bcode.c revision 315135 
1/*	$OpenBSD: bcode.c,v 1.45 2012/11/07 11:06:14 otto Exp $	*/
2
3/*
4 * Copyright (c) 2003, Otto Moerbeek <otto@drijf.net>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19#include <sys/cdefs.h>
20__FBSDID("$FreeBSD: stable/10/usr.bin/dc/bcode.c 315135 2017-03-12 05:36:31Z pfg $");
21
22#include <err.h>
23#include <limits.h>
24#include <openssl/ssl.h>
25#include <signal.h>
26#include <stdio.h>
27#include <stdlib.h>
28#include <string.h>
29
30#include "extern.h"
31
32/* #define	DEBUGGING */
33
34#define MAX_ARRAY_INDEX		2048
35#define READSTACK_SIZE		8
36
37#define NO_ELSE			-2	/* -1 is EOF */
38#define REG_ARRAY_SIZE_SMALL	(UCHAR_MAX + 1)
39#define REG_ARRAY_SIZE_BIG	(UCHAR_MAX + 1 + USHRT_MAX + 1)
40
41struct bmachine {
42	struct source		*readstack;
43	struct stack		*reg;
44	struct stack		 stack;
45	u_int			 scale;
46	u_int			 obase;
47	u_int			 ibase;
48	size_t			 readsp;
49	size_t			 reg_array_size;
50	size_t			 readstack_sz;
51	bool			 extended_regs;
52};
53
54static struct bmachine	 bmachine;
55
56static __inline int	 readch(void);
57static __inline void	 unreadch(void);
58static __inline char	*readline(void);
59static __inline void	 src_free(void);
60
61static __inline u_int	 max(u_int, u_int);
62static u_long		 get_ulong(struct number *);
63
64static __inline void	 push_number(struct number *);
65static __inline void	 push_string(char *);
66static __inline void	 push(struct value *);
67static __inline struct value *tos(void);
68static __inline struct number	*pop_number(void);
69static __inline char	*pop_string(void);
70static __inline void	 clear_stack(void);
71static __inline void	 print_tos(void);
72static void		 pop_print(void);
73static void		 pop_printn(void);
74static __inline void	 print_stack(void);
75static __inline void	 dup(void);
76static void		 swap(void);
77static void		 drop(void);
78
79static void		 get_scale(void);
80static void		 set_scale(void);
81static void		 get_obase(void);
82static void		 set_obase(void);
83static void		 get_ibase(void);
84static void		 set_ibase(void);
85static void		 stackdepth(void);
86static void		 push_scale(void);
87static u_int		 count_digits(const struct number *);
88static void		 num_digits(void);
89static void		 to_ascii(void);
90static void		 push_line(void);
91static void		 comment(void);
92static void		 bexec(char *);
93static void		 badd(void);
94static void		 bsub(void);
95static void		 bmul(void);
96static void		 bdiv(void);
97static void		 bmod(void);
98static void		 bdivmod(void);
99static void		 bexp(void);
100static bool		 bsqrt_stop(const BIGNUM *, const BIGNUM *, u_int *);
101static void		 bsqrt(void);
102static void		 not(void);
103static void		 equal_numbers(void);
104static void		 less_numbers(void);
105static void		 lesseq_numbers(void);
106static void		 equal(void);
107static void		 not_equal(void);
108static void		 less(void);
109static void		 not_less(void);
110static void		 greater(void);
111static void		 not_greater(void);
112static void		 not_compare(void);
113static bool		 compare_numbers(enum bcode_compare, struct number *,
114			     struct number *);
115static void		 compare(enum bcode_compare);
116static int		 readreg(void);
117static void		 load(void);
118static void		 store(void);
119static void		 load_stack(void);
120static void		 store_stack(void);
121static void		 load_array(void);
122static void		 store_array(void);
123static void		 nop(void);
124static void		 quit(void);
125static void		 quitN(void);
126static void		 skipN(void);
127static void		 skip_until_mark(void);
128static void		 parse_number(void);
129static void		 unknown(void);
130static void		 eval_string(char *);
131static void		 eval_line(void);
132static void		 eval_tos(void);
133
134
135typedef void		(*opcode_function)(void);
136
137struct jump_entry {
138	u_char		 ch;
139	opcode_function	 f;
140};
141
142static opcode_function jump_table[UCHAR_MAX];
143
144static const struct jump_entry jump_table_data[] = {
145	{ ' ',	nop		},
146	{ '!',	not_compare	},
147	{ '#',	comment		},
148	{ '%',	bmod		},
149	{ '(',	less_numbers	},
150	{ '*',	bmul		},
151	{ '+',	badd		},
152	{ '-',	bsub		},
153	{ '.',	parse_number	},
154	{ '/',	bdiv		},
155	{ '0',	parse_number	},
156	{ '1',	parse_number	},
157	{ '2',	parse_number	},
158	{ '3',	parse_number	},
159	{ '4',	parse_number	},
160	{ '5',	parse_number	},
161	{ '6',	parse_number	},
162	{ '7',	parse_number	},
163	{ '8',	parse_number	},
164	{ '9',	parse_number	},
165	{ ':',	store_array	},
166	{ ';',	load_array	},
167	{ '<',	less		},
168	{ '=',	equal		},
169	{ '>',	greater		},
170	{ '?',	eval_line	},
171	{ 'A',	parse_number	},
172	{ 'B',	parse_number	},
173	{ 'C',	parse_number	},
174	{ 'D',	parse_number	},
175	{ 'E',	parse_number	},
176	{ 'F',	parse_number	},
177	{ 'G',	equal_numbers	},
178	{ 'I',	get_ibase	},
179	{ 'J',	skipN		},
180	{ 'K',	get_scale	},
181	{ 'L',	load_stack	},
182	{ 'M',	nop		},
183	{ 'N',	not		},
184	{ 'O',	get_obase	},
185	{ 'P',	pop_print	},
186	{ 'Q',	quitN		},
187	{ 'R',	drop		},
188	{ 'S',	store_stack	},
189	{ 'X',	push_scale	},
190	{ 'Z',	num_digits	},
191	{ '[',	push_line	},
192	{ '\f',	nop		},
193	{ '\n',	nop		},
194	{ '\r',	nop		},
195	{ '\t',	nop		},
196	{ '^',	bexp		},
197	{ '_',	parse_number	},
198	{ 'a',	to_ascii	},
199	{ 'c',	clear_stack	},
200	{ 'd',	dup		},
201	{ 'f',	print_stack	},
202	{ 'i',	set_ibase	},
203	{ 'k',	set_scale	},
204	{ 'l',	load		},
205	{ 'n',	pop_printn	},
206	{ 'o',	set_obase	},
207	{ 'p',	print_tos	},
208	{ 'q',	quit		},
209	{ 'r',	swap		},
210	{ 's',	store		},
211	{ 'v',	bsqrt		},
212	{ 'x',	eval_tos	},
213	{ 'z',	stackdepth	},
214	{ '{',	lesseq_numbers	},
215	{ '~',	bdivmod		}
216};
217
218#define JUMP_TABLE_DATA_SIZE \
219	(sizeof(jump_table_data)/sizeof(jump_table_data[0]))
220
221void
222init_bmachine(bool extended_registers)
223{
224	unsigned int i;
225
226	bmachine.extended_regs = extended_registers;
227	bmachine.reg_array_size = bmachine.extended_regs ?
