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1   /*
2    * @(#) POP2.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 POP2 operation as defined in <a
18   * href="http://java.sun.com/docs/books/vmspec/2nd-edition/html/Instructions2.doc11.html">
19   * http://java.sun.com/docs/books/vmspec/2nd-edition/html/Instructions2.doc11.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  
37  public class POP2 extends VoidOperation
38  {
39  	/*** OP refers to the operand code */
40  	public static final int OP = 88;
41  
42  	/***
43  	 * constructs a new POP2
44  	 */
45  	public POP2()
46  	{
47  		super();
48  	}
49  
50  	/***
51  	 * @see nl.tudelft.simulation.dsol.interpreter.operations.VoidOperation#execute(
52  	 *      nl.tudelft.simulation.dsol.interpreter.OperandStack,
53  	 *      nl.tudelft.simulation.dsol.interpreter.classfile.Constant[],
54  	 *      nl.tudelft.simulation.dsol.interpreter.LocalVariable[])
55  	 */
56  	public void execute(final OperandStack stack,
57  			final Constant[] constantPool, final LocalVariable[] localVariables)
58  	{
59  		Object value = stack.pop();
60  		if (!(value instanceof Double) && !(value instanceof Long))
61  		{
62  			stack.pop();
63  		}
64  	}
65  
66  	/***
67  	 * @see nl.tudelft.simulation.dsol.interpreter.Operation#getByteLength()
68  	 */
69  	public int getByteLength()
70  	{
71  		return OPCODE_BYTE_LENGTH;
72  	}
73  
74  	/***
75  	 * @see nl.tudelft.simulation.dsol.interpreter.Operation#getOpcode()
76  	 */
77  	public int getOpcode()
78  	{
79  		return POP2.OP;
80  	}
81  }