
1069	rdx = BC_NUM_RDX_VAL(c) - BC_NUM_RDX(scale);
1070
1071	BC_SIG_LOCK;
1072
1073	bc_num_init(&cpb, len + 1);
1074
1075	BC_SETJMP_LOCKED(err);
1076
1077	BC_SIG_UNLOCK;
1078
1079	i = end - 1;
1080
1081	for (; i < end && i >= rdx && BC_NUM_NONZERO(a); --i) {
1082
1083		ssize_t cmp;
1084		BcDig *n;
1085		BcBigDig result;
1086
1087		n = a->num + i;
1088		assert(n >= a->num);
1089		result = 0;
1090
1091		cmp = bc_num_divCmp(n, b, len);
1092
1093		while (cmp >= 0) {
1094
1095			BcBigDig n1, dividend, q;
1096
1097			n1 = (BcBigDig) n[len];
1098			dividend = n1 * BC_BASE_POW + (BcBigDig) n[len - 1];
1099			q = (dividend / divisor);
1100
1101			if (q <= 1) {
1102				q = 1;
1103				bc_num_subArrays(n, b->num, len);
1104			}
1105			else {
1106
1107				assert(q <= BC_BASE_POW);
1108
1109				bc_num_mulArray(b, (BcBigDig) q, &cpb);
1110				bc_num_subArrays(n, cpb.num, cpb.len);
1111			}
1112
1113			result += q;
1114			assert(result <= BC_BASE_POW);
1115
1116			if (nonzero) cmp = bc_num_divCmp(n, b, len);
1117			else cmp = -1;
1118		}
1119
1120		assert(result < BC_BASE_POW);
1121
1122		c->num[i] = (BcDig) result;
1123	}
1124
1125err:
1126	BC_SIG_MAYLOCK;
1127	bc_num_free(&cpb);
1128	BC_LONGJMP_CONT;
1129}
1130
1131static void bc_num_d(BcNum *a, BcNum *b, BcNum *restrict c, size_t scale) {
1132
1133	size_t len, cpardx;
1134	BcNum cpa, cpb;
1135
1136	if (BC_NUM_ZERO(b)) bc_vm_err(BC_ERR_MATH_DIVIDE_BY_ZERO);
1137	if (BC_NUM_ZERO(a)) {
1138		bc_num_setToZero(c, scale);
1139		return;
1140	}
1141	if (BC_NUM_ONE(b)) {
1142		bc_num_copy(c, a);
1143		bc_num_retireMul(c, scale, BC_NUM_NEG(a), BC_NUM_NEG(b));
1144		return;
1145	}
1146	if (!BC_NUM_RDX_VAL(a) && !BC_NUM_RDX_VAL(b) && b->len == 1 && !scale) {
1147		BcBigDig rem;
1148		bc_num_divArray(a, (BcBigDig) b->num[0], c, &rem);
1149		bc_num_retireMul(c, scale, BC_NUM_NEG(a), BC_NUM_NEG(b));
1150		return;
1151	}
1152
1153	len = bc_num_divReq(a, b, scale);
1154
1155	BC_SIG_LOCK;
1156
1157	bc_num_init(&cpa, len);
1158	bc_num_copy(&cpa, a);
1159	bc_num_createCopy(&cpb, b);
1160
1161	BC_SETJMP_LOCKED(err);
1162
1163	BC_SIG_UNLOCK;
1164
1165	len = b->len;
1166
1167	if (len > cpa.len) {
1168		bc_num_expand(&cpa, bc_vm_growSize(len, 2));
1169		bc_num_extend(&cpa, (len - cpa.len) * BC_BASE_DIGS);
1170	}
1171
1172	cpardx = BC_NUM_RDX_VAL_NP(cpa);
1173	cpa.scale = cpardx * BC_BASE_DIGS;
1174
1175	bc_num_extend(&cpa, b->scale);
1176	cpardx = BC_NUM_RDX_VAL_NP(cpa) - BC_NUM_RDX(b->scale);
1177	BC_NUM_RDX_SET_NP(cpa, cpardx);
1178	cpa.scale = cpardx * BC_BASE_DIGS;
1179
1180	if (scale > cpa.scale) {
1181		bc_num_extend(&cpa, scale);
1182		cpardx = BC_NUM_RDX_VAL_NP(cpa);
1183		cpa.scale = cpardx * BC_BASE_DIGS;
1184	}
1185
1186	if (cpa.cap == cpa.len) bc_num_expand(&cpa, bc_vm_growSize(cpa.len, 1));
1187
1188	// We want an extra zero in front to make things simpler.
1189	cpa.num[cpa.len++] = 0;
1190
1191	if (cpardx == cpa.len) cpa.len = bc_num_nonzeroLen(&cpa);
1192	if (BC_NUM_RDX_VAL_NP(cpb) == cpb.len) cpb.len = bc_num_nonzeroLen(&cpb);
1193	cpb.scale = 0;
1194	BC_NUM_RDX_SET_NP(cpb, 0);
1195
1196	bc_num_d_long(&cpa, &cpb, c, scale);
1197
1198	bc_num_retireMul(c, scale, BC_NUM_NEG(a), BC_NUM_NEG(b));
1199
1200err:
1201	BC_SIG_MAYLOCK;
1202	bc_num_free(&cpb);
1203	bc_num_free(&cpa);
1204	BC_LONGJMP_CONT;
1205}
1206
1207static void bc_num_r(BcNum *a, BcNum *b, BcNum *restrict c,
1208                     BcNum *restrict d, size_t scale, size_t ts)
1209{
1210	BcNum temp;
1211	bool neg;
1212
1213	if (BC_NUM_ZERO(b)) bc_vm_err(BC_ERR_MATH_DIVIDE_BY_ZERO);
1214	if (BC_NUM_ZERO(a)) {
1215		bc_num_setToZero(c, ts);
1216		bc_num_setToZero(d, ts);
1217		return;
1218	}
1219
1220	BC_SIG_LOCK;
1221
1222	bc_num_init(&temp, d->cap);
1223
1224	BC_SETJMP_LOCKED(err);
1225
1226	BC_SIG_UNLOCK;
1227
1228	bc_num_d(a, b, c, scale);
1229
1230	if (scale) scale = ts + 1;
1231
1232	assert(BC_NUM_RDX_VALID(c));
1233	assert(BC_NUM_RDX_VALID(b));
1234
1235	bc_num_m(c, b, &temp, scale);
1236	bc_num_sub(a, &temp, d, scale);
1237
1238	if (ts > d->scale && BC_NUM_NONZERO(d)) bc_num_extend(d, ts - d->scale);
1239
1240	neg = BC_NUM_NEG(d);
1241	bc_num_retireMul(d, ts, BC_NUM_NEG(a), BC_NUM_NEG(b));
1242	d->rdx = BC_NUM_NEG_VAL(d, BC_NUM_NONZERO(d) ? neg : false);
1243
1244err:
1245	BC_SIG_MAYLOCK;
1246	bc_num_free(&temp);
1247	BC_LONGJMP_CONT;
1248}
1249
1250static void bc_num_rem(BcNum *a, BcNum *b, BcNum *restrict c, size_t scale) {
1251
1252	BcNum c1;
1253	size_t ts;
1254
1255	ts = bc_vm_growSize(scale, b->scale);
1256	ts = BC_MAX(ts, a->scale);
1257
1258	BC_SIG_LOCK;
1259
1260	bc_num_init(&c1, bc_num_mulReq(a, b, ts));
1261
1262	BC_SETJMP_LOCKED(err);
1263
1264	BC_SIG_UNLOCK;
1265
1266	bc_num_r(a, b, &c1, c, scale, ts);
1267
1268err:
1269	BC_SIG_MAYLOCK;
1270	bc_num_free(&c1);
1271	BC_LONGJMP_CONT;
1272}
1273
1274static void bc_num_p(BcNum *a, BcNum *b, BcNum *restrict c, size_t scale) {
1275
1276	BcNum copy;
1277	BcBigDig pow = 0;
1278	size_t i, powrdx, resrdx;
1279	bool neg, zero;
1280
1281	if (BC_ERR(BC_NUM_RDX_VAL(b))) bc_vm_err(BC_ERR_MATH_NON_INTEGER);
1282
1283	if (BC_NUM_ZERO(b)) {
1284		bc_num_one(c);
1285		return;
1286	}
1287	if (BC_NUM_ZERO(a)) {
1288		if (BC_NUM_NEG(b)) bc_vm_err(BC_ERR_MATH_DIVIDE_BY_ZERO);
1289		bc_num_setToZero(c, scale);
1290		return;
1291	}
1292	if (BC_NUM_ONE(b)) {
1293		if (!BC_NUM_NEG(b)) bc_num_copy(c, a);
1294		else bc_num_inv(a, c, scale);
1295		return;
1296	}
1297
1298	BC_SIG_LOCK;
1299
1300	neg = BC_NUM_NEG(b);
1301	BC_NUM_NEG_CLR(b);
1302	bc_num_bigdig(b, &pow);
1303	b->rdx = BC_NUM_NEG_VAL(b, neg);
1304
1305	bc_num_createCopy(&copy, a);
1306
1307	BC_SETJMP_LOCKED(err);
1308
1309	BC_SIG_UNLOCK;
1310
1311	if (!neg) {
1312		size_t max = BC_MAX(scale, a->scale), scalepow = a->scale * pow;
1313		scale = BC_MIN(scalepow, max);
1314	}
1315
1316	for (powrdx = a->scale; !(pow & 1); pow >>= 1) {
1317		powrdx <<= 1;
1318		assert(BC_NUM_RDX_VALID_NP(copy));
1319		bc_num_mul(&copy, &copy, &copy, powrdx);
1320	}
1321
1322	bc_num_copy(c, &copy);
1323	resrdx = powrdx;
1324
1325	while (pow >>= 1) {
1326
1327		powrdx <<= 1;
1328		assert(BC_NUM_RDX_VALID_NP(copy));
1329		bc_num_mul(&copy, &copy, &copy, powrdx);
1330
1331		if (pow & 1) {
1332			resrdx += powrdx;
1333			assert(BC_NUM_RDX_VALID(c));
1334			assert(BC_NUM_RDX_VALID_NP(copy));
1335			bc_num_mul(c, &copy, c, resrdx);
1336		}
1337	}
1338
1339	if (neg) bc_num_inv(c, c, scale);
1340
1341	if (c->scale > scale) bc_num_truncate(c, c->scale - scale);
1342
1343	// We can't use bc_num_clean() here.