228	    REG_ARRAY_SIZE_BIG : REG_ARRAY_SIZE_SMALL;
229
230	bmachine.reg = calloc(bmachine.reg_array_size,
231	    sizeof(bmachine.reg[0]));
232	if (bmachine.reg == NULL)
233		err(1, NULL);
234
235	for (i = 0; i < UCHAR_MAX; i++)
236		jump_table[i] = unknown;
237	for (i = 0; i < JUMP_TABLE_DATA_SIZE; i++)
238		jump_table[jump_table_data[i].ch] = jump_table_data[i].f;
239
240	stack_init(&bmachine.stack);
241
242	for (i = 0; i < bmachine.reg_array_size; i++)
243		stack_init(&bmachine.reg[i]);
244
245	bmachine.readstack_sz = READSTACK_SIZE;
246	bmachine.readstack = calloc(sizeof(struct source),
247	    bmachine.readstack_sz);
248	if (bmachine.readstack == NULL)
249		err(1, NULL);
250	bmachine.obase = bmachine.ibase = 10;
251}
252
253u_int
254bmachine_scale(void)
255{
256	return bmachine.scale;
257}
258
259/* Reset the things needed before processing a (new) file */
260void
261reset_bmachine(struct source *src)
262{
263
264	bmachine.readsp = 0;
265	bmachine.readstack[0] = *src;
266}
267
268static __inline int
269readch(void)
270{
271	struct source *src = &bmachine.readstack[bmachine.readsp];
272
273	return (src->vtable->readchar(src));
274}
275
276static __inline void
277unreadch(void)
278{
279	struct source *src = &bmachine.readstack[bmachine.readsp];
280
281	src->vtable->unreadchar(src);
282}
283
284static __inline char *
285readline(void)
286{
287	struct source *src = &bmachine.readstack[bmachine.readsp];
288
289	return (src->vtable->readline(src));
290}
291
292static __inline void
293src_free(void)
294{
295	struct source *src = &bmachine.readstack[bmachine.readsp];
296
297	src->vtable->free(src);
298}
299
300#ifdef DEBUGGING
301void
302pn(const char *str, const struct number *n)
303{
304	char *p = BN_bn2dec(n->number);
305
306	if (p == NULL)
307		err(1, "BN_bn2dec failed");
308	fputs(str, stderr);
309	fprintf(stderr, " %s (%u)\n" , p, n->scale);
310	OPENSSL_free(p);
311}
312
313void
314pbn(const char *str, const BIGNUM *n)
315{
316	char *p = BN_bn2dec(n);
317
318	if (p == NULL)
319		err(1, "BN_bn2dec failed");
320	fputs(str, stderr);
321	fprintf(stderr, " %s\n", p);
322	OPENSSL_free(p);
323}
324
325#endif
326
327static __inline u_int
328max(u_int a, u_int b)
329{
330
331	return (a > b ? a : b);
332}
333
334static unsigned long factors[] = {
335	0, 10, 100, 1000, 10000, 100000, 1000000, 10000000,
336	100000000, 1000000000
337};
338
339void
340scale_number(BIGNUM *n, int s)
341{
342	unsigned int abs_scale;
343
344	if (s == 0)
345		return;
346
347	abs_scale = s > 0 ? s : -s;
348
349	if (abs_scale < sizeof(factors)/sizeof(factors[0])) {
350		if (s > 0)
351			bn_check(BN_mul_word(n, factors[abs_scale]));
352		else
353			BN_div_word(n, factors[abs_scale]);
354	} else {
355		BIGNUM *a, *p;
356		BN_CTX *ctx;
357
358		a = BN_new();
359		bn_checkp(a);
360		p = BN_new();
361		bn_checkp(p);
362		ctx = BN_CTX_new();
363		bn_checkp(ctx);
364
365		bn_check(BN_set_word(a, 10));
366		bn_check(BN_set_word(p, abs_scale));
367		bn_check(BN_exp(a, a, p, ctx));
368		if (s > 0)
369			bn_check(BN_mul(n, n, a, ctx));
370		else
371			bn_check(BN_div(n, NULL, n, a, ctx));
372		BN_CTX_free(ctx);
373		BN_free(a);
374		BN_free(p);
375	}
376}
377
378void
379split_number(const struct number *n, BIGNUM *i, BIGNUM *f)
380{
381	u_long rem;
382
383	bn_checkp(BN_copy(i, n->number));
384
385	if (n->scale == 0 && f != NULL)
386		bn_check(BN_zero(f));
387	else if (n->scale < sizeof(factors)/sizeof(factors[0])) {
388		rem = BN_div_word(i, factors[n->scale]);
389		if (f != NULL)
390			bn_check(BN_set_word(f, rem));
391	} else {
392		BIGNUM	*a, *p;
393		BN_CTX	*ctx;
394
395		a = BN_new();
396		bn_checkp(a);
397		p = BN_new();
398		bn_checkp(p);
399		ctx = BN_CTX_new();
400		bn_checkp(ctx);
401
402		bn_check(BN_set_word(a, 10));
403		bn_check(BN_set_word(p, n->scale));
404		bn_check(BN_exp(a, a, p, ctx));
405		bn_check(BN_div(i, f, n->number, a, ctx));
406		BN_CTX_free(ctx);
407		BN_free(a);
408		BN_free(p);
409	}
410}
411
412void
413normalize(struct number *n, u_int s)
414{
415
416	scale_number(n->number, s - n->scale);
417	n->scale = s;
418}
419
420static u_long
421get_ulong(struct number *n)
422{
423
424	normalize(n, 0);
425	return (BN_get_word(n->number));
426}
427
428void
429negate(struct number *n)
430{
431	BN_set_negative(n->number, !BN_is_negative(n->number));
432}
433
434static __inline void
435push_number(struct number *n)
436{
