xref: /csrg-svn/usr.bin/pascal/src/proc.c (revision 1628)
1 /* Copyright (c) 1979 Regents of the University of California */
2 
3 static	char sccsid[] = "@(#)proc.c 1.3 10/28/80";
4 
5 #include "whoami.h"
6 #ifdef OBJ
7     /*
8      *	and the rest of the file
9      */
10 #include "0.h"
11 #include "tree.h"
12 #include "opcode.h"
13 #include "objfmt.h"
14 
15 /*
16  * The following array is used to determine which classes may be read
17  * from textfiles. It is indexed by the return value from classify.
18  */
19 #define rdops(x) rdxxxx[(x)-(TFIRST)]
20 
21 int rdxxxx[] = {
22 	0,		/* -7 file types */
23 	0,		/* -6 record types */
24 	0,		/* -5 array types */
25 	O_READE,	/* -4 scalar types */
26 	0,		/* -3 pointer types */
27 	0,		/* -2 set types */
28 	0,		/* -1 string types */
29 	0,		/*  0 nil, no type */
30 	O_READE,	/*  1 boolean */
31 	O_READC,	/*  2 character */
32 	O_READ4,	/*  3 integer */
33 	O_READ8		/*  4 real */
34 };
35 
36 /*
37  * Proc handles procedure calls.
38  * Non-builtin procedures are "buck-passed" to func (with a flag
39  * indicating that they are actually procedures.
40  * builtin procedures are handled here.
41  */
42 proc(r)
43 	int *r;
44 {
45 	register struct nl *p;
46 	register int *alv, *al, op;
47 	struct nl *filetype, *ap;
48 	int argc, *argv, typ, fmtspec, strfmt, stkcnt, *file;
49 	char fmt, format[20], *strptr;
50 	int prec, field, strnglen, fmtlen, fmtstart, pu;
51 	int *pua, *pui, *puz;
52 	int i, j, k;
53 	int itemwidth;
54 
55 #define	CONPREC 4
56 #define	VARPREC 8
57 #define	CONWIDTH 1
58 #define	VARWIDTH 2
59 #define SKIP 16
60 
61 	/*
62 	 * Verify that the name is
63 	 * defined and is that of a
64 	 * procedure.
65 	 */
66 	p = lookup(r[2]);
67 	if (p == NIL) {
68 		rvlist(r[3]);
69 		return;
70 	}
71 	if (p->class != PROC && p->class != FPROC) {
72 		error("Can't call %s, its %s not a procedure", p->symbol, classes[p->class]);
73 		rvlist(r[3]);
74 		return;
75 	}
76 	argv = r[3];
77 
78 	/*
79 	 * Call handles user defined
80 	 * procedures and functions.
81 	 */
82 	if (bn != 0) {
83 		call(p, argv, PROC, bn);
84 		return;
85 	}
86 
87 	/*
88 	 * Call to built-in procedure.
89 	 * Count the arguments.
90 	 */
91 	argc = 0;
92 	for (al = argv; al != NIL; al = al[2])
93 		argc++;
94 
95 	/*
96 	 * Switch on the operator
97 	 * associated with the built-in
98 	 * procedure in the namelist
99 	 */
100 	op = p->value[0] &~ NSTAND;
101 	if (opt('s') && (p->value[0] & NSTAND)) {
102 		standard();
103 		error("%s is a nonstandard procedure", p->symbol);
104 	}
105 	switch (op) {
106 
107 	case O_ABORT:
108 		if (argc != 0)
109 			error("null takes no arguments");
110 		return;
111 
112 	case O_FLUSH:
113 		if (argc == 0) {
114 			put(1, O_MESSAGE);
115 			return;
116 		}
117 		if (argc != 1) {
118 			error("flush takes at most one argument");
119 			return;
120 		}
121 		ap = stkrval(argv[1], NIL , RREQ );
122 		if (ap == NIL)
123 			return;
124 		if (ap->class != FILET) {
125 			error("flush's argument must be a file, not %s", nameof(ap));
126 			return;
127 		}
128 		put(1, op);
129 		return;
130 
131 	case O_MESSAGE:
132 	case O_WRITEF:
133 	case O_WRITLN:
134 		/*
135 		 * Set up default file "output"'s type
136 		 */
137 		file = NIL;
138 		filetype = nl+T1CHAR;
139 		/*
140 		 * Determine the file implied
141 		 * for the write and generate
142 		 * code to make it the active file.