1344	for (zero = true, i = 0; zero && i < c->len; ++i) zero = !c->num[i];
1345	if (zero) bc_num_setToZero(c, scale);
1346
1347err:
1348	BC_SIG_MAYLOCK;
1349	bc_num_free(&copy);
1350	BC_LONGJMP_CONT;
1351}
1352
1353#if BC_ENABLE_EXTRA_MATH
1354static void bc_num_place(BcNum *a, BcNum *b, BcNum *restrict c, size_t scale) {
1355
1356	BcBigDig val = 0;
1357
1358	BC_UNUSED(scale);
1359
1360	bc_num_intop(a, b, c, &val);
1361
1362	if (val < c->scale) bc_num_truncate(c, c->scale - val);
1363	else if (val > c->scale) bc_num_extend(c, val - c->scale);
1364}
1365
1366static void bc_num_left(BcNum *a, BcNum *b, BcNum *restrict c, size_t scale) {
1367
1368	BcBigDig val = 0;
1369
1370	BC_UNUSED(scale);
1371
1372	bc_num_intop(a, b, c, &val);
1373
1374	bc_num_shiftLeft(c, (size_t) val);
1375}
1376
1377static void bc_num_right(BcNum *a, BcNum *b, BcNum *restrict c, size_t scale) {
1378
1379	BcBigDig val = 0;
1380
1381	BC_UNUSED(scale);
1382
1383	bc_num_intop(a, b, c, &val);
1384
1385	if (BC_NUM_ZERO(c)) return;
1386
1387	bc_num_shiftRight(c, (size_t) val);
1388}
1389#endif // BC_ENABLE_EXTRA_MATH
1390
1391static void bc_num_binary(BcNum *a, BcNum *b, BcNum *c, size_t scale,
1392                          BcNumBinOp op, size_t req)
1393{
1394	BcNum *ptr_a, *ptr_b, num2;
1395	bool init = false;
1396
1397	assert(a != NULL && b != NULL && c != NULL && op != NULL);
1398
1399	assert(BC_NUM_RDX_VALID(a));
1400	assert(BC_NUM_RDX_VALID(b));
1401
1402	BC_SIG_LOCK;
1403
1404	if (c == a) {
1405
1406		ptr_a = &num2;
1407
1408		memcpy(ptr_a, c, sizeof(BcNum));
1409		init = true;
1410	}
1411	else {
1412		ptr_a = a;
1413	}
1414
1415	if (c == b) {
1416
1417		ptr_b = &num2;
1418
1419		if (c != a) {
1420			memcpy(ptr_b, c, sizeof(BcNum));
1421			init = true;
1422		}
1423	}
1424	else {
1425		ptr_b = b;
1426	}
1427
1428	if (init) {
1429
1430		bc_num_init(c, req);
1431
1432		BC_SETJMP_LOCKED(err);
1433		BC_SIG_UNLOCK;
1434	}
1435	else {
1436		BC_SIG_UNLOCK;
1437		bc_num_expand(c, req);
1438	}
1439
1440	op(ptr_a, ptr_b, c, scale);
1441
1442	assert(!BC_NUM_NEG(c) || BC_NUM_NONZERO(c));
1443	assert(BC_NUM_RDX_VAL(c) <= c->len || !c->len);
1444	assert(BC_NUM_RDX_VALID(c));
1445	assert(!c->len || c->num[c->len - 1] || BC_NUM_RDX_VAL(c) == c->len);
1446
1447err:
1448	if (init) {
1449		BC_SIG_MAYLOCK;
1450		bc_num_free(&num2);
1451		BC_LONGJMP_CONT;
1452	}
1453}
1454
1455#if !defined(NDEBUG) || BC_ENABLE_LIBRARY
1456bool bc_num_strValid(const char *restrict val) {
1457
1458	bool radix = false;
1459	size_t i, len = strlen(val);
1460
1461	if (!len) return true;
1462
1463	for (i = 0; i < len; ++i) {
1464
1465		BcDig c = val[i];
1466
1467		if (c == '.') {
1468
1469			if (radix) return false;
1470
1471			radix = true;
1472			continue;
1473		}
1474
1475		if (!(isdigit(c) || isupper(c))) return false;
1476	}
1477
1478	return true;
1479}
1480#endif // !defined(NDEBUG) || BC_ENABLE_LIBRARY
1481
1482static BcBigDig bc_num_parseChar(char c, size_t base_t) {
1483
1484	if (isupper(c)) {
1485		c = BC_NUM_NUM_LETTER(c);
1486		c = ((size_t) c) >= base_t ? (char) base_t - 1 : c;
1487	}
1488	else c -= '0';
1489
1490	return (BcBigDig) (uchar) c;
1491}
1492
1493static void bc_num_parseDecimal(BcNum *restrict n, const char *restrict val) {
1494
1495	size_t len, i, temp, mod;
1496	const char *ptr;
1497	bool zero = true, rdx;
1498
1499	for (i = 0; val[i] == '0'; ++i);
1500
1501	val += i;
1502	assert(!val[0] || isalnum(val[0]) || val[0] == '.');
1503
1504	// All 0's. We can just return, since this
1505	// procedure expects a virgin (already 0) BcNum.
1506	if (!val[0]) return;
1507
1508	len = strlen(val);
1509
1510	ptr = strchr(val, '.');
1511	rdx = (ptr != NULL);
1512
1513	for (i = 0; i < len && (zero = (val[i] == '0' || val[i] == '.')); ++i);
1514
1515	n->scale = (size_t) (rdx * (((uintptr_t) (val + len)) -
1516	                            (((uintptr_t) ptr) + 1)));
1517
1518	BC_NUM_RDX_SET(n, BC_NUM_RDX(n->scale));
1519	i = len - (ptr == val ? 0 : i) - rdx;
1520	temp = BC_NUM_ROUND_POW(i);
1521	mod = n->scale % BC_BASE_DIGS;
1522	i = mod ? BC_BASE_DIGS - mod : 0;
1523	n->len = ((temp + i) / BC_BASE_DIGS);
1524
1525	bc_num_expand(n, n->len);
1526	memset(n->num, 0, BC_NUM_SIZE(n->len));
1527
1528	if (zero) {
1529		// I think I can set rdx directly to zero here because n should be a
1530		// new number with sign set to false.
1531		n->len = n->rdx = 0;
1532	}
1533	else {
1534
1535		BcBigDig exp, pow;
1536
1537		assert(i <= BC_NUM_BIGDIG_MAX);
1538
1539		exp = (BcBigDig) i;
1540		pow = bc_num_pow10[exp];
1541
1542		for (i = len - 1; i < len; --i, ++exp) {
1543
1544			char c = val[i];
1545
1546			if (c == '.') exp -= 1;
1547			else {
1548
1549				size_t idx = exp / BC_BASE_DIGS;
1550
1551				if (isupper(c)) c = '9';
1552				n->num[idx] += (((BcBigDig) c) - '0') * pow;
1553
1554				if ((exp + 1) % BC_BASE_DIGS == 0) pow = 1;
1555				else pow *= BC_BASE;
1556			}
1557		}
1558	}
1559}
1560
1561static void bc_num_parseBase(BcNum *restrict n, const char *restrict val,
1562                             BcBigDig base)
1563{
1564	BcNum temp, mult1, mult2, result1, result2, *m1, *m2, *ptr;
1565	char c = 0;
1566	bool zero = true;
1567	BcBigDig v;
1568	size_t i, digs, len = strlen(val);
1569
1570	for (i = 0; zero && i < len; ++i) zero = (val[i] == '.' || val[i] == '0');
1571	if (zero) return;
1572
1573	BC_SIG_LOCK;
1574
1575	bc_num_init(&temp, BC_NUM_BIGDIG_LOG10);
1576	bc_num_init(&mult1, BC_NUM_BIGDIG_LOG10);
1577
1578	BC_SETJMP_LOCKED(int_err);
1579
1580	BC_SIG_UNLOCK;
1581
1582	for (i = 0; i < len && (c = val[i]) && c != '.'; ++i) {
1583
1584		v = bc_num_parseChar(c, base);
1585
1586		bc_num_mulArray(n, base, &mult1);
1587		bc_num_bigdig2num(&temp, v);
1588		bc_num_add(&mult1, &temp, n, 0);
1589	}
1590
1591	if (i == len && !val[i]) goto int_err;
1592
1593	assert(val[i] == '.');
1594
1595	BC_SIG_LOCK;
1596
1597	BC_UNSETJMP;
1598
1599	bc_num_init(&mult2, BC_NUM_BIGDIG_LOG10);
1600	bc_num_init(&result1, BC_NUM_DEF_SIZE);
1601	bc_num_init(&result2, BC_NUM_DEF_SIZE);
1602	bc_num_one(&mult1);
1603
1604	BC_SETJMP_LOCKED(err);
1605
1606	BC_SIG_UNLOCK;
1607
1608	m1 = &mult1;
1609	m2 = &mult2;
1610
1611	for (i += 1, digs = 0; i < len && (c = val[i]); ++i, ++digs) {
1612
1613		size_t rdx;
1614
1615		v = bc_num_parseChar(c, base);
1616
1617		bc_num_mulArray(&result1, base, &result2);
1618
1619		bc_num_bigdig2num(&temp, v);
1620		bc_num_add(&result2, &temp, &result1, 0);
1621		bc_num_mulArray(m1, base, m2);
1622
1623		rdx = BC_NUM_RDX_VAL(m2);
1624
1625		if (m2->len < rdx) m2->len = rdx;
1626
1627		ptr = m1;
1628		m1 = m2;
1629		m2 = ptr;
1630	}
1631
1632	// This one cannot be a divide by 0 because mult starts out at 1, then is
1633	// multiplied by base, and base cannot be 0, so mult cannot be 0.