437
438	stack_pushnumber(&bmachine.stack, n);
439}
440
441static __inline void
442push_string(char *string)
443{
444
445	stack_pushstring(&bmachine.stack, string);
446}
447
448static __inline void
449push(struct value *v)
450{
451
452	stack_push(&bmachine.stack, v);
453}
454
455static __inline struct value *
456tos(void)
457{
458
459	return (stack_tos(&bmachine.stack));
460}
461
462static __inline struct value *
463pop(void)
464{
465
466	return (stack_pop(&bmachine.stack));
467}
468
469static __inline struct number *
470pop_number(void)
471{
472
473	return (stack_popnumber(&bmachine.stack));
474}
475
476static __inline char *
477pop_string(void)
478{
479
480	return (stack_popstring(&bmachine.stack));
481}
482
483static __inline void
484clear_stack(void)
485{
486
487	stack_clear(&bmachine.stack);
488}
489
490static __inline void
491print_stack(void)
492{
493
494	stack_print(stdout, &bmachine.stack, "", bmachine.obase);
495}
496
497static __inline void
498print_tos(void)
499{
500	struct value *value = tos();
501
502	if (value != NULL) {
503		print_value(stdout, value, "", bmachine.obase);
504		putchar('\n');
505	}
506	else
507		warnx("stack empty");
508}
509
510static void
511pop_print(void)
512{
513	struct value *value = pop();
514
515	if (value != NULL) {
516		switch (value->type) {
517		case BCODE_NONE:
518			break;
519		case BCODE_NUMBER:
520			normalize(value->u.num, 0);
521			print_ascii(stdout, value->u.num);
522			fflush(stdout);
523			break;
524		case BCODE_STRING:
525			fputs(value->u.string, stdout);
526			fflush(stdout);
527			break;
528		}
529		stack_free_value(value);
530	}
531}
532
533static void
534pop_printn(void)
535{
536	struct value *value = pop();
537
538	if (value != NULL) {
539		print_value(stdout, value, "", bmachine.obase);
540		fflush(stdout);
541		stack_free_value(value);
542	}
543}
544
545static __inline void
546dup(void)
547{
548
549	stack_dup(&bmachine.stack);
550}
551
552static void
553swap(void)
554{
555
556	stack_swap(&bmachine.stack);
557}
558
559static void
560drop(void)
561{
562	struct value *v = pop();
563	if (v != NULL)
564		stack_free_value(v);
565}
566
567static void
568get_scale(void)
569{
570	struct number *n;
571
572	n = new_number();
573	bn_check(BN_set_word(n->number, bmachine.scale));
574	push_number(n);
575}
576
577static void
578set_scale(void)
579{
580	struct number *n;
581	u_long scale;
582
583	n = pop_number();
584	if (n != NULL) {
585		if (BN_is_negative(n->number))
586			warnx("scale must be a nonnegative number");
587		else {
588			scale = get_ulong(n);
589			if (scale != BN_MASK2 && scale <= UINT_MAX)
590				bmachine.scale = (u_int)scale;
591			else
592				warnx("scale too large");
593			}
594		free_number(n);
595	}
596}
597
598static void
599get_obase(void)
600{
601	struct number *n;
602
603	n = new_number();
604	bn_check(BN_set_word(n->number, bmachine.obase));
605	push_number(n);
606}
607
608static void
609set_obase(void)
610{
611	struct number *n;
612	u_long base;
613
614	n = pop_number();
615	if (n != NULL) {
616		base = get_ulong(n);
617		if (base != BN_MASK2 && base > 1 && base <= UINT_MAX)
618			bmachine.obase = (u_int)base;
619		else
620			warnx("output base must be a number greater than 1");
621		free_number(n);
622	}
623}
624
625static void
626get_ibase(void)
627{
628	struct number *n;
629
630	n = new_number();
631	bn_check(BN_set_word(n->number, bmachine.ibase));
632	push_number(n);
633}
634
635static void
636set_ibase(void)
637{
638	struct number *n;
639	u_long base;
640
641	n = pop_number();
642	if (n != NULL) {
643		base = get_ulong(n);
644		if (base != BN_MASK2 && 2 <= base && base <= 16)
645			bmachine.ibase = (u_int)base;
646		else
647			warnx("input base must be a number between 2 and 16 "
648			    "(inclusive)");
649		free_number(n);
650	}
651}
652
653static void
654stackdepth(void)
655{
656	struct number *n;
657	size_t i;
658
659	i = stack_size(&bmachine.stack);
660	n = new_number();
661	bn_check(BN_set_word(n->number, i));
662	push_number(n);
663}
664
665static void
666push_scale(void)
667{
668	struct number *n;
669	struct value *value;
670	u_int scale = 0;
671
672	value = pop();
673	if (value != NULL) {
674		switch (value->type) {
675		case BCODE_NONE:
676			return;
677		case BCODE_NUMBER:
678			scale = value->u.num->scale;
679			break;
680		case BCODE_STRING:
681			break;
682		}
683		stack_free_value(value);
684		n = new_number();
