aboutsummaryrefslogtreecommitdiff
path: root/engines/sci/engine/vm.h
blob: f7b5adae7de3c406b3194be70c7c0e7e4478f083 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.

 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.

 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * $URL$
 * $Id$
 *
 */

#ifndef SCI_ENGINE_VM_H
#define SCI_ENGINE_VM_H

/* VM and kernel declarations */

//#include "common/serializer.h"
#include "sci/scicore/versions.h"	// for sci_version_t
#include "sci/engine/vm_types.h"	// for reg_t

#include "common/util.h"

namespace Sci {

class SegManager;

enum MemObjectType {
	MEM_OBJ_INVALID = 0,
	MEM_OBJ_SCRIPT = 1,
	MEM_OBJ_CLONES = 2,
	MEM_OBJ_LOCALS = 3,
	MEM_OBJ_STACK = 4,
	MEM_OBJ_SYS_STRINGS = 5,
	MEM_OBJ_LISTS = 6,
	MEM_OBJ_NODES = 7,
	MEM_OBJ_HUNK = 8,
	MEM_OBJ_DYNMEM = 9,
	MEM_OBJ_STRING_FRAG = 10,

	MEM_OBJ_MAX // For sanity checking
};

struct MemObject /* : public Common::Serializable */ {
	MemObjectType _type;
	int _segmgrId; /**< Internal value used by the seg_manager's hash map */

	typedef void (*NoteCallback)(void *param, reg_t addr);	// FIXME: Bad choice of name

public:
	static MemObject *createMemObject(MemObjectType type);

public:
	virtual ~MemObject() {}

	/**
	 * Dereferences a raw memory pointer.
	 * @param reg   reference to dereference
	 * @param size  if not NULL, set to the theoretical maximum size of the referenced data block
	 * @return              the data block referenced
	 */
	virtual byte *dereference(reg_t pointer, int *size);

	inline MemObjectType getType() const { return _type; }
	inline int getSegMgrId() const { return _segmgrId; }

	// Finds the canonic address associated with sub_reg
	// Parameters: (reg_t) sub_addr: The base address whose canonic address is to be found
	// For each valid address a, there exists a canonic address c(a) such that c(a) = c(c(a)).
	// This address "governs" a in the sense that deallocating c(a) will deallocate a.
	virtual reg_t findCanonicAddress(SegManager *segmgr, reg_t sub_addr) { return sub_addr; }

	// Deallocates all memory associated with the specified address
	// Parameters: (reg_t) sub_addr: The address (within the given segment) to deallocate
	virtual void freeAtAddress(SegManager *segmgr, reg_t sub_addr) {}

	// Iterates over and reports all addresses within the current segment
	// Parameters: note : (voidptr * addr) -> (): Invoked for each address on which free_at_address()
	//                                makes sense
	//             (void *) param: Parameter passed to 'note'
	virtual void listAllDeallocatable(SegmentId segId, void *param, NoteCallback note) {}

	// Iterates over all references reachable from the specified object
	// Parameters: (reg_t) object: The object (within the current segment) to analyse
	//             (void *) param: Parameter passed to 'note'
	//             note : (voidptr * addr) -> (): Invoked for each outgoing reference within the object
	// Note: This function may also choose to report numbers (segment 0) as adresses
	virtual void listAllOutgoingReferences(EngineState *s, reg_t object, void *param, NoteCallback note) {}
};


struct IntMapper;

enum {
	SYS_STRINGS_MAX = 4,

	SYS_STRING_SAVEDIR = 0,
	SYS_STRING_PARSER_BASE = 1,

	MAX_PARSER_BASE = 64
};

struct SystemString {
	char *name;
	int max_size;
	reg_t *value;
};

struct SystemStrings : public MemObject {
	SystemString strings[SYS_STRINGS_MAX];

public:
	SystemStrings() {
		memset(strings, 0, sizeof(strings));
	}
	~SystemStrings() {
		for (int i = 0; i < SYS_STRINGS_MAX; i++) {
			SystemString *str = &strings[i];
			if (str->name) {
				free(str->name);
				str->name = NULL;

				free(str->value);
				str->value = NULL;

				str->max_size = 0;
			}
		}
	}

	virtual byte *dereference(reg_t pointer, int *size);

//	virtual void saveLoadWithSerializer(Common::Serializer &ser);
};

/** Number of bytes to be allocated for the stack */
#define VM_STACK_SIZE 0x1000

/** Maximum number of calls residing on the stack */
#define SCRIPT_MAX_EXEC_STACK 256
/** Maximum number of entries in the class table */
#define SCRIPT_MAX_CLASSTABLE_SIZE 256
/** Maximum number of cloned objects on the heap */
#define SCRIPT_MAX_CLONES 256