1634	bc_num_div(&result1, m1, &result2, digs * 2);
1635	bc_num_truncate(&result2, digs);
1636	bc_num_add(n, &result2, n, digs);
1637
1638	if (BC_NUM_NONZERO(n)) {
1639		if (n->scale < digs) bc_num_extend(n, digs - n->scale);
1640	}
1641	else bc_num_zero(n);
1642
1643err:
1644	BC_SIG_MAYLOCK;
1645	bc_num_free(&result2);
1646	bc_num_free(&result1);
1647	bc_num_free(&mult2);
1648int_err:
1649	BC_SIG_MAYLOCK;
1650	bc_num_free(&mult1);
1651	bc_num_free(&temp);
1652	BC_LONGJMP_CONT;
1653}
1654
1655static inline void bc_num_printNewline(void) {
1656#if !BC_ENABLE_LIBRARY
1657	if (vm.nchars >= vm.line_len - 1) {
1658		bc_vm_putchar('\\', bc_flush_none);
1659		bc_vm_putchar('\n', bc_flush_err);
1660	}
1661#endif // !BC_ENABLE_LIBRARY
1662}
1663
1664static void bc_num_putchar(int c) {
1665	if (c != '\n') bc_num_printNewline();
1666	bc_vm_putchar(c, bc_flush_save);
1667}
1668
1669#if DC_ENABLED && !BC_ENABLE_LIBRARY
1670static void bc_num_printChar(size_t n, size_t len, bool rdx) {
1671	BC_UNUSED(rdx);
1672	BC_UNUSED(len);
1673	assert(len == 1);
1674	bc_vm_putchar((uchar) n, bc_flush_save);
1675}
1676#endif // DC_ENABLED && !BC_ENABLE_LIBRARY
1677
1678static void bc_num_printDigits(size_t n, size_t len, bool rdx) {
1679
1680	size_t exp, pow;
1681
1682	bc_num_putchar(rdx ? '.' : ' ');
1683
1684	for (exp = 0, pow = 1; exp < len - 1; ++exp, pow *= BC_BASE);
1685
1686	for (exp = 0; exp < len; pow /= BC_BASE, ++exp) {
1687		size_t dig = n / pow;
1688		n -= dig * pow;
1689		bc_num_putchar(((uchar) dig) + '0');
1690	}
1691}
1692
1693static void bc_num_printHex(size_t n, size_t len, bool rdx) {
1694
1695	BC_UNUSED(len);
1696
1697	assert(len == 1);
1698
1699	if (rdx) bc_num_putchar('.');
1700
1701	bc_num_putchar(bc_num_hex_digits[n]);
1702}
1703
1704static void bc_num_printDecimal(const BcNum *restrict n) {
1705
1706	size_t i, j, rdx = BC_NUM_RDX_VAL(n);
1707	bool zero = true;
1708	size_t buffer[BC_BASE_DIGS];
1709
1710	if (BC_NUM_NEG(n)) bc_num_putchar('-');
1711
1712	for (i = n->len - 1; i < n->len; --i) {
1713
1714		BcDig n9 = n->num[i];
1715		size_t temp;
1716		bool irdx = (i == rdx - 1);
1717
1718		zero = (zero & !irdx);
1719		temp = n->scale % BC_BASE_DIGS;
1720		temp = i || !temp ? 0 : BC_BASE_DIGS - temp;
1721
1722		memset(buffer, 0, BC_BASE_DIGS * sizeof(size_t));
1723
1724		for (j = 0; n9 && j < BC_BASE_DIGS; ++j) {
1725			buffer[j] = ((size_t) n9) % BC_BASE;
1726			n9 /= BC_BASE;
1727		}
1728
1729		for (j = BC_BASE_DIGS - 1; j < BC_BASE_DIGS && j >= temp; --j) {
1730			bool print_rdx = (irdx & (j == BC_BASE_DIGS - 1));
1731			zero = (zero && buffer[j] == 0);
1732			if (!zero) bc_num_printHex(buffer[j], 1, print_rdx);
1733		}
1734	}
1735}
1736
1737#if BC_ENABLE_EXTRA_MATH
1738static void bc_num_printExponent(const BcNum *restrict n, bool eng) {
1739
1740	size_t places, mod, nrdx = BC_NUM_RDX_VAL(n);
1741	bool neg = (n->len <= nrdx);
1742	BcNum temp, exp;
1743	BcDig digs[BC_NUM_BIGDIG_LOG10];
1744
1745	BC_SIG_LOCK;
1746
1747	bc_num_createCopy(&temp, n);
1748
1749	BC_SETJMP_LOCKED(exit);
1750
1751	BC_SIG_UNLOCK;
1752
1753	if (neg) {
1754
1755		size_t i, idx = bc_num_nonzeroLen(n) - 1;
1756
1757		places = 1;
1758
1759		for (i = BC_BASE_DIGS - 1; i < BC_BASE_DIGS; --i) {
1760			if (bc_num_pow10[i] > (BcBigDig) n->num[idx]) places += 1;
1761			else break;
1762		}
1763
1764		places += (nrdx - (idx + 1)) * BC_BASE_DIGS;
1765		mod = places % 3;
1766
1767		if (eng && mod != 0) places += 3 - mod;
1768		bc_num_shiftLeft(&temp, places);
1769	}
1770	else {
1771		places = bc_num_intDigits(n) - 1;
1772		mod = places % 3;
1773		if (eng && mod != 0) places -= 3 - (3 - mod);
1774		bc_num_shiftRight(&temp, places);
1775	}
1776
1777	bc_num_printDecimal(&temp);
1778	bc_num_putchar('e');
1779
1780	if (!places) {
1781		bc_num_printHex(0, 1, false);
1782		goto exit;
1783	}
1784
1785	if (neg) bc_num_putchar('-');
1786
1787	bc_num_setup(&exp, digs, BC_NUM_BIGDIG_LOG10);
1788	bc_num_bigdig2num(&exp, (BcBigDig) places);
1789
1790	bc_num_printDecimal(&exp);
1791
1792exit:
1793	BC_SIG_MAYLOCK;
1794	bc_num_free(&temp);
1795	BC_LONGJMP_CONT;
1796}
1797#endif // BC_ENABLE_EXTRA_MATH
1798
1799static void bc_num_printFixup(BcNum *restrict n, BcBigDig rem,
1800                              BcBigDig pow, size_t idx)
1801{
1802	size_t i, len = n->len - idx;
1803	BcBigDig acc;
1804	BcDig *a = n->num + idx;
1805
1806	if (len < 2) return;
1807
1808	for (i = len - 1; i > 0; --i) {
1809
1810		acc = ((BcBigDig) a[i]) * rem + ((BcBigDig) a[i - 1]);
1811		a[i - 1] = (BcDig) (acc % pow);
1812		acc /= pow;
1813		acc += (BcBigDig) a[i];
1814
1815		if (acc >= BC_BASE_POW) {
1816
1817			if (i == len - 1) {
1818				len = bc_vm_growSize(len, 1);
1819				bc_num_expand(n, bc_vm_growSize(len, idx));
1820				a = n->num + idx;
1821				a[len - 1] = 0;
1822			}
1823
1824			a[i + 1] += acc / BC_BASE_POW;
1825			acc %= BC_BASE_POW;
1826		}
1827
1828		assert(acc < BC_BASE_POW);
1829		a[i] = (BcDig) acc;
1830	}
1831
1832	n->len = len + idx;
1833}
1834
1835static void bc_num_printPrepare(BcNum *restrict n, BcBigDig rem,
1836                                BcBigDig pow)
1837{
1838	size_t i;
1839
1840	for (i = 0; i < n->len; ++i) bc_num_printFixup(n, rem, pow, i);
1841
1842	for (i = 0; i < n->len; ++i) {
1843
1844		assert(pow == ((BcBigDig) ((BcDig) pow)));
1845
1846		if (n->num[i] >= (BcDig) pow) {
1847
1848			if (i + 1 == n->len) {
1849				n->len = bc_vm_growSize(n->len, 1);
1850				bc_num_expand(n, n->len);
1851				n->num[i + 1] = 0;
1852			}
1853
1854			assert(pow < BC_BASE_POW);
1855			n->num[i + 1] += n->num[i] / ((BcDig) pow);
1856			n->num[i] %= (BcDig) pow;
1857		}
1858	}
1859}
1860
1861static void bc_num_printNum(BcNum *restrict n, BcBigDig base,
1862                            size_t len, BcNumDigitOp print)
1863{
1864	BcVec stack;
1865	BcNum intp, fracp1, fracp2, digit, flen1, flen2, *n1, *n2, *temp;
1866	BcBigDig dig = 0, *ptr, acc, exp;
1867	size_t i, j, nrdx;
1868	bool radix;
1869	BcDig digit_digs[BC_NUM_BIGDIG_LOG10 + 1];
1870
1871	assert(base > 1);
1872
1873	if (BC_NUM_ZERO(n)) {
1874		print(0, len, false);
1875		return;
1876	}
1877
1878	// This function uses an algorithm that Stefan Esser <se@freebsd.org> came
1879	// up with to print the integer part of a number. What it does is convert
1880	// intp into a number of the specified base, but it does it directly,
1881	// instead of just doing a series of divisions and printing the remainders
1882	// in reverse order.