685		bn_check(BN_set_word(n->number, scale));
686		push_number(n);
687	}
688}
689
690static u_int
691count_digits(const struct number *n)
692{
693	struct number *int_part, *fract_part;
694	u_int i;
695
696	if (BN_is_zero(n->number))
697		return n->scale ? n->scale : 1;
698
699	int_part = new_number();
700	fract_part = new_number();
701	fract_part->scale = n->scale;
702	split_number(n, int_part->number, fract_part->number);
703
704	i = 0;
705	while (!BN_is_zero(int_part->number)) {
706		BN_div_word(int_part->number, 10);
707		i++;
708	}
709	free_number(int_part);
710	free_number(fract_part);
711	return (i + n->scale);
712}
713
714static void
715num_digits(void)
716{
717	struct number *n = NULL;
718	struct value *value;
719	size_t digits;
720
721	value = pop();
722	if (value != NULL) {
723		switch (value->type) {
724		case BCODE_NONE:
725			return;
726		case BCODE_NUMBER:
727			digits = count_digits(value->u.num);
728			n = new_number();
729			bn_check(BN_set_word(n->number, digits));
730			break;
731		case BCODE_STRING:
732			digits = strlen(value->u.string);
733			n = new_number();
734			bn_check(BN_set_word(n->number, digits));
735			break;
736		}
737		stack_free_value(value);
738		push_number(n);
739	}
740}
741
742static void
743to_ascii(void)
744{
745	struct number *n;
746	struct value *value;
747	char str[2];
748
749	value = pop();
750	if (value != NULL) {
751		str[1] = '\0';
752		switch (value->type) {
753		case BCODE_NONE:
754			return;
755		case BCODE_NUMBER:
756			n = value->u.num;
757			normalize(n, 0);
758			if (BN_num_bits(n->number) > 8)
759				bn_check(BN_mask_bits(n->number, 8));
760			str[0] = (char)BN_get_word(n->number);
761			break;
762		case BCODE_STRING:
763			str[0] = value->u.string[0];
764			break;
765		}
766		stack_free_value(value);
767		push_string(bstrdup(str));
768	}
769}
770
771static int
772readreg(void)
773{
774	int ch1, ch2, idx;
775
776	idx = readch();
777	if (idx == 0xff && bmachine.extended_regs) {
778		ch1 = readch();
779		ch2 = readch();
780		if (ch1 == EOF || ch2 == EOF) {
781			warnx("unexpected eof");
782			idx = -1;
783		} else
784			idx = (ch1 << 8) + ch2 + UCHAR_MAX + 1;
785	}
786	if (idx < 0 || (unsigned)idx >= bmachine.reg_array_size) {
787		warnx("internal error: reg num = %d", idx);
788		idx = -1;
789	}
790	return (idx);
791}
792
793static void
794load(void)
795{
796	struct number *n;
797	struct value *v;
798	struct value copy;
799	int idx;
800
801	idx = readreg();
802	if (idx >= 0) {
803		v = stack_tos(&bmachine.reg[idx]);
804		if (v == NULL) {
805			n = new_number();
806			bn_check(BN_zero(n->number));
807			push_number(n);
808		} else
809			push(stack_dup_value(v, &copy));
810	}
811}
812
813static void
814store(void)
815{
816	struct value *val;
817	int idx;
818
819	idx = readreg();
820	if (idx >= 0) {
821		val = pop();
822		if (val == NULL) {
823			return;
824		}
825		stack_set_tos(&bmachine.reg[idx], val);
826	}
827}
828
829static void
830load_stack(void)
831{
832	struct stack *stack;
833	struct value *value;
834	int idx;
835
836	idx = readreg();
837	if (idx >= 0) {
838		stack = &bmachine.reg[idx];
839		value = NULL;
840		if (stack_size(stack) > 0) {
841			value = stack_pop(stack);
842		}
843		if (value != NULL)
844			push(value);
845		else
846			warnx("stack register '%c' (0%o) is empty",
847			    idx, idx);
848	}
849}
850
851static void
852store_stack(void)
853{
854	struct value *value;
855	int idx;
856
857	idx = readreg();
858	if (idx >= 0) {
859		value = pop();
860		if (value == NULL)
861			return;
862		stack_push(&bmachine.reg[idx], value);
863	}
864}
865
866static void
867load_array(void)
868{
869	struct number *inumber, *n;
870	struct stack *stack;
871	struct value *v;
872	struct value copy;
873	u_long idx;
874	int reg;
875
876	reg = readreg();
877	if (reg >= 0) {
878		inumber = pop_number();
879		if (inumber == NULL)
880			return;
881		idx = get_ulong(inumber);
882		if (BN_is_negative(inumber->number))
883			warnx("negative idx");
884		else if (idx == BN_MASK2 || idx > MAX_ARRAY_INDEX)
885			warnx("idx too big");
886		else {
887			stack = &bmachine.reg[reg];
888			v = frame_retrieve(stack, idx);
889			if (v == NULL || v->type == BCODE_NONE) {
890				n = new_number();
891				bn_check(BN_zero(n->number));
892				push_number(n);
893			}
894			else
895				push(stack_dup_value(v, &copy));
896		}
897		free_number(inumber);
898	}