143 		 */
144 		if (op == O_MESSAGE) {
145 			/*
146 			 * For message, all that matters
147 			 * is that the filetype is
148 			 * a character file.
149 			 * Thus "output" will suit us fine.
150 			 */
151 			put(1, O_MESSAGE);
152 		} else if (argv != NIL && (al = argv[1])[0] != T_WEXP) {
153 			/*
154 			 * If there is a first argument which has
155 			 * no write widths, then it is potentially
156 			 * a file name.
157 			 */
158 			codeoff();
159 			ap = stkrval(argv[1], NIL , RREQ );
160 			codeon();
161 			if (ap == NIL)
162 				argv = argv[2];
163 			if (ap != NIL && ap->class == FILET) {
164 				/*
165 				 * Got "write(f, ...", make
166 				 * f the active file, and save
167 				 * it and its type for use in
168 				 * processing the rest of the
169 				 * arguments to write.
170 				 */
171 				file = argv[1];
172 				filetype = ap->type;
173 				stkrval(argv[1], NIL , RREQ );
174 				put(1, O_UNIT);
175 				/*
176 				 * Skip over the first argument
177 				 */
178 				argv = argv[2];
179 				argc--;
180 			} else
181 				/*
182 				 * Set up for writing on
183 				 * standard output.
184 				 */
185 				put(1, O_UNITOUT);
186 		} else
187 			put(1, O_UNITOUT);
188 		/*
189 		 * Loop and process each
190 		 * of the arguments.
191 		 */
192 		for (; argv != NIL; argv = argv[2]) {
193 			/*
194 			 * fmtspec indicates the type (CONstant or VARiable)
195 			 *	and number (none, WIDTH, and/or PRECision)
196 			 *	of the fields in the printf format for this
197 			 *	output variable.
198 			 * stkcnt is the number of longs pushed on the stack
199 			 * fmt is the format output indicator (D, E, F, O, X, S)
200 			 * fmtstart = 0 for leading blank; = 1 for no blank
201 			 */
202 			fmtspec = NIL;
203 			stkcnt = 0;
204 			fmt = 'D';
205 			fmtstart = 1;
206 			al = argv[1];
207 			if (al == NIL)
208 				continue;
209 			if (al[0] == T_WEXP)
210 				alv = al[1];
211 			else
212 				alv = al;
213 			if (alv == NIL)
214 				continue;
215 			codeoff();
216 			ap = stkrval(alv, NIL , RREQ );
217 			codeon();
218 			if (ap == NIL)
219 				continue;
220 			typ = classify(ap);
221 			if (al[0] == T_WEXP) {
222 				/*
223 				 * Handle width expressions.
224 				 * The basic game here is that width
225 				 * expressions get evaluated. If they
226 				 * are constant, the value is placed
227 				 * directly in the format string.
228 				 * Otherwise the value is pushed onto
229 				 * the stack and an indirection is
230 				 * put into the format string.
231 				 */
232 				if (al[3] == OCT)
233 					fmt = 'O';
234 				else if (al[3] == HEX)
235 					fmt = 'X';
236 				else if (al[3] != NIL) {
237 					/*
238 					 * Evaluate second format spec
239 					 */
240 					if ( constval(al[3])
241 					    && isa( con.ctype , "i" ) ) {
242 						fmtspec += CONPREC;
243 						prec = con.crval;
244 					} else {
245 						fmtspec += VARPREC;
246 					}
247 					fmt = 'f';
248 					switch ( typ ) {
249 					case TINT:
250 						if ( opt( 's' ) ) {
251 						    standard();
252 						    error("Writing %ss with two write widths is non-standard", clnames[typ]);
253 						}
254 						/* and fall through */
255 					case TDOUBLE:
256 						break;
257 					default:
258 						error("Cannot write %ss with two write widths", clnames[typ]);
259 						continue;
260 					}
261 				}
262 				/*
263 				 * Evaluate first format spec
264 				 */
265 				if (al[2] != NIL) {
266 					if ( constval(al[2])
267 					    && isa( con.ctype , "i" ) ) {
268 						fmtspec += CONWIDTH;
269 						field = con.crval;
270 					} else {
271 						fmtspec += VARWIDTH;
272 					}
273 				}
274 				if ((fmtspec & CONPREC) && prec < 0 ||
275 				    (fmtspec & CONWIDTH) && field < 0) {
276 					error("Negative widths are not allowed");
277 					continue;
278 				}
279 			}
280 			if (filetype != nl+T1CHAR) {
281 				if (fmt == 'O' || fmt == 'X') {
282 					error("Oct/hex allowed only on text files");
283 					continue;
284 				}
285 				if (fmtspec) {
286 					error("Write widths allowed only on text files");
287 					continue;
288 				}
289 				/*
290 				 * Generalized write, i.e.
