xref: /illumos-gate/usr/src/common/ficl/vm.c (revision 48edc7cf07b5dccc3ad84bf2dafe4150bd666d60)
1 /*
2  * v m . c
3  * Forth Inspired Command Language - virtual machine methods
4  * Author: John Sadler (john_sadler@alum.mit.edu)
5  * Created: 19 July 1997
6  * $Id: vm.c,v 1.17 2010/09/13 18:43:04 asau Exp $
7  */
8 /*
9  * This file implements the virtual machine of Ficl. Each virtual
10  * machine retains the state of an interpreter. A virtual machine
11  * owns a pair of stacks for parameters and return addresses, as
12  * well as a pile of state variables and the two dedicated registers
13  * of the interpreter.
14  */
15 /*
16  * Copyright (c) 1997-2001 John Sadler (john_sadler@alum.mit.edu)
17  * All rights reserved.
18  *
19  * Get the latest Ficl release at http://ficl.sourceforge.net
20  *
21  * I am interested in hearing from anyone who uses Ficl. If you have
22  * a problem, a success story, a defect, an enhancement request, or
23  * if you would like to contribute to the Ficl release, please
24  * contact me by email at the address above.
25  *
26  * L I C E N S E  and  D I S C L A I M E R
27  *
28  * Redistribution and use in source and binary forms, with or without
29  * modification, are permitted provided that the following conditions
30  * are met:
31  * 1. Redistributions of source code must retain the above copyright
32  *    notice, this list of conditions and the following disclaimer.
33  * 2. Redistributions in binary form must reproduce the above copyright
34  *    notice, this list of conditions and the following disclaimer in the
35  *    documentation and/or other materials provided with the distribution.
36  *
37  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
38  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
39  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
40  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
41  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
42  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
43  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
44  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
45  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
46  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
47  * SUCH DAMAGE.
48  */
49 
50 #include "ficl.h"
51 
52 #if FICL_ROBUST >= 2
53 #define	FICL_VM_CHECK(vm)	\
54 	FICL_VM_ASSERT(vm, (*(vm->ip - 1)) == vm->runningWord)
55 #else
56 #define	FICL_VM_CHECK(vm)
57 #endif
58 
59 /*
60  * v m B r a n c h R e l a t i v e
61  */
62 void
63 ficlVmBranchRelative(ficlVm *vm, int offset)
64 {
65 	vm->ip += offset;
66 }
67 
68 /*
69  * v m C r e a t e
70  * Creates a virtual machine either from scratch (if vm is NULL on entry)
71  * or by resizing and reinitializing an existing VM to the specified stack
72  * sizes.
73  */
74 ficlVm *
75 ficlVmCreate(ficlVm *vm, unsigned nPStack, unsigned nRStack)
76 {
77 	if (vm == NULL) {
78 		vm = (ficlVm *)ficlMalloc(sizeof (ficlVm));
79 		FICL_ASSERT(NULL, vm);
80 		memset(vm, 0, sizeof (ficlVm));
81 	}
82 
83 	if (vm->dataStack)
84 		ficlStackDestroy(vm->dataStack);
85 	vm->dataStack = ficlStackCreate(vm, "data", nPStack);
86 
87 	if (vm->returnStack)
88 		ficlStackDestroy(vm->returnStack);
89 	vm->returnStack = ficlStackCreate(vm, "return", nRStack);
90 
91 #if FICL_WANT_FLOAT
92 	if (vm->floatStack)
93 		ficlStackDestroy(vm->floatStack);
94 	vm->floatStack = ficlStackCreate(vm, "float", nPStack);
95 #endif
96 
97 	ficlVmReset(vm);
98 	return (vm);
99 }
100 
101 /*
102  * v m D e l e t e
103  * Free all memory allocated to the specified VM and its subordinate
104  * structures.
105  */
106 void
107 ficlVmDestroy(ficlVm *vm)
108 {
109 	if (vm) {
110 		ficlFree(vm->dataStack);
111 		ficlFree(vm->returnStack);
112 #if FICL_WANT_FLOAT
113 		ficlFree(vm->floatStack);
114 #endif
115 		ficlFree(vm);
116 	}
117 }
118 
119 /*
120  * v m E x e c u t e
121  * Sets up the specified word to be run by the inner interpreter.
122  * Executes the word's code part immediately, but in the case of
123  * colon definition, the definition itself needs the inner interpreter
124  * to complete. This does not happen until control reaches ficlExec
125  */
126 void
127 ficlVmExecuteWord(ficlVm *vm, ficlWord *pWord)
128 {
129 	ficlVmInnerLoop(vm, pWord);
130 }
131 
132 static void
133 ficlVmOptimizeJumpToJump(ficlVm *vm, ficlIp ip)
134 {
135 	ficlIp destination;
136 	switch ((ficlInstruction)(*ip)) {
137 	case ficlInstructionBranchParenWithCheck:
138 		*ip = (ficlWord *)ficlInstructionBranchParen;
139 		goto RUNTIME_FIXUP;
140 
141 	case ficlInstructionBranch0ParenWithCheck:
142 		*ip = (ficlWord *)ficlInstructionBranch0Paren;
143 RUNTIME_FIXUP:
144 		ip++;
145 		destination = ip + *(ficlInteger *)ip;
146 		switch ((ficlInstruction)*destination) {
147 		case ficlInstructionBranchParenWithCheck:
148 			/* preoptimize where we're jumping to */
149 			ficlVmOptimizeJumpToJump(vm, destination);
150 		case ficlInstructionBranchParen:
151 			destination++;
152 			destination += *(ficlInteger *)destination;
153 			*ip = (ficlWord *)(destination - ip);
154 		break;
155 		}
156 	}
157 }
158 
159 /*
160  * v m I n n e r L o o p
161  * the mysterious inner interpreter...
162  * This loop is the address interpreter that makes colon definitions
163  * work. Upon entry, it assumes that the IP points to an entry in
164  * a definition (the body of a colon word). It runs one word at a time
165  * until something does vmThrow. The catcher for this is expected to exist
166  * in the calling code.
167  * vmThrow gets you out of this loop with a longjmp()
168  */
169 
170 #if FICL_ROBUST <= 1
171 	/* turn off stack checking for primitives */
172 #define	_CHECK_STACK(stack, top, pop, push)
173 #else
174 
175 #define	_CHECK_STACK(stack, top, pop, push)	\
176 	ficlStackCheckNospill(stack, top, pop, push)
177 
178 FICL_PLATFORM_INLINE void
179 ficlStackCheckNospill(ficlStack *stack, ficlCell *top, int popCells,
180     int pushCells)
181 {
182 	/*
183 	 * Why save and restore stack->top?
184 	 * So the simple act of stack checking doesn't force a "register" spill,
185 	 * which might mask bugs (places where we needed to spill but didn't).
186 	 * --lch
187 	 */
188 	ficlCell *oldTop = stack->top;
189 	stack->top = top;
190 	ficlStackCheck(stack, popCells, pushCells);
191 	stack->top = oldTop;
192 }
193 
194 #endif /* FICL_ROBUST <= 1 */
195 
196 #define	CHECK_STACK(pop, push)		\
197 	_CHECK_STACK(vm->dataStack, dataTop, pop, push)
198 #define	CHECK_FLOAT_STACK(pop, push)	\
199 	_CHECK_STACK(vm->floatStack, floatTop, pop, push)
200 #define	CHECK_RETURN_STACK(pop, push)	\
201 	_CHECK_STACK(vm->returnStack, returnTop, pop, push)
202 
203 #if FICL_WANT_FLOAT
204 #define	FLOAT_LOCAL_VARIABLE_SPILL	\
205 	vm->floatStack->top = floatTop;
206 #define	FLOAT_LOCAL_VARIABLE_REFILL	\
207 	floatTop = vm->floatStack->top;
208 #else
209 #define	FLOAT_LOCAL_VARIABLE_SPILL
210 #define	FLOAT_LOCAL_VARIABLE_REFILL
211 #endif  /* FICL_WANT_FLOAT */
212 
213 #if FICL_WANT_LOCALS
214 #define	LOCALS_LOCAL_VARIABLE_SPILL	\
215 	vm->returnStack->frame = frame;
216 #define	LOCALS_LOCAL_VARIABLE_REFILL \
217 	frame = vm->returnStack->frame;
218 #else
219 #define	LOCALS_LOCAL_VARIABLE_SPILL
220 #define	LOCALS_LOCAL_VARIABLE_REFILL
221 #endif  /* FICL_WANT_FLOAT */
222 
223 #define	LOCAL_VARIABLE_SPILL	\
224 		vm->ip = (ficlIp)ip;	\
225 		vm->dataStack->top = dataTop;	\
226 		vm->returnStack->top = returnTop;	\
227 		FLOAT_LOCAL_VARIABLE_SPILL \
228 		LOCALS_LOCAL_VARIABLE_SPILL
229 
230 #define	LOCAL_VARIABLE_REFILL	\
231 		ip = (ficlInstruction *)vm->ip; \
232 		dataTop = vm->dataStack->top;	\
233 		returnTop = vm->returnStack->top;	\
234 		FLOAT_LOCAL_VARIABLE_REFILL	\
235 		LOCALS_LOCAL_VARIABLE_REFILL
236 
237 void
238 ficlVmInnerLoop(ficlVm *vm, ficlWord *fw)
239 {
240 	register ficlInstruction *ip;
241 	register ficlCell *dataTop;
242 	register ficlCell *returnTop;
243 #if FICL_WANT_FLOAT
244 	register ficlCell *floatTop;
245 	ficlFloat f;
246 #endif  /* FICL_WANT_FLOAT */
247 #if FICL_WANT_LOCALS
248 	register ficlCell *frame;
249 #endif  /* FICL_WANT_LOCALS */
250 	jmp_buf *oldExceptionHandler;
251 	jmp_buf exceptionHandler;
252 	int except;
253 	int once;
254 	int count;
255 	ficlInstruction instruction;
256 	ficlInteger i;
257 	ficlUnsigned u;
258 	ficlCell c;
259 	ficlCountedString *s;
260 	ficlCell *cell;
261 	char *cp;
262 
263 	once = (fw != NULL);
264 	if (once)
265 		count = 1;
266 
267 	oldExceptionHandler = vm->exceptionHandler;
268 	/* This has to come before the setjmp! */
269 	vm->exceptionHandler = &exceptionHandler;
270 	except = setjmp(exceptionHandler);
271 
272 	LOCAL_VARIABLE_REFILL;
273 
274 	if (except) {
275 		LOCAL_VARIABLE_SPILL;
276 		vm->exceptionHandler = oldExceptionHandler;
277 		ficlVmThrow(vm, except);
278 	}
279 
280 	for (;;) {
281 		if (once) {
282 			if (!count--)
283 				break;
284 			instruction = (ficlInstruction)((void *)fw);
285 		} else {
286 			instruction = *ip++;
287 			fw = (ficlWord *)instruction;
288 		}
289 
290 AGAIN:
291 		switch (instruction) {
292 		case ficlInstructionInvalid:
293 			ficlVmThrowError(vm,
294 			    "Error: NULL instruction executed!");
295 		return;
296 
297 		case ficlInstruction1:
298 		case ficlInstruction2:
299 		case ficlInstruction3:
300 		case ficlInstruction4:
301 		case ficlInstruction5:
302 		case ficlInstruction6:
303 		case ficlInstruction7:
304 		case ficlInstruction8:
305 		case ficlInstruction9:
306 		case ficlInstruction10:
307 		case ficlInstruction11:
308 		case ficlInstruction12:
309 		case ficlInstruction13:
310 		case ficlInstruction14:
311 		case ficlInstruction15:
312 		case ficlInstruction16:
313 			CHECK_STACK(0, 1);
314 			(++dataTop)->i = instruction;
315 		continue;
316 
317 		case ficlInstruction0:
318 		case ficlInstructionNeg1:
319 		case ficlInstructionNeg2:
320 		case ficlInstructionNeg3:
321 		case ficlInstructionNeg4:
322 		case ficlInstructionNeg5:
323 		case ficlInstructionNeg6:
324 		case ficlInstructionNeg7:
325 		case ficlInstructionNeg8:
326 		case ficlInstructionNeg9:
327 		case ficlInstructionNeg10:
328 		case ficlInstructionNeg11:
329 		case ficlInstructionNeg12:
330 		case ficlInstructionNeg13:
331 		case ficlInstructionNeg14:
332 		case ficlInstructionNeg15:
333 		case ficlInstructionNeg16:
334 			CHECK_STACK(0, 1);
335 			(++dataTop)->i = ficlInstruction0 - instruction;
336 		continue;
337 
338 		/*
339 		 * stringlit: Fetch the count from the dictionary, then push
340 		 * the address and count on the stack. Finally, update ip to
341 		 * point to the first aligned address after the string text.
