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/* 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 "sci/engine/vm_types.h" // for reg_t
#include "common/util.h"
namespace Sci {
class SegManager;
struct EngineState;
typedef int sci_version_t;
struct IntMapper;
struct Object;
/** 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_1 ? 14 -8 : 16)
#define SCRIPT_NAME_SELECTOR (s->_version < SCI_VERSION_1_1 ? 3 : 8)
/** Object-relative offset of the -info- selector */
#define SCRIPT_INFO_OFFSET (s->_version < SCI_VERSION_1_1 ? 12 -8 : 14)
#define SCRIPT_INFO_SELECTOR (s->_version < SCI_VERSION_1_1 ? 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_1 ? -8 : 0)
/** Script-relative offset of the species ID */
#define SCRIPT_SPECIES_OFFSET 8 -8
#define SCRIPT_SUPERCLASS_OFFSET (s->_version < SCI_VERSION_1_1 ? 10 -8 : 12)
/*---------------------------------*/
/* Script selector index variables */
/*---------------------------------*/
#define SCRIPT_SPECIES_SELECTOR (s->_version < SCI_VERSION_1_1 ? 0 : 5)
#define SCRIPT_SUPERCLASS_SELECTOR (s->_version < SCI_VERSION_1_1 ? 1 : 6)
#define SCRIPT_CLASSSCRIPT_SELECTOR 4
/** 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)
/** 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;
Selector printLang; /**< Used for i18n */
Selector subtitleLang;
Selector parseLang;
};
// A reference to an object's variable.
// The object is stored as a reg_t, the variable as an index into _variables
struct ObjVarRef {
reg_t obj;
int varindex;
reg_t* getPointer(EngineState *s) const;
};
struct ViewObject {
reg_t obj;
ObjVarRef signalp; /* Used only indirectly */
ObjVarRef 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; // Pointer to the beginning of the current object
reg_t sendp; // Pointer to the object containing the invoked method
union {
ObjVarRef varp; // Variable pointer for r/w access
reg_t pc; // Pointer to the initial program counter. Not accurate for the TOS element
} addr;
StackPtr fp; // Frame pointer
StackPtr sp; // Stack pointer
int argc;
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;
reg_t* getVarPointer(EngineState *s) const;
};
// These types are used both as identifiers and as elements of bitfields
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 abort script execution immediately. Aborting will
* leave the debug exec stack intact.
* Set it to 2 to force a replay afterwards.
*/
extern int script_abort_flag;
/** Number of kernel calls in between gcs; should be < 50000 */
enum {
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;
/**
* Executes function pubfunct of the specified script.
* @param[in] s The state which is to be executed with
* @param[in] script The script which is called
* @param[in] pubfunct The exported script function which is to
* be called
* @param[in] sp Stack pointer position
* @param[in] calling_obj The heap address of the object that
* executed the call
* @param[in] argc Number of arguments supplied
* @param[in] argp Pointer to the first supplied argument
* @return A pointer to the new exec stack TOS entry
*/
ExecStack *execute_method(EngineState *s, uint16 script, uint16 pubfunct,
StackPtr sp, reg_t calling_obj, uint16 argc, StackPtr argp);
/**
* Executes a "send" or related operation to a selector.
* @param[in] s The EngineState to operate on
* @param[in] send_obj Heap address of the object to send to
* @param[in] work_obj Heap address of the object initiating the send
* @param[in] sp Stack pointer position
* @param[in] framesize Size of the send as determined by the "send"
* operation
* @param[in] argp Pointer to the beginning of the heap block
* containing the data to be sent. 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.
* @return A pointer to the new execution stack TOS entry
*/
ExecStack *send_selector(EngineState *s, reg_t send_obj, reg_t work_obj,
StackPtr sp, int framesize, StackPtr argp);
#define SCI_XS_CALLEE_LOCALS -1
/**
* Adds an entry to the top of the execution stack.
*
* @param[in] s The state with which to execute
* @param[in] pc The initial program counter
* @param[in] sp The initial stack pointer
* @param[in] objp Pointer to the beginning of the current object
* @param[in] argc Number of parameters to call with
* @param[in] argp Heap pointer to the first parameter
* @param[in] selector The selector by which it was called or
* NULL_SELECTOR if n.a. For debugging.