291 				 * to a non-textfile.
292 				 */
293 				stkrval(file, NIL , RREQ );
294 				put(1, O_FNIL);
295 				/*
296 				 * file^ := ...
297 				 */
298 				ap = rvalue(argv[1], NIL);
299 				if (ap == NIL)
300 					continue;
301 				if (incompat(ap, filetype, argv[1])) {
302 					cerror("Type mismatch in write to non-text file");
303 					continue;
304 				}
305 				convert(ap, filetype);
306 				put(2, O_AS, width(filetype));
307 				/*
308 				 * put(file)
309 				 */
310 				put(1, O_PUT);
311 				continue;
312 			}
313 			/*
314 			 * Write to a textfile
315 			 *
316 			 * Evaluate the expression
317 			 * to be written.
318 			 */
319 			if (fmt == 'O' || fmt == 'X') {
320 				if (opt('s')) {
321 					standard();
322 					error("Oct and hex are non-standard");
323 				}
324 				if (typ == TSTR || typ == TDOUBLE) {
325 					error("Can't write %ss with oct/hex", clnames[typ]);
326 					continue;
327 				}
328 				if (typ == TCHAR || typ == TBOOL)
329 					typ = TINT;
330 			}
331 			/*
332 			 * Place the arguement on the stack. If there is
333 			 * no format specified by the programmer, implement
334 			 * the default.
335 			 */
336 			switch (typ) {
337 			case TINT:
338 				if (fmt != 'f') {
339 					ap = stkrval(alv, NIL , RREQ );
340 					stkcnt++;
341 				} else {
342 					ap = stkrval(alv, NIL , RREQ );
343 					put(1, O_ITOD);
344 					stkcnt += 2;
345 					typ = TDOUBLE;
346 					goto tdouble;
347 				}
348 				if (fmtspec == NIL) {
349 					if (fmt == 'D')
350 						field = 10;
351 					else if (fmt == 'X')
352 						field = 8;
353 					else if (fmt == 'O')
354 						field = 11;
355 					else
356 						panic("fmt1");
357 					fmtspec = CONWIDTH;
358 				}
359 				break;
360 			case TCHAR:
361 			     tchar:
362 				ap = stkrval(alv, NIL , RREQ );
363 				stkcnt++;
364 				fmt = 'c';
365 				break;
366 			case TSCAL:
367 				warning();
368 				if (opt('s')) {
369 					standard();
370 				}
371 				error("Writing scalars to text files is non-standard");
372 			case TBOOL:
373 				stkrval(alv, NIL , RREQ );
374 				put(2, O_NAM, listnames(ap));
375 				stkcnt++;
376 				fmt = 's';
377 				break;
378 			case TDOUBLE:
379 				ap = stkrval(alv, TDOUBLE , RREQ );
380 				stkcnt += 2;
381 			     tdouble:
382 				switch (fmtspec) {
383 				case NIL:
384 					field = 21;
385 					prec = 14;
386 					fmt = 'E';
387 					fmtspec = CONWIDTH + CONPREC;
388 					break;
389 				case CONWIDTH:
390 					if (--field < 1)
391 						field = 1;
392 					prec = field - 7;
393 					if (prec < 1)
394 						prec = 1;
395 					fmtspec += CONPREC;
396 					fmt = 'E';
397 					break;
398 				case CONWIDTH + CONPREC:
399 				case CONWIDTH + VARPREC:
400 					if (--field < 1)
401 						field = 1;
402 				}
403 				format[0] = ' ';
404 				fmtstart = 0;
405 				break;
406 			case TSTR:
407 				constval( alv );
408 				switch ( classify( con.ctype ) ) {
409 				    case TCHAR:
410 					typ = TCHAR;
411 					goto tchar;
412 				    case TSTR:
413 					strptr = con.cpval;