899}
900
901static void
902store_array(void)
903{
904	struct number *inumber;
905	struct value *value;
906	struct stack *stack;
907	u_long idx;
908	int reg;
909
910	reg = readreg();
911	if (reg >= 0) {
912		inumber = pop_number();
913		if (inumber == NULL)
914			return;
915		value = pop();
916		if (value == NULL) {
917			free_number(inumber);
918			return;
919		}
920		idx = get_ulong(inumber);
921		if (BN_is_negative(inumber->number)) {
922			warnx("negative idx");
923			stack_free_value(value);
924		} else if (idx == BN_MASK2 || idx > MAX_ARRAY_INDEX) {
925			warnx("idx too big");
926			stack_free_value(value);
927		} else {
928			stack = &bmachine.reg[reg];
929			frame_assign(stack, idx, value);
930		}
931		free_number(inumber);
932	}
933}
934
935static void
936push_line(void)
937{
938
939	push_string(read_string(&bmachine.readstack[bmachine.readsp]));
940}
941
942static void
943comment(void)
944{
945
946	free(readline());
947}
948
949static void
950bexec(char *line)
951{
952
953	system(line);
954	free(line);
955}
956
957static void
958badd(void)
959{
960	struct number	*a, *b, *r;
961
962	a = pop_number();
963	if (a == NULL)
964		return;
965	b = pop_number();
966	if (b == NULL) {
967		push_number(a);
968		return;
969	}
970
971	r = new_number();
972	r->scale = max(a->scale, b->scale);
973	if (r->scale > a->scale)
974		normalize(a, r->scale);
975	else if (r->scale > b->scale)
976		normalize(b, r->scale);
977	bn_check(BN_add(r->number, a->number, b->number));
978	push_number(r);
979	free_number(a);
980	free_number(b);
981}
982
983static void
984bsub(void)
985{
986	struct number	*a, *b, *r;
987
988	a = pop_number();
989	if (a == NULL)
990		return;
991	b = pop_number();
992	if (b == NULL) {
993		push_number(a);
994		return;
995	}
996
997	r = new_number();
998
999	r->scale = max(a->scale, b->scale);
1000	if (r->scale > a->scale)
1001		normalize(a, r->scale);
1002	else if (r->scale > b->scale)
1003		normalize(b, r->scale);
1004	bn_check(BN_sub(r->number, b->number, a->number));
1005	push_number(r);
1006	free_number(a);
1007	free_number(b);
1008}
1009
1010void
1011bmul_number(struct number *r, struct number *a, struct number *b, u_int scale)
1012{
1013	BN_CTX *ctx;
1014
1015	/* Create copies of the scales, since r might be equal to a or b */
1016	u_int ascale = a->scale;
1017	u_int bscale = b->scale;
1018	u_int rscale = ascale + bscale;
1019
1020	ctx = BN_CTX_new();
1021	bn_checkp(ctx);
1022	bn_check(BN_mul(r->number, a->number, b->number, ctx));
1023	BN_CTX_free(ctx);
1024
1025	r->scale = rscale;
1026	if (rscale > bmachine.scale && rscale > ascale && rscale > bscale)
1027		normalize(r, max(scale, max(ascale, bscale)));
1028}
1029
1030static void
1031bmul(void)
1032{
1033	struct number *a, *b, *r;
1034
1035	a = pop_number();
1036	if (a == NULL)
1037		return;
1038	b = pop_number();
1039	if (b == NULL) {
1040		push_number(a);
1041		return;
1042	}
1043
1044	r = new_number();
1045	bmul_number(r, a, b, bmachine.scale);
1046
1047	push_number(r);
1048	free_number(a);
1049	free_number(b);
1050}
1051
1052static void
1053bdiv(void)
1054{
1055	struct number *a, *b, *r;
1056	BN_CTX *ctx;
1057	u_int scale;
1058
1059	a = pop_number();
1060	if (a == NULL)
1061		return;
1062	b = pop_number();
1063	if (b == NULL) {
1064		push_number(a);
1065		return;
1066	}
1067
1068	r = new_number();
1069	r->scale = bmachine.scale;
1070	scale = max(a->scale, b->scale);
1071
1072	if (BN_is_zero(a->number))
1073		warnx("divide by zero");
1074	else {
1075		normalize(a, scale);
1076		normalize(b, scale + r->scale);
1077
1078		ctx = BN_CTX_new();
1079		bn_checkp(ctx);
1080		bn_check(BN_div(r->number, NULL, b->number, a->number, ctx));
1081		BN_CTX_free(ctx);
1082	}
1083	push_number(r);
1084	free_number(a);
1085	free_number(b);
1086}
1087
1088static void
1089bmod(void)
1090{
1091	struct number *a, *b, *r;
1092	BN_CTX *ctx;
1093	u_int scale;
1094
1095	a = pop_number();
1096	if (a == NULL)
1097		return;
1098	b = pop_number();
1099	if (b == NULL) {
1100		push_number(a);
1101		return;
1102	}
1103
1104	r = new_number();
1105	scale = max(a->scale, b->scale);
1106	r->scale = max(b->scale, a->scale + bmachine.scale);
1107
1108	if (BN_is_zero(a->number))
1109		warnx("remainder by zero");
1110	else {
1111		normalize(a, scale);
1112		normalize(b, scale + bmachine.scale);
1113
1114		ctx = BN_CTX_new();
1115		bn_checkp(ctx);
