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1   /*
2    * @(#) DUP_X2.java Jan 8, 2004
3    * 
4    * Copyright (c) 2003 Delft University of Technology Jaffalaan 5, 2628 BX Delft,
5    * the Netherlands All rights reserved.
6    * 
7    * This software is proprietary information of Delft University of Technology
8    * The code is published under the General Public License
9    */
10  package nl.tudelft.simulation.dsol.interpreter.operations;
11  
12  import nl.tudelft.simulation.dsol.interpreter.LocalVariable;
13  import nl.tudelft.simulation.dsol.interpreter.OperandStack;
14  import nl.tudelft.simulation.dsol.interpreter.classfile.Constant;
15  
16  /***
17   * The DUP_X2 operation as defined in <a
18   * href="http://java.sun.com/docs/books/vmspec/2nd-edition/html/Instructions2.doc3.html">
19   * http://java.sun.com/docs/books/vmspec/2nd-edition/html/Instructions2.doc3.html
20   * </a>.
21   * <p>
22   * (c) copyright 2003 <a href="http://www.simulation.tudelft.nl">Delft
23   * University of Technology </a>, the Netherlands. <br>
24   * See for project information <a
25   * href="http://www.simulation.tudelft.nl">www.simulation.tudelft.nl </a> <br>
26   * License of use: <a href="http://www.gnu.org/copyleft/gpl.html">General Public
27   * License (GPL) </a>, no warranty <br>
28   * 
29   * @author <a href="http://www.tbm.tudelft.nl/webstaf/peterja/index.htm">Peter
30   *         Jacobs </a><a
31   *         href="http://www.tbm.tudelft.nl/webstaf/alexandv/index.htm">Alexander
32   *         Verbraeck </a>
33   * @version 1.3 Apr 6, 2004
34   * @since 1.4
35   */
36  public class DUP_X2 extends VoidOperation
37  {
38  	/*** OP refers to the operand code */
39  	public static final int OP = 91;
40  
41  	/***
42  	 * constructs a new DUP_X2
43  	 */
44  	public DUP_X2()
45  	{
46  		super();
47  	}
48  
49  	/***
50  	 * @see nl.tudelft.simulation.dsol.interpreter.operations.VoidOperation
51  	 *      #execute(nl.tudelft.simulation.dsol.interpreter.OperandStack,
52  	 *      nl.tudelft.simulation.dsol.interpreter.classfile.Constant[],
53  	 *      nl.tudelft.simulation.dsol.interpreter.LocalVariable[])
54  	 */
55  	public void execute(final OperandStack stack,
56  			final Constant[] constantPool, final LocalVariable[] localVariables)
57  	{
58  		Object obj1 = stack.pop();
59  		Object obj2 = stack.pop();
60  		if ((obj2 instanceof Long) || (obj2 instanceof Double))
61  		{
62  			stack.push(obj1);
63  			stack.push(obj2);
64  			stack.push(obj1);
65  		} else
66  		{
67  			Object obj3 = stack.pop();
68  			stack.push(obj1);
69  			stack.push(obj3);
70  			stack.push(obj2);
71  			stack.push(obj1);
72  		}
73  	}
74  
75  	/***
76  	 * @see nl.tudelft.simulation.dsol.interpreter.Operation#getByteLength()
77  	 */
78  	public int getByteLength()
79  	{
80  		return OPCODE_BYTE_LENGTH;
81  	}
82  
83  	/***
84  	 * @see nl.tudelft.simulation.dsol.interpreter.Operation#getOpcode()
85  	 */
86  	public int getOpcode()
87  	{
88  		return DUP_X2.OP;
89  	}
90  }