KickJava   Java API By Example, From Geeks To Geeks.

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


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  * Compare double
31  * ..., value1, value2 => ..., result
32  */
33 public class DCMPG 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     double v1 = Types.longToDouble(th.longPop());
39     double v2 = Types.longToDouble(th.longPop());
40
41     if (!th.getVM().checkNaNcompare(v1,v2)){
42       return th.createAndThrowException("java.lang.ArithmeticException",
43                                    "comparing in-exact values: " + v2 + "<" + v1);
44     }
45     
46     if (Double.isNaN(v1) || Double.isNaN(v2)) {
47       th.push(1, false);
48     } else if (v1 == v2) {
49       th.push(0, false);
50     } else if (v2 > v1) {
51       th.push(1, false);
52     } else {
53       th.push(-1, false);
54     }
55
56     return getNext(th);
57   }
58   
59
60   public int getByteCode () {
61     return 0x98;
62   }
63 }
64
Popular Tags