public String interpret(String str)
{
String stdout = "";
StringReader stdin = null;
if(str!=null)
stdin = new StringReader(str);
int[] runtimeStack = new int[stackSize];
Console.WriteLine("**Start Interpret the P_code**");
int pc = 0, // pc:指令指针，
bp = 0, //bp:指令基址，
sp = 0;//sp:栈顶指针
do
{
Pcode index = pcodeArray[pc++];// index :存放当前指令, 读当前指令
//Console.WriteLine(pc + " " + Pcode.pcode[index.f] + " " + index.l + " " + index.a);
//Console.WriteLine(Pcode.pcode[index.f]);
switch (index.f)
{
case Pcode.LIT: // 将a的值取到栈顶
runtimeStack[sp++] = index.a;
break;
case Pcode.OPR: // 数学、逻辑运算
switch (index.a)
{
case 0: //OPR 0 0;RETURN 返回
sp = bp;
pc = runtimeStack[sp + 2];
bp = runtimeStack[sp + 1];
break;
case 1: //OPR 0 1 ;NEG取反
runtimeStack[sp - 1] = -runtimeStack[sp - 1];
break;
case 2: //OPR 0 2;ADD加法
sp--;
runtimeStack[sp - 1] += runtimeStack[sp];
break;
case 3: //OPR 0 3;SUB减法
sp--;
runtimeStack[sp - 1] -= runtimeStack[sp];
break;
case 4: //OPR 0 4;MUL乘法
sp--;
runtimeStack[sp - 1] = runtimeStack[sp - 1] * runtimeStack[sp];
break;
case 5: //OPR 0 5;DIV除法
sp--;
runtimeStack[sp - 1] /= runtimeStack[sp];
break;
case 6: //OPR 0 6;ODD对2取模mod 2
runtimeStack[sp - 1] %= 2;
break;
case 7: //OPR 0 7;MOD取模
sp--;
runtimeStack[sp - 1] %= runtimeStack[sp];
break;
case 8: //OPR 0 8;==判断相等
sp--;
runtimeStack[sp - 1] = (runtimeStack[sp - 1] == runtimeStack[sp ] ? 1 : 0);
break;
case 9: //OPR 0 9;!=判断不相等
sp--;
runtimeStack[sp - 1] = (runtimeStack[sp - 1] != runtimeStack[sp] ? 1 : 0);
break;
case 10: //OPR 0 10;<判断小于
sp--;
runtimeStack[sp - 1] = (runtimeStack[sp - 1] < runtimeStack[sp] ? 1 : 0);
break;
case 11: //OPR 0 11;>=判断大于等于
sp--;
runtimeStack[sp - 1] = (runtimeStack[sp - 1] >= runtimeStack[sp] ? 1 : 0);
break;
case 12: //OPG 0 12;>判断大于
sp--;
runtimeStack[sp - 1] = (runtimeStack[sp-1] > runtimeStack[sp ] ? 1 : 0);
break;
case 13: //OPG 0 13;<=判断小于等于
sp--;
runtimeStack[sp - 1] = (runtimeStack[sp - 1] <= runtimeStack[sp ] ? 1 : 0);
break;
case 14: //OPG 0 14;输出栈顶值
Console.WriteLine("runtimeStack[sp - 1]" + runtimeStack[sp - 1] + ' ');
try
{
stdout += " " + runtimeStack[sp - 1] + ' ';
//stdout.Flush();
}
catch (Exception ex)
{
Console.WriteLine("***case 14 meet with error***");
}
sp--;
break;
case 15: //OPG 0 15;输出换行
Console.WriteLine("\n");
try
{
stdout += ("\n");
}
catch (Exception ex)
{
Console.WriteLine("***case 15 meet with error***");
}
break;
case 16: //OPG 0 16;读入一行输入，置入栈顶
Console.WriteLine("Please Input a Integer : ");
runtimeStack[sp] = 0;
try
{
runtimeStack[sp] = Int32.Parse(stdin.ReadLine().Trim()); //读入一个整型数字
Console.WriteLine(runtimeStack[sp]);
sp++;
}
catch (Exception e)
{
//e.printStackTrace();
Console.WriteLine("***read data meet with error***");
}
break;
}
break;
case Pcode.LOD: //取相对当前过程的数据基地址为a的内存的值到栈顶
runtimeStack[sp] = runtimeStack[Base(index.l, bp) + index.a];
sp++;
break;
case Pcode.STO: //栈顶的值存到相对当前的过程的数据基地址为a的内存
sp--;
runtimeStack[Base(index.l, bp) + index.a] = runtimeStack[sp];
break;
case Pcode.CAL: //调用子程序
runtimeStack[sp] = Base(index.l, bp); //将静态作用域基地址入栈
runtimeStack[sp + 1] = bp; //将动态作用域基地址
runtimeStack[sp + 2] = pc; //将当前指针入栈
bp = sp; //改变基地址指针值为新过程的基地址
pc = index.a; //跳转至地址a
break;
case Pcode.INT: //开辟空间大小为a
sp += index.a;
break;
case Pcode.JMP: //直接跳转至a
pc = index.a;
break;
case Pcode.JPC:
sp--;
if (runtimeStack[sp] == 0) //条件跳转至a(当栈顶指针为0时)
{
pc = index.a;
}
break;
}
} while (pc != 0);
return stdout;
}
