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


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.JPFException;
22 import gov.nasa.jpf.jvm.ElementInfo;
23 import gov.nasa.jpf.jvm.KernelState;
24 import gov.nasa.jpf.jvm.SystemState;
25 import gov.nasa.jpf.jvm.ThreadInfo;
26
27 import gov.nasa.jpf.jvm.FieldInfo;
28
29
30 /**
31  * Get static field from class
32  * ..., => ..., value
33  */
34 public class GETSTATIC extends StaticFieldInstruction {
35   public Instruction execute (SystemState ss, KernelState ks, ThreadInfo ti) {
36     ElementInfo ei = ks.sa.get(className);
37     FieldInfo fi = getFieldInfo();
38     
39     switch (size) {
40       case 1:
41         int ival = ei.getIntField(fi);
42         ti.push(ival, fi.isReference());
43         break;
44       case 2:
45         long lval = ei.getLongField(fi);
46         ti.longPush(lval);
47         break;
48       default:
49         throw new JPFException("invalid field type");
50     }
51     
52     return getNext(ti);
53   }
54   
55   public int getByteCode () {
56     return 0xB2;
57   }
58   
59   public boolean isSchedulingRelevant (SystemState ss, KernelState ks, ThreadInfo ti) {
60     // again very conservative - doesn't take into account if the object
61 // can be accessed from different threads, but that would be a static
62 // attribute (i.e. require statis analysis)
63
64     if (ti.usePorFieldBoundaries()) {
65       return isSchedulingRelevant(ks, ti);
66     }
67     return false;
68   }
69 }
70
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