OneP.c

#define _GNU_SOURCE 
#include<stdio.h>
#include<string.h>

int findInSYMTAB(char findLabel[]){
	FILE *SYMTAB;
	char label[30],addr[30];
	SYMTAB=fopen("symtab.txt","r");
	fscanf(SYMTAB,"%s%s",label,addr);
	while(1){
		if(feof(SYMTAB)){
			fclose(SYMTAB);
			break;
		}
		if(strcmp(findLabel,label)==0){
			fclose(SYMTAB);
			return atoi(addr);
		}
		fscanf(SYMTAB,"%s%s",label,addr);
	}
}

int getMnemonicCode(char mnemonic[]){
	
		if(strcmp(mnemonic,"LDA")==0)
			return 33;
		else if(strcmp(mnemonic,"STA")==0)
			return 44;
		else if(strcmp(mnemonic,"LDCH")==0)
			return 53;
		else if(strcmp(mnemonic,"STCH")==0)
			return 57;
		else
			return -1;
}


void main(){
	
	FILE *INPUT,*OUTPUT,*SYMTAB,*INTERMEDIATE,*FINAL,*OBJ;
	char mnemonic[10][10]={"START","LDA","STA","LDCH","STCH","END"};
	int LOCCTR,start=0,j=0,i,length,Tlength,count=0,finalAddress,startAddr;
	char label[20],opcode[20],operand[20],address[20];
	
	INPUT=fopen("input.txt","r");
	OUTPUT=fopen("output.txt","w");
	SYMTAB=fopen("symtab.txt","w");
	
	fscanf(INPUT,"%s%s%s",label,opcode,operand);

	if(strcmp(opcode,"START")==0){
		start=atoi(operand);
		LOCCTR=start;
		fprintf(OUTPUT,"\t%s\t%s\t%s\n",label,opcode,operand);
		fscanf(INPUT,"%s%s%s",label,opcode,operand);
	}else 
		LOCCTR=0;
		
	while(strcmp(opcode,"END")!=0){
		j=0;
		fprintf(OUTPUT,"%d",LOCCTR);
		if(strcmp(label,"**")!=0)
			fprintf(SYMTAB,"\t%s\t%d\n",label,LOCCTR);
		while(strcmp(mnemonic[j],"END")!=0){
			if(strcmp(mnemonic[j],opcode)==0){
				LOCCTR+=3;	
			}
			j++;	
		}
		
		if(strcmp(opcode,"WORD")==0)
			LOCCTR+=3;
		else if (strcmp(opcode,"RESW")==0){
			LOCCTR=LOCCTR+(3* atoi(operand));
			count+=(3* atoi(operand));
		}	
		else if (strcmp(opcode,"RESB")==0){
			LOCCTR=LOCCTR+atoi(operand);
			count+=atoi(operand);
		}	
		else if (strcmp(opcode,"BYTE")==0){	
			LOCCTR=LOCCTR+(strlen(operand)-3);
		}	
		else {
			printf(" ");	
		}
		fprintf(OUTPUT,"\t%s\t%s\t%s\n",label,opcode,operand);
		fscanf(INPUT,"%s%s%s",label,opcode,operand);
	}	
	fprintf(OUTPUT,"%d",LOCCTR);	
	fprintf(OUTPUT,"\t%s\t%s\t%s\n",label,opcode,operand);
	printf("THE LENGTH OF THE PROGRAM IS %d",LOCCTR-start); 
	length=LOCCTR-start;
	finalAddress=LOCCTR;
	Tlength=length-count;
	_fcloseall();
	
	INTERMEDIATE=fopen("output.txt","r");
	OBJ=fopen("obj.txt","w");
	FINAL=fopen("final.txt","w");
	fscanf(INTERMEDIATE,"%s%s%s",label,opcode,operand);

	startAddr=atoi(operand);
	
	if(strcmp(opcode,"START")==0){
		fprintf(FINAL,"\t%s\t%s\t%s\t\n",label,opcode,operand);
		fprintf(OBJ,"H^%s^00%s^00%d\n",label,operand,length);
		fscanf(INTERMEDIATE,"%s%s%s%s",address,label,opcode,operand);
		fprintf(OBJ,"T^%06d^%d^",atoi(address),Tlength);

	}
	while(strcmp(opcode,"END")!=0){
	
		if(strcmp(label,"**")==0 ){
			fprintf(OBJ,"%d%d^",getMnemonicCode(opcode),findInSYMTAB(operand));
			fprintf(FINAL,"%s\t%s\t%s\t%s\t%d%d\n",address,label,opcode,operand,getMnemonicCode(opcode),findInSYMTAB(operand));
			fscanf(INTERMEDIATE,"%s%s%s%s",address,label,opcode,operand);
		}
		else if(strcmp(opcode,"BYTE")==0){
			fprintf(FINAL,"%s\t%s\t%s\t%s",address,label,opcode,operand);
			for(i=2;i<(strlen(operand)-1);i++){
				fprintf(OBJ,"%x",operand[i]);
				fprintf(FINAL,"%x",operand[i]);	
			}		
			fprintf(FINAL,"\n");
			fscanf(INTERMEDIATE,"%s%s%s%s",address,label,opcode,operand);					
		}	
		else if(strcmp(opcode,"WORD")==0){
			fprintf(OBJ,"%06x^",atoi(operand));
			fprintf(FINAL,"%s\t%s\t%s\t%s\t%06x\n",address,label,opcode,operand,atoi(operand));		
			fscanf(INTERMEDIATE,"%s%s%s%s",address,label,opcode,operand);		
		}	
		else{
			fscanf(INTERMEDIATE,"%s%s%s%s",address,label,opcode,operand);
		}
			
	}
	fprintf(FINAL,"%s\t%s\t%s\t%s\n",address,label,opcode,operand);	
	fprintf(OBJ,"\nE^%06d\n",startAddr); 
	_fcloseall();
	remove("output.txt");
}