342 		 */
343 		case ficlInstructionStringLiteralParen: {
344 			ficlUnsigned8 length;
345 			CHECK_STACK(0, 2);
346 
347 			s = (ficlCountedString *)(ip);
348 			length = s->length;
349 			cp = s->text;
350 			(++dataTop)->p = cp;
351 			(++dataTop)->i = length;
352 
353 			cp += length + 1;
354 			cp = ficlAlignPointer(cp);
355 			ip = (void *)cp;
356 		continue;
357 		}
358 
359 		case ficlInstructionCStringLiteralParen:
360 			CHECK_STACK(0, 1);
361 
362 			s = (ficlCountedString *)(ip);
363 			cp = s->text + s->length + 1;
364 			cp = ficlAlignPointer(cp);
365 			ip = (void *)cp;
366 			(++dataTop)->p = s;
367 		continue;
368 
369 #if FICL_WANT_OPTIMIZE == FICL_OPTIMIZE_FOR_SIZE
370 #if FICL_WANT_FLOAT
371 FLOAT_PUSH_CELL_POINTER_DOUBLE_MINIPROC:
372 			*++floatTop = cell[1];
373 			/* intentional fall-through */
374 FLOAT_PUSH_CELL_POINTER_MINIPROC:
375 			*++floatTop = cell[0];
376 		continue;
377 
378 FLOAT_POP_CELL_POINTER_MINIPROC:
379 			cell[0] = *floatTop--;
380 		continue;
381 
382 FLOAT_POP_CELL_POINTER_DOUBLE_MINIPROC:
383 			cell[0] = *floatTop--;
384 			cell[1] = *floatTop--;
385 		continue;
386 
387 #define	FLOAT_PUSH_CELL_POINTER_DOUBLE(cp)	\
388 	cell = (cp); goto FLOAT_PUSH_CELL_POINTER_DOUBLE_MINIPROC
389 #define	FLOAT_PUSH_CELL_POINTER(cp)		\
390 	cell = (cp); goto FLOAT_PUSH_CELL_POINTER_MINIPROC
391 #define	FLOAT_POP_CELL_POINTER_DOUBLE(cp)	\
392 	cell = (cp); goto FLOAT_POP_CELL_POINTER_DOUBLE_MINIPROC
393 #define	FLOAT_POP_CELL_POINTER(cp)		\
394 	cell = (cp); goto FLOAT_POP_CELL_POINTER_MINIPROC
395 #endif /* FICL_WANT_FLOAT */
396 
397 		/*
398 		 * Think of these as little mini-procedures.
399 		 * --lch
400 		 */
401 PUSH_CELL_POINTER_DOUBLE_MINIPROC:
402 			*++dataTop = cell[1];
403 			/* intentional fall-through */
404 PUSH_CELL_POINTER_MINIPROC:
405 			*++dataTop = cell[0];
406 		continue;
407 
408 POP_CELL_POINTER_MINIPROC:
409 			cell[0] = *dataTop--;
410 		continue;
411 POP_CELL_POINTER_DOUBLE_MINIPROC:
412 			cell[0] = *dataTop--;
413 			cell[1] = *dataTop--;
414 		continue;
415 
416 #define	PUSH_CELL_POINTER_DOUBLE(cp)	\
417 	cell = (cp); goto PUSH_CELL_POINTER_DOUBLE_MINIPROC
418 #define	PUSH_CELL_POINTER(cp)		\
419 	cell = (cp); goto PUSH_CELL_POINTER_MINIPROC
420 #define	POP_CELL_POINTER_DOUBLE(cp)	\
421 	cell = (cp); goto POP_CELL_POINTER_DOUBLE_MINIPROC
422 #define	POP_CELL_POINTER(cp)		\
423 	cell = (cp); goto POP_CELL_POINTER_MINIPROC
424 
425 BRANCH_MINIPROC:
426 			ip += *(ficlInteger *)ip;
427 		continue;
428 
429 #define	BRANCH()	goto BRANCH_MINIPROC
430 
431 EXIT_FUNCTION_MINIPROC:
432 			ip = (ficlInstruction *)((returnTop--)->p);
433 				continue;
434 
435 #define	EXIT_FUNCTION	goto EXIT_FUNCTION_MINIPROC
436 
437 #else /* FICL_WANT_SIZE */
438 
439 #if FICL_WANT_FLOAT
440 #define	FLOAT_PUSH_CELL_POINTER_DOUBLE(cp)	\
441 	cell = (cp); *++floatTop = cell[1]; *++floatTop = *cell; continue
442 #define	FLOAT_PUSH_CELL_POINTER(cp)		\
443 	cell = (cp); *++floatTop = *cell; continue
444 #define	FLOAT_POP_CELL_POINTER_DOUBLE(cp)	\
445 	cell = (cp); *cell = *floatTop--; cell[1] = *floatTop--; continue
446 #define	FLOAT_POP_CELL_POINTER(cp)		\
447 	cell = (cp); *cell = *floatTop--; continue
448 #endif /* FICL_WANT_FLOAT */
449 
450 #define	PUSH_CELL_POINTER_DOUBLE(cp)	\
451 	cell = (cp); *++dataTop = cell[1]; *++dataTop = *cell; continue
452 #define	PUSH_CELL_POINTER(cp)		\
453 	cell = (cp); *++dataTop = *cell; continue
454 #define	POP_CELL_POINTER_DOUBLE(cp)	\
455 	cell = (cp); *cell = *dataTop--; cell[1] = *dataTop--; continue
456 #define	POP_CELL_POINTER(cp)		\
457 	cell = (cp); *cell = *dataTop--; continue
458 
459 #define	BRANCH()	ip += *(ficlInteger *)ip; continue
460 #define	EXIT_FUNCTION()	ip = (ficlInstruction *)((returnTop--)->p); continue
461 
462 #endif /* FICL_WANT_SIZE */
463 
464 
465 		/*
466 		 * This is the runtime for (literal). It assumes that it is
467 		 * part of a colon definition, and that the next ficlCell
468 		 * contains a value to be pushed on the parameter stack at
469 		 * runtime. This code is compiled by "literal".
470 		 */
471 
472 		case ficlInstructionLiteralParen:
473 			CHECK_STACK(0, 1);
474 			(++dataTop)->i = *ip++;
475 		continue;
476 
477 		case ficlInstruction2LiteralParen:
478 			CHECK_STACK(0, 2);
479 			(++dataTop)->i = ip[1];
480 			(++dataTop)->i = ip[0];
481 			ip += 2;
482 		continue;
483 
484 #if FICL_WANT_LOCALS
485 		/*
486 		 * Link a frame on the return stack, reserving nCells of space
487 		 * for locals - the value of nCells is the next ficlCell in
488 		 * the instruction stream.
489 		 * 1) Push frame onto returnTop
490 		 * 2) frame = returnTop
491 		 * 3) returnTop += nCells
492 		 */
493 		case ficlInstructionLinkParen: {
494 			ficlInteger nCells = *ip++;
495 			(++returnTop)->p = frame;
496 			frame = returnTop + 1;
497 			returnTop += nCells;
498 		continue;
499 		}
500 
501 		/*
502 		 * Unink a stack frame previously created by stackLink
503 		 * 1) dataTop = frame
504 		 * 2) frame = pop()
505 		 */
506 		case ficlInstructionUnlinkParen:
507 			returnTop = frame - 1;
508 			frame = (returnTop--)->p;
509 		continue;
510 
511 		/*
512 		 * Immediate - cfa of a local while compiling - when executed,
513 		 * compiles code to fetch the value of a local given the
514 		 * local's index in the word's pfa
515 		 */
516 #if FICL_WANT_FLOAT
517 		case ficlInstructionGetF2LocalParen:
518 			FLOAT_PUSH_CELL_POINTER_DOUBLE(frame + *ip++);
519 
520 		case ficlInstructionGetFLocalParen:
521 			FLOAT_PUSH_CELL_POINTER(frame + *ip++);
522 
523 		case ficlInstructionToF2LocalParen:
524 			FLOAT_POP_CELL_POINTER_DOUBLE(frame + *ip++);
525 
526 		case ficlInstructionToFLocalParen:
527 			FLOAT_POP_CELL_POINTER(frame + *ip++);
528 #endif /* FICL_WANT_FLOAT */
529 
530 		case ficlInstructionGet2LocalParen:
531 			PUSH_CELL_POINTER_DOUBLE(frame + *ip++);
532 
533 		case ficlInstructionGetLocalParen:
534 			PUSH_CELL_POINTER(frame + *ip++);
535 
536 		/*
537 		 * Immediate - cfa of a local while compiling - when executed,
538 		 * compiles code to store the value of a local given the
539 		 * local's index in the word's pfa
540 		 */
541 
542 		case ficlInstructionTo2LocalParen:
543 			POP_CELL_POINTER_DOUBLE(frame + *ip++);
544 
545 		case ficlInstructionToLocalParen:
546 			POP_CELL_POINTER(frame + *ip++);
547 
548 		/*
549 		 * Silly little minor optimizations.
550 		 * --lch
551 		 */
552 		case ficlInstructionGetLocal0:
553 			PUSH_CELL_POINTER(frame);
554 
555 		case ficlInstructionGetLocal1:
556 			PUSH_CELL_POINTER(frame + 1);
557 
558 		case ficlInstructionGet2Local0:
559 			PUSH_CELL_POINTER_DOUBLE(frame);
560 
561 		case ficlInstructionToLocal0:
562 			POP_CELL_POINTER(frame);
563 
564 		case ficlInstructionToLocal1:
565 			POP_CELL_POINTER(frame + 1);
566 
567 		case ficlInstructionTo2Local0:
568 			POP_CELL_POINTER_DOUBLE(frame);
569 
570 #endif /* FICL_WANT_LOCALS */
571 
572 		case ficlInstructionPlus:
573 			CHECK_STACK(2, 1);
574 			i = (dataTop--)->i;
575 			dataTop->i += i;
576 		continue;
577 
578 		case ficlInstructionMinus:
579 			CHECK_STACK(2, 1);
580 			i = (dataTop--)->i;
581 			dataTop->i -= i;
582 		continue;
583 
584 		case ficlInstruction1Plus:
585 			CHECK_STACK(1, 1);
586 			dataTop->i++;
587 		continue;
588 
589 		case ficlInstruction1Minus:
590 			CHECK_STACK(1, 1);
591 			dataTop->i--;
592 		continue;
593 
594 		case ficlInstruction2Plus:
595 			CHECK_STACK(1, 1);
596 			dataTop->i += 2;
597 		continue;
598 
599 		case ficlInstruction2Minus:
600 			CHECK_STACK(1, 1);
601 			dataTop->i -= 2;
602 		continue;
603 
604 		case ficlInstructionDup: {
605 			ficlInteger i = dataTop->i;
606 			CHECK_STACK(0, 1);
607 			(++dataTop)->i = i;
608 			continue;
609 		}
610 
611 		case ficlInstructionQuestionDup:
612 			CHECK_STACK(1, 2);
613 
614 			if (dataTop->i != 0) {
615 				dataTop[1] = dataTop[0];
616 				dataTop++;
617 			}
618 
619 		continue;
620 
621 		case ficlInstructionSwap: {
622 			ficlCell swap;
623 			CHECK_STACK(2, 2);
624 			swap = dataTop[0];
625 			dataTop[0] = dataTop[-1];
626 			dataTop[-1] = swap;
627 		}
628 		continue;
629 
630 		case ficlInstructionDrop:
631 			CHECK_STACK(1, 0);
632 			dataTop--;
633 		continue;
634 
635 		case ficlInstruction2Drop:
636 			CHECK_STACK(2, 0);
637 			dataTop -= 2;
638 		continue;
639 
640 		case ficlInstruction2Dup:
641 			CHECK_STACK(2, 4);
642 			dataTop[1] = dataTop[-1];
643 			dataTop[2] = *dataTop;
644 			dataTop += 2;
645 		continue;
646 
647 		case ficlInstructionOver:
648 			CHECK_STACK(2, 3);
649 			dataTop[1] = dataTop[-1];
650 			dataTop++;
651 		continue;
652 
653 		case ficlInstruction2Over:
654 			CHECK_STACK(4, 6);
655 			dataTop[1] = dataTop[-3];
656 			dataTop[2] = dataTop[-2];
657 			dataTop += 2;
658 		continue;
659 
660 		case ficlInstructionPick:
661 			CHECK_STACK(1, 0);
662 			i = dataTop->i;
663 			if (i < 0)
664 				continue;
665 			CHECK_STACK(i + 2, i + 3);
666 			*dataTop = dataTop[-i - 1];
667 		continue;
668 
669 		/*
670 		 * Do stack rot.
671 		 * rot ( 1 2 3  -- 2 3 1 )
672 		 */
673 		case ficlInstructionRot:
674 			i = 2;
675 		goto ROLL;
676 
677 		/*
678 		 * Do stack roll.