1883	//
1884	// Let me explain in a bit more detail:
1885	//
1886	// The algorithm takes the current least significant digit (after intp has
1887	// been converted to an integer) and the next to least significant digit,
1888	// and it converts the least significant digit into one of the specified
1889	// base, putting any overflow into the next to least significant digit. It
1890	// iterates through the whole number, from least significant to most
1891	// significant, doing this conversion. At the end of that iteration, the
1892	// least significant digit is converted, but the others are not, so it
1893	// iterates again, starting at the next to least significant digit. It keeps
1894	// doing that conversion, skipping one more digit than the last time, until
1895	// all digits have been converted. Then it prints them in reverse order.
1896	//
1897	// That is the gist of the algorithm. It leaves out several things, such as
1898	// the fact that digits are not always converted into the specified base,
1899	// but into something close, basically a power of the specified base. In
1900	// Stefan's words, "You could consider BcDigs to be of base 10^BC_BASE_DIGS
1901	// in the normal case and obase^N for the largest value of N that satisfies
1902	// obase^N <= 10^BC_BASE_DIGS. [This means that] the result is not in base
1903	// "obase", but in base "obase^N", which happens to be printable as a number
1904	// of base "obase" without consideration for neighbouring BcDigs." This fact
1905	// is what necessitates the existence of the loop later in this function.
1906	//
1907	// The conversion happens in bc_num_printPrepare() where the outer loop
1908	// happens and bc_num_printFixup() where the inner loop, or actual
1909	// conversion, happens.
1910
1911	nrdx = BC_NUM_RDX_VAL(n);
1912
1913	BC_SIG_LOCK;
1914
1915	bc_vec_init(&stack, sizeof(BcBigDig), NULL);
1916	bc_num_init(&fracp1, nrdx);
1917
1918	bc_num_createCopy(&intp, n);
1919
1920	BC_SETJMP_LOCKED(err);
1921
1922	BC_SIG_UNLOCK;
1923
1924	bc_num_truncate(&intp, intp.scale);
1925
1926	bc_num_sub(n, &intp, &fracp1, 0);
1927
1928	if (base != vm.last_base) {
1929
1930		vm.last_pow = 1;
1931		vm.last_exp = 0;
1932
1933		while (vm.last_pow * base <= BC_BASE_POW) {
1934			vm.last_pow *= base;
1935			vm.last_exp += 1;
1936		}
1937
1938		vm.last_rem = BC_BASE_POW - vm.last_pow;
1939		vm.last_base = base;
1940	}
1941
1942	exp = vm.last_exp;
1943
1944	if (vm.last_rem != 0) bc_num_printPrepare(&intp, vm.last_rem, vm.last_pow);
1945
1946	for (i = 0; i < intp.len; ++i) {
1947
1948		acc = (BcBigDig) intp.num[i];
1949
1950		for (j = 0; j < exp && (i < intp.len - 1 || acc != 0); ++j)
1951		{
1952			if (j != exp - 1) {
1953				dig = acc % base;
1954				acc /= base;
1955			}
1956			else {
1957				dig = acc;
1958				acc = 0;
1959			}
1960
1961			assert(dig < base);
1962
1963			bc_vec_push(&stack, &dig);
1964		}
1965
1966		assert(acc == 0);
1967	}
1968
1969	for (i = 0; i < stack.len; ++i) {
1970		ptr = bc_vec_item_rev(&stack, i);
1971		assert(ptr != NULL);
1972		print(*ptr, len, false);
1973	}
1974
1975	if (!n->scale) goto err;
1976
1977	BC_SIG_LOCK;
1978
1979	BC_UNSETJMP;
1980
1981	bc_num_init(&fracp2, nrdx);
1982	bc_num_setup(&digit, digit_digs, sizeof(digit_digs) / sizeof(BcDig));
1983	bc_num_init(&flen1, BC_NUM_BIGDIG_LOG10);
1984	bc_num_init(&flen2, BC_NUM_BIGDIG_LOG10);
1985
1986	BC_SETJMP_LOCKED(frac_err);
1987
1988	BC_SIG_UNLOCK;
1989
1990	bc_num_one(&flen1);
1991
1992	radix = true;
1993	n1 = &flen1;
1994	n2 = &flen2;
1995
1996	fracp2.scale = n->scale;
1997	BC_NUM_RDX_SET_NP(fracp2, BC_NUM_RDX(fracp2.scale));
1998
1999	while (bc_num_intDigits(n1) < n->scale + 1) {
2000
2001		bc_num_expand(&fracp2, fracp1.len + 1);
2002		bc_num_mulArray(&fracp1, base, &fracp2);
2003
2004		nrdx = BC_NUM_RDX_VAL_NP(fracp2);
2005
2006		if (fracp2.len < nrdx) fracp2.len = nrdx;
2007
2008		// fracp is guaranteed to be non-negative and small enough.
2009		bc_num_bigdig2(&fracp2, &dig);
2010
2011		bc_num_bigdig2num(&digit, dig);
2012		bc_num_sub(&fracp2, &digit, &fracp1, 0);
2013
2014		print(dig, len, radix);
2015		bc_num_mulArray(n1, base, n2);
2016
2017		radix = false;
2018		temp = n1;
2019		n1 = n2;
2020		n2 = temp;
2021	}
2022
2023frac_err:
2024	BC_SIG_MAYLOCK;
2025	bc_num_free(&flen2);
2026	bc_num_free(&flen1);
2027	bc_num_free(&fracp2);
2028err:
2029	BC_SIG_MAYLOCK;
2030	bc_num_free(&fracp1);
2031	bc_num_free(&intp);
2032	bc_vec_free(&stack);
2033	BC_LONGJMP_CONT;
2034}
2035
2036static void bc_num_printBase(BcNum *restrict n, BcBigDig base) {
2037
2038	size_t width;
2039	BcNumDigitOp print;
2040	bool neg = BC_NUM_NEG(n);
2041
2042	if (neg) bc_num_putchar('-');
2043
2044	BC_NUM_NEG_CLR(n);
2045
2046	if (base <= BC_NUM_MAX_POSIX_IBASE) {
2047		width = 1;
2048		print = bc_num_printHex;
2049	}
2050	else {
2051		assert(base <= BC_BASE_POW);
2052		width = bc_num_log10(base - 1);
2053		print = bc_num_printDigits;
2054	}
2055
2056	bc_num_printNum(n, base, width, print);
2057	n->rdx = BC_NUM_NEG_VAL(n, neg);
2058}
2059
2060#if DC_ENABLED && !BC_ENABLE_LIBRARY
2061void bc_num_stream(BcNum *restrict n, BcBigDig base) {
2062	bc_num_printNum(n, base, 1, bc_num_printChar);
2063}
2064#endif // DC_ENABLED && !BC_ENABLE_LIBRARY
2065
2066void bc_num_setup(BcNum *restrict n, BcDig *restrict num, size_t cap) {
2067	assert(n != NULL);
2068	n->num = num;
2069	n->cap = cap;
2070	bc_num_zero(n);
2071}
2072
2073void bc_num_init(BcNum *restrict n, size_t req) {
2074
2075	BcDig *num;
2076
2077	BC_SIG_ASSERT_LOCKED;
2078
2079	assert(n != NULL);
2080
2081	req = req >= BC_NUM_DEF_SIZE ? req : BC_NUM_DEF_SIZE;
2082
2083	if (req == BC_NUM_DEF_SIZE && vm.temps.len) {
2084		BcNum *nptr = bc_vec_top(&vm.temps);
2085		num = nptr->num;
2086		bc_vec_pop(&vm.temps);
2087	}
2088	else num = bc_vm_malloc(BC_NUM_SIZE(req));
2089
2090	bc_num_setup(n, num, req);
2091}
2092
2093void bc_num_clear(BcNum *restrict n) {
2094	n->num = NULL;
2095	n->cap = 0;
2096}
2097
2098void bc_num_free(void *num) {
2099
2100	BcNum *n = (BcNum*) num;
2101
2102	BC_SIG_ASSERT_LOCKED;
2103
2104	assert(n != NULL);
2105
2106	if (n->cap == BC_NUM_DEF_SIZE) bc_vec_push(&vm.temps, n);
2107	else free(n->num);
2108}
2109
2110void bc_num_copy(BcNum *d, const BcNum *s) {
2111	assert(d != NULL && s != NULL);
2112	if (d == s) return;
2113	bc_num_expand(d, s->len);
2114	d->len = s->len;
2115	// I can just copy directly here.
