decode.c

DM64+系列 interpreter 程序

/*
 *  Copyright 2002 by Texas Instruments Incorporated.
 *  All rights reserved. Property of Texas Instruments Incorporated.
 *  Restricted rights to use, duplicate or disclose this code are
 *  granted through contract.
 *  
 */

#include "decode.h"
#include "instr.h"
#include "utils.h"


/* Decode the input program */

void decode(FILE * in_file){
	
	/* Read the file one string at a time */
	char instr[MAX_CHAR];
	char dest[MAX_CHAR];
	char src[MAX_CHAR];
	char line[1024];
	char temp[100];
	unsigned long line_no = 1;
	
	printf("Started Decoding...\n");
	while (fscanf(in_file,"%[^;\n]",line) != EOF){
		
		if (is_space(line)){ /* Comment */
			/* Read till end of line */
			fscanf(in_file,"%[^\n]",temp);
			/* Read the \n charater */
			fgetc(in_file);
			line_no++;
			strcpy(line,"");
			continue;	
		}
		printf("%s\n",line);
		
		/* Read the instruction */	
		sscanf(line,"%s",instr);
		if (!strcmp(instr,"READ") || !strcmp(instr,"WRITE")){
			/* Read the operand */
			sscanf(line,"%s %s",instr, src);
			if (strlen(src) != 1){
				printf("Error: Line %d. Expecting operand...Aborting\n",line_no,instr);
				return;
			}
			
			if (!strcmp(instr,"READ")){
				read_src(src);	
			}
			else if (!strcmp(instr,"WRITE")){
				write_dest(src);
			}
			
			/* Read till end of line */
			fscanf(in_file,"%[^\n]",temp);
			/* Read the new line character */
			fgetc(in_file);
			line_no++;
			strcpy(line,"");
			continue;
		}
	
		/* Assume two operand instructions */
		/* Read the operands */

		sscanf(line,"%s %s %s",instr,dest,src);
		if (strlen(dest) != 1){
			printf("Error: Line %d. Expecting operand %s...Aborting\n",line_no,line);
			return;
		}
		
		if ( (strlen(src) != 1) && !(isnum(src))  ){
			printf("Error: Line %d. Expecting operand...Aborting\n",line_no,instr);
			return;
		}
		
		if (!strcmp(instr,"ADD")){
			add(dest, src);
		}
		else if (!strcmp(instr,"ADDI")){
			if (!isnum(src)){
				printf("Error: Line %d. Illegal operand...Aborting\n",line_no,src);		
				return;
			}
			addi(dest, src);
		}
		else if (!strcmp(instr,"SUB")){
			sub(dest, src);
		}
		else if (!strcmp(instr,"SUBI")){
			if (!isnum(src)){
				printf("Error: Line %d. Illegal operand...Aborting\n",line_no,src);		
				return;
			}
			subi(dest, src);
		}
		else if (!strcmp(instr,"MULT")){
			mult(dest, src);
		}
		else if (!strcmp(instr, "MULTI")){
			if (!isnum(src)){
				printf("Error: Line %d. Illegal operand...Aborting\n",line_no,src);		
				return;
			}
			multi(dest, src);
		}
		else if (!strcmp(instr,"DIV")){
			my_div(dest, src);
		}
		else if (!strcmp(instr,"DIVI")){
			if (!isnum(src)){
				printf("Error: Line %d. Illegal operand...Aborting\n",line_no,src);		
				return;
			}
			divi(dest, src);
		}
		else if (!strcmp(instr,"MOV")){
			mov(dest, src);
		}
		else if (!strcmp(instr,"MOVI")){
			if (!isnum(src)){
				printf("Error: Line %d. Illegal operand...Aborting\n",line_no,src);		
				return;
			}
			movi(dest, src);
		}
		else{
			printf("Illegal instruction %s at line %d\n",instr, line_no);
		}
		
		/* Read till end of line */
		fscanf(in_file,"%[^\n]",temp);
		
		/* Read the new line character*/
		fgetc(in_file);
		strcpy(line,"");
		line_no++;
	}
	
	printf("Stopped Decoding...\n");

}