679 		 * roll ( n -- )
680 		 */
681 		case ficlInstructionRoll:
682 			CHECK_STACK(1, 0);
683 			i = (dataTop--)->i;
684 
685 			if (i < 1)
686 				continue;
687 
688 ROLL:
689 			CHECK_STACK(i+1, i+2);
690 			c = dataTop[-i];
691 			memmove(dataTop - i, dataTop - (i - 1),
692 			    i * sizeof (ficlCell));
693 			*dataTop = c;
694 		continue;
695 
696 		/*
697 		 * Do stack -rot.
698 		 * -rot ( 1 2 3  -- 3 1 2 )
699 		 */
700 		case ficlInstructionMinusRot:
701 			i = 2;
702 		goto MINUSROLL;
703 
704 		/*
705 		 * Do stack -roll.
706 		 * -roll ( n -- )
707 		 */
708 		case ficlInstructionMinusRoll:
709 			CHECK_STACK(1, 0);
710 			i = (dataTop--)->i;
711 
712 			if (i < 1)
713 				continue;
714 
715 MINUSROLL:
716 			CHECK_STACK(i+1, i+2);
717 			c = *dataTop;
718 			memmove(dataTop - (i - 1), dataTop - i,
719 			    i * sizeof (ficlCell));
720 			dataTop[-i] = c;
721 
722 		continue;
723 
724 		/*
725 		 * Do stack 2swap
726 		 * 2swap ( 1 2 3 4  -- 3 4 1 2 )
727 		 */
728 		case ficlInstruction2Swap: {
729 			ficlCell c2;
730 			CHECK_STACK(4, 4);
731 
732 			c = *dataTop;
733 			c2 = dataTop[-1];
734 
735 			*dataTop = dataTop[-2];
736 			dataTop[-1] = dataTop[-3];
737 
738 			dataTop[-2] = c;
739 			dataTop[-3] = c2;
740 		continue;
741 		}
742 
743 		case ficlInstructionPlusStore: {
744 			ficlCell *cell;
745 			CHECK_STACK(2, 0);
746 			cell = (ficlCell *)(dataTop--)->p;
747 			cell->i += (dataTop--)->i;
748 		continue;
749 		}
750 
751 		case ficlInstructionQuadFetch: {
752 			ficlUnsigned32 *integer32;
753 			CHECK_STACK(1, 1);
754 			integer32 = (ficlUnsigned32 *)dataTop->i;
755 			dataTop->u = (ficlUnsigned)*integer32;
756 		continue;
757 		}
758 
759 		case ficlInstructionQuadStore: {
760 			ficlUnsigned32 *integer32;
761 			CHECK_STACK(2, 0);
762 			integer32 = (ficlUnsigned32 *)(dataTop--)->p;
763 			*integer32 = (ficlUnsigned32)((dataTop--)->u);
764 		continue;
765 		}
766 
767 		case ficlInstructionWFetch: {
768 			ficlUnsigned16 *integer16;
769 			CHECK_STACK(1, 1);
770 			integer16 = (ficlUnsigned16 *)dataTop->p;
771 			dataTop->u = ((ficlUnsigned)*integer16);
772 		continue;
773 		}
774 
775 		case ficlInstructionWStore: {
776 			ficlUnsigned16 *integer16;
777 			CHECK_STACK(2, 0);
778 			integer16 = (ficlUnsigned16 *)(dataTop--)->p;
779 			*integer16 = (ficlUnsigned16)((dataTop--)->u);
780 		continue;
781 		}
782 
783 		case ficlInstructionCFetch: {
784 			ficlUnsigned8 *integer8;
785 			CHECK_STACK(1, 1);
786 			integer8 = (ficlUnsigned8 *)dataTop->p;
787 			dataTop->u = ((ficlUnsigned)*integer8);
788 		continue;
789 		}
790 
791 		case ficlInstructionCStore: {
792 			ficlUnsigned8 *integer8;
793 			CHECK_STACK(2, 0);
794 			integer8 = (ficlUnsigned8 *)(dataTop--)->p;
795 			*integer8 = (ficlUnsigned8)((dataTop--)->u);
796 		continue;
797 		}
798 
799 
800 		/*
801 		 * l o g i c   a n d   c o m p a r i s o n s
802 		 */
803 
804 		case ficlInstruction0Equals:
805 			CHECK_STACK(1, 1);
806 			dataTop->i = FICL_BOOL(dataTop->i == 0);
807 		continue;
808 
809 		case ficlInstruction0Less:
810 			CHECK_STACK(1, 1);
811 			dataTop->i = FICL_BOOL(dataTop->i < 0);
812 		continue;
813 
814 		case ficlInstruction0Greater:
815 			CHECK_STACK(1, 1);
816 			dataTop->i = FICL_BOOL(dataTop->i > 0);
817 		continue;
818 
819 		case ficlInstructionEquals:
820 			CHECK_STACK(2, 1);
821 			i = (dataTop--)->i;
822 			dataTop->i = FICL_BOOL(dataTop->i == i);
823 		continue;
824 
825 		case ficlInstructionLess:
826 			CHECK_STACK(2, 1);
827 			i = (dataTop--)->i;
828 			dataTop->i = FICL_BOOL(dataTop->i < i);
829 		continue;
830 
831 		case ficlInstructionULess:
832 			CHECK_STACK(2, 1);
833 			u = (dataTop--)->u;
834 			dataTop->i = FICL_BOOL(dataTop->u < u);
835 		continue;
836 
837 		case ficlInstructionAnd:
838 			CHECK_STACK(2, 1);
839 			i = (dataTop--)->i;
840 			dataTop->i = dataTop->i & i;
841 		continue;
842 
843 		case ficlInstructionOr:
844 			CHECK_STACK(2, 1);
845 			i = (dataTop--)->i;
846 			dataTop->i = dataTop->i | i;
847 		continue;
848 
849 		case ficlInstructionXor:
850 			CHECK_STACK(2, 1);
851 			i = (dataTop--)->i;
852 			dataTop->i = dataTop->i ^ i;
853 		continue;
854 
855 		case ficlInstructionInvert:
856 			CHECK_STACK(1, 1);
857 			dataTop->i = ~dataTop->i;
858 		continue;
859 
860 		/*
861 		 * r e t u r n   s t a c k
862 		 */
863 		case ficlInstructionToRStack:
864 			CHECK_STACK(1, 0);
865 			CHECK_RETURN_STACK(0, 1);
866 			*++returnTop = *dataTop--;
867 		continue;
868 
869 		case ficlInstructionFromRStack:
870 			CHECK_STACK(0, 1);
871 			CHECK_RETURN_STACK(1, 0);
872 			*++dataTop = *returnTop--;
873 		continue;
874 
875 		case ficlInstructionFetchRStack:
876 			CHECK_STACK(0, 1);
877 			CHECK_RETURN_STACK(1, 1);
878 			*++dataTop = *returnTop;
879 		continue;
880 
881 		case ficlInstruction2ToR:
882 			CHECK_STACK(2, 0);
883 			CHECK_RETURN_STACK(0, 2);
884 			*++returnTop = dataTop[-1];
885 			*++returnTop = dataTop[0];
886 			dataTop -= 2;
887 		continue;
888 
889 		case ficlInstruction2RFrom:
890 			CHECK_STACK(0, 2);
891 			CHECK_RETURN_STACK(2, 0);
892 			*++dataTop = returnTop[-1];
893 			*++dataTop = returnTop[0];
894 			returnTop -= 2;
895 		continue;
896 
897 		case ficlInstruction2RFetch:
898 			CHECK_STACK(0, 2);
899 			CHECK_RETURN_STACK(2, 2);
900 			*++dataTop = returnTop[-1];
901 			*++dataTop = returnTop[0];
902 		continue;
903 
904 		/*
905 		 * f i l l
906 		 * CORE ( c-addr u char -- )
907 		 * If u is greater than zero, store char in each of u
908 		 * consecutive characters of memory beginning at c-addr.
909 		 */
910 		case ficlInstructionFill: {
911 			char c;
912 			char *memory;
913 			CHECK_STACK(3, 0);
914 			c = (char)(dataTop--)->i;
915 			u = (dataTop--)->u;
916 			memory = (char *)(dataTop--)->p;
917 
918 			/*
919 			 * memset() is faster than the previous hand-rolled
920 			 * solution.  --lch
921 			 */
922 			memset(memory, c, u);
923 		continue;
924 		}
925 
926 		/*
927 		 * l s h i f t
928 		 * l-shift CORE ( x1 u -- x2 )
929 		 * Perform a logical left shift of u bit-places on x1,
930 		 * giving x2. Put zeroes into the least significant bits
931 		 * vacated by the shift. An ambiguous condition exists if
932 		 * u is greater than or equal to the number of bits in a
933 		 * ficlCell.
934 		 *
935 		 * r-shift CORE ( x1 u -- x2 )
936 		 * Perform a logical right shift of u bit-places on x1,
937 		 * giving x2. Put zeroes into the most significant bits
938 		 * vacated by the shift. An ambiguous condition exists
939 		 * if u is greater than or equal to the number of bits
940 		 * in a ficlCell.
941 		 */
942 		case ficlInstructionLShift: {
943 			ficlUnsigned nBits;
944 			ficlUnsigned x1;
945 			CHECK_STACK(2, 1);
946 
947 			nBits = (dataTop--)->u;
948 			x1 = dataTop->u;
949 			dataTop->u = x1 << nBits;
950 		continue;
951 		}
952 
953 		case ficlInstructionRShift: {
954 			ficlUnsigned nBits;
955 			ficlUnsigned x1;
956 			CHECK_STACK(2, 1);
957 
958 			nBits = (dataTop--)->u;
959 			x1 = dataTop->u;
960 			dataTop->u = x1 >> nBits;
961 			continue;
962 		}
963 
964 		/*
965 		 * m a x   &   m i n
966 		 */
967 		case ficlInstructionMax: {
968 			ficlInteger n2;
969 			ficlInteger n1;
970 			CHECK_STACK(2, 1);
971 
972 			n2 = (dataTop--)->i;
973 			n1 = dataTop->i;
974 
975 			dataTop->i = ((n1 > n2) ? n1 : n2);
976 		continue;
977 		}
978 
979 		case ficlInstructionMin: {
980 			ficlInteger n2;
981 			ficlInteger n1;
982 			CHECK_STACK(2, 1);
983 
984 			n2 = (dataTop--)->i;
985 				n1 = dataTop->i;
986 
987 			dataTop->i = ((n1 < n2) ? n1 : n2);
988 			continue;
989 		}
990 
991 		/*
992 		 * m o v e
993 		 * CORE ( addr1 addr2 u -- )
994 		 * If u is greater than zero, copy the contents of u
995 		 * consecutive address units at addr1 to the u consecutive
996 		 * address units at addr2. After MOVE completes, the u
997 		 * consecutive address units at addr2 contain exactly
998 		 * what the u consecutive address units at addr1 contained
999 		 * before the move.
1000 		 * NOTE! This implementation assumes that a char is the same
1001 		 * size as an address unit.
1002 		 */
1003 		case ficlInstructionMove: {
1004 			ficlUnsigned u;
1005 			char *addr2;
1006 			char *addr1;
1007 			CHECK_STACK(3, 0);
1008 
1009 			u = (dataTop--)->u;
1010 			addr2 = (dataTop--)->p;
1011 			addr1 = (dataTop--)->p;
1012 
1013 			if (u == 0)
1014 				continue;
1015 			/*
1016 			 * Do the copy carefully, so as to be
1017 			 * correct even if the two ranges overlap
1018 			 */
1019 			/* Which ANSI C's memmove() does for you! Yay!  --lch */
1020 			memmove(addr2, addr1, u);
1021 		continue;
1022 		}
1023 
1024 		/*
1025 		 * s t o d
1026 		 * s-to-d CORE ( n -- d )
1027 		 * Convert the number n to the double-ficlCell number d with
1028 		 * the same numerical value.
1029 		 */
1030 		case ficlInstructionSToD: {
1031 			ficlInteger s;
1032 			CHECK_STACK(1, 2);
1033 
1034 			s = dataTop->i;
1035 
1036 			/* sign extend to 64 bits.. */
1037 			(++dataTop)->i = (s < 0) ? -1 : 0;
1038 		continue;
1039 		}
1040 
1041 		/*
1042 		 * c o m p a r e
1043 		 * STRING ( c-addr1 u1 c-addr2 u2 -- n )
1044 		 * Compare the string specified by c-addr1 u1 to the string
1045 		 * specified by c-addr2 u2. The strings are compared, beginning
1046 		 * at the given addresses, character by character, up to the
1047 		 * length of the shorter string or until a difference is found.
