interpret.cpp

一个编译器原码

#include "compile.h"

//******************************************************************/
//函数原型：void printDesCode()
//参数说明：无
//函数功能：打印生成的目标代码
//返回值  ：无
//******************************************************************/
void printDesCode()
{
	maxCodeCount=codeCount;
	for(int i=0; i<maxCodeCount; i++)
	{
		switch(code[i].funCode)
		{
		case INT:	printf("%d\tINT\t%d\n",i,code[i].offset);break;
		case LIT:	printf("%d\tLIT\t%d\n",i,code[i].offset);break;
		case LOD:	printf("%d\tLOD\t%s\n",i,table[code[i].offset+1].name);break;
		case STO:	printf("%d\tSTO\t%s\n",i,table[code[i].offset+1].name);break;
		case JMP:	printf("%d\tJMP\t%d\n",i,code[i].offset);break;
		case JPC:	printf("%d\tJPC\t%d\n",i,code[i].offset);break;
		case OPR:	printf("%d\tOPR\t%d\n",i,code[i].offset);break;
		case WRT:	printf("%d\tWRT\t%d\n",i,code[i].offset);break;
		}
	}
	printf("\n");
	return;
}

//******************************************************************/
//函数原型：void interpret()
//参数说明：无
//函数功能：解释程序
//返回值  ：无
//******************************************************************/
void interpret()
{
	printf("result:\n");

	maxCodeCount=codeCount;
	for(int i=0; i<maxCodeCount; i++)
	{
		switch(code[i].funCode)
		{
		case INT:
			stackCount=code[i].offset;
			break;
		case LIT:
			dataStack[stackCount++]=code[i].offset;
			break;
		case LOD:
			dataStack[stackCount++]=dataStack[code[i].offset];
			break;
		case STO:
			dataStack[code[i].offset]=dataStack[--stackCount];
			break;
		case JMP:
			i=code[i].offset;
			i--;//为了抵消每次都要执行的i++
			break;
		case JPC:
			if(dataStack[--stackCount] == FALSE)
			{
				i=code[i].offset;
				i--;//为了抵消每次都要执行的i++
			}
			break;
		case OPR:
			switch(code[i].offset)
			{
			case OPR_PLUS:
				dataStack[stackCount-2] = dataStack[stackCount-2] + dataStack[stackCount-1];
				stackCount--;
				break;
			case OPR_MINUS:
				dataStack[stackCount-2] = dataStack[stackCount-2] - dataStack[stackCount-1];
				stackCount--;
				break;
			case OPR_TIMES:
				dataStack[stackCount-2] = dataStack[stackCount-2] * dataStack[stackCount-1];
				stackCount--;
				break;
			case OPR_SLASH:
				dataStack[stackCount-2] = dataStack[stackCount-2] / dataStack[stackCount-1];
				stackCount--;
				break;
			case OPR_OPPO:
				dataStack[stackCount-1] = -dataStack[stackCount-1];
				break;
			case OPR_EQL:
				if(dataStack[stackCount-2] == dataStack[stackCount-1])
					dataStack[stackCount-2] = TRUE;
				else
					dataStack[stackCount-2] = FALSE;
				stackCount--;
				break;
			case OPR_LSS:
				if(dataStack[stackCount-2] < dataStack[stackCount-1])
					dataStack[stackCount-2] = TRUE;
				else
					dataStack[stackCount-2] = FALSE;
				stackCount--;
				break;
			case OPR_LEQ:
				if(dataStack[stackCount-2] <= dataStack[stackCount-1])
					dataStack[stackCount-2] = TRUE;
				else
					dataStack[stackCount-2] = FALSE;
				stackCount--;
				break;
			case OPR_GTR:
				if(dataStack[stackCount-2] > dataStack[stackCount-1])
					dataStack[stackCount-2] = TRUE;
				else
					dataStack[stackCount-2] = FALSE;
				stackCount--;
				break;
			case OPR_GEQ:
				if(dataStack[stackCount-2] >= dataStack[stackCount-1])
					dataStack[stackCount-2] = TRUE;
				else
					dataStack[stackCount-2] = FALSE;
				stackCount--;
				break;
			case OPR_OR:
				if(dataStack[stackCount-2] == TRUE || dataStack[stackCount-1] == TRUE)
					dataStack[stackCount-2] = TRUE;
				else
					dataStack[stackCount-2] = FALSE;
				break;
			case OPR_AND:
				if(dataStack[stackCount-2] == TRUE && dataStack[stackCount-1] == TRUE)
					dataStack[stackCount-2] = TRUE;
				else
					dataStack[stackCount-2] = FALSE;
				break;
			}
			break;
		case WRT:
			printf("%d\n",dataStack[stackCount-1]);
			break;
		}
	}

	return;
}