1116		bn_check(BN_mod(r->number, b->number, a->number, ctx));
1117		BN_CTX_free(ctx);
1118	}
1119	push_number(r);
1120	free_number(a);
1121	free_number(b);
1122}
1123
1124static void
1125bdivmod(void)
1126{
1127	struct number *a, *b, *rdiv, *rmod;
1128	BN_CTX *ctx;
1129	u_int scale;
1130
1131	a = pop_number();
1132	if (a == NULL)
1133		return;
1134	b = pop_number();
1135	if (b == NULL) {
1136		push_number(a);
1137		return;
1138	}
1139
1140	rdiv = new_number();
1141	rmod = new_number();
1142	rdiv->scale = bmachine.scale;
1143	rmod->scale = max(b->scale, a->scale + bmachine.scale);
1144	scale = max(a->scale, b->scale);
1145
1146	if (BN_is_zero(a->number))
1147		warnx("divide by zero");
1148	else {
1149		normalize(a, scale);
1150		normalize(b, scale + bmachine.scale);
1151
1152		ctx = BN_CTX_new();
1153		bn_checkp(ctx);
1154		bn_check(BN_div(rdiv->number, rmod->number,
1155		    b->number, a->number, ctx));
1156		BN_CTX_free(ctx);
1157	}
1158	push_number(rdiv);
1159	push_number(rmod);
1160	free_number(a);
1161	free_number(b);
1162}
1163
1164static void
1165bexp(void)
1166{
1167	struct number	*a, *p;
1168	struct number	*r;
1169	bool		neg;
1170	u_int		rscale;
1171
1172	p = pop_number();
1173	if (p == NULL)
1174		return;
1175	a = pop_number();
1176	if (a == NULL) {
1177		push_number(p);
1178		return;
1179	}
1180
1181	if (p->scale != 0) {
1182		BIGNUM *i, *f;
1183		i = BN_new();
1184		bn_checkp(i);
1185		f = BN_new();
1186		bn_checkp(f);
1187		split_number(p, i, f);
1188		if (!BN_is_zero(f))
1189			warnx("Runtime warning: non-zero fractional part in exponent");
1190		BN_free(i);
1191		BN_free(f);
1192	}
1193
1194	normalize(p, 0);
1195
1196	neg = false;
1197	if (BN_is_negative(p->number)) {
1198		neg = true;
1199		negate(p);
1200		rscale = bmachine.scale;
1201	} else {
1202		/* Posix bc says min(a.scale * b, max(a.scale, scale) */
1203		u_long b;
1204		u_int m;
1205
1206		b = BN_get_word(p->number);
1207		m = max(a->scale, bmachine.scale);
1208		rscale = a->scale * (u_int)b;
1209		if (rscale > m || (a->scale > 0 && (b == BN_MASK2 ||
1210		    b > UINT_MAX)))
1211			rscale = m;
1212	}
1213
1214	if (BN_is_zero(p->number)) {
1215		r = new_number();
1216		bn_check(BN_one(r->number));
1217		normalize(r, rscale);
1218	} else {
1219		u_int ascale, mscale;
1220
1221		ascale = a->scale;
1222		while (!BN_is_bit_set(p->number, 0)) {
1223			ascale *= 2;
1224			bmul_number(a, a, a, ascale);
1225			bn_check(BN_rshift1(p->number, p->number));
1226		}
1227
1228		r = dup_number(a);
1229		bn_check(BN_rshift1(p->number, p->number));
1230
1231		mscale = ascale;
1232		while (!BN_is_zero(p->number)) {
1233			ascale *= 2;
1234			bmul_number(a, a, a, ascale);
1235			if (BN_is_bit_set(p->number, 0)) {
1236				mscale += ascale;
1237				bmul_number(r, r, a, mscale);
1238			}
1239			bn_check(BN_rshift1(p->number, p->number));
1240		}
1241
1242		if (neg) {
1243			BN_CTX *ctx;
1244			BIGNUM *one;
1245
1246			one = BN_new();
1247			bn_checkp(one);
1248			bn_check(BN_one(one));
1249			ctx = BN_CTX_new();
1250			bn_checkp(ctx);
1251			scale_number(one, r->scale + rscale);
1252
1253			if (BN_is_zero(r->number))
1254				warnx("divide by zero");
1255			else
1256				bn_check(BN_div(r->number, NULL, one,
1257				    r->number, ctx));
1258			BN_free(one);
1259			BN_CTX_free(ctx);
1260			r->scale = rscale;
1261		} else
1262			normalize(r, rscale);
1263	}
1264	push_number(r);
1265	free_number(a);
1266	free_number(p);
1267}
1268
1269static bool
1270bsqrt_stop(const BIGNUM *x, const BIGNUM *y, u_int *onecount)
1271{
1272	BIGNUM *r;
1273	bool ret;
1274
1275	r = BN_new();
1276	bn_checkp(r);
1277	bn_check(BN_sub(r, x, y));
1278	if (BN_is_one(r))
1279		(*onecount)++;
1280	ret = BN_is_zero(r);
1281	BN_free(r);
1282	return (ret || *onecount > 1);
1283}
1284
1285static void
1286bsqrt(void)
1287{
1288	struct number *n, *r;
1289	BIGNUM *x, *y;
1290	BN_CTX *ctx;
1291	u_int onecount, scale;
1292
1293	onecount = 0;
1294	n = pop_number();
1295	if (n == NULL)
1296		return;
1297	if (BN_is_zero(n->number)) {
1298		r = new_number();
1299		push_number(r);
1300	} else if (BN_is_negative(n->number))
1301		warnx("square root of negative number");
1302	else {
1303		scale = max(bmachine.scale, n->scale);
1304		normalize(n, 2*scale);
1305		x = BN_dup(n->number);
1306		bn_checkp(x);
1307		bn_check(BN_rshift(x, x, BN_num_bits(x)/2));
1308		y = BN_new();
1309		bn_checkp(y);
1310		ctx = BN_CTX_new();
