修正：pc处理逻辑；新增：跳转指令(if_cmple, goto)+iload_n指令

README.md

@@ -2,31 +2,90 @@
 
 这是一个Java实现的JAVA虚拟机，它会非常简单，实际上简单的只够运行HelloWorld。虽然简单，但尽量符合 JVM 标准，目前主要参考依据是[《Java虚拟机规范 （Java SE 7 中文版）》](http://www.iteye.com/topic/1117824)。
 
-关于此项目的说明，[详见此文](http://www.jianshu.com/p/4d81465c2fb8)。
+非原创，原项目来自 https://github.com/caoym/jjvm ，
+	运行方式有改动(原项目运行方式在我的环境不work)
+	pc和opcode运行时处理有修改(原实现无法支持条件跳转; 且增加一些其他opcode)
 
-## 运行
+## 参考项目
+	java版jvm实现( https://github.com/zachaxy/JVM )
+	go版jvm实现( https://github.com/zxh0/jvmgo-book )
 
-先写一个HelloWorld，代码如下：
 
-```java
-package org.caoym;
+# 用法
 
-public class HelloWorld {
-    public static void main(String[] args){
-        System.out.println("Hello World");
-    }
-}
+## 环境
+SUN jdk1.8 (OpenJdk1.8 运行缺少一些jar，用SUN JDK重装后解决)
+
+```shell
+$java -version
+java version "1.8.0_211"
+Java(TM) SE Runtime Environment (build 1.8.0_211-b12)
+Java HotSpot(TM) 64-Bit Server VM (build 25.211-b12, mixed mode)
+```
+
+### 设置java环境
+将以下内容加入 /etc/profile ，保存后执行 source /etc/profile 使之生效
+
+```shell
+JAVA_HOME=/usr/java/jdk1.8.0_211-amd64
+JRE_HOME=$JAVA_HOME/jre
+PATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/bin
+CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JRE_HOME/lib
+export JAVA_HOME JRE_HOME PATH CLASSPATH
 ```
 
-可以通过以下命令运行：
+## 编译和运行
+可以通过以下编译命令运行：
+### Sample1
+基本HelloWorld
 