/** Object-relative offset of the selector area inside a script */
#define SCRIPT_SELECTOR_OFFSET 8 -8

/** Object-relative offset of the pointer to the underlying script's local variables */
#define SCRIPT_LOCALVARPTR_OFFSET 2 -8

/** Object-relative offset of the selector counter */
#define SCRIPT_SELECTORCTR_OFFSET 6 -8

/** Object-relative offset of the offset of the function area */
#define SCRIPT_FUNCTAREAPTR_OFFSET 4 -8

/** Offset that has to be added to the function area pointer */
#define SCRIPT_FUNCTAREAPTR_MAGIC 8 -8

/** Offset of the name pointer */
#define SCRIPT_NAME_OFFSET (s->version < SCI_VERSION(1,001,000) ? 14 -8 : 16)
#define SCRIPT_NAME_SELECTOR (s->version < SCI_VERSION(1,001,000) ? 3 : 8)

/** Object-relative offset of the -info- selector */
#define SCRIPT_INFO_OFFSET (s->version < SCI_VERSION(1,001,000) ? 12 -8 : 14)
#define SCRIPT_INFO_SELECTOR (s->version < SCI_VERSION(1,001,000) ? 2 : 7)

/** Flag fo the -info- selector */
#define SCRIPT_INFO_CLONE 0x0001

/** Flag for the -info- selector */
#define SCRIPT_INFO_CLASS 0x8000


/** Magical object identifier */
#define SCRIPT_OBJECT_MAGIC_NUMBER 0x1234
/** Offset of this identifier */
#define SCRIPT_OBJECT_MAGIC_OFFSET (s->version < SCI_VERSION(1,001,000) ? -8 : 0)

/** Script-relative offset of the species ID */
#define SCRIPT_SPECIES_OFFSET 8 -8

#define SCRIPT_SUPERCLASS_OFFSET (s->version < SCI_VERSION(1,001,000) ? 10 -8 : 12)

/*---------------------------------*/
/* Script selector index variables */
/*---------------------------------*/
#define SCRIPT_SPECIES_SELECTOR (s->version < SCI_VERSION(1,001,000) ? 0 : 5)
#define SCRIPT_SUPERCLASS_SELECTOR (s->version < SCI_VERSION(1,001,000) ? 1 : 6)

/** Magic adjustment value for lofsa and lofss */
#define SCRIPT_LOFS_MAGIC 3


/** Stack pointer value: Use predecessor's value */
#define CALL_SP_CARRY NULL

/** Types of selectors as returned by lookup_selector() below. */
enum SelectorType {
	kSelectorNone = 0,
	kSelectorVariable,
	kSelectorMethod
};

struct Class {
	int script; /**< number of the script the class is in, -1 for non-existing */
	reg_t reg; /**< offset; script-relative offset, segment: 0 if not instantiated */
};

#define RAW_GET_CLASS_INDEX(scr, reg) ((scr)->obj_indices->checkKey(reg.offset, false))
#define RAW_IS_OBJECT(datablock) (READ_LE_UINT16(((byte *) datablock) + SCRIPT_OBJECT_MAGIC_OFFSET) == SCRIPT_OBJECT_MAGIC_NUMBER)

#define IS_CLASS(obj) (obj->variables[SCRIPT_INFO_SELECTOR].offset & SCRIPT_INFO_CLASS)

/** This struct is used to buffer the list of send calls in send_selector() */
struct CallsStruct {
	union {
		reg_t func;
		reg_t *var;
	} address;
	StackPtr argp;
	int argc;
	Selector selector;
	StackPtr sp; /**< Stack pointer */
	int type; /**< Same as ExecStack.type */
};

struct LocalVariables : public MemObject {
	int script_id; /**< Script ID this local variable block belongs to */
	reg_t *locals;
	int nr;

public:
	LocalVariables() {
		script_id = 0;
		locals = 0;
		nr = 0;
	}
	~LocalVariables() {
		free(locals);
		locals = NULL;
	}

	virtual byte *dereference(reg_t pointer, int *size);
	virtual reg_t findCanonicAddress(SegManager *segmgr, reg_t sub_addr);
	virtual void listAllOutgoingReferences(EngineState *s, reg_t object, void *param, NoteCallback note);

//	virtual void saveLoadWithSerializer(Common::Serializer &ser);
};