1048 		 * If the two strings are identical, n is zero. If the two
1049 		 * strings are identical up to the length of the shorter string,
1050 		 * n is minus-one (-1) if u1 is less than u2 and one (1)
1051 		 * otherwise. If the two strings are not identical up to the
1052 		 * length of the shorter string, n is minus-one (-1) if the
1053 		 * first non-matching character in the string specified by
1054 		 * c-addr1 u1 has a lesser numeric value than the corresponding
1055 		 * character in the string specified by c-addr2 u2 and
1056 		 * one (1) otherwise.
1057 		 */
1058 		case ficlInstructionCompare:
1059 			i = FICL_FALSE;
1060 		goto COMPARE;
1061 
1062 
1063 		case ficlInstructionCompareInsensitive:
1064 			i = FICL_TRUE;
1065 		goto COMPARE;
1066 
1067 COMPARE:
1068 		{
1069 			char *cp1, *cp2;
1070 			ficlUnsigned u1, u2, uMin;
1071 			int n = 0;
1072 
1073 			CHECK_STACK(4, 1);
1074 			u2  = (dataTop--)->u;
1075 			cp2 = (char *)(dataTop--)->p;
1076 			u1  = (dataTop--)->u;
1077 			cp1 = (char *)(dataTop--)->p;
1078 
1079 			uMin = (u1 < u2)? u1 : u2;
1080 			for (; (uMin > 0) && (n == 0); uMin--) {
1081 				int c1 = (unsigned char)*cp1++;
1082 				int c2 = (unsigned char)*cp2++;
1083 
1084 				if (i) {
1085 					c1 = tolower(c1);
1086 					c2 = tolower(c2);
1087 				}
1088 				n = (c1 - c2);
1089 			}
1090 
1091 			if (n == 0)
1092 				n = (int)(u1 - u2);
1093 
1094 			if (n < 0)
1095 				n = -1;
1096 			else if (n > 0)
1097 				n = 1;
1098 
1099 			(++dataTop)->i = n;
1100 		continue;
1101 		}
1102 
1103 		/*
1104 		 * r a n d o m
1105 		 * Ficl-specific
1106 		 */
1107 		case ficlInstructionRandom:
1108 			(++dataTop)->i = random();
1109 		continue;
1110 
1111 		/*
1112 		 * s e e d - r a n d o m
1113 		 * Ficl-specific
1114 		 */
1115 		case ficlInstructionSeedRandom:
1116 			srandom((dataTop--)->i);
1117 		continue;
1118 
1119 		case ficlInstructionGreaterThan: {
1120 			ficlInteger x, y;
1121 			CHECK_STACK(2, 1);
1122 			y = (dataTop--)->i;
1123 			x = dataTop->i;
1124 			dataTop->i = FICL_BOOL(x > y);
1125 		continue;
1126 		}
1127 
1128 		/*
1129 		 * This function simply pops the previous instruction
1130 		 * pointer and returns to the "next" loop. Used for exiting
1131 		 * from within a definition. Note that exitParen is identical
1132 		 * to semiParen - they are in two different functions so that
1133 		 * "see" can correctly identify the end of a colon definition,
1134 		 * even if it uses "exit".
1135 		 */
1136 		case ficlInstructionExitParen:
1137 		case ficlInstructionSemiParen:
1138 			EXIT_FUNCTION();
1139 
1140 		/*
1141 		 * The first time we run "(branch)", perform a "peephole
1142 		 * optimization" to see if we're jumping to another
1143 		 * unconditional jump.  If so, just jump directly there.
1144 		 */
1145 		case ficlInstructionBranchParenWithCheck:
1146 			LOCAL_VARIABLE_SPILL;
1147 			ficlVmOptimizeJumpToJump(vm, vm->ip - 1);
1148 			LOCAL_VARIABLE_REFILL;
1149 		goto BRANCH_PAREN;
1150 
1151 		/*
1152 		 * Same deal with branch0.
1153 		 */
1154 		case ficlInstructionBranch0ParenWithCheck:
1155 			LOCAL_VARIABLE_SPILL;
1156 			ficlVmOptimizeJumpToJump(vm, vm->ip - 1);
1157 			LOCAL_VARIABLE_REFILL;
1158 			/* intentional fall-through */
1159 
1160 		/*
1161 		 * Runtime code for "(branch0)"; pop a flag from the stack,
1162 		 * branch if 0. fall through otherwise.
1163 		 * The heart of "if" and "until".
1164 		 */
1165 		case ficlInstructionBranch0Paren:
1166 			CHECK_STACK(1, 0);
1167 
1168 			if ((dataTop--)->i) {
1169 				/*
1170 				 * don't branch, but skip over branch
1171 				 * relative address
1172 				 */
1173 				ip += 1;
1174 				continue;
1175 			}
1176 			/* otherwise, take branch (to else/endif/begin) */
1177 			/* intentional fall-through! */
1178 
1179 		/*
1180 		 * Runtime for "(branch)" -- expects a literal offset in the
1181 		 * next compilation address, and branches to that location.
1182 		 */
1183 		case ficlInstructionBranchParen:
1184 BRANCH_PAREN:
1185 			BRANCH();
1186 
1187 		case ficlInstructionOfParen: {
1188 			ficlUnsigned a, b;
1189 
1190 			CHECK_STACK(2, 1);
1191 
1192 			a = (dataTop--)->u;
1193 			b = dataTop->u;
1194 
1195 			if (a == b) {
1196 				/* fall through */
1197 				ip++;
1198 				/* remove CASE argument */
1199 				dataTop--;
1200 			} else {
1201 				/* take branch to next of or endcase */
1202 				BRANCH();
1203 			}
1204 
1205 		continue;
1206 		}
1207 
1208 		case ficlInstructionDoParen: {
1209 			ficlCell index, limit;
1210 
1211 			CHECK_STACK(2, 0);
1212 
1213 			index = *dataTop--;
1214 			limit = *dataTop--;
1215 
1216 			/* copy "leave" target addr to stack */
1217 			(++returnTop)->i = *(ip++);
1218 			*++returnTop = limit;
1219 			*++returnTop = index;
1220 
1221 		continue;
1222 		}
1223 
1224 		case ficlInstructionQDoParen: {
1225 			ficlCell index, limit, leave;
1226 
1227 			CHECK_STACK(2, 0);
1228 
1229 			index = *dataTop--;
1230 			limit = *dataTop--;
1231 
1232 			leave.i = *ip;
1233 
1234 			if (limit.u == index.u) {
1235 				ip = leave.p;
1236 			} else {
1237 				ip++;
1238 				*++returnTop = leave;
1239 				*++returnTop = limit;
1240 				*++returnTop = index;
1241 			}
1242 
1243 		continue;
1244 		}
1245 
1246 		case ficlInstructionLoopParen:
1247 		case ficlInstructionPlusLoopParen: {
1248 			ficlInteger index;
1249 			ficlInteger limit;
1250 			int direction = 0;
1251 
1252 			index = returnTop->i;
1253 			limit = returnTop[-1].i;
1254 
1255 			if (instruction == ficlInstructionLoopParen)
1256 				index++;
1257 			else {
1258 				ficlInteger increment;
1259 				CHECK_STACK(1, 0);
1260 				increment = (dataTop--)->i;
1261 				index += increment;
1262 				direction = (increment < 0);
1263 			}
1264 
1265 			if (direction ^ (index >= limit)) {
1266 				/* nuke the loop indices & "leave" addr */
1267 				returnTop -= 3;
1268 				ip++;  /* fall through the loop */
1269 			} else {	/* update index, branch to loop head */
1270 				returnTop->i = index;
1271 				BRANCH();
1272 			}
1273 
1274 		continue;
1275 		}
1276 
1277 
1278 		/*
1279 		 * Runtime code to break out of a do..loop construct
1280 		 * Drop the loop control variables; the branch address
1281 		 * past "loop" is next on the return stack.
1282 		 */
1283 		case ficlInstructionLeave:
1284 			/* almost unloop */
1285 			returnTop -= 2;
1286 			/* exit */
1287 			EXIT_FUNCTION();
1288 
1289 		case ficlInstructionUnloop:
1290 			returnTop -= 3;
1291 		continue;
1292 
1293 		case ficlInstructionI:
1294 			*++dataTop = *returnTop;
1295 		continue;
1296 
1297 		case ficlInstructionJ:
1298 			*++dataTop = returnTop[-3];
1299 		continue;
1300 
1301 		case ficlInstructionK:
1302 			*++dataTop = returnTop[-6];
1303 		continue;
1304 
1305 		case ficlInstructionDoesParen: {
1306 			ficlDictionary *dictionary = ficlVmGetDictionary(vm);
1307 			dictionary->smudge->code =
1308 			    (ficlPrimitive)ficlInstructionDoDoes;
1309 			dictionary->smudge->param[0].p = ip;
1310 			ip = (ficlInstruction *)((returnTop--)->p);
1311 		continue;
1312 		}
1313 
1314 		case ficlInstructionDoDoes: {
1315 			ficlCell *cell;
1316 			ficlIp tempIP;
1317 
1318 			CHECK_STACK(0, 1);
1319 
1320 			cell = fw->param;
1321 			tempIP = (ficlIp)((*cell).p);
1322 			(++dataTop)->p = (cell + 1);
1323 			(++returnTop)->p = (void *)ip;
1324 			ip = (ficlInstruction *)tempIP;
1325 		continue;
1326 		}
1327 
1328 #if FICL_WANT_FLOAT
1329 		case ficlInstructionF2Fetch:
1330 			CHECK_FLOAT_STACK(0, 2);
1331 			CHECK_STACK(1, 0);
1332 			FLOAT_PUSH_CELL_POINTER_DOUBLE((dataTop--)->p);
1333 
1334 		case ficlInstructionFFetch:
1335 			CHECK_FLOAT_STACK(0, 1);
1336 			CHECK_STACK(1, 0);
1337 			FLOAT_PUSH_CELL_POINTER((dataTop--)->p);
1338 
1339 		case ficlInstructionF2Store:
1340 			CHECK_FLOAT_STACK(2, 0);
1341 			CHECK_STACK(1, 0);
1342 			FLOAT_POP_CELL_POINTER_DOUBLE((dataTop--)->p);
1343 
1344 		case ficlInstructionFStore:
1345 			CHECK_FLOAT_STACK(1, 0);
1346 			CHECK_STACK(1, 0);
1347 			FLOAT_POP_CELL_POINTER((dataTop--)->p);
1348 #endif /* FICL_WANT_FLOAT */
1349 
1350 		/*
1351 		 * two-fetch CORE ( a-addr -- x1 x2 )
1352 		 *
1353 		 * Fetch the ficlCell pair x1 x2 stored at a-addr.
1354 		 * x2 is stored at a-addr and x1 at the next consecutive
1355 		 * ficlCell. It is equivalent to the sequence
1356 		 * DUP ficlCell+ @ SWAP @ .
1357 		 */
1358 		case ficlInstruction2Fetch:
1359 			CHECK_STACK(1, 2);
1360 			PUSH_CELL_POINTER_DOUBLE((dataTop--)->p);
1361 
1362 		/*
1363 		 * fetch CORE ( a-addr -- x )
1364 		 *
1365 		 * x is the value stored at a-addr.
1366 		 */
1367 		case ficlInstructionFetch:
1368 			CHECK_STACK(1, 1);
1369 			PUSH_CELL_POINTER((dataTop--)->p);
1370 
1371 		/*
1372 		 * two-store    CORE ( x1 x2 a-addr -- )
1373 		 * Store the ficlCell pair x1 x2 at a-addr, with x2 at a-addr
1374 		 * and x1 at the next consecutive ficlCell. It is equivalent
1375 		 * to the sequence SWAP OVER ! ficlCell+ !
1376 		 */
1377 		case ficlInstruction2Store:
1378 			CHECK_STACK(3, 0);
1379 			POP_CELL_POINTER_DOUBLE((dataTop--)->p);
1380 
1381 		/*
1382 		 * store	CORE ( x a-addr -- )
1383 		 * Store x at a-addr.
