forunconditionalstatement.java

来自「tinyos最新版」· Java 代码 · 共 87 行

/*									tab:4
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 * Copyright (c) 2002-2003 Intel Corporation
 * All rights reserved.
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package net.tinyos.script.tree;

import java.io.*;

import net.tinyos.script.*;

public class ForUnconditionalStatement extends Statement  {
    private SingleReference variable;
    private Expression initialValue;
    private ConstantExpression endValue;
    private ForStep step;
    private StatementList statements;
    private SingleReference variable2;
    private int constantValue;
    
    public ForUnconditionalStatement(SingleReference variable, Expression initialValue, ConstantExpression endValue, ForStep step, StatementList statements, SingleReference variable2) {
	this.variable = variable;
	this.initialValue = initialValue;
	this.endValue = endValue;
	this.step = step;
	this.statements = statements;
	this.variable2 = variable2;
    }

        
    public void checkStatement(SymbolTable table) throws SemanticException {
	if (!variable.toString().equals(variable2.toString())) {
	    throw new SemanticException("Loop value and increment value must be same variable: " + variable + "(" + variable.symbol() + ") and " + variable2 + "(" + variable2.symbol() + ")");
	}

	variable.checkStatement(table);
	initialValue.checkStatement(table);
	endValue.checkStatement(table);
	statements.checkStatement(table);
	variable2.checkStatement(table);
    }
    
    public void generateCode(SymbolTable table, CodeWriter writer) throws IOException {
	writer.writeComment("Beginning of unconditional loop");
	initialValue.generateCode(table, writer);
	variable.generateCode(table, writer);
	String label = "label" + table.getBranchSym();
	writer.writeLabel(label);
	statements.generateCode(table, writer);
	int index = table.getVariable(variable.name());
	writer.writeInstr("getvar4 " + index);
	int stepVal = step.getStep().intValue();
	writer.writeInstr("pushc6 " + stepVal);
	writer.writeInstr("add");
	writer.writeInstr("copy");
	writer.writeInstr("setvar4 " + index);
	writer.writeInstr("pushc6 " + endValue.value());
	writer.writeInstr("lt");
	writer.writeInstr("2jumps10 " + label);
	writer.writeComment("End of unconditional loop");
    }
    
}