01: //
02: // Copyright (C) 2005 United States Government as represented by the
03: // Administrator of the National Aeronautics and Space Administration
04: // (NASA). All Rights Reserved.
05: //
06: // This software is distributed under the NASA Open Source Agreement
07: // (NOSA), version 1.3. The NOSA has been approved by the Open Source
08: // Initiative. See the file NOSA-1.3-JPF at the top of the distribution
09: // 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:
25: import org.apache.bcel.classfile.ConstantPool;
26: import gov.nasa.jpf.jvm.ElementInfo;
27:
28: /**
29: * Enter monitor for object
30: * ..., objectref => ...
31: */
32: public class MONITORENTER extends Instruction {
33: public boolean isExecutable(SystemState ss, KernelState ks,
34: ThreadInfo th) {
35: int objref = th.peek();
36: boolean isExec = ks.da.get(objref).canLock(th);
37:
38: return isExec;
39: }
40:
41: public void setPeer(org.apache.bcel.generic.Instruction i,
42: ConstantPool cp) {
43: }
44:
45: public Instruction execute(SystemState ss, KernelState ks,
46: ThreadInfo th) {
47: int objref = th.pop();
48:
49: ks.da.get(objref).lock(th);
50:
51: return getNext(th);
52: }
53:
54: public boolean isSchedulingRelevant(SystemState ss, KernelState ks,
55: ThreadInfo ti) {
56: int objref = ti.peek();
57: ElementInfo ei = ks.da.get(objref);
58:
59: if (mi.isBodySchedulingRelevant(ti, ei)
60: && (ei.getLockCount() == 0)) {
61: // only relevant if there are other runnables
62: return ti.hasOtherRunnables();
63: } else {
64: // it's either not executable, or we already have the lock, or we don't care
65: return false;
66: }
67: }
68:
69: public int getByteCode() {
70: return 0xC2;
71: }
72: }
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