414 					for (strnglen = 0;  *strptr++;  strnglen++) /* void */;
415 					strptr = con.cpval;
416 					break;
417 				    default:
418 					strnglen = width(ap);
419 					break;
420 				}
421 				fmt = 's';
422 				strfmt = fmtspec;
423 				if (fmtspec == NIL) {
424 					fmtspec = SKIP;
425 					break;
426 				}
427 				if (fmtspec & CONWIDTH) {
428 					if (field <= strnglen) {
429 						fmtspec = SKIP;
430 						break;
431 					} else
432 						field -= strnglen;
433 				}
434 				/*
435 				 * push string to implement leading blank padding
436 				 */
437 				put(2, O_LVCON, 2);
438 				putstr("", 0);
439 				stkcnt++;
440 				break;
441 			default:
442 				error("Can't write %ss to a text file", clnames[typ]);
443 				continue;
444 			}
445 			/*
446 			 * If there is a variable precision, evaluate it onto
447 			 * the stack
448 			 */
449 			if (fmtspec & VARPREC) {
450 				ap = stkrval(al[3], NIL , RREQ );
451 				if (ap == NIL)
452 					continue;
453 				if (isnta(ap,"i")) {
454 					error("Second write width must be integer, not %s", nameof(ap));
455 					continue;
456 				}
457 				if ( opt( 't' ) ) {
458 				    put(3, O_MAX, 0, 0);
459 				}
460 				stkcnt++;
461 			}
462 			/*
463 			 * If there is a variable width, evaluate it onto
464 			 * the stack
465 			 */
466 			if (fmtspec & VARWIDTH) {
467 				if ( ( typ == TDOUBLE && fmtspec == VARWIDTH )
468 				    || typ == TSTR ) {
469 					i = sizes[cbn].om_off -= sizeof(int);
470 					if (i < sizes[cbn].om_max)
471 						sizes[cbn].om_max = i;
472 					put(2, O_LV | cbn << 8 + INDX, i);
473 				}
474 				ap = stkrval(al[2], NIL , RREQ );
475 				if (ap == NIL)
476 					continue;
477 				if (isnta(ap,"i")) {
478 					error("First write width must be integer, not %s", nameof(ap));
479 					continue;
480 				}
481 				stkcnt++;
482 				/*
483 				 * Perform special processing on widths based
484 				 * on data type
485 				 */
486 				switch (typ) {
487 				case TDOUBLE:
488 					if (fmtspec == VARWIDTH) {
489 						fmt = 'E';
490 						put(1, O_AS4);
491 						put(2, O_RV4 | cbn << 8 + INDX, i);
492 						put(3, O_MAX, 8, 1);
493 						put(2, O_RV4 | cbn << 8 + INDX, i);
494 						stkcnt++;
495 						fmtspec += VARPREC;
496 					}
497 					put(3, O_MAX, 1, 1);
498 					break;
499 				case TSTR:
500 					put(1, O_AS4);
501 					put(2, O_RV4 | cbn << 8 + INDX, i);
502 					put(3, O_MAX, strnglen, 0);
503 					break;
504 				default:
505 					if ( opt( 't' ) ) {
506 					    put(3, O_MAX, 0, 0);
507 					}
508 					break;
509 				}
510 			}
511 			/*
512 			 * Generate the format string
513 			 */
514 			switch (fmtspec) {
515 			default:
516 				panic("fmt2");
517 			case NIL:
518 				if (fmt == 'c')
519 					put(1, O_WRITEC);
520 				else  {
521 					sprintf(&format[1], "%%%c", fmt);
522 					goto fmtgen;
523 				}
524 			case SKIP:
525 				break;
526 			case CONWIDTH:
527 				sprintf(&format[1], "%%%1D%c", field, fmt);
528 				goto fmtgen;
529 			case VARWIDTH:
530 				sprintf(&format[1], "%%*%c", fmt);
531 				goto fmtgen;
532 			case CONWIDTH + CONPREC:
533 				sprintf(&format[1], "%%%1D.%1D%c", field, prec, fmt);
534 				goto fmtgen;
535 			case CONWIDTH + VARPREC:
536 				sprintf(&format[1], "%%%1D.*%c", field, fmt);
537 				goto fmtgen;
538 			case VARWIDTH + CONPREC:
539 				sprintf(&format[1], "%%*.%1D%c", prec, fmt);
540 				goto fmtgen;
541 			case VARWIDTH + VARPREC:
542 				sprintf(&format[1], "%%*.*%c", fmt);
543 			fmtgen:
544 				fmtlen = lenstr(&format[fmtstart], 0);
545 				put(2, O_LVCON, fmtlen);
546 				putstr(&format[fmtstart], 0);
547 				put(1, O_FILE);
548 				stkcnt += 2;
549 				put(2, O_WRITEF, stkcnt);
550 			}
551 			/*
552 			 * Write the string after its blank padding
553 			 */
554 			if (typ == TSTR) {
555 				put(1, O_FILE);
556 				put(2, O_CON24, 1);
557 				if (strfmt & VARWIDTH) {
558 					put(2, O_RV4 | cbn << 8 + INDX , i );
559 					put(2, O_MIN, strnglen);
560 				} else {
561 					if ((fmtspec & SKIP) &&
562 					   (strfmt & CONWIDTH)) {
563 						strnglen = field;
564 					}
565 					put(2, O_CON24, strnglen);
566 				}
567 				ap = stkrval(alv, NIL , RREQ );
568 				put(1, O_WRITES);
569 			}
570 		}
571 		/*
572 		 * Done with arguments.
573 		 * Handle writeln and
574 		 * insufficent number of args.
575 		 */
576 		switch (p->value[0] &~ NSTAND) {
577 			case O_WRITEF:
578 				if (argc == 0)
579 					error("Write requires an argument");
580 				break;
581 			case O_MESSAGE:
582 				if (argc == 0)
583 					error("Message requires an argument");
584 			case O_WRITLN:
585 				if (filetype != nl+T1CHAR)
586 					error("Can't 'writeln' a non text file");
587 				put(1, O_WRITLN);
588 				break;
589 		}
590 		return;
591 
592 	case O_READ4:
593 	case O_READLN:
594 		/*
595 		 * Set up default
596 		 * file "input".
597 		 */
598 		file = NIL;
599 		filetype = nl+T1CHAR;
600 		/*
601 		 * Determine the file implied
602 		 * for the read and generate
603 		 * code to make it the active file.
604 		 */
605 		if (argv != NIL) {
606 			codeoff();
607 			ap = stkrval(argv[1], NIL , RREQ );
608 			codeon();
609 			if (ap == NIL)
610 				argv = argv[2];
611 			if (ap != NIL && ap->class == FILET) {
612 				/*
613 				 * Got "read(f, ...", make
614 				 * f the active file, and save
615 				 * it and its type for use in
616 				 * processing the rest of the
617 				 * arguments to read.
618 				 */
619 				file = argv[1];
620 				filetype = ap->type;
621 				stkrval(argv[1], NIL , RREQ );
622 				put(1, O_UNIT);
623 				argv = argv[2];
624 				argc--;
625 			} else {
626 				/*
627 				 * Default is read from
628 				 * standard input.
629 				 */
630 				put(1, O_UNITINP);
631 				input->nl_flags |= NUSED;
632 			}
633 		} else {
634 			put(1, O_UNITINP);
635 			input->nl_flags |= NUSED;
636 		}
637 		/*
638 		 * Loop and process each
639 		 * of the arguments.
640 		 */
641 		for (; argv != NIL; argv = argv[2]) {
642 			/*
643 			 * Get the address of the target
644 			 * on the stack.
