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Java > Open Source Codes > gov > nasa > jpf > jvm > bytecode > FSUB


1 //
2 // Copyright (C) 2005 United States Government as represented by the
3 // Administrator of the National Aeronautics and Space Administration
4 // (NASA). All Rights Reserved.
5 //
6 // This software is distributed under the NASA Open Source Agreement
7 // (NOSA), version 1.3. The NOSA has been approved by the Open Source
8 // Initiative. See the file NOSA-1.3-JPF at the top of the distribution
9 // directory tree for the complete NOSA document.
10 //
11 // THE SUBJECT SOFTWARE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY OF ANY
12 // KIND, EITHER EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT
13 // LIMITED TO, ANY WARRANTY THAT THE SUBJECT SOFTWARE WILL CONFORM TO
14 // SPECIFICATIONS, ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR
15 // A PARTICULAR PURPOSE, OR FREEDOM FROM INFRINGEMENT, ANY WARRANTY THAT
16 // THE SUBJECT SOFTWARE WILL BE ERROR FREE, OR ANY WARRANTY THAT
17 // DOCUMENTATION, IF PROVIDED, WILL CONFORM TO THE SUBJECT SOFTWARE.
18 //
19 package gov.nasa.jpf.jvm.bytecode;
20
21 import gov.nasa.jpf.jvm.KernelState;
22 import gov.nasa.jpf.jvm.SystemState;
23 import gov.nasa.jpf.jvm.ThreadInfo;
24 import gov.nasa.jpf.jvm.Types;
25
26 import org.apache.bcel.classfile.ConstantPool;
27
28
29 /**
30  * Subtract float
31  * ..., value1, value2 => ..., result
32  */
33 public class FSUB extends Instruction {
34   public void setPeer (org.apache.bcel.generic.Instruction i, ConstantPool cp) {
35   }
36
37   public Instruction execute (SystemState ss, KernelState ks, ThreadInfo th) {
38     float v1 = Types.intToFloat(th.pop());
39     float v2 = Types.intToFloat(th.pop());
40     float r = v2 - v1;
41     
42     if (!th.getVM().checkNaN(r)) {
43       return th.createAndThrowException("java.lang.ArithmeticException",
44                                    "inexact result: " + v2 + "-" + v1 + "=" + r);
45     }
46
47     th.push(Types.floatToInt(r), false);
48
49     return getNext(th);
50   }
51
52   public int getByteCode () {
53     return 0x66;
54   }
55 }
56
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