/** Clone has been marked as 'freed' */
#define OBJECT_FLAG_FREED (0x1 << 0)

struct Object {
	int flags;
	reg_t pos; /**< Object offset within its script; for clones, this is their base */
	int variables_nr;
	int variable_names_nr; /**< Number of variable names, may be less than variables_nr */
	int methods_nr;
	byte *base; /**< Points to a buffer all relative references (code, strings) point to */
	byte *base_obj; /**< base + object offset within base */
	uint16 *base_method; /**< Pointer to the method selector area for this object */
	uint16 *base_vars; /**< Pointer to the varselector area for this object */
	reg_t *variables;
};

struct CodeBlock {
	reg_t pos;
	int size;
};

#define VM_OBJECT_GET_VARSELECTOR(obj, i)  \
	(s->version < SCI_VERSION(1,001,000) ? \
	 READ_LE_UINT16(obj->base_obj + obj->variables_nr * 2 + i*2) : \
	 *(obj->base_vars + i))
#define VM_OBJECT_READ_PROPERTY(obj, i) (obj->variables[i])
#define VM_OBJECT_GET_FUNCSELECTOR(obj, i) \
	(s->version < SCI_VERSION(1,001,000) ? \
	 READ_LE_UINT16((byte *) (obj->base_method + i)) : \
	 READ_LE_UINT16((byte *) (obj->base_method + i*2 + 1)))
#define VM_OBJECT_READ_FUNCTION(obj, i) \
	(s->version < SCI_VERSION(1,001,000) ? \
	 make_reg(obj->pos.segment, \
		 READ_LE_UINT16((byte *) (obj->base_method \
				 + obj->methods_nr + 1 \
				 + i))) : \
	 make_reg(obj->pos.segment, \
		 READ_LE_UINT16((byte *) (obj->base_method \
				 + i * 2 + 2))))




struct Script : public MemObject {
	int nr; /**< Script number */
	byte *buf; /**< Static data buffer, or NULL if not used */
	size_t buf_size;
	size_t script_size;
	size_t heap_size;

	byte *synonyms; /**< Synonyms block or 0 if not present*/
	byte *heap_start; /**< Start of heap if SCI1.1, NULL otherwise */
	uint16 *export_table; /**< Abs. offset of the export table or 0 if not present */

	IntMapper *obj_indices;

	int exports_nr; /**< Number of entries in the exports table */
	int synonyms_nr; /**< Number of entries in the synonyms block */
	int lockers; /**< Number of classes and objects that require this script */

	/**
	 * Table for objects, contains property variables.
	 * Indexed by the value stored at SCRIPT_LOCALVARPTR_OFFSET,
	 * see VM_OBJECT_[GS]ET_INDEX()
	 */
	Common::Array<Object> _objects;

	int locals_offset;
	int locals_segment; /**< The local variable segment */
	LocalVariables *locals_block;

	Common::Array<CodeBlock> _codeBlocks;
	int relocated;
	int marked_as_deleted;

public:
	Script() {
		nr = 0;
		buf = NULL;
		buf_size = 0;
		script_size = 0;
		heap_size = 0;

		synonyms = NULL;
		heap_start = NULL;
		export_table = NULL;

		obj_indices = NULL;

		locals_offset = 0;
		locals_segment = 0;
		locals_block = NULL;

		relocated = 0;
		marked_as_deleted = 0;
	}

	~Script() {
		freeScript();
	}

	void freeScript();

	virtual byte *dereference(reg_t pointer, int *size);
	virtual reg_t findCanonicAddress(SegManager *segmgr, reg_t sub_addr);
	virtual void freeAtAddress(SegManager *segmgr, reg_t sub_addr);
	virtual void listAllDeallocatable(SegmentId segId, void *param, NoteCallback note);
	virtual void listAllOutgoingReferences(EngineState *s, reg_t object, void *param, NoteCallback note);

//	virtual void saveLoadWithSerializer(Common::Serializer &ser);
};

/** Data stack */
struct DataStack : MemObject {
	int nr; /**< Number of stack entries */
	reg_t *entries;

public:
	DataStack() {
		nr = 0;
		entries = NULL;
	}
	~DataStack() {
		free(entries);
		entries = NULL;
	}

	virtual byte *dereference(reg_t pointer, int *size);
	virtual reg_t findCanonicAddress(SegManager *segmgr, reg_t sub_addr);
	virtual void listAllOutgoingReferences(EngineState *s, reg_t object, void *param, NoteCallback note);

//	virtual void saveLoadWithSerializer(Common::Serializer &ser);
};

#define CLONE_USED -1
#define CLONE_NONE -1

typedef Object Clone;

struct Node {
	reg_t pred; /**< Predecessor node */
	reg_t succ; /**< Successor node */
	reg_t key;
	reg_t value;
}; /* List nodes */

struct List {
	reg_t first;
	reg_t last;
};

struct Hunk {
	void *mem;
	unsigned int size;
	const char *type;
};

template<typename T>
struct Table : public MemObject {
	typedef T value_type;
	struct Entry : public T {
		int next_free; /* Only used for free entries */
	};
	enum { HEAPENTRY_INVALID = -1 };


	int first_free; /**< Beginning of a singly linked list for entries */
	int entries_used; /**< Statistical information */