2116	d->rdx = s->rdx;
2117	d->scale = s->scale;
2118	memcpy(d->num, s->num, BC_NUM_SIZE(d->len));
2119}
2120
2121void bc_num_createCopy(BcNum *d, const BcNum *s) {
2122	BC_SIG_ASSERT_LOCKED;
2123	bc_num_init(d, s->len);
2124	bc_num_copy(d, s);
2125}
2126
2127void bc_num_createFromBigdig(BcNum *n, BcBigDig val) {
2128	BC_SIG_ASSERT_LOCKED;
2129	bc_num_init(n, BC_NUM_BIGDIG_LOG10);
2130	bc_num_bigdig2num(n, val);
2131}
2132
2133size_t bc_num_scale(const BcNum *restrict n) {
2134	return n->scale;
2135}
2136
2137size_t bc_num_len(const BcNum *restrict n) {
2138
2139	size_t len = n->len;
2140
2141	if (BC_NUM_ZERO(n)) return n->scale ? n->scale : 1;
2142
2143	if (BC_NUM_RDX_VAL(n) == len) {
2144
2145		size_t zero, scale;
2146
2147		len = bc_num_nonzeroLen(n);
2148
2149		scale = n->scale % BC_BASE_DIGS;
2150		scale = scale ? scale : BC_BASE_DIGS;
2151
2152		zero = bc_num_zeroDigits(n->num + len - 1);
2153
2154		len = len * BC_BASE_DIGS - zero - (BC_BASE_DIGS - scale);
2155	}
2156	else len = bc_num_intDigits(n) + n->scale;
2157
2158	return len;
2159}
2160
2161void bc_num_parse(BcNum *restrict n, const char *restrict val, BcBigDig base) {
2162
2163	assert(n != NULL && val != NULL && base);
2164	assert(base >= BC_NUM_MIN_BASE && base <= vm.maxes[BC_PROG_GLOBALS_IBASE]);
2165	assert(bc_num_strValid(val));
2166
2167	if (!val[1]) {
2168		BcBigDig dig = bc_num_parseChar(val[0], BC_NUM_MAX_LBASE);
2169		bc_num_bigdig2num(n, dig);
2170	}
2171	else if (base == BC_BASE) bc_num_parseDecimal(n, val);
2172	else bc_num_parseBase(n, val, base);
2173
2174	assert(BC_NUM_RDX_VALID(n));
2175}
2176
2177void bc_num_print(BcNum *restrict n, BcBigDig base, bool newline) {
2178
2179	assert(n != NULL);
2180	assert(BC_ENABLE_EXTRA_MATH || base >= BC_NUM_MIN_BASE);
2181
2182	bc_num_printNewline();
2183
2184	if (BC_NUM_ZERO(n)) bc_num_printHex(0, 1, false);
2185	else if (base == BC_BASE) bc_num_printDecimal(n);
2186#if BC_ENABLE_EXTRA_MATH
2187	else if (base == 0 || base == 1) bc_num_printExponent(n, base != 0);
2188#endif // BC_ENABLE_EXTRA_MATH
2189	else bc_num_printBase(n, base);
2190
2191	if (newline) bc_num_putchar('\n');
2192}
2193
2194void bc_num_bigdig2(const BcNum *restrict n, BcBigDig *result) {
2195
2196	// This function returns no errors because it's guaranteed to succeed if
2197	// its preconditions are met. Those preconditions include both parameters
2198	// being non-NULL, n being non-negative, and n being less than vm.max. If
2199	// all of that is true, then we can just convert without worrying about
2200	// negative errors or overflow.
2201
2202	BcBigDig r = 0;
2203	size_t nrdx = BC_NUM_RDX_VAL(n);
2204
2205	assert(n != NULL && result != NULL);
2206	assert(!BC_NUM_NEG(n));
2207	assert(bc_num_cmp(n, &vm.max) < 0);
2208	assert(n->len - nrdx <= 3);
2209
2210	// There is a small speed win from unrolling the loop here, and since it
2211	// only adds 53 bytes, I decided that it was worth it.
2212	switch (n->len - nrdx) {
2213
2214		case 3:
2215		{
2216			r = (BcBigDig) n->num[nrdx + 2];
2217		}
2218		// Fallthrough.
2219		BC_FALLTHROUGH
2220
2221		case 2:
2222		{
2223			r = r * BC_BASE_POW + (BcBigDig) n->num[nrdx + 1];
2224		}
2225		// Fallthrough.
2226		BC_FALLTHROUGH
2227
2228		case 1:
2229		{
2230			r = r * BC_BASE_POW + (BcBigDig) n->num[nrdx];
2231		}
2232	}
2233
2234	*result = r;
2235}
2236
2237void bc_num_bigdig(const BcNum *restrict n, BcBigDig *result) {
2238
2239	assert(n != NULL && result != NULL);
2240
2241	if (BC_ERR(BC_NUM_NEG(n))) bc_vm_err(BC_ERR_MATH_NEGATIVE);
2242	if (BC_ERR(bc_num_cmp(n, &vm.max) >= 0))
2243		bc_vm_err(BC_ERR_MATH_OVERFLOW);
2244
2245	bc_num_bigdig2(n, result);
2246}
2247
2248void bc_num_bigdig2num(BcNum *restrict n, BcBigDig val) {
2249
2250	BcDig *ptr;
2251	size_t i;
2252
2253	assert(n != NULL);
2254
2255	bc_num_zero(n);
2256
2257	if (!val) return;
2258
2259	bc_num_expand(n, BC_NUM_BIGDIG_LOG10);
2260
2261	for (ptr = n->num, i = 0; val; ++i, val /= BC_BASE_POW)
2262		ptr[i] = val % BC_BASE_POW;
2263
2264	n->len = i;
2265}
2266
2267#if BC_ENABLE_EXTRA_MATH && BC_ENABLE_RAND
2268void bc_num_rng(const BcNum *restrict n, BcRNG *rng) {
2269
2270	BcNum temp, temp2, intn, frac;
2271	BcRand state1, state2, inc1, inc2;
2272	size_t nrdx = BC_NUM_RDX_VAL(n);
2273
2274	BC_SIG_LOCK;
2275
2276	bc_num_init(&temp, n->len);
2277	bc_num_init(&temp2, n->len);
2278	bc_num_init(&frac, nrdx);
2279	bc_num_init(&intn, bc_num_int(n));
2280
2281	BC_SETJMP_LOCKED(err);
2282
2283	BC_SIG_UNLOCK;
2284
2285	assert(BC_NUM_RDX_VALID_NP(vm.max));
2286
2287	memcpy(frac.num, n->num, BC_NUM_SIZE(nrdx));
2288	frac.len = nrdx;
2289	BC_NUM_RDX_SET_NP(frac, nrdx);
2290	frac.scale = n->scale;
2291
2292	assert(BC_NUM_RDX_VALID_NP(frac));
2293	assert(BC_NUM_RDX_VALID_NP(vm.max2));
2294
2295	bc_num_mul(&frac, &vm.max2, &temp, 0);
2296
2297	bc_num_truncate(&temp, temp.scale);
2298	bc_num_copy(&frac, &temp);
2299
2300	memcpy(intn.num, n->num + nrdx, BC_NUM_SIZE(bc_num_int(n)));
2301	intn.len = bc_num_int(n);
2302
2303	// This assert is here because it has to be true. It is also here to justify
2304	// the use of BC_ERR_SIGNAL_ONLY() on each of the divmod's and mod's below.
2305	assert(BC_NUM_NONZERO(&vm.max));
2306
2307	if (BC_NUM_NONZERO(&frac)) {
2308
2309		bc_num_divmod(&frac, &vm.max, &temp, &temp2, 0);
2310
2311		// frac is guaranteed to be smaller than vm.max * vm.max (pow).
2312		// This means that when dividing frac by vm.max, as above, the
2313		// quotient and remainder are both guaranteed to be less than vm.max,
2314		// which means we can use bc_num_bigdig2() here and not worry about
2315		// overflow.
2316		bc_num_bigdig2(&temp2, (BcBigDig*) &state1);
2317		bc_num_bigdig2(&temp, (BcBigDig*) &state2);
2318	}
2319	else state1 = state2 = 0;
2320
2321	if (BC_NUM_NONZERO(&intn)) {
2322
2323		bc_num_divmod(&intn, &vm.max, &temp, &temp2, 0);
2324
2325		// Because temp2 is the mod of vm.max, from above, it is guaranteed
2326		// to be small enough to use bc_num_bigdig2().
