four.java

基于c0文法写的生成p-code的编译器

/*
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/**
 *
 * @author lilac
 */
public class Four {

    public int op;                    //操作符
    public String first;                 //第一操作数
    public String last;                   //第二操作数
    public String result;                 //结果

    public Four(int op, String first, String last, String result) {
        this.first = first;
        this.last = last;
        this.op = op;
        this.result = result;
    }

    public Four(Four get) {
        this.first = get.first;
        this.last = get.last;
        this.op = get.op;
        this.result = get.result;
    }

    @Override
    public String toString() {
        String ss=new String();
        String cc=new String();
        if (this.op == 1) {
            ss = "ADD";
            cc=this.first;
        } else if (this.op == 2) {
            ss = "SUB";
            cc=this.first;
        } else if (this.op == 3) {
            ss = "MUL";
            cc=this.first;
        } else if (this.op == 4) {
            ss = "DIV";
            cc=this.first;
        } else if (this.op == Compile.CONDITION) {
            ss="condition";
            if (this.first.equals("24")) {
                cc = "G";
            } else if (this.first.equals("25")) {
                cc = "L";
            } else if (this.first.equals("26")) {
                cc = "GE";
            } else if (this.first.equals("27")) {
                cc = "LE";
            } else if (this.first.equals("28")) {
                cc = "NE";
            } else if (this.first.equals("29")) {
                cc = "EE";
            }
        }else if(this.op==5){
            ss="MOV";
            cc=this.first;
        }else if (this.op == 6) {
            ss = "STAMP";
            cc=this.first;
        } else if (this.op == 7) {
            ss = "J";
            cc=this.first;
        } else if (this.op == 8) {
            ss = "JFALSE";
            cc=this.first;
        }
        else if(this.op==13){
            ss="PRINTF";
            cc=this.first;
        }else if (this.op == 10) {
            ss = "CMP";
            cc=this.first;
        } else if (this.op == 11) {
            ss = "PUSHPARA";
            cc=this.first;
        } else if (this.op == 12) {
            ss = "CALL";
            cc=this.first;
        }else if (this.op == 14) {
            ss = "SCANF";
            cc=this.first;
        } else if (this.op == 15) {
            ss = "RETURN";
            cc=this.first;
        }
        return (ss + "\t" + cc + "\t" + this.last + "\t" + this.result);
    }
}