--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/gov/nasa/jpf/vm/bytecode/InstanceFieldInstruction.java	Fri Jan 23 10:14:01 2015 -0800
@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2014, United States Government, as represented by the
+ * Administrator of the National Aeronautics and Space Administration.
+ * All rights reserved.
+ *
+ * The Java Pathfinder core (jpf-core) platform is licensed under the
+ * Apache License, Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ * 
+ *        http://www.apache.org/licenses/LICENSE-2.0. 
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and 
+ * limitations under the License.
+ */
+
+package gov.nasa.jpf.vm.bytecode;
+
+import gov.nasa.jpf.vm.ClassInfo;
+import gov.nasa.jpf.vm.ClassLoaderInfo;
+import gov.nasa.jpf.vm.ElementInfo;
+import gov.nasa.jpf.vm.FieldInfo;
+import gov.nasa.jpf.vm.MJIEnv;
+import gov.nasa.jpf.vm.StackFrame;
+import gov.nasa.jpf.vm.ThreadInfo;
+import gov.nasa.jpf.vm.VM;
+
+/**
+ * common machine independent type for all instance field access instructions
+ */
+public abstract class InstanceFieldInstruction extends FieldInstruction {
+
+  protected int lastThis = MJIEnv.NULL;
+
+  protected InstanceFieldInstruction (String fieldName, String classType, String fieldDescriptor){
+    super(fieldName, classType, fieldDescriptor);
+  }
+
+  public abstract int getObjectSlot (StackFrame frame);
+  
+  @Override
+  public ElementInfo getElementInfo (ThreadInfo ti){
+    if (isCompleted(ti)){
+      return ti.getElementInfo(lastThis);
+    } else {
+      return peekElementInfo(ti);
+    }
+  }
+  
+  @Override
+  public String toPostExecString(){
+    StringBuilder sb = new StringBuilder();
+    sb.append(getMnemonic());
+    sb.append(' ');
+    sb.append( getLastElementInfo());
+    sb.append('.');
+    sb.append(fname);
+    
+    return sb.toString();
+  }
+
+  @Override
+  public FieldInfo getFieldInfo () {
+    if (fi == null) {
+      ClassInfo ci = ClassLoaderInfo.getCurrentResolvedClassInfo(className);
+      if (ci != null) {
+        fi = ci.getInstanceField(fname);
+      }
+    }
+    return fi;
+  }
+
+  /**
+   * NOTE - the return value is *only* valid in a instructionExecuted() context, since
+   * the same instruction can be executed from different threads
+   */
+  public int getLastThis() {
+    return lastThis;
+  }
+
+  /**
+   * since this is based on getLastThis(), the same context restrictions apply
+   */
+  @Override
+  public ElementInfo getLastElementInfo () {
+    if (lastThis != MJIEnv.NULL) {
+      return VM.getVM().getHeap().get(lastThis); // <2do> remove - should be in clients
+    }
+
+    return null;
+  }
+
+  public String getFieldDescriptor () {
+    ElementInfo ei = getLastElementInfo();
+    FieldInfo fi = getFieldInfo();
+
+    return ei.toString() + '.' + fi.getName();
+  }
+
+}