mirror of
https://github.com/libretro/scummvm.git
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224 lines
6.2 KiB
C++
224 lines
6.2 KiB
C++
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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*/
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#ifndef GLK_ADVSYS_VM
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#define GLK_ADVSYS_VM
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#include "glk/advsys/glk_interface.h"
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#include "glk/advsys/game.h"
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#include "common/array.h"
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namespace Glk {
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namespace AdvSys {
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/**
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* Execution result states
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*/
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enum ExecutionResult {
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IN_PROGRESS = 0, ///< Default state whilst script is in progress
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FINISH = 1, ///< Script was finished
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CHAIN = 2, ///< Another script is being chained to
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ABORT = 3 ///< Script was aborted
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};
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/**
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* Opcode list
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*/
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enum Opcode {
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OP_BRT = 0x01, ///< Branch on true
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OP_BRF = 0x02, ///< Branch on false
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OP_BR = 0x03, ///< Branch unconditionally
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OP_T = 0x04, ///< Load top of stack with t
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OP_NIL = 0x05, ///< Load top of stack with nil
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OP_PUSH = 0x06, ///< Push nil onto stack
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OP_NOT = 0x07, ///< Logical negate top of stack
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OP_ADD = 0x08, ///< Add two numeric expressions
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OP_SUB = 0x09, ///< Subtract two numeric expressions
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OP_MUL = 0x0A, ///< Multiply two numeric expressions
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OP_DIV = 0x0B, ///< Divide two numeric expressions
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OP_REM = 0x0C, ///< Remainder of two numeric expressions
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OP_BAND = 0x0D, ///< Bitwise and of two numeric expressions
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OP_BOR = 0x0E, ///< Bitwise or of two numeric expressions
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OP_BNOT = 0x0F, ///< Bitwise not
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OP_LT = 0x10, ///< Less than
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OP_EQ = 0x11, ///< Equal to
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OP_GT = 0x12, ///< Greater than
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OP_LIT = 0x13, ///< Load literal
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OP_VAR = 0x14, ///< Load a variable value
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OP_GETP = 0x15, ///< Get the value of an object property
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OP_SETP = 0x16, ///< Set the value of an object property
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OP_SET = 0x17, ///< Set the value of a variable
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OP_PRINT = 0x18, ///< Print messages
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OP_TERPRI = 0x19, ///< Terminate the print line
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OP_PNUMBER = 0x1A, ///< Print a number
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OP_FINISH = 0x1B, ///< Finish handling this command
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OP_CHAIN = 0x1C, ///< Chain to the next handler
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OP_ABORT = 0x1D, ///< Abort this command
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OP_EXIT = 0x1E, ///< Exit the game
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OP_RETURN = 0x1F, ///< Return from function
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OP_CALL = 0x20, ///< Call subroutine
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OP_SVAR = 0x21, ///< Short load a variable
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OP_SSET = 0x22, ///< Short set a variable
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OP_SPLIT = 0x23, ///< Short load a positive literal
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OP_SNLIT = 0x24, ///< Short load a negative literal
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OP_YORN = 0x25, ///< Yes or No predicate
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OP_SAVE = 0x26, ///< Save data structures
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OP_RESTORE = 0x27, ///< Restore data structures
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OP_ARG = 0x28, ///< Load an argument value
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OP_ASET = 0x29, ///< Set an argument value
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OP_TMP = 0x2A, ///< Load a temporary variable value
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OP_TSET = 0x2B, ///< Set a temporary variable
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OP_TSPACE = 0x2C, ///< Allocate temporary variable space
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OP_CLASS = 0x2D, ///< Get the class of an object
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OP_MATCH = 0x2E, ///< Match a noun phrase with an object
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OP_PNOUN = 0x2F, ///< Print a noun phrase
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OP_RESTART = 0x30, ///< Restart the current game
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OP_RAND = 0x31, ///< Generate a random number
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OP_RNDMIZE = 0x32, ///< Seed the random number generator
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OP_SEND = 0x33, ///< Send a message to an object
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OP_VOWEL = 0x34, ///< Check for vowel beginning string
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OP_XVAR = 0x40, ///< Extra short load a variable
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OP_XSET = 0x60, ///< Extra short set a variable
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OP_XPLIT = 0x80, ///< Extra short load a positive literal
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OP_XNLIT = 0xC0 ///< Extra short load a negative literal
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};
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class VM;
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typedef void (VM::*OpcodeMethod)();
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/**
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* Main VM for AdvSys
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*/
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class VM : public GlkInterface, public Game {
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class ArrayStack : public Common::Array<int> {
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public:
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/**
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* Push a value onto the stack
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*/
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void push(int v) { push_back(v); }
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/**
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* Pop a value from the stack
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*/
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int pop() {
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int v = back();
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pop_back();
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return v;
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}
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};
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private:
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static OpcodeMethod _METHODS[0x34];
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int _pc;
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ExecutionResult _status;
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ArrayStack _stack;
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private:
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/**
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* Execute a single opcode within the script
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*/
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void executeOpcode();
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/**
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* Get the next code byte and increments the PC counter
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*/
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int readCodeByte() {
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return getCodeByte(_pc++);
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}
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/**
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* Gets the next code word and increases the PC counter to after it
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*/
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int readCodeWord() {
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return getCodeWord(_pc += 2);
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}
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private:
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void opBRT();
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void opBRF();
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void opBR();
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void opT();
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void opNIL();
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void opPUSH();
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void opNOT();
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void opADD();
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void opSUB();
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void opMUL();
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void opDIV();
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void opREM();
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void opBAND();
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void opBOR();
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void opBNOT();
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void opLT();
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void opEQ();
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void opGT();
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void opLIT();
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void opVAR();
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void opGETP();
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void opSETP();
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void opSET();
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void opPRINT();
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void opTERPRI();
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void opPNUMBER();
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void opFINISH();
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void opCHAIN();
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void opABORT();
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void opEXIT();
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void opRETURN();
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void opCALL();
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void opSVAR();
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void opSSET();
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void opSPLIT();
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void opSNLIT();
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void opYORN();
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void opSAVE();
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void opRESTORE();
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void opARG();
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void opASET();
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void opTMP();
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void opTSET();
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void opTSPACE();
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void opCLASS();
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void opMATCH();
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void opPNOUN();
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void opRESTART();
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void opRAND();
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void opRNDMIZE();
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void opSEND();
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void opVOWEL();
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public:
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/**
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* Constructor
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*/
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VM(OSystem *syst, const GlkGameDescription &gameDesc);
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/**
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* Exeecute a script
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* @param offset Script offset
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* @returns Script result code
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*/
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ExecutionResult execute(int offset);
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};
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} // End of namespace AdvSys
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} // End of namespace Glk
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#endif
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