1384 		 */
1385 		case ficlInstructionStore:
1386 			CHECK_STACK(2, 0);
1387 			POP_CELL_POINTER((dataTop--)->p);
1388 
1389 		case ficlInstructionComma: {
1390 			ficlDictionary *dictionary;
1391 			CHECK_STACK(1, 0);
1392 
1393 			dictionary = ficlVmGetDictionary(vm);
1394 			ficlDictionaryAppendCell(dictionary, *dataTop--);
1395 		continue;
1396 		}
1397 
1398 		case ficlInstructionCComma: {
1399 			ficlDictionary *dictionary;
1400 			char c;
1401 			CHECK_STACK(1, 0);
1402 
1403 			dictionary = ficlVmGetDictionary(vm);
1404 			c = (char)(dataTop--)->i;
1405 			ficlDictionaryAppendCharacter(dictionary, c);
1406 		continue;
1407 		}
1408 
1409 		case ficlInstructionCells:
1410 			CHECK_STACK(1, 1);
1411 			dataTop->i *= sizeof (ficlCell);
1412 		continue;
1413 
1414 		case ficlInstructionCellPlus:
1415 			CHECK_STACK(1, 1);
1416 			dataTop->i += sizeof (ficlCell);
1417 		continue;
1418 
1419 		case ficlInstructionStar:
1420 			CHECK_STACK(2, 1);
1421 			i = (dataTop--)->i;
1422 			dataTop->i *= i;
1423 		continue;
1424 
1425 		case ficlInstructionNegate:
1426 			CHECK_STACK(1, 1);
1427 			dataTop->i = - dataTop->i;
1428 		continue;
1429 
1430 		case ficlInstructionSlash:
1431 			CHECK_STACK(2, 1);
1432 			i = (dataTop--)->i;
1433 			dataTop->i /= i;
1434 		continue;
1435 
1436 		/*
1437 		 * slash-mod	CORE ( n1 n2 -- n3 n4 )
1438 		 * Divide n1 by n2, giving the single-ficlCell remainder n3
1439 		 * and the single-ficlCell quotient n4. An ambiguous condition
1440 		 * exists if n2 is zero. If n1 and n2 differ in sign, the
1441 		 * implementation-defined result returned will be the
1442 		 * same as that returned by either the phrase
1443 		 * >R S>D R> FM/MOD or the phrase >R S>D R> SM/REM.
1444 		 * NOTE: Ficl complies with the second phrase
1445 		 * (symmetric division)
1446 		 */
1447 		case ficlInstructionSlashMod: {
1448 			ficl2Integer n1;
1449 			ficlInteger n2;
1450 			ficl2IntegerQR qr;
1451 
1452 			CHECK_STACK(2, 2);
1453 			n2    = dataTop[0].i;
1454 			FICL_INTEGER_TO_2INTEGER(dataTop[-1].i, n1);
1455 
1456 			qr = ficl2IntegerDivideSymmetric(n1, n2);
1457 			dataTop[-1].i = qr.remainder;
1458 			dataTop[0].i = FICL_2UNSIGNED_GET_LOW(qr.quotient);
1459 		continue;
1460 		}
1461 
1462 		case ficlInstruction2Star:
1463 			CHECK_STACK(1, 1);
1464 			dataTop->i <<= 1;
1465 		continue;
1466 
1467 		case ficlInstruction2Slash:
1468 			CHECK_STACK(1, 1);
1469 			dataTop->i >>= 1;
1470 		continue;
1471 
1472 		case ficlInstructionStarSlash: {
1473 			ficlInteger x, y, z;
1474 			ficl2Integer prod;
1475 			CHECK_STACK(3, 1);
1476 
1477 			z = (dataTop--)->i;
1478 			y = (dataTop--)->i;
1479 			x = dataTop->i;
1480 
1481 			prod = ficl2IntegerMultiply(x, y);
1482 			dataTop->i = FICL_2UNSIGNED_GET_LOW(
1483 			    ficl2IntegerDivideSymmetric(prod, z).quotient);
1484 		continue;
1485 		}
1486 
1487 		case ficlInstructionStarSlashMod: {
1488 			ficlInteger x, y, z;
1489 			ficl2Integer prod;
1490 			ficl2IntegerQR qr;
1491 
1492 			CHECK_STACK(3, 2);
1493 
1494 			z = (dataTop--)->i;
1495 			y = dataTop[0].i;
1496 			x = dataTop[-1].i;
1497 
1498 			prod = ficl2IntegerMultiply(x, y);
1499 			qr   = ficl2IntegerDivideSymmetric(prod, z);
1500 
1501 			dataTop[-1].i = qr.remainder;
1502 			dataTop[0].i = FICL_2UNSIGNED_GET_LOW(qr.quotient);
1503 			continue;
1504 		}
1505 
1506 #if FICL_WANT_FLOAT
1507 		case ficlInstructionF0:
1508 			CHECK_FLOAT_STACK(0, 1);
1509 			(++floatTop)->f = 0.0f;
1510 		continue;
1511 
1512 		case ficlInstructionF1:
1513 			CHECK_FLOAT_STACK(0, 1);
1514 			(++floatTop)->f = 1.0f;
1515 		continue;
1516 
1517 		case ficlInstructionFNeg1:
1518 			CHECK_FLOAT_STACK(0, 1);
1519 			(++floatTop)->f = -1.0f;
1520 		continue;
1521 
1522 		/*
1523 		 * Floating point literal execution word.
1524 		 */
1525 		case ficlInstructionFLiteralParen:
1526 			CHECK_FLOAT_STACK(0, 1);
1527 
1528 			/*
1529 			 * Yes, I'm using ->i here,
1530 			 * but it's really a float.  --lch
1531 			 */
1532 			(++floatTop)->i = *ip++;
1533 				continue;
1534 
1535 		/*
1536 		 * Do float addition r1 + r2.
1537 		 * f+ ( r1 r2 -- r )
1538 		 */
1539 		case ficlInstructionFPlus:
1540 			CHECK_FLOAT_STACK(2, 1);
1541 
1542 			f = (floatTop--)->f;
1543 			floatTop->f += f;
1544 		continue;
1545 
1546 		/*
1547 		 * Do float subtraction r1 - r2.
1548 		 * f- ( r1 r2 -- r )
1549 		 */
1550 		case ficlInstructionFMinus:
1551 			CHECK_FLOAT_STACK(2, 1);
1552 
1553 			f = (floatTop--)->f;
1554 			floatTop->f -= f;
1555 		continue;
1556 
1557 		/*
1558 		 * Do float multiplication r1 * r2.
1559 		 * f* ( r1 r2 -- r )
1560 		 */
1561 		case ficlInstructionFStar:
1562 			CHECK_FLOAT_STACK(2, 1);
1563 
1564 			f = (floatTop--)->f;
1565 			floatTop->f *= f;
1566 		continue;
1567 
1568 		/*
1569 		 * Do float negation.
1570 		 * fnegate ( r -- r )
1571 		 */
1572 		case ficlInstructionFNegate:
1573 			CHECK_FLOAT_STACK(1, 1);
1574 
1575 			floatTop->f = -(floatTop->f);
1576 		continue;
1577 
1578 		/*
1579 		 * Do float division r1 / r2.
1580 		 * f/ ( r1 r2 -- r )
1581 		 */
1582 		case ficlInstructionFSlash:
1583 			CHECK_FLOAT_STACK(2, 1);
1584 
1585 			f = (floatTop--)->f;
1586 			floatTop->f /= f;
1587 		continue;
1588 
1589 		/*
1590 		 * Do float + integer r + n.
1591 		 * f+i ( r n -- r )
1592 		 */
1593 		case ficlInstructionFPlusI:
1594 			CHECK_FLOAT_STACK(1, 1);
1595 			CHECK_STACK(1, 0);
1596 
1597 			f = (ficlFloat)(dataTop--)->f;
1598 			floatTop->f += f;
1599 		continue;
1600 
1601 		/*
1602 		 * Do float - integer r - n.
1603 		 * f-i ( r n -- r )
1604 		 */
1605 		case ficlInstructionFMinusI:
1606 			CHECK_FLOAT_STACK(1, 1);
1607 			CHECK_STACK(1, 0);
1608 
1609 			f = (ficlFloat)(dataTop--)->f;
1610 			floatTop->f -= f;
1611 		continue;
1612 
1613 		/*
1614 		 * Do float * integer r * n.
1615 		 * f*i ( r n -- r )
1616 		 */
1617 		case ficlInstructionFStarI:
1618 			CHECK_FLOAT_STACK(1, 1);
1619 			CHECK_STACK(1, 0);
1620 
1621 			f = (ficlFloat)(dataTop--)->f;
1622 			floatTop->f *= f;
1623 		continue;
1624 
1625 		/*
1626 		 * Do float / integer r / n.
1627 		 * f/i ( r n -- r )
1628 		 */
1629 		case ficlInstructionFSlashI:
1630 			CHECK_FLOAT_STACK(1, 1);
1631 			CHECK_STACK(1, 0);
1632 
1633 			f = (ficlFloat)(dataTop--)->f;
1634 			floatTop->f /= f;
1635 			continue;
1636 
1637 		/*
1638 		 * Do integer - float n - r.
1639 		 * i-f ( n r -- r )
1640 		 */
1641 		case ficlInstructionIMinusF:
1642 			CHECK_FLOAT_STACK(1, 1);
1643 			CHECK_STACK(1, 0);
1644 
1645 			f = (ficlFloat)(dataTop--)->f;
1646 			floatTop->f = f - floatTop->f;
1647 		continue;
1648 
1649 		/*
1650 		 * Do integer / float n / r.
1651 		 * i/f ( n r -- r )
1652 		 */
1653 		case ficlInstructionISlashF:
1654 			CHECK_FLOAT_STACK(1, 1);
1655 			CHECK_STACK(1, 0);
1656 
1657 			f = (ficlFloat)(dataTop--)->f;
1658 			floatTop->f = f / floatTop->f;
1659 		continue;
1660 
1661 		/*
1662 		 * Do integer to float conversion.
1663 		 * int>float ( n -- r )
1664 		 */
1665 		case ficlInstructionIntToFloat:
1666 			CHECK_STACK(1, 0);
1667 			CHECK_FLOAT_STACK(0, 1);
1668 
1669 			(++floatTop)->f = ((dataTop--)->f);
1670 		continue;
1671 
1672 		/*
1673 		 * Do float to integer conversion.
1674 		 * float>int ( r -- n )
1675 		 */
1676 		case ficlInstructionFloatToInt:
1677 			CHECK_STACK(0, 1);
1678 			CHECK_FLOAT_STACK(1, 0);
1679 
1680 			(++dataTop)->i = ((floatTop--)->i);
1681 		continue;
1682 
1683 		/*
1684 		 * Add a floating point number to contents of a variable.
1685 		 * f+! ( r n -- )
1686 		 */
1687 		case ficlInstructionFPlusStore: {
1688 			ficlCell *cell;
1689 
1690 			CHECK_STACK(1, 0);
1691 			CHECK_FLOAT_STACK(1, 0);
1692 
1693 			cell = (ficlCell *)(dataTop--)->p;
1694 			cell->f += (floatTop--)->f;
1695 		continue;
1696 		}
1697 
1698 		/*
1699 		 * Do float stack drop.
1700 		 * fdrop ( r -- )
1701 		 */
1702 		case ficlInstructionFDrop:
1703 			CHECK_FLOAT_STACK(1, 0);
1704 			floatTop--;
1705 		continue;
1706 
1707 		/*
1708 		 * Do float stack ?dup.
1709 		 * f?dup ( r -- r )
1710 		 */
1711 		case ficlInstructionFQuestionDup:
1712 			CHECK_FLOAT_STACK(1, 2);
1713 
1714 			if (floatTop->f != 0)
1715 				goto FDUP;
1716 
1717 		continue;
1718 
1719 		/*
1720 		 * Do float stack dup.
1721 		 * fdup ( r -- r r )
1722 		 */
1723 		case ficlInstructionFDup:
1724 			CHECK_FLOAT_STACK(1, 2);
1725 
1726 FDUP:
1727 			floatTop[1] = floatTop[0];
1728 			floatTop++;
1729 			continue;
1730 
1731 		/*
1732 		 * Do float stack swap.
1733 		 * fswap ( r1 r2 -- r2 r1 )
1734 		 */
1735 		case ficlInstructionFSwap:
1736 			CHECK_FLOAT_STACK(2, 2);
1737 
1738 			c = floatTop[0];
1739 			floatTop[0] = floatTop[-1];
1740 			floatTop[-1] = c;
1741 		continue;
1742 
1743 		/*
1744 		 * Do float stack 2drop.
1745 		 * f2drop ( r r -- )
1746 		 */
1747 		case ficlInstructionF2Drop:
1748 			CHECK_FLOAT_STACK(2, 0);
1749 
1750 			floatTop -= 2;
1751 		continue;
1752 
1753 		/*
1754 		 * Do float stack 2dup.
1755 		 * f2dup ( r1 r2 -- r1 r2 r1 r2 )
1756 		 */
1757 		case ficlInstructionF2Dup:
1758 			CHECK_FLOAT_STACK(2, 4);
1759 
1760 			floatTop[1] = floatTop[-1];
1761 			floatTop[2] = *floatTop;
1762 			floatTop += 2;
1763 		continue;
1764 
1765 		/*
1766 		 * Do float stack over.