645 			 */
646 			al = argv[1];
647 			if (al == NIL)
648 				continue;
649 			if (al[0] != T_VAR) {
650 				error("Arguments to %s must be variables, not expressions", p->symbol);
651 				continue;
652 			}
653 			ap = stklval(al, MOD|ASGN|NOUSE);
654 			if (ap == NIL)
655 				continue;
656 			if (filetype != nl+T1CHAR) {
657 				/*
658 				 * Generalized read, i.e.
659 				 * from a non-textfile.
660 				 */
661 				if (incompat(filetype, ap, argv[1] )) {
662 					error("Type mismatch in read from non-text file");
663 					continue;
664 				}
665 				/*
666 				 * var := file ^;
667 				 */
668 				if (file != NIL)
669 					stkrval(file, NIL , RREQ );
670 				else /* Magic */
671 					put(2, O_RV2, input->value[0]);
672 				put(1, O_FNIL);
673 				put(2, O_IND, width(filetype));
674 				convert(filetype, ap);
675 				if (isa(ap, "bsci"))
676 					rangechk(ap, ap);
677 				put(2, O_AS, width(ap));
678 				/*
679 				 * get(file);
680 				 */
681 				put(1, O_GET);
682 				continue;
683 			}
684 			typ = classify(ap);
685 			op = rdops(typ);
686 			if (op == NIL) {
687 				error("Can't read %ss from a text file", clnames[typ]);
688 				continue;
689 			}
690 			if (op != O_READE)
691 				put(1, op);
692 			else {
693 				put(2, op, listnames(ap));
694 				warning();
695 				if (opt('s')) {
696 					standard();
697 				}
698 				error("Reading scalars from text files is non-standard");
699 			}
700 			/*
701 			 * Data read is on the stack.
702 			 * Assign it.
703 			 */
704 			if (op != O_READ8 && op != O_READE)
705 				rangechk(ap, op == O_READC ? ap : nl+T4INT);
706 			gen(O_AS2, O_AS2, width(ap),
707 				op == O_READ8 ? 8 : op == O_READ4 ? 4 : 2);
708 		}
709 		/*
710 		 * Done with arguments.
711 		 * Handle readln and
712 		 * insufficient number of args.
713 		 */
714 		if (p->value[0] == O_READLN) {
715 			if (filetype != nl+T1CHAR)
716 				error("Can't 'readln' a non text file");
717 			put(1, O_READLN);
718 		}
719 		else if (argc == 0)
720 			error("read requires an argument");
721 		return;
722 
723 	case O_GET:
724 	case O_PUT:
725 		if (argc != 1) {
726 			error("%s expects one argument", p->symbol);
727 			return;
728 		}
729 		ap = stkrval(argv[1], NIL , RREQ );
730 		if (ap == NIL)
731 			return;
732 		if (ap->class != FILET) {
733 			error("Argument to %s must be a file, not %s", p->symbol, nameof(ap));
734 			return;
735 		}
736 		put(1, O_UNIT);
737 		put(1, op);
738 		return;
739 
740 	case O_RESET:
741 	case O_REWRITE:
742 		if (argc == 0 || argc > 2) {
743 			error("%s expects one or two arguments", p->symbol);
744 			return;
745 		}
746 		if (opt('s') && argc == 2) {
747 			standard();
748 			error("Two argument forms of reset and rewrite are non-standard");
749 		}
750 		ap = stklval(argv[1], MOD|NOUSE);
751 		if (ap == NIL)
752 			return;
753 		if (ap->class != FILET) {
754 			error("First argument to %s must be a file, not %s", p->symbol, nameof(ap));
755 			return;
756 		}
757 		if (argc == 2) {
758 			/*
759 			 * Optional second argument
760 			 * is a string name of a
761 			 * UNIX (R) file to be associated.