	Common::Array<Entry> _table;

public:
	Table() {
		entries_used = 0;
		first_free = HEAPENTRY_INVALID;
	}

	void initTable() {
		entries_used = 0;
		first_free = HEAPENTRY_INVALID;
	}

	int allocEntry() {
		entries_used++;
		if (first_free != HEAPENTRY_INVALID) {
			int oldff = first_free;
			first_free = _table[oldff].next_free;

			_table[oldff].next_free = oldff;
			return oldff;
		} else {
			uint newIdx = _table.size();
			_table.push_back(Entry());
			_table[newIdx].next_free = newIdx;	// Tag as 'valid'
			return newIdx;
		}
	}

	bool isValidEntry(int idx) {
		return idx >= 0 && (uint)idx < _table.size() && _table[idx].next_free == idx;
	}

	virtual void freeEntry(int idx) {
		if (idx < 0 || (uint)idx >= _table.size())
			::error("Table::freeEntry: Attempt to release invalid table index %d", idx);

		_table[idx].next_free = first_free;
		first_free = idx;
		entries_used--;
	}

	virtual void listAllDeallocatable(SegmentId segId, void *param, NoteCallback note);

//	virtual void saveLoadWithSerializer(Common::Serializer &ser);
};

// FIXME: Replace ENTRY_IS_VALID by a direct method call
#define ENTRY_IS_VALID(t, i) ((t)->isValidEntry(i))


/* CloneTable */
struct CloneTable : public Table<Clone> {
	virtual void freeEntry(int idx) {
		Table<Clone>::freeEntry(idx);

		free(_table[idx].variables); // Free the dynamically allocated memory part
	}

	virtual void freeAtAddress(SegManager *segmgr, reg_t sub_addr);
	virtual void listAllOutgoingReferences(EngineState *s, reg_t object, void *param, NoteCallback note);
};


/* NodeTable */
struct NodeTable : public Table<Node> {
	virtual void freeAtAddress(SegManager *segmgr, reg_t sub_addr);
	virtual void listAllOutgoingReferences(EngineState *s, reg_t object, void *param, NoteCallback note);
};


/* ListTable */
struct ListTable : public Table<List> {
	virtual void freeAtAddress(SegManager *segmgr, reg_t sub_addr);
	virtual void listAllOutgoingReferences(EngineState *s, reg_t object, void *param, NoteCallback note);
};


/* HunkTable */
struct HunkTable : public Table<Hunk> {
	virtual void freeEntry(int idx) {
		Table<Hunk>::freeEntry(idx);

		free(_table[idx].mem);
	}
};


// Free-style memory
struct DynMem : public MemObject {
	int _size;
	char *_description;
	byte *_buf;

public:
	DynMem() : _size(0), _description(0), _buf(0) {}
	~DynMem() {
		free(_description);
		_description = NULL;
		free(_buf);
		_buf = NULL;
	}

	virtual byte *dereference(reg_t pointer, int *size);
	virtual reg_t findCanonicAddress(SegManager *segmgr, reg_t sub_addr);
	virtual void listAllDeallocatable(SegmentId segId, void *param, NoteCallback note);

//	virtual void saveLoadWithSerializer(Common::Serializer &ser);
};

/** Contains selector IDs for a few selected selectors */
struct selector_map_t {
	Selector init; /**< Init function */
	Selector play; /**< Play function (first function to be called) */
	Selector replay; /**< Replay function */
	Selector x, y, z; /**< Coordinates */
	Selector priority;
	Selector view, loop, cel; /**< Description of a specific image */
	Selector brLeft, brRight, brTop, brBottom; /**< Bounding Rectangle */
	Selector xStep, yStep; /**< BR adjustments */
	Selector nsLeft, nsRight, nsTop, nsBottom; /**< View boundaries ('now seen') */
	Selector text, font; /**< Used by controls */
	Selector type, state; /**< Used by contols as well */
	Selector doit; /**< Called (!) by the Animate() system call */
	Selector signal; /**< Used by Animate() to control a view's behaviour */
	Selector underBits; /**< Used by the graphics subroutines to store backupped BG pic data */

	/* The following selectors are used by the Bresenham syscalls: */
	Selector canBeHere; /**< Funcselector: Checks for movement validity */
	Selector client; /**< The object that wants to be moved */
	Selector cycler; /**< The cycler of the client */
	Selector dx, dy; /**< Deltas */
	Selector edgeHit;
	Selector b_movCnt, b_i1, b_i2, b_di, b_xAxis, b_incr; /**< Various Bresenham vars */
	Selector completed;