1767 		 * fover ( r1 r2 -- r1 r2 r1 )
1768 		 */
1769 		case ficlInstructionFOver:
1770 			CHECK_FLOAT_STACK(2, 3);
1771 
1772 			floatTop[1] = floatTop[-1];
1773 			floatTop++;
1774 		continue;
1775 
1776 		/*
1777 		 * Do float stack 2over.
1778 		 * f2over ( r1 r2 r3 -- r1 r2 r3 r1 r2 )
1779 		 */
1780 		case ficlInstructionF2Over:
1781 			CHECK_FLOAT_STACK(4, 6);
1782 
1783 			floatTop[1] = floatTop[-2];
1784 			floatTop[2] = floatTop[-1];
1785 			floatTop += 2;
1786 		continue;
1787 
1788 		/*
1789 		 * Do float stack pick.
1790 		 * fpick ( n -- r )
1791 		 */
1792 		case ficlInstructionFPick:
1793 			CHECK_STACK(1, 0);
1794 			c = *dataTop--;
1795 			CHECK_FLOAT_STACK(c.i+2, c.i+3);
1796 
1797 			floatTop[1] = floatTop[- c.i - 1];
1798 		continue;
1799 
1800 		/*
1801 		 * Do float stack rot.
1802 		 * frot ( r1 r2 r3  -- r2 r3 r1 )
1803 		 */
1804 		case ficlInstructionFRot:
1805 			i = 2;
1806 		goto FROLL;
1807 
1808 		/*
1809 		 * Do float stack roll.
1810 		 * froll ( n -- )
1811 		 */
1812 		case ficlInstructionFRoll:
1813 			CHECK_STACK(1, 0);
1814 			i = (dataTop--)->i;
1815 
1816 			if (i < 1)
1817 				continue;
1818 
1819 FROLL:
1820 			CHECK_FLOAT_STACK(i+1, i+2);
1821 			c = floatTop[-i];
1822 			memmove(floatTop - i, floatTop - (i - 1),
1823 			    i * sizeof (ficlCell));
1824 			*floatTop = c;
1825 
1826 		continue;
1827 
1828 		/*
1829 		 * Do float stack -rot.
1830 		 * f-rot ( r1 r2 r3  -- r3 r1 r2 )
1831 		 */
1832 		case ficlInstructionFMinusRot:
1833 			i = 2;
1834 			goto FMINUSROLL;
1835 
1836 
1837 		/*
1838 		 * Do float stack -roll.
1839 		 * f-roll ( n -- )
1840 		 */
1841 		case ficlInstructionFMinusRoll:
1842 			CHECK_STACK(1, 0);
1843 			i = (dataTop--)->i;
1844 
1845 			if (i < 1)
1846 				continue;
1847 
1848 FMINUSROLL:
1849 			CHECK_FLOAT_STACK(i+1, i+2);
1850 			c = *floatTop;
1851 			memmove(floatTop - (i - 1), floatTop - i,
1852 			    i * sizeof (ficlCell));
1853 			floatTop[-i] = c;
1854 
1855 		continue;
1856 
1857 		/*
1858 		 * Do float stack 2swap
1859 		 * f2swap ( r1 r2 r3 r4  -- r3 r4 r1 r2 )
1860 		 */
1861 		case ficlInstructionF2Swap: {
1862 			ficlCell c2;
1863 			CHECK_FLOAT_STACK(4, 4);
1864 
1865 			c = *floatTop;
1866 			c2 = floatTop[-1];
1867 
1868 			*floatTop = floatTop[-2];
1869 			floatTop[-1] = floatTop[-3];
1870 
1871 			floatTop[-2] = c;
1872 			floatTop[-3] = c2;
1873 		continue;
1874 		}
1875 
1876 		/*
1877 		 * Do float 0= comparison r = 0.0.
1878 		 * f0= ( r -- T/F )
1879 		 */
1880 		case ficlInstructionF0Equals:
1881 			CHECK_FLOAT_STACK(1, 0);
1882 			CHECK_STACK(0, 1);
1883 
1884 			(++dataTop)->i = FICL_BOOL((floatTop--)->f != 0.0f);
1885 		continue;
1886 
1887 		/*
1888 		 * Do float 0< comparison r < 0.0.
1889 		 * f0< ( r -- T/F )
1890 		 */
1891 		case ficlInstructionF0Less:
1892 			CHECK_FLOAT_STACK(1, 0);
1893 			CHECK_STACK(0, 1);
1894 
1895 			(++dataTop)->i = FICL_BOOL((floatTop--)->f < 0.0f);
1896 		continue;
1897 
1898 		/*
1899 		 * Do float 0> comparison r > 0.0.
1900 		 * f0> ( r -- T/F )
1901 		 */
1902 		case ficlInstructionF0Greater:
1903 			CHECK_FLOAT_STACK(1, 0);
1904 			CHECK_STACK(0, 1);
1905 
1906 			(++dataTop)->i = FICL_BOOL((floatTop--)->f > 0.0f);
1907 		continue;
1908 
1909 		/*
1910 		 * Do float = comparison r1 = r2.
1911 		 * f= ( r1 r2 -- T/F )
1912 		 */
1913 		case ficlInstructionFEquals:
1914 			CHECK_FLOAT_STACK(2, 0);
1915 			CHECK_STACK(0, 1);
1916 
1917 			f = (floatTop--)->f;
1918 			(++dataTop)->i = FICL_BOOL((floatTop--)->f == f);
1919 		continue;
1920 
1921 		/*
1922 		 * Do float < comparison r1 < r2.
1923 		 * f< ( r1 r2 -- T/F )
1924 		 */
1925 		case ficlInstructionFLess:
1926 			CHECK_FLOAT_STACK(2, 0);
1927 			CHECK_STACK(0, 1);
1928 
1929 			f = (floatTop--)->f;
1930 			(++dataTop)->i = FICL_BOOL((floatTop--)->f < f);
1931 		continue;
1932 
1933 		/*
1934 		 * Do float > comparison r1 > r2.
1935 		 * f> ( r1 r2 -- T/F )
1936 		 */
1937 		case ficlInstructionFGreater:
1938 			CHECK_FLOAT_STACK(2, 0);
1939 			CHECK_STACK(0, 1);
1940 
1941 			f = (floatTop--)->f;
1942 			(++dataTop)->i = FICL_BOOL((floatTop--)->f > f);
1943 		continue;
1944 
1945 
1946 		/*
1947 		 * Move float to param stack (assumes they both fit in a
1948 		 * single ficlCell) f>s
1949 		 */
1950 		case ficlInstructionFFrom:
1951 			CHECK_FLOAT_STACK(1, 0);
1952 			CHECK_STACK(0, 1);
1953 
1954 			*++dataTop = *floatTop--;
1955 		continue;
1956 
1957 		case ficlInstructionToF:
1958 			CHECK_FLOAT_STACK(0, 1);
1959 			CHECK_STACK(1, 0);
1960 
1961 			*++floatTop = *dataTop--;
1962 		continue;
1963 
1964 #endif /* FICL_WANT_FLOAT */
1965 
1966 		/*
1967 		 * c o l o n P a r e n
1968 		 * This is the code that executes a colon definition. It
1969 		 * assumes that the virtual machine is running a "next" loop
1970 		 * (See the vm.c for its implementation of member function
1971 		 * vmExecute()). The colon code simply copies the address of
1972 		 * the first word in the list of words to interpret into IP
1973 		 * after saving its old value. When we return to the "next"
1974 		 * loop, the virtual machine will call the code for each
1975 		 * word in turn.
1976 		 */
1977 		case ficlInstructionColonParen:
1978 			(++returnTop)->p = (void *)ip;
1979 			ip = (ficlInstruction *)(fw->param);
1980 		continue;
1981 
1982 		case ficlInstructionCreateParen:
1983 			CHECK_STACK(0, 1);
1984 			(++dataTop)->p = (fw->param + 1);
1985 		continue;
1986 
1987 		case ficlInstructionVariableParen:
1988 			CHECK_STACK(0, 1);
1989 			(++dataTop)->p = fw->param;
1990 		continue;
1991 
1992 		/*
1993 		 * c o n s t a n t P a r e n
1994 		 * This is the run-time code for "constant". It simply returns
1995 		 * the contents of its word's first data ficlCell.
1996 		 */
1997 
1998 #if FICL_WANT_FLOAT
1999 		case ficlInstructionF2ConstantParen:
2000 			CHECK_FLOAT_STACK(0, 2);
2001 			FLOAT_PUSH_CELL_POINTER_DOUBLE(fw->param);
2002 
2003 		case ficlInstructionFConstantParen:
2004 			CHECK_FLOAT_STACK(0, 1);
2005 			FLOAT_PUSH_CELL_POINTER(fw->param);
2006 #endif /* FICL_WANT_FLOAT */
2007 
2008 		case ficlInstruction2ConstantParen:
2009 			CHECK_STACK(0, 2);
2010 			PUSH_CELL_POINTER_DOUBLE(fw->param);
2011 
2012 		case ficlInstructionConstantParen:
2013 			CHECK_STACK(0, 1);
2014 			PUSH_CELL_POINTER(fw->param);
2015 
2016 #if FICL_WANT_USER
2017 		case ficlInstructionUserParen: {
2018 			ficlInteger i = fw->param[0].i;
2019 			(++dataTop)->p = &vm->user[i];
2020 		continue;
2021 		}
2022 #endif
2023 
2024 		default:
2025 		/*
2026 		 * Clever hack, or evil coding?  You be the judge.
2027 		 *
2028 		 * If the word we've been asked to execute is in fact
2029 		 * an *instruction*, we grab the instruction, stow it
2030 		 * in "i" (our local cache of *ip), and *jump* to the
2031 		 * top of the switch statement.  --lch
2032 		 */
2033 			if (((ficlInstruction)fw->code >
2034 			    ficlInstructionInvalid) &&
2035 			    ((ficlInstruction)fw->code < ficlInstructionLast)) {
2036 				instruction = (ficlInstruction)fw->code;
2037 				goto AGAIN;
2038 			}
2039 
2040 			LOCAL_VARIABLE_SPILL;
2041 			(vm)->runningWord = fw;
2042 			fw->code(vm);
2043 			LOCAL_VARIABLE_REFILL;
2044 		continue;
2045 		}
2046 	}
2047 
2048 	LOCAL_VARIABLE_SPILL;
2049 	vm->exceptionHandler = oldExceptionHandler;
2050 }
2051 
2052 /*
2053  * v m G e t D i c t
2054  * Returns the address dictionary for this VM's system
2055  */
2056 ficlDictionary *
2057 ficlVmGetDictionary(ficlVm *vm)
2058 {
2059 	FICL_VM_ASSERT(vm, vm);
2060 	return (vm->callback.system->dictionary);
2061 }
2062 
2063 /*
2064  * v m G e t S t r i n g
2065  * Parses a string out of the VM input buffer and copies up to the first
2066  * FICL_COUNTED_STRING_MAX characters to the supplied destination buffer, a
2067  * ficlCountedString. The destination string is NULL terminated.
2068  *
2069  * Returns the address of the first unused character in the dest buffer.
2070  */
2071 char *
2072 ficlVmGetString(ficlVm *vm, ficlCountedString *counted, char delimiter)
2073 {
2074 	ficlString s = ficlVmParseStringEx(vm, delimiter, 0);
2075 
2076 	if (FICL_STRING_GET_LENGTH(s) > FICL_COUNTED_STRING_MAX) {
2077 		FICL_STRING_SET_LENGTH(s, FICL_COUNTED_STRING_MAX);
2078 	}
2079 
2080 	strncpy(counted->text, FICL_STRING_GET_POINTER(s),
2081 	    FICL_STRING_GET_LENGTH(s));
2082 	counted->text[FICL_STRING_GET_LENGTH(s)] = '\0';
2083 	counted->length = (ficlUnsigned8)FICL_STRING_GET_LENGTH(s);
2084 
2085 	return (counted->text + FICL_STRING_GET_LENGTH(s) + 1);
2086 }
2087 
2088 /*
2089  * v m G e t W o r d
2090  * vmGetWord calls vmGetWord0 repeatedly until it gets a string with
2091  * non-zero length.
2092  */
2093 ficlString
2094 ficlVmGetWord(ficlVm *vm)
2095 {
2096 	ficlString s = ficlVmGetWord0(vm);
2097 
2098 	if (FICL_STRING_GET_LENGTH(s) == 0) {
2099 		ficlVmThrow(vm, FICL_VM_STATUS_RESTART);
2100 	}
2101 
2102 	return (s);
2103 }
2104 
2105 /*
2106  * v m G e t W o r d 0
2107  * Skip leading whitespace and parse a space delimited word from the tib.
2108  * Returns the start address and length of the word. Updates the tib
2109  * to reflect characters consumed, including the trailing delimiter.
2110  * If there's nothing of interest in the tib, returns zero. This function
2111  * does not use vmParseString because it uses isspace() rather than a
2112  * single  delimiter character.