762 			 */
763 			al = argv[2];
764 			al = stkrval(al[1], NOFLAGS , RREQ );
765 			if (al == NIL)
766 				return;
767 			if (classify(al) != TSTR) {
768 				error("Second argument to %s must be a string, not %s", p->symbol, nameof(al));
769 				return;
770 			}
771 			strnglen = width(al);
772 		} else {
773 			put(2, O_CON24, NIL);
774 			strnglen = 0;
775 		}
776 		put(2, O_CON24, strnglen);
777 		put(2, O_CON24, text(ap) ? 0: width(ap->type));
778 		put(1, op);
779 		return;
780 
781 	case O_NEW:
782 	case O_DISPOSE:
783 		if (argc == 0) {
784 			error("%s expects at least one argument", p->symbol);
785 			return;
786 		}
787 		ap = stklval(argv[1], op == O_NEW ? ( MOD | NOUSE ) : MOD );
788 		if (ap == NIL)
789 			return;
790 		if (ap->class != PTR) {
791 			error("(First) argument to %s must be a pointer, not %s", p->symbol, nameof(ap));
792 			return;
793 		}
794 		ap = ap->type;
795 		if (ap == NIL)
796 			return;
797 		argv = argv[2];
798 		if (argv != NIL) {
799 			if (ap->class != RECORD) {
800 				error("Record required when specifying variant tags");
801 				return;
802 			}
803 			for (; argv != NIL; argv = argv[2]) {
804 				if (ap->ptr[NL_VARNT] == NIL) {
805 					error("Too many tag fields");
806 					return;
807 				}
808 				if (!isconst(argv[1])) {
809 					error("Second and successive arguments to %s must be constants", p->symbol);
810 					return;
811 				}
812 				gconst(argv[1]);
813 				if (con.ctype == NIL)
814 					return;
815 				if (incompat(con.ctype, (ap->ptr[NL_TAG])->type , NIL )) {
816 					cerror("Specified tag constant type clashed with variant case selector type");
817 					return;
818 				}
819 				for (ap = ap->ptr[NL_VARNT]; ap != NIL; ap = ap->chain)
820 					if (ap->range[0] == con.crval)
821 						break;
822 				if (ap == NIL) {
823 					error("No variant case label value equals specified constant value");
824 					return;
825 				}
826 				ap = ap->ptr[NL_VTOREC];
827 			}
828 		}
829 		put(2, op, width(ap));
830 		return;
831 
832 	case O_DATE:
833 	case O_TIME:
834 		if (argc != 1) {
835 			error("%s expects one argument", p->symbol);
836 			return;
837 		}
838 		ap = stklval(argv[1], MOD|NOUSE);
839 		if (ap == NIL)
840 			return;
841 		if (classify(ap) != TSTR || width(ap) != 10) {
842 			error("Argument to %s must be a alfa, not %s", p->symbol, nameof(ap));
843 			return;
844 		}
845 		put(1, op);
846 		return;
847 
848 	case O_HALT:
849 		if (argc != 0) {
850 			error("halt takes no arguments");
851 			return;
852 		}
853 		put(1, op);
854 		noreach = 1;
855 		return;
856 
857 	case O_ARGV:
858 		if (argc != 2) {
859 			error("argv takes two arguments");
860 			return;
861 		}
862 		ap = stkrval(argv[1], NIL , RREQ );
863 		if (ap == NIL)
864 			return;
865 		if (isnta(ap, "i")) {
866 			error("argv's first argument must be an integer, not %s", nameof(ap));
867 			return;
868 		}
869 		al = argv[2];
870 		ap = stklval(al[1], MOD|NOUSE);
871 		if (ap == NIL)
872 			return;
873 		if (classify(ap) != TSTR) {
874 			error("argv's second argument must be a string, not %s", nameof(ap));
875 			return;
876 		}
877 		put(2, op, width(ap));
878 		return;
879 
880 	case O_STLIM:
881 		if (argc != 1) {
882 			error("stlimit requires one argument");
883 			return;
884 		}
885 		ap = stkrval(argv[1], NIL , RREQ );
886 		if (ap == NIL)
887 			return;
888 		if (isnta(ap, "i")) {
889 			error("stlimit's argument must be an integer, not %s", nameof(ap));
890 			return;
891 		}
892 		if (width(ap) != 4)
893 			put(1, O_STOI);
894 		put(1, op);
895 		return;
896 