	Selector illegalBits; /**< Used by CanBeHere */
	Selector dispose;

	Selector prevSignal; /**< Used by DoSound */

	Selector message, modifiers; /**< Used by GetEvent */

	Selector owner, handle;
	Selector cue;
	Selector number;

	Selector max, cursor; /**< Used by EditControl */
	Selector mode; /**< Used by text controls (-> DrawControl()) */

	Selector wordFail, syntaxFail, semanticFail; /**< Used by Parse() */

	Selector claimed; /**< Used generally by the event mechanism */

	Selector elements; /**< Used by SetSynonyms() */

	Selector lsTop, lsBottom, lsRight, lsLeft; /**< Used by Animate() subfunctions and scroll list controls */

	Selector baseSetter; /**< Alternative baseSetter */

	Selector who, distance; /**< Used for 'chasing' movers */

	Selector looper, mover, isBlocked, heading; /**< Used in DoAvoider */

	Selector caller, moveDone, moveSpeed; /**< Used for DoBresen */

	Selector delete_; /**< Called by Animate() to dispose a view object */

	Selector vol;
	Selector pri;

	Selector min; /**< SMPTE time format */
	Selector sec;
	Selector frame;

	Selector dataInc;
	Selector size;
	Selector palette;
	Selector cantBeHere;
	Selector nodePtr;
	Selector flags;

	Selector points; /**< Used by AvoidPath() */

	Selector syncCue; /**< Used by DoSync() */
	Selector syncTime; /**< Used by DoSync() */
};

struct ViewObject {
	reg_t obj;
	reg_t *signalp;    /* Used only indirectly */
	reg_t *underBitsp; /* The same goes for the handle storage */
	int underBits; /* Copy of the underbits: Needed for cleanup */

	int x, y;
	int priority;
	byte *view;
	int view_nr, loop, cel; /* view_nr is ised for save/restore */
	int nsTop, nsLeft, nsRight, nsBottom;
	int real_y, z, index_nr; /* Used for sorting */
};

enum {
	VAR_GLOBAL = 0,
	VAR_LOCAL = 1,
	VAR_TEMP = 2,
	VAR_PARAM = 3
};

enum ExecStackType {
	EXEC_STACK_TYPE_CALL = 0,
	EXEC_STACK_TYPE_KERNEL = 1,
	EXEC_STACK_TYPE_VARSELECTOR = 2
};

struct ExecStack {
	reg_t objp;
	reg_t sendp; /**< Pointer to the object containing the invoked method */
	union {
		reg_t *varp; /**< Variable pointer for read/write access */
		reg_t pc; /**< Not accurate for the TOS element */
	} addr;
	StackPtr fp; /**< Frame pointer */
	StackPtr sp; /**< Stack pointer */
	int argc;

	/* former variables[4]: [all other values are derived] */
	StackPtr variables_argp; /**< Argument pointer */
	SegmentId local_segment; /**< local variables etc. */

	Selector selector; /**< The selector which was used to call or -1 if not applicable */
	int origin;   /**< The stack frame position the call was made from, or -1 if it was the initial call.  */
	ExecStackType type;
};


enum BreakpointType {
	/**
	 * Break when selector is executed. data contains (char *) selector name
	 * (in the format Object::Method)
	 */
	BREAK_SELECTOR = 1,

	/**
	 * Break when an exported function is called. data contains
	 * script_no << 16 | export_no.
	 */
	BREAK_EXPORT = 2
};

struct Breakpoint {
	BreakpointType type;
	union {
		uint32 address;  /**< Breakpoints on exports */
		char *name; /**< Breakpoints on selector names */
	} data;
	Breakpoint *next;
};

/** Set this to 1 to activate script debugging */
extern int script_debug_flag;

/** Set to 1 to move pc back to last position, even though action is executed */
extern int script_error_flag;

/** Displays the numbers of scripts when they are (un)loaded */
extern int script_checkloads_flag;

#define SCRIPT_ABORT_WITH_REPLAY 1025

/**
 * Set this to 1 to abort script execution immediately. Aborting will leave the
 * debug exec stack intact.
 * Set it to SCRIPT_ABORT_WITH_REPLAY to force a replay afterwards.
 */
extern int script_abort_flag;

/** Number of kernel calls in between gcs; should be < 50000 */
#define GC_INTERVAL 32768

/** Initially GC_DELAY, can be set at runtime */
extern int script_gc_interval;

/** Number of steps executed */
extern int script_step_counter;