1311		bn_checkp(ctx);
1312		for (;;) {
1313			bn_checkp(BN_copy(y, x));
1314			bn_check(BN_div(x, NULL, n->number, x, ctx));
1315			bn_check(BN_add(x, x, y));
1316			bn_check(BN_rshift1(x, x));
1317			if (bsqrt_stop(x, y, &onecount))
1318				break;
1319		}
1320		r = bmalloc(sizeof(*r));
1321		r->scale = scale;
1322		r->number = y;
1323		BN_free(x);
1324		BN_CTX_free(ctx);
1325		push_number(r);
1326	}
1327
1328	free_number(n);
1329}
1330
1331static void
1332not(void)
1333{
1334	struct number *a;
1335
1336	a = pop_number();
1337	if (a == NULL)
1338		return;
1339	a->scale = 0;
1340	bn_check(BN_set_word(a->number, BN_get_word(a->number) ? 0 : 1));
1341	push_number(a);
1342}
1343
1344static void
1345equal(void)
1346{
1347
1348	compare(BCODE_EQUAL);
1349}
1350
1351static void
1352equal_numbers(void)
1353{
1354	struct number *a, *b, *r;
1355
1356	a = pop_number();
1357	if (a == NULL)
1358		return;
1359	b = pop_number();
1360	if (b == NULL) {
1361		push_number(a);
1362		return;
1363	}
1364	r = new_number();
1365	bn_check(BN_set_word(r->number,
1366	    compare_numbers(BCODE_EQUAL, a, b) ? 1 : 0));
1367	push_number(r);
1368}
1369
1370static void
1371less_numbers(void)
1372{
1373	struct number *a, *b, *r;
1374
1375	a = pop_number();
1376	if (a == NULL)
1377		return;
1378	b = pop_number();
1379	if (b == NULL) {
1380		push_number(a);
1381		return;
1382	}
1383	r = new_number();
1384	bn_check(BN_set_word(r->number,
1385	    compare_numbers(BCODE_LESS, a, b) ? 1 : 0));
1386	push_number(r);
1387}
1388
1389static void
1390lesseq_numbers(void)
1391{
1392	struct number *a, *b, *r;
1393
1394	a = pop_number();
1395	if (a == NULL)
1396		return;
1397	b = pop_number();
1398	if (b == NULL) {
1399		push_number(a);
1400		return;
1401	}
1402	r = new_number();
1403	bn_check(BN_set_word(r->number,
1404	    compare_numbers(BCODE_NOT_GREATER, a, b) ? 1 : 0));
1405	push_number(r);
1406}
1407
1408static void
1409not_equal(void)
1410{
1411
1412	compare(BCODE_NOT_EQUAL);
1413}
1414
1415static void
1416less(void)
1417{
1418
1419	compare(BCODE_LESS);
1420}
1421
1422static void
1423not_compare(void)
1424{
1425
1426	switch (readch()) {
1427	case '<':
1428		not_less();
1429		break;
1430	case '>':
1431		not_greater();
1432		break;
1433	case '=':
1434		not_equal();
1435		break;
1436	default:
1437		unreadch();
1438		bexec(readline());
1439		break;
1440	}
1441}
1442
1443static void
1444not_less(void)
1445{
1446
1447	compare(BCODE_NOT_LESS);
1448}
1449
1450static void
1451greater(void)
1452{
1453
1454	compare(BCODE_GREATER);
1455}
1456
1457static void
1458not_greater(void)
1459{
1460
1461	compare(BCODE_NOT_GREATER);
1462}
1463
1464static bool
1465compare_numbers(enum bcode_compare type, struct number *a, struct number *b)
1466{
1467	u_int scale;
1468	int cmp;
1469
1470	scale = max(a->scale, b->scale);
1471
1472	if (scale > a->scale)
1473		normalize(a, scale);
1474	else if (scale > b->scale)
1475		normalize(b, scale);
1476
1477	cmp = BN_cmp(a->number, b->number);
1478
1479	free_number(a);
1480	free_number(b);
1481
1482	switch (type) {
1483	case BCODE_EQUAL:
1484		return (cmp == 0);
1485	case BCODE_NOT_EQUAL:
1486		return (cmp != 0);
1487	case BCODE_LESS:
1488		return (cmp < 0);
1489	case BCODE_NOT_LESS:
1490		return (cmp >= 0);
1491	case BCODE_GREATER:
1492		return (cmp > 0);
1493	case BCODE_NOT_GREATER:
1494		return (cmp <= 0);
1495	}
1496	return (false);
1497}
1498
1499static void
1500compare(enum bcode_compare type)
1501{
1502	struct number *a, *b;
1503	struct value *v;
1504	int idx, elseidx;
1505	bool ok;
1506
1507	elseidx = NO_ELSE;
1508	idx = readreg();
1509	if (readch() == 'e')
1510		elseidx = readreg();
1511	else
1512		unreadch();
1513
1514	a = pop_number();
1515	if (a == NULL)
1516		return;
1517	b = pop_number();
1518	if (b == NULL) {
1519		push_number(a);
1520		return;
1521	}
1522
1523	ok = compare_numbers(type, a, b);
1524
1525	if (!ok && elseidx != NO_ELSE)
1526		idx = elseidx;
1527
1528	if (idx >= 0 && (ok || (!ok && elseidx != NO_ELSE))) {
1529		v = stack_tos(&bmachine.reg[idx]);
1530		if (v == NULL)
1531			warnx("register '%c' (0%o) is empty", idx, idx);
1532		else {
1533			switch(v->type) {
1534			case BCODE_NONE:
1535				warnx("register '%c' (0%o) is empty", idx, idx);
1536				break;
1537			case BCODE_NUMBER:
1538				warn("eval called with non-string argument");
1539				break;
1540			case BCODE_STRING:
1541				eval_string(bstrdup(v->u.string));