 ```shell
-$ java /home/myclasspath org.caoym.jjvm.JJvm org.caoym.HelloWorld
-Hello World
+#编译 sample1
+$javac org/caoym/jjvm/JJvm.java -XDignore.symbol.file=true
+$javac org/caoym/jjvm/JJvm.java -Xlint:unchecked
+$javac org/caoym/samples/sample1/HelloWorld.java 
+
+#运行
+$java org.caoym.jjvm.JJvm . org.caoym.samples.sample1.HelloWorld
 ```
 
-## 可运行的示例
+### Sample2
+带有Interface、父子类继承的Helloworld
 
-[用于测试 JJvm 的示例代码可在此处下载](https://github.com/caoym/jjvm-samples)
+```shell
+#编译 sample2
+$javac org/caoym/jjvm/JJvm.java -XDignore.symbol.file=true
+$javac org/caoym/jjvm/JJvm.java -Xlint:unchecked
+$javac org/caoym/samples/sample2/Main.java 
+
+#运行(不加运行参数如inputVar1，会报错)
+$java org.caoym.jjvm.JJvm . org.caoym.samples.sample2.Main inputVar1         
+```
 
+### Sample3
+带有条件跳转的Helloworld
 
+```shell
+#编译 sample3
+$javac org/caoym/jjvm/JJvm.java -XDignore.symbol.file=true
+$javac org/caoym/jjvm/JJvm.java -Xlint:unchecked
+$javac org/caoym/samples/sample3/HelloWorld.java 
+
+#运行
+$java org.caoym.jjvm.JJvm . org.caoym.samples.sample3.HelloWorld
+```
+
+## FAQ
+### error: package jdk.internal.org.objectweb.asm does not exist
+```shell
+默认 javac 不读取 rt.jar 中 classes内容，只读取符号表
+	符号表一般只包括标准API和部分其他API，如 com.sun., com.oracle. and sun.*
+
+编译选项加上 -XDignore.symbol.file=true
+	javac org/caoym/jjvm/JJvm.java -XDignore.symbol.file=true
+```
+
+### 未能自动清理旧class文件，重新编译前手动清理一下，执行
+```shell
+$find . -name *.class -type f -print -exec rm -rf {} \;
+```

src/main/java/org/caoym/jjvm/VirtualMachine.java

@@ -41,7 +41,7 @@ public void run(String[] args) throws Exception {
                 "main",
                 "([Ljava/lang/String;)V");
         //执行入口方法
-        method.call(env, null, new Object[]{args});
+        method.call(env, null, new Object[]{args});//TODO:多个class文件，是如何组织？何时加载的？
     }
 
     public JvmClass getClass(String className) throws ClassNotFoundException {

src/main/java/org/caoym/jjvm/opcode/BytecodeInterpreter.java

@@ -34,8 +34,9 @@ public static void run(Env env) throws Exception {
                 }
                 continue;
             }
-            OpcodeInvoker[] codes = frame.getOpcodes();
-            int pc = frame.increasePC();
+            OpcodeInvoker[] ops = frame.getOps();
+            int pc = frame.getPC();
+
             StringBuilder sb = new StringBuilder();
             sb.append("> ");
             sb.append(frame.getCurrentClass().getName());
@@ -44,12 +45,30 @@ public static void run(Env env) throws Exception {
             sb.append("@");
             sb.append(pc);
             sb.append(":");
-            sb.append(codes[pc]);
+            sb.append(ops[pc]);
+            sb.append("[");
+            sb.append(ops[pc].getNoOfOperands());
+            sb.append("]");
             System.out.println(sb);
-            codes[pc].invoke(env, frame);
+
+            //execute opcode
+            int ret = ops[pc].invoke(env, frame);
+
+            //move forward
+            if(ret == 0) {
+            	frame.increasePC(1+ops[pc].getNoOfOperands());
+            }else {
+            	frame.increasePC(pc + ret);
+            }
         }
     }
 
+    /**
+     * 返回内容以 opcode 为主
+     * 
+     * @param codes
+     * @return
+     */
     public static OpcodeInvoker[] parseCodes(byte[] codes){
         ArrayList<OpcodeInvoker> opcodes = new ArrayList<>();
         for(int i=0; i<codes.length; i++){
@@ -59,17 +78,57 @@ public static OpcodeInvoker[] parseCodes(byte[] codes){
             byte[] operands = Arrays.copyOfRange(codes, i + 1, i + 1 + noOfOperands);
             opcodes.add(new OpcodeInvoker() {
                 @Override
-                public void invoke(Env env, StackFrame frame) throws Exception {
+                public int invoke(Env env, StackFrame frame) throws Exception {
                     route.invoke(env, frame, operands);
+                    return 0;
                 }
                 @Override
                 public String toString() {
                     return route.name();
                 }
+				@Override
+				public int getNoOfOperands() {
+					// TODO Auto-generated method stub
+					return 0;
+				}
             });
             i += noOfOperands;
         }
         return Arrays.copyOf(opcodes.toArray(), opcodes.size(), OpcodeInvoker[].class);
     }
-
+
+    /**
+     * 返回内容以 opcode 和 operands 为主
+     * @param codes
+     * @return
+     */
+    public static OpcodeInvoker[] parseOps(byte[] codes){
+    	ArrayList<OpcodeInvoker> ops = new ArrayList<>();
+    	for(int i=0; i<codes.length; i++){
+    		short opcode = (short)(0xff&codes[i]);
+            final OpcodeRout route = OpcodeRout.valueOf(opcode);
+            short noOfOperands = Constants.NO_OF_OPERANDS[opcode];
+            byte[] operands = Arrays.copyOfRange(codes, i + 1, i + 1 + noOfOperands);
+            ops.add(new OpcodeInvoker() {
+                @Override
+                public int invoke(Env env, StackFrame frame) throws Exception {
+                    route.invoke(env, frame, operands);
+                    return 0;
+                }
+                @Override
+                public String toString() {
+                    return route.name();
+                }
+                public int getNoOfOperands() {
+                	return noOfOperands;
+                }
+            });
+
+            for(int si = 0; si < noOfOperands; si++) {
+            	ops.add(null);
+            }
+            i += noOfOperands;
+    	}
+    	return Arrays.copyOf(ops.toArray(), ops.size(), OpcodeInvoker[].class);
+    }
 }

src/main/java/org/caoym/jjvm/opcode/JvmOpcodeMethod.java

@@ -1,5 +1,6 @@
 package org.caoym.jjvm.opcode;
 
+
 import com.sun.tools.classfile.*;
 import org.caoym.jjvm.lang.JvmMethod;
 import org.caoym.jjvm.runtime.*;
@@ -12,6 +13,7 @@ public class JvmOpcodeMethod implements JvmMethod {
     private final JvmOpcodeClass clazz;
     private final Method method;
     private final OpcodeInvoker[] opcodes;
+    private final OpcodeInvoker[] ops;
     private final Code_attribute codeAttribute;
     private final String name;
     private final int parameterCount;
@@ -21,6 +23,7 @@ public JvmOpcodeMethod(JvmOpcodeClass clazz, Method method) throws ConstantPoolE
         this.clazz = clazz;
         this.method = method;
         codeAttribute = (Code_attribute)method.attributes.get("Code");
+        ops = BytecodeInterpreter.parseOps(codeAttribute.code);
         opcodes = BytecodeInterpreter.parseCodes(codeAttribute.code);
         String temp = "";
         temp = method.getName(clazz.getClassFile().constant_pool);
@@ -40,6 +43,7 @@ public void call(Env env, Object thiz, Object ...args) throws Exception {
                 this,
                 clazz.getClassFile().constant_pool,
                 opcodes,
+                ops,
                 codeAttribute.max_locals,
                 codeAttribute.max_stack);
 

src/main/java/org/caoym/jjvm/opcode/OpcodeInvoker.java

@@ -4,5 +4,8 @@
 import org.caoym.jjvm.runtime.StackFrame;
 
 public interface OpcodeInvoker {
-    public void invoke(Env env, StackFrame frame) throws Exception ;
+
+    public int invoke(Env env, StackFrame frame) throws Exception ;
+
+	public int getNoOfOperands();
 }