* @param[in] sendp Pointer to the object which the message was
* sent to. Equal to objp for anything but super.
* @param[in] origin Number of the execution stack element this
* entry was created by (usually the current TOS
* number, except for multiple sends).
* @param[in] local_segment The segment to use for local variables,
* or SCI_XS_CALLEE_LOCALS to use obj's segment.
* @return A pointer to the new exec stack TOS entry
*/
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 one varselector access to the execution stack.
* This function is called from send_selector only.
* @param[in] s The EngineState to use
* @param[in] objp Pointer to the object owning the selector
* @param[in] argc 1 for writing, 0 for reading
* @param[in] argp Pointer to the address of the data to write -2
* @param[in] selector Selector name
* @param[in] address Heap address of the selector
* @param[in] origin Stack frame which the access originated from
* @return Pointer to the new exec-TOS element
*/
ExecStack *add_exec_stack_varselector(EngineState *s, reg_t objp, int argc,
StackPtr argp, Selector selector, const ObjVarRef& address,
int origin);
/**
* This function executes SCI bytecode
* It executes the code on s->heap[pc] until it hits a 'ret' operation
* while (stack_base == stack_pos). Requires s to be set up correctly.
* @param[in] s The state to use
* @param[in] restoring 1 if s has just been restored, 0 otherwise
*/
void run_vm(EngineState *s, int restoring);
/**
* Handles a fatal error condition
* @param[in] s The state to recover from
* @param[in] line Source code line number the error occured in
* @param[in] file File the error occured in
*/
void vm_handle_fatal_error(EngineState *s, int line, const char *file);
/**
* Debugger functionality
* @param[in] s The state at which debugging should take place
* @param[in] bp Flag, set to true when a breakpoint is triggered
*/
void script_debug(EngineState *s, bool bp);
/**
* Initializes a EngineState block
* @param[in] s The state to initialize
* @return 0 on success, 1 if vocab.996 (the class table) is missing
* or corrupted
*/
int script_init_engine(EngineState *);
/**
* Sets the gamestate's save_dir to the parameter path
* @param[in] s The state to set
* @param[in] path Path where save_dir will point to
*/
void script_set_gamestate_save_dir(EngineState *s, const char *path);
/**
* Frees all additional memory associated with a EngineState block
* @param[in] s The EngineState whose elements should be cleared
*/
void script_free_engine(EngineState *s);
/**
* Frees all script memory (heap, hunk, and class tables).
* This operation is implicit in script_free_engine(), but is required for
* restoring the game state.
* @param[in] s The EngineState to free
*/
void script_free_vm_memory(EngineState *s);
/**
* Looks up a selector and returns its type and value
* varindex is written to iff it is non-NULL and the selector indicates a property of the object.
* @param[in] s The EngineState to use
* @param[in] obj Address of the object to look the selector up in
* @param[in] selectorid The selector to look up
* @param[out] varp A reference to the selector, if it is a
* variable.
* @param[out] fptr A reference to the function described by that
* selector, if it is a valid function selector.
* fptr is written to iff it is non-NULL and the
* selector indicates a member function of that
* object.
* @return 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
*/
SelectorType lookup_selector(EngineState *s, reg_t obj, Selector selectorid,
ObjVarRef *varp, reg_t *fptr);
/**
* Parameters for script_get_segment()
*/
typedef 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 */
} SCRIPT_GET;
/**
* Determines the segment occupied by a certain script
* @param[in] s The state to operate on
* @param[in] script_id The script in question
* @param[in] load One of SCRIPT_GET_*
* @return The script's segment, or 0 on failure
*/
SegmentId script_get_segment(EngineState *s, int script_id, SCRIPT_GET load);
/**
* Looks up an entry of the exports table of a script
* @param[in] s The state to operate on
* @param[in] script_nr The script to look up in
* @param[out] export_index The index of the export entry to look up
* @return The handle
*/
reg_t script_lookup_export(EngineState *s, int script_nr, int export_index);
/**
* Makes sure that a script and its superclasses get loaded to the heap.