1542				break;
1543			}
1544		}
1545	}
1546}
1547
1548
1549static void
1550nop(void)
1551{
1552
1553}
1554
1555static void
1556quit(void)
1557{
1558
1559	if (bmachine.readsp < 2)
1560		exit(0);
1561	src_free();
1562	bmachine.readsp--;
1563	src_free();
1564	bmachine.readsp--;
1565}
1566
1567static void
1568quitN(void)
1569{
1570	struct number *n;
1571	u_long i;
1572
1573	n = pop_number();
1574	if (n == NULL)
1575		return;
1576	i = get_ulong(n);
1577	free_number(n);
1578	if (i == BN_MASK2 || i == 0)
1579		warnx("Q command requires a number >= 1");
1580	else if (bmachine.readsp < i)
1581		warnx("Q command argument exceeded string execution depth");
1582	else {
1583		while (i-- > 0) {
1584			src_free();
1585			bmachine.readsp--;
1586		}
1587	}
1588}
1589
1590static void
1591skipN(void)
1592{
1593	struct number *n;
1594	u_long i;
1595
1596	n = pop_number();
1597	if (n == NULL)
1598		return;
1599	i = get_ulong(n);
1600	if (i == BN_MASK2)
1601		warnx("J command requires a number >= 0");
1602	else if (i > 0 && bmachine.readsp < i)
1603		warnx("J command argument exceeded string execution depth");
1604	else {
1605		while (i-- > 0) {
1606			src_free();
1607			bmachine.readsp--;
1608		}
1609		skip_until_mark();
1610	}
1611}
1612
1613static void
1614skip_until_mark(void)
1615{
1616
1617	for (;;) {
1618		switch (readch()) {
1619		case 'M':
1620			return;
1621		case EOF:
1622			errx(1, "mark not found");
1623			return;
1624		case 'l':
1625		case 'L':
1626		case 's':
1627		case 'S':
1628		case ':':
1629		case ';':
1630		case '<':
1631		case '>':
1632		case '=':
1633			readreg();
1634			if (readch() == 'e')
1635				readreg();
1636			else
1637				unreadch();
1638			break;
1639		case '[':
1640			free(read_string(&bmachine.readstack[bmachine.readsp]));
1641			break;
1642		case '!':
1643			switch (readch()) {
1644				case '<':
1645				case '>':
1646				case '=':
1647					readreg();
1648					if (readch() == 'e')
1649						readreg();
1650					else
1651						unreadch();
1652					break;
1653				default:
1654					free(readline());
1655					break;
1656			}
1657			break;
1658		default:
1659			break;
1660		}
1661	}
1662}
1663
1664static void
1665parse_number(void)
1666{
1667
1668	unreadch();
1669	push_number(readnumber(&bmachine.readstack[bmachine.readsp],
1670	    bmachine.ibase));
1671}
1672
1673static void
1674unknown(void)
1675{
1676	int ch = bmachine.readstack[bmachine.readsp].lastchar;
1677	warnx("%c (0%o) is unimplemented", ch, ch);
1678}
1679
1680static void
1681eval_string(char *p)
1682{
1683	int ch;
1684
1685	if (bmachine.readsp > 0) {
1686		/* Check for tail call. Do not recurse in that case. */
1687		ch = readch();
1688		if (ch == EOF) {
1689			src_free();
1690			src_setstring(&bmachine.readstack[bmachine.readsp], p);
1691			return;
1692		} else
1693			unreadch();
1694	}
1695	if (bmachine.readsp == bmachine.readstack_sz - 1) {
1696		size_t newsz = bmachine.readstack_sz * 2;
1697		struct source *stack;
1698		stack = realloc(bmachine.readstack, newsz *
1699		    sizeof(struct source));
1700		if (stack == NULL)
1701			err(1, "recursion too deep");
1702		bmachine.readstack_sz = newsz;
1703		bmachine.readstack = stack;
1704	}
1705	src_setstring(&bmachine.readstack[++bmachine.readsp], p);
1706}
1707
1708static void
1709eval_line(void)
1710{
1711	/* Always read from stdin */
1712	struct source in;
1713	char *p;
1714
1715	clearerr(stdin);
1716	src_setstream(&in, stdin);
1717	p = (*in.vtable->readline)(&in);
1718	eval_string(p);
1719}
1720
1721static void
1722eval_tos(void)
1723{
1724	char *p;
1725
1726	p = pop_string();
1727	if (p != NULL)
1728		eval_string(p);
1729}
1730
1731void
1732eval(void)
1733{
1734	int ch;
1735
1736	for (;;) {
1737		ch = readch();
1738		if (ch == EOF) {
1739			if (bmachine.readsp == 0)
1740				return;
1741			src_free();
1742			bmachine.readsp--;
1743			continue;
1744		}
1745#ifdef DEBUGGING
1746		fprintf(stderr, "# %c\n", ch);
1747		stack_print(stderr, &bmachine.stack, "* ",
1748		    bmachine.obase);
1749		fprintf(stderr, "%zd =>\n", bmachine.readsp);
1750#endif
1751
1752		if (0 <= ch && ch < (signed)UCHAR_MAX)
1753			(*jump_table[ch])();
1754		else
1755			warnx("internal error: opcode %d", ch);
1756
1757#ifdef DEBUGGING
1758		stack_print(stderr, &bmachine.stack, "* ",
1759		    bmachine.obase);
1760		fprintf(stderr, "%zd ==\n", bmachine.readsp);
1761#endif
1762	}
1763}
1764