Mercurial > hg > Members > kono > jpf-core

comparison src/main/gov/nasa/jpf/jvm/bytecode/RUNSTART.java @ 0:61d41facf527

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initial v8 import (history reset)
author Peter Mehlitz <Peter.C.Mehlitz@nasa.gov>
date Fri, 23 Jan 2015 10:14:01 -0800
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1 /*
2 * Copyright (C) 2014, United States Government, as represented by the
3 * Administrator of the National Aeronautics and Space Administration.
4 * All rights reserved.
5 *
6 * The Java Pathfinder core (jpf-core) platform is licensed under the
7 * Apache License, Version 2.0 (the "License"); you may not use this file except
8 * in compliance with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0.
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18
19 package gov.nasa.jpf.jvm.bytecode;
20
21 import gov.nasa.jpf.vm.Instruction;
22 import gov.nasa.jpf.vm.ThreadInfo;
23
24 /**
25 * this is an artificial instruction that is automatically prepended to
26 * a run()/main() method call.
27 *
28 * The main purpose is to have a special instruction marking the beginning
29 * of a new thread execution which does not cause CGs or is otherwise subject
30 * to execution semantics that change the program state.
31 *
32 * For instance, without it we would have to add a new ThreadInfo state to
33 * determine if the first instruction within this thread was re-executed or
34 * just happens to be the first transition we execute within this thread
35 *
36 */
37 public class RUNSTART extends Instruction implements JVMInstruction {
38
39 public RUNSTART () {
40 }
41
42 @Override
43 public Instruction execute (ThreadInfo ti) {
44 // nothing here, we could have used a NOP
45 return getNext(ti);
46 }
47
48 public static final int OPCODE = 257;
49
50 @Override
51 public int getByteCode () {
52 return OPCODE;
53 }
54
55 @Override
56 public boolean isExtendedInstruction() {
57 return true;
58 }
59
60 @Override
61 public void accept(JVMInstructionVisitor insVisitor) {
62 insVisitor.visit(this);
63 }
64 }