2327		bc_num_bigdig2(&temp2, (BcBigDig*) &inc1);
2328
2329		if (bc_num_cmp(&temp, &vm.max) >= 0) {
2330			bc_num_copy(&temp2, &temp);
2331			bc_num_mod(&temp2, &vm.max, &temp, 0);
2332		}
2333
2334		// The if statement above ensures that temp is less than vm.max, which
2335		// means that we can use bc_num_bigdig2() here.
2336		bc_num_bigdig2(&temp, (BcBigDig*) &inc2);
2337	}
2338	else inc1 = inc2 = 0;
2339
2340	bc_rand_seed(rng, state1, state2, inc1, inc2);
2341
2342err:
2343	BC_SIG_MAYLOCK;
2344	bc_num_free(&intn);
2345	bc_num_free(&frac);
2346	bc_num_free(&temp2);
2347	bc_num_free(&temp);
2348	BC_LONGJMP_CONT;
2349}
2350
2351void bc_num_createFromRNG(BcNum *restrict n, BcRNG *rng) {
2352
2353	BcRand s1, s2, i1, i2;
2354	BcNum conv, temp1, temp2, temp3;
2355	BcDig temp1_num[BC_RAND_NUM_SIZE], temp2_num[BC_RAND_NUM_SIZE];
2356	BcDig conv_num[BC_NUM_BIGDIG_LOG10];
2357
2358	BC_SIG_LOCK;
2359
2360	bc_num_init(&temp3, 2 * BC_RAND_NUM_SIZE);
2361
2362	BC_SETJMP_LOCKED(err);
2363
2364	BC_SIG_UNLOCK;
2365
2366	bc_num_setup(&temp1, temp1_num, sizeof(temp1_num) / sizeof(BcDig));
2367	bc_num_setup(&temp2, temp2_num, sizeof(temp2_num) / sizeof(BcDig));
2368	bc_num_setup(&conv, conv_num, sizeof(conv_num) / sizeof(BcDig));
2369
2370	// This assert is here because it has to be true. It is also here to justify
2371	// the assumption that vm.max2 is not zero.
2372	assert(BC_NUM_NONZERO(&vm.max));
2373
2374	// Because this is true, we can just use BC_ERR_SIGNAL_ONLY() below when
2375	// dividing by vm.max2.
2376	assert(BC_NUM_NONZERO(&vm.max2));
2377
2378	bc_rand_getRands(rng, &s1, &s2, &i1, &i2);
2379
2380	bc_num_bigdig2num(&conv, (BcBigDig) s2);
2381
2382	assert(BC_NUM_RDX_VALID_NP(conv));
2383
2384	bc_num_mul(&conv, &vm.max, &temp1, 0);
2385
2386	bc_num_bigdig2num(&conv, (BcBigDig) s1);
2387
2388	bc_num_add(&conv, &temp1, &temp2, 0);
2389
2390	bc_num_div(&temp2, &vm.max2, &temp3, BC_RAND_STATE_BITS);
2391
2392	bc_num_bigdig2num(&conv, (BcBigDig) i2);
2393
2394	assert(BC_NUM_RDX_VALID_NP(conv));
2395
2396	bc_num_mul(&conv, &vm.max, &temp1, 0);
2397
2398	bc_num_bigdig2num(&conv, (BcBigDig) i1);
2399
2400	bc_num_add(&conv, &temp1, &temp2, 0);
2401
2402	bc_num_add(&temp2, &temp3, n, 0);
2403
2404	assert(BC_NUM_RDX_VALID(n));
2405
2406err:
2407	BC_SIG_MAYLOCK;
2408	bc_num_free(&temp3);
2409	BC_LONGJMP_CONT;
2410}
2411
2412void bc_num_irand(const BcNum *restrict a, BcNum *restrict b,
2413                  BcRNG *restrict rng)
2414{
2415	BcRand r;
2416	BcBigDig modl;
2417	BcNum pow, pow2, cp, cp2, mod, temp1, temp2, rand;
2418	BcNum *p1, *p2, *t1, *t2, *c1, *c2, *tmp;
2419	BcDig rand_num[BC_NUM_BIGDIG_LOG10];
2420	bool carry;
2421	ssize_t cmp;
2422
2423	assert(a != b);
2424
2425	if (BC_ERR(BC_NUM_NEG(a))) bc_vm_err(BC_ERR_MATH_NEGATIVE);
2426	if (BC_ERR(BC_NUM_RDX_VAL(a))) bc_vm_err(BC_ERR_MATH_NON_INTEGER);
2427	if (BC_NUM_ZERO(a) || BC_NUM_ONE(a)) return;
2428
2429	cmp = bc_num_cmp(a, &vm.max);
2430
2431	if (cmp <= 0) {
2432
2433		BcRand bits = 0;
2434
2435		if (cmp < 0) bc_num_bigdig2(a, (BcBigDig*) &bits);
2436
2437		// This condition means that bits is a power of 2. In that case, we
2438		// can just grab a full-size int and mask out the unneeded bits.
2439		// Also, this condition says that 0 is a power of 2, which works for
2440		// us, since a value of 0 means a == rng->max. The bitmask will mask
2441		// nothing in that case as well.
2442		if (!(bits & (bits - 1))) r = bc_rand_int(rng) & (bits - 1);
2443		else r = bc_rand_bounded(rng, bits);
2444
2445		// We made sure that r is less than vm.max,
2446		// so we can use bc_num_bigdig2() here.
2447		bc_num_bigdig2num(b, r);
2448
2449		return;
2450	}
2451
2452	// In the case where a is less than rng->max, we have to make sure we have
2453	// an exclusive bound. This ensures that it happens. (See below.)
2454	carry = (cmp < 0);
2455
2456	BC_SIG_LOCK;
2457
2458	bc_num_createCopy(&cp, a);
2459
2460	bc_num_init(&cp2, cp.len);
2461	bc_num_init(&mod, BC_NUM_BIGDIG_LOG10);
2462	bc_num_init(&temp1, BC_NUM_DEF_SIZE);
2463	bc_num_init(&temp2, BC_NUM_DEF_SIZE);
2464	bc_num_init(&pow2, BC_NUM_DEF_SIZE);
2465	bc_num_init(&pow, BC_NUM_DEF_SIZE);
2466	bc_num_one(&pow);
2467	bc_num_setup(&rand, rand_num, sizeof(rand_num) / sizeof(BcDig));
2468
2469	BC_SETJMP_LOCKED(err);
2470
2471	BC_SIG_UNLOCK;
2472
2473	p1 = &pow;
2474	p2 = &pow2;
2475	t1 = &temp1;
2476	t2 = &temp2;
2477	c1 = &cp;
2478	c2 = &cp2;
2479
2480	// This assert is here because it has to be true. It is also here to justify
2481	// the use of BC_ERR_SIGNAL_ONLY() on each of the divmod's and mod's below.
2482	assert(BC_NUM_NONZERO(&vm.max));
2483
2484	while (BC_NUM_NONZERO(c1)) {
2485
2486		bc_num_divmod(c1, &vm.max, c2, &mod, 0);
2487
2488		// Because mod is the mod of vm.max, it is guaranteed to be smaller,
2489		// which means we can use bc_num_bigdig2() here.
2490		bc_num_bigdig(&mod, &modl);
2491
2492		if (bc_num_cmp(c1, &vm.max) < 0) {
2493
2494			// In this case, if there is no carry, then we know we can generate
2495			// an integer *equal* to modl. Thus, we add one if there is no
2496			// carry. Otherwise, we add zero, and we are still bounded properly.
2497			// Since the last portion is guaranteed to be greater than 1, we
2498			// know modl isn't 0 unless there is no carry.
