interpret.cpp

这是我们的一个上机题,做词法分析和语法的,希望对大家的学习有所帮助

# include "common.h"

void INTERPRET()  //翻译的主过程
{
	//////////  初始化部分  /////////
	oldTop=0;     
	stop=0;
	top=0;
	bp=0;
	pc=0;
	DISPLAY[1]=0;
	S[1]=0;
	S[2]=0;
	S[3]=0;
	/////////  初始化结束  //////////

	printf("翻译开始\n");
	do
	{
		instruction=CODE[pc];  //取指令
		pc++;                  //PC加一
		switch(instruction.func)  //翻译执行
		{
		case LIT:
		case LIT1:
			top++;
			S[top]=instruction.address;
			break;
		case LOD:
			top++;
			S[top]=S[DISPLAY[instruction.level]+instruction.address];
			break;
		case LODA:
			top++;
			S[top]=DISPLAY[instruction.level]+instruction.address;
			break;		
		case ILOD:
			top++;
			S[top]=S[S[DISPLAY[instruction.level]+instruction.address]];
			break;
		case LODT:
			S[top]=S[S[top]];
			break;
		case LODB:
			h=S[top];
			top--;
			hh=instruction.address+top;
			while(top<hh)
			{
				top++;
				S[top]=S[h];
				h++;
			}
			break;
		case CPYB:
			h=S[top-1];
			hh=S[top];
			hhh=h+instruction.address;
			while(h<hhh)
			{
				S[h]=S[hh];
				h++;
				hh++;
			}
			top-=2;
			break;
		case STO:
			S[S[top-1]]=S[top];
			top-=2;
			break;
		case OPAC:
			oldTop=top;
			top+=3;
			break;
		case CAL:
			S[oldTop+1]=pc;
			S[oldTop+2]=DISPLAY[instruction.level];
			S[oldTop+3]=bp;
			pc=instruction.address;
			break;
		case ENTP:
			bp=oldTop+1;
			DISPLAY[instruction.level]=bp;
			top=oldTop+instruction.address;
			break;
		case UDIS:
			h=instruction.address;
			hh=instruction.level;
			hhh=bp;
			do
			{
				DISPLAY[h]=hhh;
				h--;
				hhh=S[hhh+1];
			}while(h!=hh);
			break;
		case JMP:
			pc=instruction.address;
			break;
		case JPC:
			if(S[top]==0)
			{
				pc=instruction.address;
			}
			top--;//严重错误，已更正
			break;
		case RETP:
			top=bp-1;
			pc=S[top+1];
			bp=S[top+3];
			break;
		case ENDP:
			stop=1;
			break;
		case RED:
			if(instruction.address==0)
			{
				printf("Your Input:");
				scanf("%d",&temp);
			}
			else
				getch();
			S[S[top]]=temp;
			break;
		case WRT:
			if(instruction.address==0)
				printf("Your Output:%d\n",S[top]);		
			else
			{
				ch=(char)S[top];
				printf("Your Output%c\n",ch);
			}
			top--;
			break;
		case MUS:
			S[top]=-S[top];
		case ADD:
		case ADD1:
			top--;
			S[top]=S[top]+S[top+1];
			break;
		case SUB:
			top--;
			S[top]=S[top]-S[top+1];
			break;
		case MULT:
			top--;
			S[top]=S[top]*S[top+1];
			break;
		case IDIV:
			top--;
			S[top]=S[top]/S[top+1];
			break;
		case IMOD:
			top--;
			S[top]=S[top]%S[top+1];
			break;
		case ANDS:
			top--;
			S[top]=S[top]&S[top+1];
			break;
		case ORS:
			top--;
			S[top]=S[top]|S[top+1];
			break;
		case NOTS:
			top--;
			S[top]=~S[top];
			break;
		case EQ:
			top--;
			S[top]=(S[top]==S[top+1])?1:0;
			break;
		case NE:
			top--;
			S[top]=(S[top]!=S[top+1])?1:0;
			break;
		case LS:
			top--;
			S[top]=(S[top]<S[top+1])?1:0;
			break;
		case GE:
			top--;
			S[top]=(S[top]>=S[top+1])?1:0;
			break;
		case GT:
			top--;
			S[top]=(S[top]>S[top+1])?1:0;
			break;
		case LE:
			top--;
			S[top]=(S[top]<=S[top+1])?1:0;
			break;
		}
	}while(!stop);
	
	//printf("翻译结束，请输入任意字符退出。\n");
	printf("翻译结束。\n");
}


void main(int arg,char ** argv)
{	
	char objFileName[255];
	FILE * objFile;
	int objLength;
	int unitlength;//指令单元大小
	//INSTRUCTION tempIns;
	
	if(arg>1)
		strcpy(objFileName,argv[1]);
	else
	{
		printf("请输入代码源文件的名字：");
		scanf("%s",objFileName);
	}

	if(!(objFile=fopen(objFileName,"rb")))
	{
		printf("错误产生：代码源文件%s不能打开！\n",objFileName);
		exit(1);
	}

	fseek(objFile,0,SEEK_END);
	objLength=ftell(objFile);   //获得代码文件的长度
	rewind(objFile);
	
	if(objLength%(3*sizeof(int)))   //判断代码文件是否完整
	{
		printf("错误的代码源文件！");
		exit(2);
	}
    unitlength=2*sizeof(int)+sizeof(OPCOD);
	int codeSize=objLength/unitlength;   //获得代码文件里面的指令条数
	printf("codeSize is %d\n",codeSize);
	CODE=new INSTRUCTION[codeSize];   //生成代码数组
   

	if(!CODE)
	{
		printf("没有足够的堆可分配！");
		exit(3);
	}

	
     //致命错误
	int count=fread(CODE,unitlength,codeSize,objFile);    //将代码文件读入代码数组

    if(count!=0)	
	{
		printf("%d",count);
		INTERPRET();//开始翻译执行
	}
	else
		printf("wrong！\n");
	delete CODE;   //翻译完毕，删除数组
	fclose(objFile);
	
	//int a;         //小关卡，可以查看运行结果
	//scanf("%d",a);
}