public bool Interpret()
{
int runtimeCount = 0;
output = "";
do
{
Pcode currentCode = pcodeList[pc++];
switch (currentCode.f)
{
case Pcode.PC.LIT: //将常量值取到运行栈顶，a是常数值
sta[sp++] = currentCode.a;
break;
case Pcode.PC.OPR:
switch (currentCode.a)
{
case 0: //OPR 0 0;函数调用结束后的返回
sp = bp;
pc = sta[sp + 2];
bp = sta[sp + 1];
break;
case 1: //OPR 0 1;栈顶元素取反
sta[sp - 1] = -sta[sp - 1];
break;
case 2: //OPR 0 2;次栈顶与栈顶相加，退两个栈元素，相加值进栈
sp--;
sta[sp - 1] += sta[sp];
break;
case 3: //OPR 0 3;次栈顶减栈顶
sp--;
sta[sp - 1] -= sta[sp];
break;
case 4: //OPR 0 4;次栈顶乘以栈顶
sp--;
sta[sp - 1] = sta[sp - 1] * sta[sp];
break;
case 5: //OPR 0 5;次栈顶处以栈顶
sp--;
sta[sp - 1] /= sta[sp];
break;
case 6: //OPR 0 6;栈顶元素的奇偶判断
sta[sp - 1] %= 2;
break;
case 7: //OPR 0 7;次栈顶对栈顶取模，退两个栈元素，余数进栈
sp--;
sta[sp - 1] %= sta[sp];
break;
case 8: //OPR 0 8;==判断相等
sp--;
sta[sp - 1] = (sta[sp] == sta[sp - 1] ? 1 : 0);
break;
case 9: //OPR 0 9;!=判断不相等
sp--;
sta[sp - 1] = (sta[sp] != sta[sp - 1] ? 1 : 0);
break;
case 10: //OPR 0 10;<判断小于
sp--;
sta[sp - 1] = (sta[sp - 1] < sta[sp] ? 1 : 0);
break;
case 11: //OPR 0 11;>=判断大于等于
sp--;
sta[sp - 1] = (sta[sp - 1] >= sta[sp] ? 1 : 0);
break;
case 12: //OPG 0 12;>判断大于
sp--;
sta[sp - 1] = (sta[sp - 1] > sta[sp] ? 1 : 0);
break;
case 13: //OPG 0 13;<=判断小于等于
sp--;
sta[sp - 1] = (sta[sp - 1] <= sta[sp] ? 1 : 0);
break;
}
break;
case Pcode.PC.LOD: //LOD 0 a;将变量值放到栈顶，a是存储空间，l是调用层与说明层的层次差
sta[sp] = sta[Base(currentCode.l, sta, bp) + currentCode.a];
sp++;
break;
case Pcode.PC.STO: //STO 0 a; 将栈顶内容送入某变量单元中 ，a是存储空间
sp--;
sta[Base(currentCode.l, sta, bp) + currentCode.a] = sta[sp];
break;
case Pcode.PC.CAL: //CAL 0 a; 调用过程,a是被调用过程的目标程序入口地址
sta[sp] = Base(currentCode.l, sta, bp);
sta[sp + 1] = bp;
sta[sp + 2] = pc;
bp = sp;
pc = currentCode.a;
break;
case Pcode.PC.INT: //INT 0 a; 在运行栈中为被调用的过程开辟a个单元的数据区
sp += currentCode.a;
break;
case Pcode.PC.JMP: //JMP 0 a; 无条件跳转至a地址
pc = currentCode.a;
break;
case Pcode.PC.JPC: //JPC 0 a; 条件跳转，当栈顶布尔值非真则跳转至a地址，否则顺序执行（假转）
sp--;
if (sta[sp] == 0)
{
pc = currentCode.a;
}
break;
case Pcode.PC.WRT: //WRT 0 a:栈顶值输出至屏幕
output += sta[sp - 1].ToString() + " ";
sp--;
break;
case Pcode.PC.RED: //RED 0 a: 读入一个输入置于栈顶
if (inputptr >= input.Length)
{
return(false);
}
int tmp = int.Parse(input[inputptr++]);
sta[sp] = tmp;
sta[Base(currentCode.l, sta, bp) + currentCode.a] = sta[sp];
break;
}
runtimeCount++;
if (runtimeCount > 1400)
{
StackOverflowException e = new StackOverflowException();
throw e;
}
} while (pc != 0);
return(true);
}
public void AddPcode(Pcode.PC f, int l, int a)
{
pcodeList[currentCode] = new Pcode(f, l, a);
currentCode++;
}