2499			modl += !carry;
2500
2501			if (modl == 1) r = 0;
2502			else if (!modl) r = bc_rand_int(rng);
2503			else r = bc_rand_bounded(rng, (BcRand) modl);
2504		}
2505		else {
2506			if (modl) modl -= carry;
2507			r = bc_rand_int(rng);
2508			carry = (r >= (BcRand) modl);
2509		}
2510
2511		bc_num_bigdig2num(&rand, r);
2512
2513		assert(BC_NUM_RDX_VALID_NP(rand));
2514		assert(BC_NUM_RDX_VALID(p1));
2515
2516		bc_num_mul(&rand, p1, p2, 0);
2517		bc_num_add(p2, t1, t2, 0);
2518
2519		if (BC_NUM_NONZERO(c2)) {
2520
2521			assert(BC_NUM_RDX_VALID_NP(vm.max));
2522			assert(BC_NUM_RDX_VALID(p1));
2523
2524			bc_num_mul(&vm.max, p1, p2, 0);
2525
2526			tmp = p1;
2527			p1 = p2;
2528			p2 = tmp;
2529
2530			tmp = c1;
2531			c1 = c2;
2532			c2 = tmp;
2533		}
2534		else c1 = c2;
2535
2536		tmp = t1;
2537		t1 = t2;
2538		t2 = tmp;
2539	}
2540
2541	bc_num_copy(b, t1);
2542	bc_num_clean(b);
2543
2544	assert(BC_NUM_RDX_VALID(b));
2545
2546err:
2547	BC_SIG_MAYLOCK;
2548	bc_num_free(&pow);
2549	bc_num_free(&pow2);
2550	bc_num_free(&temp2);
2551	bc_num_free(&temp1);
2552	bc_num_free(&mod);
2553	bc_num_free(&cp2);
2554	bc_num_free(&cp);
2555	BC_LONGJMP_CONT;
2556}
2557#endif // BC_ENABLE_EXTRA_MATH && BC_ENABLE_RAND
2558
2559size_t bc_num_addReq(const BcNum *a, const BcNum *b, size_t scale) {
2560
2561	size_t aint, bint, ardx, brdx;
2562
2563	BC_UNUSED(scale);
2564
2565	ardx = BC_NUM_RDX_VAL(a);
2566	aint = bc_num_int(a);
2567	assert(aint <= a->len && ardx <= a->len);
2568
2569	brdx = BC_NUM_RDX_VAL(b);
2570	bint = bc_num_int(b);
2571	assert(bint <= b->len && brdx <= b->len);
2572
2573	ardx = BC_MAX(ardx, brdx);
2574	aint = BC_MAX(aint, bint);
2575
2576	return bc_vm_growSize(bc_vm_growSize(ardx, aint), 1);
2577}
2578
2579size_t bc_num_mulReq(const BcNum *a, const BcNum *b, size_t scale) {
2580	size_t max, rdx;
2581	rdx = bc_vm_growSize(BC_NUM_RDX_VAL(a), BC_NUM_RDX_VAL(b));
2582	max = BC_NUM_RDX(scale);
2583	max = bc_vm_growSize(BC_MAX(max, rdx), 1);
2584	rdx = bc_vm_growSize(bc_vm_growSize(bc_num_int(a), bc_num_int(b)), max);
2585	return rdx;
2586}
2587
2588size_t bc_num_divReq(const BcNum *a, const BcNum *b, size_t scale) {
2589	size_t max, rdx;
2590	rdx = bc_vm_growSize(BC_NUM_RDX_VAL(a), BC_NUM_RDX_VAL(b));
2591	max = BC_NUM_RDX(scale);
2592	max = bc_vm_growSize(BC_MAX(max, rdx), 1);
2593	rdx = bc_vm_growSize(bc_num_int(a), max);
2594	return rdx;
2595}
2596
2597size_t bc_num_powReq(const BcNum *a, const BcNum *b, size_t scale) {
2598	BC_UNUSED(scale);
2599	return bc_vm_growSize(bc_vm_growSize(a->len, b->len), 1);
2600}
2601
2602#if BC_ENABLE_EXTRA_MATH
2603size_t bc_num_placesReq(const BcNum *a, const BcNum *b, size_t scale) {
2604	BC_UNUSED(scale);
2605	return a->len + b->len - BC_NUM_RDX_VAL(a) - BC_NUM_RDX_VAL(b);
2606}
2607#endif // BC_ENABLE_EXTRA_MATH
2608
2609void bc_num_add(BcNum *a, BcNum *b, BcNum *c, size_t scale) {
2610	assert(BC_NUM_RDX_VALID(a));
2611	assert(BC_NUM_RDX_VALID(b));
2612	bc_num_binary(a, b, c, false, bc_num_as, bc_num_addReq(a, b, scale));
2613}
2614
2615void bc_num_sub(BcNum *a, BcNum *b, BcNum *c, size_t scale) {
2616	assert(BC_NUM_RDX_VALID(a));
2617	assert(BC_NUM_RDX_VALID(b));
2618	bc_num_binary(a, b, c, true, bc_num_as, bc_num_addReq(a, b, scale));
2619}
2620
2621void bc_num_mul(BcNum *a, BcNum *b, BcNum *c, size_t scale) {
2622	assert(BC_NUM_RDX_VALID(a));
2623	assert(BC_NUM_RDX_VALID(b));
2624	bc_num_binary(a, b, c, scale, bc_num_m, bc_num_mulReq(a, b, scale));
2625}
2626
2627void bc_num_div(BcNum *a, BcNum *b, BcNum *c, size_t scale) {
2628	assert(BC_NUM_RDX_VALID(a));
2629	assert(BC_NUM_RDX_VALID(b));
2630	bc_num_binary(a, b, c, scale, bc_num_d, bc_num_divReq(a, b, scale));
2631}
2632
2633void bc_num_mod(BcNum *a, BcNum *b, BcNum *c, size_t scale) {
2634	assert(BC_NUM_RDX_VALID(a));
2635	assert(BC_NUM_RDX_VALID(b));
2636	bc_num_binary(a, b, c, scale, bc_num_rem, bc_num_divReq(a, b, scale));
2637}
2638
2639void bc_num_pow(BcNum *a, BcNum *b, BcNum *c, size_t scale) {
2640	assert(BC_NUM_RDX_VALID(a));
2641	assert(BC_NUM_RDX_VALID(b));
2642	bc_num_binary(a, b, c, scale, bc_num_p, bc_num_powReq(a, b, scale));
2643}
2644
2645#if BC_ENABLE_EXTRA_MATH
2646void bc_num_places(BcNum *a, BcNum *b, BcNum *c, size_t scale) {
2647	assert(BC_NUM_RDX_VALID(a));
2648	assert(BC_NUM_RDX_VALID(b));
2649	bc_num_binary(a, b, c, scale, bc_num_place, bc_num_placesReq(a, b, scale));
2650}
2651
2652void bc_num_lshift(BcNum *a, BcNum *b, BcNum *c, size_t scale) {
2653	assert(BC_NUM_RDX_VALID(a));
2654	assert(BC_NUM_RDX_VALID(b));
2655	bc_num_binary(a, b, c, scale, bc_num_left, bc_num_placesReq(a, b, scale));
2656}
2657
2658void bc_num_rshift(BcNum *a, BcNum *b, BcNum *c, size_t scale) {
2659	assert(BC_NUM_RDX_VALID(a));
2660	assert(BC_NUM_RDX_VALID(b));
2661	bc_num_binary(a, b, c, scale, bc_num_right, bc_num_placesReq(a, b, scale));
2662}
2663#endif // BC_ENABLE_EXTRA_MATH
2664
2665void bc_num_sqrt(BcNum *restrict a, BcNum *restrict b, size_t scale) {
2666
2667	BcNum num1, num2, half, f, fprime, *x0, *x1, *temp;
2668	size_t pow, len, rdx, req, resscale;
2669	BcDig half_digs[1];
2670
2671	assert(a != NULL && b != NULL && a != b);
2672
2673	if (BC_ERR(BC_NUM_NEG(a))) bc_vm_err(BC_ERR_MATH_NEGATIVE);
2674
2675	if (a->scale > scale) scale = a->scale;
2676
2677	len = bc_vm_growSize(bc_num_intDigits(a), 1);
2678	rdx = BC_NUM_RDX(scale);
2679	req = bc_vm_growSize(BC_MAX(rdx, BC_NUM_RDX_VAL(a)), len >> 1);
2680
2681	BC_SIG_LOCK;
2682
2683	bc_num_init(b, bc_vm_growSize(req, 1));
2684
2685	BC_SIG_UNLOCK;
2686
2687	assert(a != NULL && b != NULL && a != b);
2688	assert(a->num != NULL && b->num != NULL);
2689
2690	if (BC_NUM_ZERO(a)) {
2691		bc_num_setToZero(b, scale);
2692		return;
2693	}
2694	if (BC_NUM_ONE(a)) {
2695		bc_num_one(b);
2696		bc_num_extend(b, scale);
2697		return;
2698	}
2699
2700	rdx = BC_NUM_RDX(scale);
2701	rdx = BC_MAX(rdx, BC_NUM_RDX_VAL(a));
2702	len = bc_vm_growSize(a->len, rdx);
2703
2704	BC_SIG_LOCK;
2705
2706	bc_num_init(&num1, len);
2707	bc_num_init(&num2, len);
2708	bc_num_setup(&half, half_digs, sizeof(half_digs) / sizeof(BcDig));
2709
2710	bc_num_one(&half);
2711	half.num[0] = BC_BASE_POW / 2;
2712	half.len = 1;
2713	BC_NUM_RDX_SET_NP(half, 1);
2714	half.scale = 1;
2715
2716	bc_num_init(&f, len);
2717	bc_num_init(&fprime, len);
2718
2719	BC_SETJMP_LOCKED(err);
2720
2721	BC_SIG_UNLOCK;
2722
2723	x0 = &num1;
2724	x1 = &num2;
2725
2726	bc_num_one(x0);
2727	pow = bc_num_intDigits(a);
2728
2729	if (pow) {
2730
2731		if (pow & 1) x0->num[0] = 2;
2732		else x0->num[0] = 6;
2733
2734		pow -= 2 - (pow & 1);
2735		bc_num_shiftLeft(x0, pow / 2);
2736	}
2737
2738	// I can set the rdx here directly because neg should be false.