* If the script already has been loaded, only the number of lockers is
* increased. All scripts containing superclasses of this script are loaded
* recursively as well, unless 'recursive' is set to zero. The
* complementary function is "script_uninstantiate()" below.
* @param[in] s The state to operate on
* @param[in] script_nr The script number to load
* @return The script's segment ID or 0 if out of heap
*/
int script_instantiate(EngineState *s, int script_nr);
/**
* Decreases the numer of lockers of a script and unloads it if that number
* reaches zero.
* This function will recursively unload scripts containing its
* superclasses, if those aren't locked by other scripts as well.
* @param[in] s The state to operate on
* @param[in] script_nr The script number that is requestet to be unloaded
*/
void script_uninstantiate(EngineState *s, int script_nr);
/**
* Initializes an SCI game
* This function must be run before script_run() is executed. Graphics data
* is initialized iff s->gfx_state != NULL.
* @param[in] s The state to operate on
* @return 0 on success, 1 if an error occured.
*/
int game_init(EngineState *s);
/**
* Initializes the graphics part of an SCI game
* This function may only be called if game_init() did not initialize
* the graphics data.
* @param[in] s The state to initialize the graphics in
* @return 0 on success, 1 if an error occured
*/
int game_init_graphics(EngineState *s);
/**
* Initializes the sound part of an SCI game
* This function may only be called if game_init() did not initialize
* the sound data.
* @param[in] s The state to initialize the sound in
* @param[in] sound_flags Flags to pass to the sound subsystem
* @return 0 on success, 1 if an error occured
*/
int game_init_sound(EngineState *s, int sound_flags);
/**
* Runs an SCI game
* 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.
* Note that, EngineState *s may be changed during the game, e.g. if a game
* state is restored.
* @param[in] s Pointer to the pointer of the state to operate on
* @return 0 on success, 1 if an error occured.
*/
int game_run(EngineState **s);
/**
* Restores an SCI game state and runs the game
* This restores a savegame; otherwise, it behaves just like game_run().
* @param[in] s Pointer to the pointer of the state to
* operate on
* @param[in] savegame_name Name of the savegame to restore
* @return 0 on success, 1 if an error occured.
*/
int game_restore(EngineState **s, char *savegame_name);
/**
* Uninitializes an initialized SCI game
* This function should be run after each script_run() call.
* @param[in] s The state to operate on
* @return 0 on success, 1 if an error occured.
*/
int game_exit(EngineState *s);
/**
* Instructs the virtual machine to abort
*/
void quit_vm();
/**
* Allocates "kernel" memory and returns a handle suitable to be passed on
* to SCI scripts
* @param[in] s Pointer to the EngineState to operate on
* @param[in] type A free-form type description string (static)
* @param[in] space The space to allocate
* @return The handle
*/
reg_t kalloc(EngineState *s, const char *type, int space);
/**
* Returns a pointer to "kernel" memory based on the handle
* @param[in] s Pointer to the EngineState to operate on
* @param[in] handle The handle to use
* @return A pointer to the allocated memory
*/
byte *kmem(EngineState *s, reg_t handle);
/**
* Frees all "kernel" memory associated with a handle
* @param[in] s Pointer to the EngineState to operate on
* @param[in] handle The handle to free
* @return 0 on success, 1 otherwise
*/
int kfree(EngineState *s, reg_t handle);
/**
* Determines the name of an object
* @param[in] s Pointer to the EngineState to operate on
* @param[in] pos Location of the object whose name we want to inspect
* @return 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).
*/
const char *obj_get_name(EngineState *s, reg_t pos);
/**
* Retrieves an object from the specified location
* @param[in] s Pointer to the EngineState to operate on
* @param[in] offset The object's offset
* @return The object in question, or NULL if there is none
*/
Object *obj_get(EngineState *s, reg_t offset);
/**
* Shrink execution stack to size.
* Contains an assert it is not already smaller.
*/
void shrink_execution_stack(EngineState *s, uint size);
} // End of namespace Sci
#endif // SCI_ENGINE_VM_H
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