897 	case O_REMOVE:
898 		if (argc != 1) {
899 			error("remove expects one argument");
900 			return;
901 		}
902 		ap = stkrval(argv[1], NOFLAGS , RREQ );
903 		if (ap == NIL)
904 			return;
905 		if (classify(ap) != TSTR) {
906 			error("remove's argument must be a string, not %s", nameof(ap));
907 			return;
908 		}
909 		put(2, O_CON24, width(ap));
910 		put(1, op);
911 		return;
912 
913 	case O_LLIMIT:
914 		if (argc != 2) {
915 			error("linelimit expects two arguments");
916 			return;
917 		}
918 		ap = stklval(argv[1], NOFLAGS|NOUSE);
919 		if (ap == NIL)
920 			return;
921 		if (!text(ap)) {
922 			error("linelimit's first argument must be a text file, not %s", nameof(ap));
923 			return;
924 		}
925 		al = argv[2];
926 		ap = stkrval(al[1], NIL , RREQ );
927 		if (ap == NIL)
928 			return;
929 		if (isnta(ap, "i")) {
930 			error("linelimit's second argument must be an integer, not %s", nameof(ap));
931 			return;
932 		}
933 		put(1, op);
934 		return;
935 	case O_PAGE:
936 		if (argc != 1) {
937 			error("page expects one argument");
938 			return;
939 		}
940 		ap = stkrval(argv[1], NIL , RREQ );
941 		if (ap == NIL)
942 			return;
943 		if (!text(ap)) {
944 			error("Argument to page must be a text file, not %s", nameof(ap));
945 			return;
946 		}
947 		put(1, O_UNIT);
948 		put(1, op);
949 		return;
950 
951 	case O_PACK:
952 		if (argc != 3) {
953 			error("pack expects three arguments");
954 			return;
955 		}
956 		pu = "pack(a,i,z)";
957 		pua = (al = argv)[1];
958 		pui = (al = al[2])[1];
959 		puz = (al = al[2])[1];
960 		goto packunp;
961 	case O_UNPACK:
962 		if (argc != 3) {
963 			error("unpack expects three arguments");
964 			return;
965 		}
966 		pu = "unpack(z,a,i)";
967 		puz = (al = argv)[1];
968 		pua = (al = al[2])[1];
969 		pui = (al = al[2])[1];
970 packunp:
971 		ap = stkrval((int *) pui, NLNIL , RREQ );
972 		if (ap == NIL)
973 			return;
974 		ap = stklval(pua, op == O_PACK ? NOFLAGS : MOD|NOUSE);
975 		if (ap == NIL)
976 			return;
977 		if (ap->class != ARRAY) {
978 			error("%s requires a to be an unpacked array, not %s", pu, nameof(ap));
979 			return;
980 		}
981 		al = (struct nl *) stklval(puz, op == O_UNPACK ? NOFLAGS : MOD|NOUSE);
982 		if (al->class != ARRAY) {
983 			error("%s requires z to be a packed array, not %s", pu, nameof(ap));
984 			return;
985 		}
986 		if (al->type == NIL || ap->type == NIL)
987 			return;
988 		if (al->type != ap->type) {
989 			error("%s requires a and z to be arrays of the same type", pu, nameof(ap));
990 			return;
991 		}
992 		k = width(al);
993 		itemwidth = width(ap->type);
994 		ap = ap->chain;
995 		al = al->chain;
996 		if (ap->chain != NIL || al->chain != NIL) {
997 			error("%s requires a and z to be single dimension arrays", pu);
998 			return;
999 		}
1000 		if (ap == NIL || al == NIL)
1001 			return;
1002 		/*
1003 		 * al is the range for z i.e. u..v
1004 		 * ap is the range for a i.e. m..n
1005 		 * i will be n-m+1
1006 		 * j will be v-u+1
1007 		 */
1008 		i = ap->range[1] - ap->range[0] + 1;
1009 		j = al->range[1] - al->range[0] + 1;
1010 		if (i < j) {
1011 			error("%s cannot have more elements in a (%d) than in z (%d)", pu, j, i);
1012 			return;
1013 		}
1014 		/*
1015 		 * get n-m-(v-u) and m for the interpreter
1016 		 */
1017 		i -= j;
1018 		j = ap->range[0];
1019 		put(5, op, itemwidth , j, i, k);
1020 		return;
1021 	case 0:
1022 		error("%s is an unimplemented 6400 extension", p->symbol);
1023 		return;
1024 
1025 	default:
1026 		panic("proc case");
1027 	}
1028 }
1029 #endif OBJ
1030