/** The function used to get input for debugging */
extern const char *(*_debug_get_input)(void);

extern int _debugstate_valid;
extern int _debug_seeking;
extern int _debug_step_running;


typedef int kernel_function(struct EngineState *s);

extern kernel_function* kfuncs[];
extern int max_instance;

/*inline*/
ExecStack *execute_method(EngineState *s, uint16 script, uint16 pubfunct, StackPtr sp, reg_t calling_obj,
	uint16 argc, StackPtr argp);
/* Executes function pubfunct of the specified script.
** Parameters: (EngineState *) s: The state which is to be executed with
**             (uint16) script: The script which is called
**             (uint16) pubfunct: The exported script function which is to be called
**             (StackPtr) sp: Stack pointer position
**             (reg_t) calling_obj: The heap address of the object which executed the call
**             (uint16) argc: Number of arguments supplied
**             (StackPtr) argp: Pointer to the first supplied argument
** Returns   : (ExecStack *): A pointer to the new exec stack TOS entry
*/


ExecStack *send_selector(EngineState *s, reg_t send_obj, reg_t work_obj,
	StackPtr sp, int framesize, StackPtr argp);
/* Executes a "send" or related operation to a selector
** Parameters: (EngineState *) s: The EngineState to operate on
**             (reg_t) send_obj: Heap address of the object to send to
**             (reg_t) work_obj: Heap address of the object initiating the send
**             (StackPtr) sp: Stack pointer position
**             (int) framesize: Size of the send as determined by the "send" operation
**             (StackPtr) argp: Pointer to the beginning of the heap block containing the
**                              data to be send. This area is a succession of one or more
**                              sequences of [selector_number][argument_counter] and then
**                              "argument_counter" word entries with the parameter values.
** Returns   : (ExecStack *): A pointer to the new execution stack TOS entry
*/


#define SCI_XS_CALLEE_LOCALS -1

ExecStack *add_exec_stack_entry(EngineState *s, reg_t pc, StackPtr sp, reg_t objp, int argc,
	StackPtr argp, Selector selector, reg_t sendp, int origin, SegmentId local_segment);
/* Adds an entry to the top of the execution stack
** Parameters: (EngineState *) s: The state with which to execute
**             (reg_t) pc: The initial program counter
**             (StackPtr) sp: The initial stack pointer
**             (reg_t) objp: Pointer to the beginning of the current object
**             (int) argc: Number of parameters to call with
**             (StackPtr) argp: Heap pointer to the first parameter
**             (Selector) selector: The selector by which it was called or
**			  NULL_SELECTOR if n.a. For debugging.
**             (reg_t) sendp: Pointer to the object which the message was sent to.
**                       Equal to objp for anything but super.
**             (int) origin: Number of the execution stack element this entry was created by
**                       (usually the current TOS number, except for multiple sends).
**             (SegmentId) local_segment: The segment to use for local variables,
**                        or SCI_XS_CALLEE_LOCALS to use obj's segment.
** Returns   : (ExecStack *): A pointer to the new exec stack TOS entry
*/


ExecStack *add_exec_stack_varselector(EngineState *s, reg_t objp, int argc, StackPtr argp,
	Selector selector, reg_t *address, int origin);
/* Adds one varselector access to the execution stack
** Parameters: (EngineState *) s: The EngineState to use
**             (reg_t) objp: Pointer to the object owning the selector
**             (int) argc: 1 for writing, 0 for reading
**             (StackPtr) argp: Pointer to the address of the data to write -2
**             (int) selector: Selector name
**             (reg_t *) address: Heap address of the selector
**             (int) origin: Stack frame which the access originated from
** Returns   : (ExecStack *): Pointer to the new exec-TOS element
** This function is called from send_selector only.
*/


void run_vm(EngineState *s, int restoring);
/* Executes the code on s->heap[pc] until it hits a 'ret' operation while (stack_base == stack_pos)
** Parameters: (EngineState *) s: The state to use
**             (int) restoring: 1 if s has just been restored, 0 otherwise
** Returns   : (void)
** This function will execute SCI bytecode. It requires s to be set up
** correctly.
*/

void vm_handle_fatal_error(EngineState *s, int line, const char *file);
/* Handles a fatal error condition
** Parameters: (EngineState *) s: The state to recover from
**             (int) line: Source code line number the error occured in
**             (const char *) file: File the error occured in
*/


