NoOperandCmd.java

package minijvm.cmd;

import minijvm.clz.ClassFile;
import minijvm.engine.ExecutionResult;
import minijvm.engine.Heap;
import minijvm.engine.JavaObject;
import minijvm.engine.StackFrame;

public class NoOperandCmd extends ByteCodeCommand{

	public NoOperandCmd(ClassFile clzFile, String opCode) {
		super(clzFile, opCode);
	}

	@Override
	public String toString() {
		return this.getOffset()+":" +this.getOpCode() + " "+ this.getReadableCodeText();
	}

	
	
	@Override
    public  int getLength(){
		return 1;
	}

    @Override
    public void execute(StackFrame frame, ExecutionResult result) {
        String opCode = this.getOpCode();
        if (ByteCodeCommand.aload_0.equalsIgnoreCase(opCode)) {
            JavaObject jo = frame.getLocalVariableValue(0);
            frame.getOprandStack().push(jo);
        } else if (ByteCodeCommand.aload_1.equalsIgnoreCase(opCode)) {
            JavaObject jo = frame.getLocalVariableValue(1);
            frame.getOprandStack().push(jo);
        } else if (ByteCodeCommand.aload_2.equalsIgnoreCase(opCode)) {
            JavaObject jo = frame.getLocalVariableValue(2);
            frame.getOprandStack().push(jo);
        } else if (ByteCodeCommand.iload_1.equalsIgnoreCase(opCode)) {
            JavaObject jo = frame.getLocalVariableValue(1);
            frame.getOprandStack().push(jo);
        } else if (ByteCodeCommand.iload_2.equalsIgnoreCase(opCode)) {
            JavaObject jo = frame.getLocalVariableValue(2);
            frame.getOprandStack().push(jo);
        } else if (ByteCodeCommand.iload_3.equalsIgnoreCase(opCode)) {
            JavaObject jo = frame.getLocalVariableValue(3);
            frame.getOprandStack().push(jo);
        } else if (ByteCodeCommand.fload_3.equalsIgnoreCase(opCode)) {
            JavaObject jo = frame.getLocalVariableValue(3);
            frame.getOprandStack().push(jo);
        } else if (ByteCodeCommand.voidreturn.equalsIgnoreCase(opCode)) {
            result.setNextAction(ExecutionResult.EXIT_CURRENT_FRAME);
        } else if (ByteCodeCommand.ireturn.equalsIgnoreCase(opCode)) {
            StackFrame callerFrame = frame.getCallerFrame();
            JavaObject jo = frame.getOprandStack().pop();
            callerFrame.getOprandStack().push(jo);
        } else if (ByteCodeCommand.freturn.equalsIgnoreCase(opCode)) {
            StackFrame callerFrame = frame.getCallerFrame();
            JavaObject jo = frame.getOprandStack().pop();
            callerFrame.getOprandStack().push(jo);
        } else if (ByteCodeCommand.astore_1.equalsIgnoreCase(opCode)) {
            JavaObject jo = frame.getOprandStack().pop();
            frame.setLocalVariableValue(1, jo);
        } else if (ByteCodeCommand.dup.equalsIgnoreCase(opCode)) {
            JavaObject jo = frame.getOprandStack().peek();
            frame.getOprandStack().push(jo);
        } else if (ByteCodeCommand.iconst_0.equalsIgnoreCase(opCode)) {
            JavaObject jo = Heap.getInstance().newInt(0);
            frame.getOprandStack().push(jo);
        } else if (ByteCodeCommand.iconst_1.equalsIgnoreCase(opCode)) {
            JavaObject jo = Heap.getInstance().newInt(1);
            frame.getOprandStack().push(jo);
        } else if (ByteCodeCommand.istore_1.equalsIgnoreCase(opCode)) {
            JavaObject jo = frame.getOprandStack().pop();
            frame.setLocalVariableValue(1, jo);
        } else if (ByteCodeCommand.istore_2.equalsIgnoreCase(opCode)) {
            JavaObject jo = frame.getOprandStack().pop();
            frame.setLocalVariableValue(2, jo);
        } else if (ByteCodeCommand.iadd.equalsIgnoreCase(opCode)) {
            JavaObject jo1 = frame.getOprandStack().pop();
            JavaObject jo2 = frame.getOprandStack().pop();
            JavaObject sum = Heap.getInstance().newInt(jo1.getIntValue() + jo2.getIntValue());
            frame.getOprandStack().push(sum);
        } else if (ByteCodeCommand.aconst_null.equalsIgnoreCase(opCode)) {
            frame.getOprandStack().push(null);
        } else {
            throw new RuntimeException("未实现的指令：" + opCode);
        }
    }

}