2113  */
2114 ficlString
2115 ficlVmGetWord0(ficlVm *vm)
2116 {
2117 	char *trace = ficlVmGetInBuf(vm);
2118 	char *stop = ficlVmGetInBufEnd(vm);
2119 	ficlString s;
2120 	ficlUnsigned length = 0;
2121 	char c = 0;
2122 
2123 	trace = ficlStringSkipSpace(trace, stop);
2124 	FICL_STRING_SET_POINTER(s, trace);
2125 
2126 	/* Please leave this loop this way; it makes Purify happier.  --lch */
2127 	for (;;) {
2128 		if (trace == stop)
2129 			break;
2130 		c = *trace;
2131 		if (isspace((unsigned char)c))
2132 			break;
2133 		length++;
2134 		trace++;
2135 	}
2136 
2137 	FICL_STRING_SET_LENGTH(s, length);
2138 
2139 	/* skip one trailing delimiter */
2140 	if ((trace != stop) && isspace((unsigned char)c))
2141 		trace++;
2142 
2143 	ficlVmUpdateTib(vm, trace);
2144 
2145 	return (s);
2146 }
2147 
2148 /*
2149  * v m G e t W o r d T o P a d
2150  * Does vmGetWord and copies the result to the pad as a NULL terminated
2151  * string. Returns the length of the string. If the string is too long
2152  * to fit in the pad, it is truncated.
2153  */
2154 int
2155 ficlVmGetWordToPad(ficlVm *vm)
2156 {
2157 	ficlString s;
2158 	char *pad = (char *)vm->pad;
2159 	s = ficlVmGetWord(vm);
2160 
2161 	if (FICL_STRING_GET_LENGTH(s) > FICL_PAD_SIZE)
2162 		FICL_STRING_SET_LENGTH(s, FICL_PAD_SIZE);
2163 
2164 	strncpy(pad, FICL_STRING_GET_POINTER(s), FICL_STRING_GET_LENGTH(s));
2165 	pad[FICL_STRING_GET_LENGTH(s)] = '\0';
2166 	return ((int)(FICL_STRING_GET_LENGTH(s)));
2167 }
2168 
2169 /*
2170  * v m P a r s e S t r i n g
2171  * Parses a string out of the input buffer using the delimiter
2172  * specified. Skips leading delimiters, marks the start of the string,
2173  * and counts characters to the next delimiter it encounters. It then
2174  * updates the vm input buffer to consume all these chars, including the
2175  * trailing delimiter.
2176  * Returns the address and length of the parsed string, not including the
2177  * trailing delimiter.
2178  */
2179 ficlString
2180 ficlVmParseString(ficlVm *vm, char delimiter)
2181 {
2182 	return (ficlVmParseStringEx(vm, delimiter, 1));
2183 }
2184 
2185 ficlString
2186 ficlVmParseStringEx(ficlVm *vm, char delimiter, char skipLeadingDelimiters)
2187 {
2188 	ficlString s;
2189 	char *trace = ficlVmGetInBuf(vm);
2190 	char *stop = ficlVmGetInBufEnd(vm);
2191 	char c;
2192 
2193 	if (skipLeadingDelimiters) {
2194 		while ((trace != stop) && (*trace == delimiter))
2195 			trace++;
2196 	}
2197 
2198 	FICL_STRING_SET_POINTER(s, trace);    /* mark start of text */
2199 
2200 	/* find next delimiter or end of line */
2201 	for (c = *trace;
2202 	    (trace != stop) && (c != delimiter) && (c != '\r') && (c != '\n');
2203 	    c = *++trace) {
2204 		;
2205 	}
2206 
2207 	/* set length of result */
2208 	FICL_STRING_SET_LENGTH(s, trace - FICL_STRING_GET_POINTER(s));
2209 
2210 	/* gobble trailing delimiter */
2211 	if ((trace != stop) && (*trace == delimiter))
2212 		trace++;
2213 
2214 	ficlVmUpdateTib(vm, trace);
2215 	return (s);
2216 }
2217 
2218 
2219 /*
2220  * v m P o p
2221  */
2222 ficlCell
2223 ficlVmPop(ficlVm *vm)
2224 {
2225 	return (ficlStackPop(vm->dataStack));
2226 }
2227 
2228 /*
2229  * v m P u s h
2230  */
2231 void
2232 ficlVmPush(ficlVm *vm, ficlCell c)
2233 {
2234 	ficlStackPush(vm->dataStack, c);
2235 }
2236 
2237 /*
2238  * v m P o p I P
2239  */
2240 void
2241 ficlVmPopIP(ficlVm *vm)
2242 {
2243 	vm->ip = (ficlIp)(ficlStackPopPointer(vm->returnStack));
2244 }
2245 
2246 /*
2247  * v m P u s h I P
2248  */
2249 void
2250 ficlVmPushIP(ficlVm *vm, ficlIp newIP)
2251 {
2252 	ficlStackPushPointer(vm->returnStack, (void *)vm->ip);
2253 	vm->ip = newIP;
2254 }
2255 
2256 /*
2257  * v m P u s h T i b
2258  * Binds the specified input string to the VM and clears >IN (the index)
2259  */
2260 void
2261 ficlVmPushTib(ficlVm *vm, char *text, ficlInteger nChars, ficlTIB *pSaveTib)
2262 {
2263 	if (pSaveTib) {
2264 		*pSaveTib = vm->tib;
2265 	}
2266 	vm->tib.text = text;
2267 	vm->tib.end = text + nChars;
2268 	vm->tib.index = 0;
2269 }
2270 
2271 void
2272 ficlVmPopTib(ficlVm *vm, ficlTIB *pTib)
2273 {
2274 	if (pTib) {
2275 		vm->tib = *pTib;
2276 	}
2277 }
2278 
2279 /*
2280  * v m Q u i t
2281  */
2282 void
2283 ficlVmQuit(ficlVm *vm)
2284 {
2285 	ficlStackReset(vm->returnStack);
2286 	vm->restart = 0;
2287 	vm->ip = NULL;
2288 	vm->runningWord = NULL;
2289 	vm->state = FICL_VM_STATE_INTERPRET;
2290 	vm->tib.text = NULL;
2291 	vm->tib.end = NULL;
2292 	vm->tib.index = 0;
2293 	vm->pad[0] = '\0';
2294 	vm->sourceId.i = 0;
2295 }
2296 
2297 /*
2298  * v m R e s e t
2299  */
2300 void
2301 ficlVmReset(ficlVm *vm)
2302 {
2303 	ficlVmQuit(vm);
2304 	ficlStackReset(vm->dataStack);
2305 #if FICL_WANT_FLOAT
2306 	ficlStackReset(vm->floatStack);
2307 #endif
2308 	vm->base = 10;
2309 }
2310 
2311 /*
2312  * v m S e t T e x t O u t
2313  * Binds the specified output callback to the vm. If you pass NULL,
2314  * binds the default output function (ficlTextOut)
2315  */
2316 void
2317 ficlVmSetTextOut(ficlVm *vm, ficlOutputFunction textOut)
2318 {
2319 	vm->callback.textOut = textOut;
2320 }
2321 
2322 void
2323 ficlVmTextOut(ficlVm *vm, char *text)
2324 {
2325 	ficlCallbackTextOut((ficlCallback *)vm, text);
2326 }
2327 
2328 
2329 void
2330 ficlVmErrorOut(ficlVm *vm, char *text)
2331 {
2332 	ficlCallbackErrorOut((ficlCallback *)vm, text);
2333 }
2334 
2335 
2336 /*
2337  * v m T h r o w
2338  */
2339 void
2340 ficlVmThrow(ficlVm *vm, int except)
2341 {
2342 	if (vm->exceptionHandler)
2343 		longjmp(*(vm->exceptionHandler), except);
2344 }
2345 
2346 void
2347 ficlVmThrowError(ficlVm *vm, char *fmt, ...)
2348 {
2349 	va_list list;
2350 
2351 	va_start(list, fmt);
2352 	vsprintf(vm->pad, fmt, list);
2353 	va_end(list);
2354 	strcat(vm->pad, "\n");
2355 
2356 	ficlVmErrorOut(vm, vm->pad);
2357 	longjmp(*(vm->exceptionHandler), FICL_VM_STATUS_ERROR_EXIT);
2358 }
2359 
2360 void
2361 ficlVmThrowErrorVararg(ficlVm *vm, char *fmt, va_list list)
2362 {
2363 	vsprintf(vm->pad, fmt, list);
2364 	/*
2365 	 * well, we can try anyway, we're certainly not
2366 	 * returning to our caller!
2367 	 */
2368 	va_end(list);
2369 	strcat(vm->pad, "\n");
2370 
2371 	ficlVmErrorOut(vm, vm->pad);
2372 	longjmp(*(vm->exceptionHandler), FICL_VM_STATUS_ERROR_EXIT);
2373 }
2374 
2375 /*
2376  * f i c l E v a l u a t e
2377  * Wrapper for ficlExec() which sets SOURCE-ID to -1.
2378  */
2379 int
2380 ficlVmEvaluate(ficlVm *vm, char *s)
2381 {
2382 	int returnValue;
2383 	ficlCell id = vm->sourceId;
2384 	ficlString string;
2385 	vm->sourceId.i = -1;
2386 	FICL_STRING_SET_FROM_CSTRING(string, s);
2387 	returnValue = ficlVmExecuteString(vm, string);
2388 	vm->sourceId = id;
2389 	return (returnValue);
2390 }
2391 
2392 /*
2393  * f i c l E x e c
2394  * Evaluates a block of input text in the context of the
2395  * specified interpreter. Emits any requested output to the
2396  * interpreter's output function.
2397  *
2398  * Contains the "inner interpreter" code in a tight loop
2399  *
2400  * Returns one of the VM_XXXX codes defined in ficl.h:
2401  * VM_OUTOFTEXT is the normal exit condition
2402  * VM_ERREXIT means that the interpreter encountered a syntax error
2403  *      and the vm has been reset to recover (some or all
2404  *      of the text block got ignored
2405  * VM_USEREXIT means that the user executed the "bye" command
2406  *      to shut down the interpreter. This would be a good
2407  *      time to delete the vm, etc -- or you can ignore this
2408  *      signal.
2409  */
2410 int
2411 ficlVmExecuteString(ficlVm *vm, ficlString s)
2412 {
2413 	ficlSystem *system = vm->callback.system;
2414 	ficlDictionary *dictionary = system->dictionary;
2415 
2416 	int except;
2417 	jmp_buf vmState;
2418 	jmp_buf *oldState;
2419 	ficlTIB saveficlTIB;
2420 
2421 	FICL_VM_ASSERT(vm, vm);
2422 	FICL_VM_ASSERT(vm, system->interpreterLoop[0]);
2423 
2424 	ficlVmPushTib(vm, FICL_STRING_GET_POINTER(s),
2425 	    FICL_STRING_GET_LENGTH(s), &saveficlTIB);
2426 
2427 	/*
2428 	 * Save and restore VM's jmp_buf to enable nested calls to ficlExec
2429 	 */
2430 	oldState = vm->exceptionHandler;
2431 
2432 	/* This has to come before the setjmp! */
2433 	vm->exceptionHandler = &vmState;
2434 	except = setjmp(vmState);
2435 
2436 	switch (except) {
2437 	case 0:
2438 		if (vm->restart) {
2439 			vm->runningWord->code(vm);
2440 			vm->restart = 0;
2441 		} else {	/* set VM up to interpret text */
2442 			ficlVmPushIP(vm, &(system->interpreterLoop[0]));
2443 		}
2444 
2445 		ficlVmInnerLoop(vm, 0);
2446 	break;
2447 
2448 	case FICL_VM_STATUS_RESTART:
2449 		vm->restart = 1;
2450 		except = FICL_VM_STATUS_OUT_OF_TEXT;
2451 	break;
2452 
2453 	case FICL_VM_STATUS_OUT_OF_TEXT:
2454 		ficlVmPopIP(vm);
2455 #if 0	/* we dont output prompt in loader */
2456 		if ((vm->state != FICL_VM_STATE_COMPILE) &&
2457 		    (vm->sourceId.i == 0))
2458 			ficlVmTextOut(vm, FICL_PROMPT);
2459 #endif
2460 	break;
2461 
2462 	case FICL_VM_STATUS_USER_EXIT:
2463 	case FICL_VM_STATUS_INNER_EXIT:
2464 	case FICL_VM_STATUS_BREAK:
2465 	break;
2466 
2467 	case FICL_VM_STATUS_QUIT:
2468 		if (vm->state == FICL_VM_STATE_COMPILE) {
2469 			ficlDictionaryAbortDefinition(dictionary);
2470 #if FICL_WANT_LOCALS
2471 			ficlDictionaryEmpty(system->locals,
2472 			    system->locals->forthWordlist->size);
2473 #endif
2474 		}
2475 		ficlVmQuit(vm);
2476 	break;
2477 
2478 	case FICL_VM_STATUS_ERROR_EXIT:
2479 	case FICL_VM_STATUS_ABORT:
2480 	case FICL_VM_STATUS_ABORTQ:
2481 	default:		/* user defined exit code?? */
2482 		if (vm->state == FICL_VM_STATE_COMPILE) {
2483 			ficlDictionaryAbortDefinition(dictionary);
2484 #if FICL_WANT_LOCALS
2485 			ficlDictionaryEmpty(system->locals,
2486 			    system->locals->forthWordlist->size);
2487 #endif
2488 		}
2489 		ficlDictionaryResetSearchOrder(dictionary);
2490 		ficlVmReset(vm);
2491 	break;
2492 	}
2493 
2494 	vm->exceptionHandler = oldState;
2495 	ficlVmPopTib(vm, &saveficlTIB);
2496 	return (except);
2497 }
2498 
2499 /*
2500  * f i c l E x e c X T
2501  * Given a pointer to a ficlWord, push an inner interpreter and
2502  * execute the word to completion. This is in contrast with vmExecute,
2503  * which does not guarantee that the word will have completed when
2504  * the function returns (ie in the case of colon definitions, which
2505  * need an inner interpreter to finish)
2506  *
2507  * Returns one of the VM_XXXX exception codes listed in ficl.h. Normal
2508  * exit condition is VM_INNEREXIT, Ficl's private signal to exit the
2509  * inner loop under normal circumstances. If another code is thrown to
2510  * exit the loop, this function will re-throw it if it's nested under
2511  * itself or ficlExec.