void script_debug(EngineState *s, reg_t *pc, StackPtr *sp, StackPtr *pp, reg_t *objp,
	int *restadjust, SegmentId *segids, reg_t **variables, reg_t **variables_base,
	int *variables_nr, int bp);
/* Debugger functionality
** Parameters: (EngineState *) s: The state at which debugging should take place
**             (reg_t *) pc: Pointer to the program counter
**             (StackPtr *) sp: Pointer to the stack pointer
**             (StackPtr *) pp: Pointer to the frame pointer
**             (reg_t *) objp: Pointer to the object base pointer
**             (int *) restadjust: Pointer to the &rest adjustment value
**	       (SegmentId *) segids: four-element array containing segment IDs for locals etc.
**	       (reg_t **) variables: four-element array referencing registers for globals etc.
**	       (reg_t **) variables_base: four-element array referencing
**                                        register bases for temps etc.
**	       (int *) variables_nr: four-element array giving sizes for params etc. (may be NULL)
**             (int) bp: Flag, set to 1 when a breakpoint is triggered
** Returns   : (void)
*/

int script_init_engine(EngineState *s, sci_version_t version);
/* Initializes a EngineState block
** Parameters: (EngineState *) s: The state to initialize
** Returns   : 0 on success, 1 if vocab.996 (the class table) is missing or corrupted
*/

void script_set_gamestate_save_dir(EngineState *s, const char *path);
/* Sets the gamestate's save_dir to the parameter path
** Parameters: (EngineState *) s: The state to set
**             (const char *) path: Path where save_dir will point to
** Returns   : (void)
*/

void script_free_engine(EngineState *s);
/* Frees all additional memory associated with a EngineState block
** Parameters: (EngineState *) s: The EngineState whose elements should be cleared
** Returns   : (void)
*/

void script_free_vm_memory(EngineState *s);
/* Frees all script memory (heap, hunk, and class tables).
** Parameters: (EngineState *) s: The EngineState to free
** Returns   : (void)
** This operation is implicit in script_free_engine(), but is required for restoring
** the game state.
*/


SelectorType lookup_selector(EngineState *s, reg_t obj, Selector selectorid, reg_t **vptr, reg_t *fptr);
/* Looks up a selector and returns its type and value
** Parameters: (EngineState *) s: The EngineState to use
**             (reg_t) obj: Address of the object to look the selector up in
**             (Selector) selectorid: The selector to look up
** Returns   : (SelectorType) kSelectorNone if the selector was not found in the object or its superclasses.
**                            kSelectorVariable if the selector represents an object-relative variable
**                            kSelectorMethod if the selector represents a method
**             (reg_t *) *vptr: A pointer to the storage space associated with the selector, if
**                              it is a variable
**             (reg_t) *fptr: A reference to the function described by that selector, if it is
**                            a valid function selector.
** *vptr is written to iff it is non-NULL and the selector indicates a property of the object.
** *fptr is written to iff it is non-NULL and the selector indicates a member function of that object.
*/

enum {
	SCRIPT_GET_DONT_LOAD = 0, /**< Fail if not loaded */
	SCRIPT_GET_LOAD = 1, /**< Load, if neccessary */
	SCRIPT_GET_LOCK = 3 /**< Load, if neccessary, and lock */
};

SegmentId script_get_segment(EngineState *s, int script_id, int load);
/* Determines the segment occupied by a certain script
** Parameters: (EngineState *) s: The state to operate on
**             (int) script_id: The script in question
**             (int) load: One of SCRIPT_GET_*
** Returns   : The script's segment, or 0 on failure
*/

reg_t script_lookup_export(EngineState *s, int script_nr, int export_index);
/* Looks up an entry of the exports table of a script
** Parameters: (EngineState *) s: The state to operate on
**             (int) script_nr: The script to look up in
** Returns   : (int) export_index: index of the export entry to look up
*/

int script_instantiate(EngineState *s, int script_nr);
/* Makes sure that a script and its superclasses get loaded to the heap
** Parameters: (EngineState *) s: The state to operate on
**             (int) script_nr: The script number to load
** Returns   : (int) The script's segment ID or 0 if out of heap
** If the script already has been loaded, only the number of lockers is increased.
** All scripts containing superclasses of this script aret loaded recursively as well,
** unless 'recursive' is set to zero.
** The complementary function is "script_uninstantiate()" below.
*/


void script_uninstantiate(EngineState *s, int script_nr);
/* Decreases the numer of lockers of a script and unloads it if that number reaches zero
** Parameters: (EngineState *) s: The state to operate on
**             (int) script_nr: The script number that is requestet to be unloaded
** Returns   : (void)
** This function will recursively unload scripts containing its superclasses, if those
** aren't locked by other scripts as well.
*/


int game_init(EngineState *s);
/* Initializes an SCI game
** Parameters: (EngineState *) s: The state to operate on
** Returns   : (int): 0 on success, 1 if an error occured.
** This function must be run before script_run() is executed.
** Graphics data is initialized iff s->gfx_state != NULL.
*/