2739	x0->scale = x0->rdx = 0;
2740	resscale = (scale + BC_BASE_DIGS) + 2;
2741
2742	while (bc_num_cmp(x1, x0)) {
2743
2744		assert(BC_NUM_NONZERO(x0));
2745
2746		bc_num_div(a, x0, &f, resscale);
2747		bc_num_add(x0, &f, &fprime, resscale);
2748
2749		assert(BC_NUM_RDX_VALID_NP(fprime));
2750		assert(BC_NUM_RDX_VALID_NP(half));
2751
2752		bc_num_mul(&fprime, &half, x1, resscale);
2753
2754		temp = x0;
2755		x0 = x1;
2756		x1 = temp;
2757	}
2758
2759	bc_num_copy(b, x0);
2760	if (b->scale > scale) bc_num_truncate(b, b->scale - scale);
2761
2762	assert(!BC_NUM_NEG(b) || BC_NUM_NONZERO(b));
2763	assert(BC_NUM_RDX_VALID(b));
2764	assert(BC_NUM_RDX_VAL(b) <= b->len || !b->len);
2765	assert(!b->len || b->num[b->len - 1] || BC_NUM_RDX_VAL(b) == b->len);
2766
2767err:
2768	BC_SIG_MAYLOCK;
2769	bc_num_free(&fprime);
2770	bc_num_free(&f);
2771	bc_num_free(&num2);
2772	bc_num_free(&num1);
2773	BC_LONGJMP_CONT;
2774}
2775
2776void bc_num_divmod(BcNum *a, BcNum *b, BcNum *c, BcNum *d, size_t scale) {
2777
2778	size_t ts, len;
2779	BcNum *ptr_a, num2;
2780	bool init = false;
2781
2782	ts = BC_MAX(scale + b->scale, a->scale);
2783	len = bc_num_mulReq(a, b, ts);
2784
2785	assert(a != NULL && b != NULL && c != NULL && d != NULL);
2786	assert(c != d && a != d && b != d && b != c);
2787
2788	if (c == a) {
2789
2790		memcpy(&num2, c, sizeof(BcNum));
2791		ptr_a = &num2;
2792
2793		BC_SIG_LOCK;
2794
2795		bc_num_init(c, len);
2796
2797		init = true;
2798
2799		BC_SETJMP_LOCKED(err);
2800
2801		BC_SIG_UNLOCK;
2802	}
2803	else {
2804		ptr_a = a;
2805		bc_num_expand(c, len);
2806	}
2807
2808	if (BC_NUM_NONZERO(a) && !BC_NUM_RDX_VAL(a) &&
2809	    !BC_NUM_RDX_VAL(b) && b->len == 1 && !scale)
2810	{
2811		BcBigDig rem;
2812
2813		bc_num_divArray(ptr_a, (BcBigDig) b->num[0], c, &rem);
2814
2815		assert(rem < BC_BASE_POW);
2816
2817		d->num[0] = (BcDig) rem;
2818		d->len = (rem != 0);
2819	}
2820	else bc_num_r(ptr_a, b, c, d, scale, ts);
2821
2822	assert(!BC_NUM_NEG(c) || BC_NUM_NONZERO(c));
2823	assert(BC_NUM_RDX_VALID(c));
2824	assert(BC_NUM_RDX_VAL(c) <= c->len || !c->len);
2825	assert(!c->len || c->num[c->len - 1] || BC_NUM_RDX_VAL(c) == c->len);
2826	assert(!BC_NUM_NEG(d) || BC_NUM_NONZERO(d));
2827	assert(BC_NUM_RDX_VALID(d));
2828	assert(BC_NUM_RDX_VAL(d) <= d->len || !d->len);
2829	assert(!d->len || d->num[d->len - 1] || BC_NUM_RDX_VAL(d) == d->len);
2830
2831err:
2832	if (init) {
2833		BC_SIG_MAYLOCK;
2834		bc_num_free(&num2);
2835		BC_LONGJMP_CONT;
2836	}
2837}
2838
2839#if DC_ENABLED
2840void bc_num_modexp(BcNum *a, BcNum *b, BcNum *c, BcNum *restrict d) {
2841
2842	BcNum base, exp, two, temp;
2843	BcDig two_digs[2];
2844
2845	assert(a != NULL && b != NULL && c != NULL && d != NULL);
2846	assert(a != d && b != d && c != d);
2847
2848	if (BC_ERR(BC_NUM_ZERO(c))) bc_vm_err(BC_ERR_MATH_DIVIDE_BY_ZERO);
2849	if (BC_ERR(BC_NUM_NEG(b))) bc_vm_err(BC_ERR_MATH_NEGATIVE);
2850	if (BC_ERR(BC_NUM_RDX_VAL(a) || BC_NUM_RDX_VAL(b) || BC_NUM_RDX_VAL(c)))
2851		bc_vm_err(BC_ERR_MATH_NON_INTEGER);
2852
2853	bc_num_expand(d, c->len);
2854
2855	BC_SIG_LOCK;
2856
2857	bc_num_init(&base, c->len);
2858	bc_num_setup(&two, two_digs, sizeof(two_digs) / sizeof(BcDig));
2859	bc_num_init(&temp, b->len + 1);
2860	bc_num_createCopy(&exp, b);
2861
2862	BC_SETJMP_LOCKED(err);
2863
2864	BC_SIG_UNLOCK;
2865
2866	bc_num_one(&two);
2867	two.num[0] = 2;
2868	bc_num_one(d);
2869
2870	// We already checked for 0.
2871	bc_num_rem(a, c, &base, 0);
2872
2873	while (BC_NUM_NONZERO(&exp)) {
2874
2875		// Num two cannot be 0, so no errors.
2876		bc_num_divmod(&exp, &two, &exp, &temp, 0);
2877
2878		if (BC_NUM_ONE(&temp) && !BC_NUM_NEG_NP(temp)) {
2879
2880			assert(BC_NUM_RDX_VALID(d));
2881			assert(BC_NUM_RDX_VALID_NP(base));
2882
2883			bc_num_mul(d, &base, &temp, 0);
2884
2885			// We already checked for 0.
2886			bc_num_rem(&temp, c, d, 0);
2887		}
2888
2889		assert(BC_NUM_RDX_VALID_NP(base));
2890
2891		bc_num_mul(&base, &base, &temp, 0);
2892
2893		// We already checked for 0.
2894		bc_num_rem(&temp, c, &base, 0);
2895	}
2896
2897err:
2898	BC_SIG_MAYLOCK;
2899	bc_num_free(&exp);
2900	bc_num_free(&temp);
2901	bc_num_free(&base);
2902	BC_LONGJMP_CONT;
2903	assert(!BC_NUM_NEG(d) || d->len);
2904	assert(BC_NUM_RDX_VALID(d));
2905	assert(!d->len || d->num[d->len - 1] || BC_NUM_RDX_VAL(d) == d->len);
2906}
2907#endif // DC_ENABLED
2908
2909#if BC_DEBUG_CODE
2910void bc_num_printDebug(const BcNum *n, const char *name, bool emptyline) {
2911	bc_file_puts(&vm.fout, bc_flush_none, name);
2912	bc_file_puts(&vm.fout, bc_flush_none, ": ");
2913	bc_num_printDecimal(n);
2914	bc_file_putchar(&vm.fout, bc_flush_err, '\n');
2915	if (emptyline) bc_file_putchar(&vm.fout, bc_flush_err, '\n');
2916	vm.nchars = 0;
2917}
2918
2919void bc_num_printDigs(const BcDig *n, size_t len, bool emptyline) {
2920
2921	size_t i;
2922
2923	for (i = len - 1; i < len; --i)
2924		bc_file_printf(&vm.fout, " %lu", (unsigned long) n[i]);
2925
2926	bc_file_putchar(&vm.fout, bc_flush_err, '\n');
2927	if (emptyline) bc_file_putchar(&vm.fout, bc_flush_err, '\n');
2928	vm.nchars = 0;
2929}
2930
2931void bc_num_printWithDigs(const BcNum *n, const char *name, bool emptyline) {
2932	bc_file_puts(&vm.fout, bc_flush_none, name);
2933	bc_file_printf(&vm.fout, " len: %zu, rdx: %zu, scale: %zu\n",
2934	               name, n->len, BC_NUM_RDX_VAL(n), n->scale);
2935	bc_num_printDigs(n->num, n->len, emptyline);
2936}
2937
2938void bc_num_dump(const char *varname, const BcNum *n) {
2939
2940	ulong i, scale = n->scale;
2941
2942	bc_file_printf(&vm.ferr, "\n%s = %s", varname,
2943	               n->len ? (BC_NUM_NEG(n) ? "-" : "+") : "0 ");
2944
2945	for (i = n->len - 1; i < n->len; --i) {
2946
2947		if (i + 1 == BC_NUM_RDX_VAL(n))
2948			bc_file_puts(&vm.ferr, bc_flush_none, ". ");
2949
2950		if (scale / BC_BASE_DIGS != BC_NUM_RDX_VAL(n) - i - 1)
2951			bc_file_printf(&vm.ferr, "%lu ", (unsigned long) n->num[i]);
2952		else {
2953
2954			int mod = scale % BC_BASE_DIGS;
2955			int d = BC_BASE_DIGS - mod;
2956			BcDig div;
2957
2958			if (mod != 0) {
2959				div = n->num[i] / ((BcDig) bc_num_pow10[(ulong) d]);
2960				bc_file_printf(&vm.ferr, "%lu", (unsigned long) div);
2961			}
2962
2963			div = n->num[i] % ((BcDig) bc_num_pow10[(ulong) d]);
2964			bc_file_printf(&vm.ferr, " ' %lu ", (unsigned long) div);
2965		}
2966	}
2967
2968	bc_file_printf(&vm.ferr, "(%zu | %zu.%zu / %zu) %lu\n",
2969	               n->scale, n->len, BC_NUM_RDX_VAL(n), n->cap,
2970	               (unsigned long) (void*) n->num);
2971
2972	bc_file_flush(&vm.ferr, bc_flush_err);
2973}
2974#endif // BC_DEBUG_CODE
2975