2512  *
2513  * NOTE: this function is intended so that C code can execute ficlWords
2514  * given their address in the dictionary (xt).
2515  */
2516 int
2517 ficlVmExecuteXT(ficlVm *vm, ficlWord *pWord)
2518 {
2519 	int except;
2520 	jmp_buf vmState;
2521 	jmp_buf *oldState;
2522 	ficlWord *oldRunningWord;
2523 
2524 	FICL_VM_ASSERT(vm, vm);
2525 	FICL_VM_ASSERT(vm, vm->callback.system->exitInnerWord);
2526 
2527 	/*
2528 	 * Save the runningword so that RESTART behaves correctly
2529 	 * over nested calls.
2530 	 */
2531 	oldRunningWord = vm->runningWord;
2532 	/*
2533 	 * Save and restore VM's jmp_buf to enable nested calls
2534 	 */
2535 	oldState = vm->exceptionHandler;
2536 	/* This has to come before the setjmp! */
2537 	vm->exceptionHandler = &vmState;
2538 	except = setjmp(vmState);
2539 
2540 	if (except)
2541 		ficlVmPopIP(vm);
2542 	else
2543 		ficlVmPushIP(vm, &(vm->callback.system->exitInnerWord));
2544 
2545 	switch (except) {
2546 	case 0:
2547 		ficlVmExecuteWord(vm, pWord);
2548 		ficlVmInnerLoop(vm, 0);
2549 	break;
2550 
2551 	case FICL_VM_STATUS_INNER_EXIT:
2552 	case FICL_VM_STATUS_BREAK:
2553 	break;
2554 
2555 	case FICL_VM_STATUS_RESTART:
2556 	case FICL_VM_STATUS_OUT_OF_TEXT:
2557 	case FICL_VM_STATUS_USER_EXIT:
2558 	case FICL_VM_STATUS_QUIT:
2559 	case FICL_VM_STATUS_ERROR_EXIT:
2560 	case FICL_VM_STATUS_ABORT:
2561 	case FICL_VM_STATUS_ABORTQ:
2562 	default:		/* user defined exit code?? */
2563 		if (oldState) {
2564 			vm->exceptionHandler = oldState;
2565 			ficlVmThrow(vm, except);
2566 		}
2567 	break;
2568 	}
2569 
2570 	vm->exceptionHandler = oldState;
2571 	vm->runningWord = oldRunningWord;
2572 	return (except);
2573 }
2574 
2575 /*
2576  * f i c l P a r s e N u m b e r
2577  * Attempts to convert the NULL terminated string in the VM's pad to
2578  * a number using the VM's current base. If successful, pushes the number
2579  * onto the param stack and returns FICL_TRUE. Otherwise, returns FICL_FALSE.
2580  * (jws 8/01) Trailing decimal point causes a zero ficlCell to be pushed. (See
2581  * the standard for DOUBLE wordset.
2582  */
2583 int
2584 ficlVmParseNumber(ficlVm *vm, ficlString s)
2585 {
2586 	ficlInteger accumulator = 0;
2587 	char isNegative = 0;
2588 	char isDouble = 0;
2589 	unsigned base = vm->base;
2590 	char *trace = FICL_STRING_GET_POINTER(s);
2591 	ficlUnsigned8 length = (ficlUnsigned8)FICL_STRING_GET_LENGTH(s);
2592 	unsigned c;
2593 	unsigned digit;
2594 
2595 	if (length > 1) {
2596 		switch (*trace) {
2597 		case '-':
2598 			trace++;
2599 			length--;
2600 			isNegative = 1;
2601 		break;
2602 		case '+':
2603 			trace++;
2604 			length--;
2605 			isNegative = 0;
2606 		break;
2607 		default:
2608 		break;
2609 		}
2610 	}
2611 
2612 	/* detect & remove trailing decimal */
2613 	if ((length > 0) && (trace[length - 1] == '.')) {
2614 		isDouble = 1;
2615 		length--;
2616 	}
2617 
2618 	if (length == 0)		/* detect "+", "-", ".", "+." etc */
2619 		return (0);		/* false */
2620 
2621 	while ((length--) && ((c = *trace++) != '\0')) {
2622 		if (!isalnum(c))
2623 			return (0);	/* false */
2624 
2625 		digit = c - '0';
2626 
2627 		if (digit > 9)
2628 			digit = tolower(c) - 'a' + 10;
2629 
2630 		if (digit >= base)
2631 			return (0);	/* false */
2632 
2633 		accumulator = accumulator * base + digit;
2634 	}
2635 
2636 	if (isNegative)
2637 		accumulator = -accumulator;
2638 
2639 	ficlStackPushInteger(vm->dataStack, accumulator);
2640 	if (vm->state == FICL_VM_STATE_COMPILE)
2641 		ficlPrimitiveLiteralIm(vm);
2642 
2643 	if (isDouble) {			/* simple (required) DOUBLE support */
2644 		if (isNegative)
2645 			ficlStackPushInteger(vm->dataStack, -1);
2646 		else
2647 			ficlStackPushInteger(vm->dataStack, 0);
2648 		if (vm->state == FICL_VM_STATE_COMPILE)
2649 			ficlPrimitiveLiteralIm(vm);
2650 	}
2651 
2652 	return (1); /* true */
2653 }
2654 
2655 /*
2656  * d i c t C h e c k
2657  * Checks the dictionary for corruption and throws appropriate
2658  * errors.
2659  * Input: +n number of ADDRESS UNITS (not ficlCells) proposed to allot
2660  *        -n number of ADDRESS UNITS proposed to de-allot
2661  *         0 just do a consistency check
2662  */
2663 void
2664 ficlVmDictionarySimpleCheck(ficlVm *vm, ficlDictionary *dictionary, int cells)
2665 {
2666 #if FICL_ROBUST >= 1
2667 	if ((cells >= 0) &&
2668 	    (ficlDictionaryCellsAvailable(dictionary) *
2669 	    (int)sizeof (ficlCell) < cells)) {
2670 		ficlVmThrowError(vm, "Error: dictionary full");
2671 	}
2672 
2673 	if ((cells <= 0) &&
2674 	    (ficlDictionaryCellsUsed(dictionary) *
2675 	    (int)sizeof (ficlCell) < -cells)) {
2676 		ficlVmThrowError(vm, "Error: dictionary underflow");
2677 	}
2678 #else /* FICL_ROBUST >= 1 */
2679 	FICL_IGNORE(vm);
2680 	FICL_IGNORE(dictionary);
2681 	FICL_IGNORE(cells);
2682 #endif /* FICL_ROBUST >= 1 */
2683 }
2684 
2685 void
2686 ficlVmDictionaryCheck(ficlVm *vm, ficlDictionary *dictionary, int cells)
2687 {
2688 #if FICL_ROBUST >= 1
2689 	ficlVmDictionarySimpleCheck(vm, dictionary, cells);
2690 
2691 	if (dictionary->wordlistCount > FICL_MAX_WORDLISTS) {
2692 		ficlDictionaryResetSearchOrder(dictionary);
2693 		ficlVmThrowError(vm, "Error: search order overflow");
2694 	} else if (dictionary->wordlistCount < 0) {
2695 		ficlDictionaryResetSearchOrder(dictionary);
2696 		ficlVmThrowError(vm, "Error: search order underflow");
2697 	}
2698 #else /* FICL_ROBUST >= 1 */
2699 	FICL_IGNORE(vm);
2700 	FICL_IGNORE(dictionary);
2701 	FICL_IGNORE(cells);
2702 #endif /* FICL_ROBUST >= 1 */
2703 }
2704 
2705 void
2706 ficlVmDictionaryAllot(ficlVm *vm, ficlDictionary *dictionary, int n)
2707 {
2708 	FICL_VM_DICTIONARY_SIMPLE_CHECK(vm, dictionary, n);
2709 	FICL_IGNORE(vm);
2710 	ficlDictionaryAllot(dictionary, n);
2711 }
2712 
2713 void
2714 ficlVmDictionaryAllotCells(ficlVm *vm, ficlDictionary *dictionary, int cells)
2715 {
2716 	FICL_VM_DICTIONARY_SIMPLE_CHECK(vm, dictionary, cells);
2717 	FICL_IGNORE(vm);
2718 	ficlDictionaryAllotCells(dictionary, cells);
2719 }
2720 
2721 /*
2722  * f i c l P a r s e W o r d
2723  * From the standard, section 3.4
2724  * b) Search the dictionary name space (see 3.4.2). If a definition name
2725  * matching the string is found:
2726  *  1.if interpreting, perform the interpretation semantics of the definition
2727  *  (see 3.4.3.2), and continue at a);
2728  *  2.if compiling, perform the compilation semantics of the definition
2729  *  (see 3.4.3.3), and continue at a).
2730  *
2731  * c) If a definition name matching the string is not found, attempt to
2732  * convert the string to a number (see 3.4.1.3). If successful:
2733  *  1.if interpreting, place the number on the data stack, and continue at a);
2734  *  2.if compiling, FICL_VM_STATE_COMPILE code that when executed will place
2735  *  the number on the stack (see 6.1.1780 LITERAL), and continue at a);
2736  *
2737  * d) If unsuccessful, an ambiguous condition exists (see 3.4.4).
2738  *
2739  * (jws 4/01) Modified to be a ficlParseStep
2740  */
2741 int
2742 ficlVmParseWord(ficlVm *vm, ficlString name)
2743 {
2744 	ficlDictionary *dictionary = ficlVmGetDictionary(vm);
2745 	ficlWord *tempFW;
2746 
2747 	FICL_VM_DICTIONARY_CHECK(vm, dictionary, 0);
2748 	FICL_STACK_CHECK(vm->dataStack, 0, 0);
2749 
2750 #if FICL_WANT_LOCALS
2751 	if (vm->callback.system->localsCount > 0) {
2752 		tempFW = ficlSystemLookupLocal(vm->callback.system, name);
2753 	} else
2754 #endif
2755 		tempFW = ficlDictionaryLookup(dictionary, name);
2756 
2757 	if (vm->state == FICL_VM_STATE_INTERPRET) {
2758 		if (tempFW != NULL) {
2759 			if (ficlWordIsCompileOnly(tempFW)) {
2760 				ficlVmThrowError(vm,
2761 				    "Error: FICL_VM_STATE_COMPILE only!");
2762 			}
2763 
2764 			ficlVmExecuteWord(vm, tempFW);
2765 			return (1); /* true */
2766 		}
2767 	} else {	/* (vm->state == FICL_VM_STATE_COMPILE) */
2768 		if (tempFW != NULL) {
2769 			if (ficlWordIsImmediate(tempFW)) {
2770 				ficlVmExecuteWord(vm, tempFW);
2771 			} else {
2772 				ficlCell c;
2773 				c.p = tempFW;
2774 				if (tempFW->flags & FICL_WORD_INSTRUCTION)
2775 					ficlDictionaryAppendUnsigned(dictionary,
2776 					    (ficlInteger)tempFW->code);
2777 				else
2778 					ficlDictionaryAppendCell(dictionary, c);
2779 			}
2780 			return (1); /* true */
2781 		}
2782 	}
2783 
2784 	return (0); /* false */
2785 }
2786