int game_init_graphics(EngineState *s);
/* Initializes the graphics part of an SCI game
** Parameters: (EngineState *) s: The state to initialize the graphics in
** Returns   : (int) 0 on success, 1 if an error occured
** This function may only be called if game_init() did not initialize
** the graphics data.
*/

int game_init_sound(EngineState *s, int sound_flags);
/* Initializes the sound part of an SCI game
** Parameters: (EngineState *) s: The state to initialize the sound in
**             (int) sound_flags:  Flags to pass to the sound subsystem
** Returns   : (int) 0 on success, 1 if an error occured
** This function may only be called if game_init() did not initialize
** the graphics data.
*/


int game_run(EngineState **s);
/* Runs an SCI game
** Parameters: (EngineState **) s: Pointer to the pointer of the state to operate on
** Returns   : (int): 0 on success, 1 if an error occured.
** This is the main function for SCI games. It takes a valid state, loads script 0 to it,
** finds the game object, allocates a stack, and runs the init method of the game object.
** In layman's terms, this runs an SCI game.
** By the way, *s may be changed during the game, e.g. if a game state is restored.
*/

int game_restore(EngineState **s, char *savegame_name);
/* Restores an SCI game state and runs the game
** Parameters: (EngineState **) s: Pointer to the pointer of the state to operate on
**             (char *) savegame_name: Name of the savegame to restore
** Returns   : (int): 0 on success, 1 if an error occured.
** This restores a savegame; otherwise, it behaves just like game_run().
*/

int game_exit(EngineState *s);
/* Uninitializes an initialized SCI game
** Parameters: (EngineState *) s: The state to operate on
** Returns   : (int): 0 on success, 1 if an error occured.
** This function should be run after each script_run() call.
*/

void quit_vm();
/* Instructs the virtual machine to abort
** Paramteres: (void)
** Returns   : (void)
*/

void script_map_selectors(EngineState *s, selector_map_t *map);
/* Maps special selectors
** Parameters: (EngineState *) s: The state from which the selector information should be taken
**             (selector_map_t *) map: Pointer to the selector map to map
** Returns   : (void)
** Called by script_run();
*/

int script_map_kernel(EngineState *s);
/* Maps kernel functions
** Parameters: (EngineState *) s: The state which the _kernelNames are retrieved from
** Returns   : (void)
** This function reads from and writes to s. It is called by script_run().
*/


void script_detect_versions(EngineState *s);
/* Detects SCI versions by their different script header
** Parameters: (EngineState *) s: The state to operate on
** Returns   : (void)
*/

reg_t kalloc(EngineState *s, const char *type, int space);
/* Allocates "kernel" memory and returns a handle suitable to be passed on to SCI scripts
** Parameters: (EngineState *) s: Pointer to the EngineState to operate on
**             (const char *) type: A free-form type description string (static)
**             (int) space: The space to allocate
** Returns   : (reg_t) The handle
*/

bool has_kernel_function(EngineState *s, const char *kname);
/* Detects whether a particular kernel function is required in the game
** Parameters: (EngineState *) s: Pointer to the EngineState to operate on
**             (const char *) kname: The name of the desired kernel function
** Returns   : (bool) 1 if the kernel function is listed in the kernel table,
**                   0 otherwise
*/

byte *kmem(EngineState *s, reg_t handle);
/* Returns a pointer to "kernel" memory based on the handle
** Parameters: (EngineState *) s: Pointer to the EngineState to operate on
**             (reg_t) handle: The handle to use
** Returns   : (byte *) A pointer to the allocated memory
*/


int kfree(EngineState *s, reg_t handle);
/* Frees all "kernel" memory associated with a handle
** Parameters: (EngineState *) s: Pointer to the EngineState to operate on
**             (reg_t) handle: The handle to free
** Returns   : (int) 0 on success, 1 otherwise
*/

const char *obj_get_name(EngineState *s, reg_t pos);
/* Determines the name of an object
** Parameters: (EngineState *) s: Pointer to the EngineState to operate on
**             (reg_t) pos: Location of the object whose name we want to
**                          inspect
** Returns   : (const char *) A name for that object, or a string describing
**                            an error that occured while looking it up
** The string is stored in a static buffer and need not be freed (neither
** may it be modified).
*/

Object *obj_get(EngineState *s, reg_t offset);
/* Retrieves an object from the specified location
** Parameters: (EngineState *) s: Pointer to the EngineState to operate on
**             (reg_t) offset: The object's offset
** Returns   : (Object *) The object in question, or NULL if there is none
*/

} // End of namespace Sci

#endif // SCI_ENGINE_VM_H