void get_OPformat(void){
char *temp;
OPCODE_extended = 0; // Initialization extended tag
/* if OPCODE is extended format */
if(OPCODE[0] == '+'){
temp = &OPCODE[1];
strcpy(OPCODE, temp);
OPCODE_extended = 1;
}
/* Search OPTAB, if OPCODE is found, then */
if(search_OPTAB(&instPtr)){
OPCODE_format = inst_Length(instPtr);
}
/* else if OPCODE is "BYTE" */
else if(!strcmp(OPCODE, "BYTE")){
OPCODE_format = 5;
}
/* else if OPCODE is "WORD" */
else if(!strcmp(OPCODE, "WORD")){
OPCODE_format = 6;
}
/* else if OPCODE is "RESB" */
else if(!strcmp(OPCODE, "RESB")){
OPCODE_format = 0;
}
/* else if OPCODE is "RESW" */
else if(!strcmp(OPCODE, "RESW")){
OPCODE_format = 0;
}
/* else if OPCODE is "BASE" */
else if(!strcmp(OPCODE, "BASE")){
OPCODE_format = 7;
}
/* else if OPCODE is "START" */
else if(!strcmp(OPCODE, "START")){
OPCODE_format = 0;
}
/* else if OPCODE is "END" */
else if(!strcmp(OPCODE, "END")){
OPCODE_format = -0;
}
/* else (undefined OPCODE) */
else{
printf("ERROR. %s is undefined OPCODE.\n", OPCODE);
exit(0);
}
return ;
}
//Pass 1
void PASS_ONE()
{
FILE * fp1,*fp2; //file pointers
char line[100], s1[100], s2[100], s3[100], s4[100],startingADDRESS[5], saveLOCCTR[5];
int t,flag_SYMTAB, flag_OPTAB;
printf("Enter the input file name :");
scanf("%s",in_file); //input file name
fp1 = fopen(in_file, "r"); //corresponding file opened
if(fp1 == NULL) //if '.txt' not in entered file name
{
strcat(in_file, ".txt"); //concatenating '.txt'
fp1 = fopen(in_file, "r");
if(fp1 == NULL)
{
printf("Could not open source file!!\n");
exit(0);
}
}
strcpy(out_file, in_file);
out_file[strlen(out_file)-4] = '\0';
strcat(out_file, "-intermediate.txt"); //to get intermediate file name
fp2 = fopen(out_file, "w");
if(fp2 == NULL)
{
printf("Could not open Intermediate file!!\n");
exit(0);
}
//fgets(line, 100, fp1);//For column headers
//Read first line
fgets(line, 100 ,fp1); //reading a line of the input
t = sscanf(line,"%s %s %s %s",s1,s2,s3,s4); //t stores the number of words read
if(t==2) //two words read
{
strcpy(s3, s2); //shifting the words read
strcpy(s2, s1);
strcpy(s1, "");
}
char temp[10];
if(strcmp(s2,"START")==0) //start line
{
strcpy(LOCCTR,s3);
make_length(LOCCTR,temp,4);
line[strlen(line)-1] = '\0';
if(t==1)
fprintf(fp2, "%s %s %s",temp,line," Syntax error : less arguments");
else if(t>3)
fprintf(fp2, "%s %s %s",temp,line," Syntax error : more arguments");
else
fprintf(fp2, "%s %s",temp,line);//Write to Intermediate file
fprintf(fp2,"\n");
fgets(line, 100 ,fp1);//Read next line
t = sscanf(line,"%s %s %s %s",s1,s2,s3,s4);
if(t==2)
{
strcpy(s3, s2);
strcpy(s2, s1);
strcpy(s1, "");
}
}
else //if START was not found
{
strcpy(LOCCTR, "0000");
printf("Syntax Error : NO START found!!\n");
}
strcpy(startingADDRESS, LOCCTR);
while(!feof(fp1) && (strcmp(s2, "END")!=0))
{
flag_SYMTAB = 0;flag_OPTAB = 0;
strcpy(saveLOCCTR, LOCCTR);
if(line[0] != '#')//Not a comment line
{
if(t==3)//Symbol exists in Label Field
{
if(search_SYMTAB(s1))//Label exists in SYMTAB
flag_SYMTAB = 1;
else
insert_SYMTAB(s1,LOCCTR);
}
strcpy(saveLOCCTR, LOCCTR);
char * OPCODE = search_OPTAB(s2);
if(OPCODE != NULL)
increment_LOCCTR(3);
else if(strcmp(s2, "WORD") == 0) //WORD detected
increment_LOCCTR(3);
else if(strcmp(s2, "RESW") == 0) //RESW detected
increment_LOCCTR(3 * atoi(s3));
else if(strcmp(s2, "RESB") == 0) //RESB detected
increment_LOCCTR(atoi(s3));
else if(strcmp(s2, "BYTE") == 0) //BYTE detected
increment_LOCCTR(find_length_BYTE(s3));
else
{
increment_LOCCTR(3);
flag_OPTAB = 1;//OPCODE not found and is not an assembler directive
}
}
make_length(saveLOCCTR,temp,4);
strcpy(saveLOCCTR,temp);
char write[100];//Line to write in Intermediate file
line[strlen(line)-1] = '\0';//Remove newline character from line read so taht it writes error on same line
if(flag_OPTAB == 0 )
{
if(flag_SYMTAB == 0)
sprintf(write, "%s %s",saveLOCCTR, line);
else
sprintf(write,"%s %s %s",saveLOCCTR, line, "Duplicate Symbol");
}
else
{
if(flag_SYMTAB == 0)
sprintf(write,"%s %s %s",saveLOCCTR, line, "Invalid Operation Code");
else
sprintf(write,"%s %s %s %s",saveLOCCTR, line, "Duplicate Symbol", "Invalid Operation Code");
}
if(t==1)
fprintf(fp2, "%s %s",write," Syntax error : less arguments");
else if(t>3)
fprintf(fp2, "%s %s",write," Syntax error : more arguments");
else
fprintf(fp2, "%s",write);//Write to Intermediate file
fprintf(fp2,"\n");
//Read next line
fgets(line, 100, fp1);
t = sscanf(line,"%s %s %s %s",s1,s2,s3,s4);
if(t==2)
{
strcpy(s3, s2);
strcpy(s2, s1);
strcpy(s1, "");
}
}
make_length(LOCCTR,temp,4);
//Write last line to Intermediate file
fprintf(fp2, "%s %s",temp, line);
fclose(fp1);
fclose(fp2);
//Computing Program Length
int start, location,l;
char length[5];
sscanf(startingADDRESS, "%x", &start);
sscanf(LOCCTR, "%x", &location);
l = location - start;
itoa(l, length, 16); //getting the length of the code in a string
strcpy(out_file, in_file);
out_file[strlen(out_file)-4] = '\0';
strcat(out_file, "-length.txt");
fp2 = fopen(out_file, "w");
if(fp2 != NULL)
fprintf(fp2, "%s", length);
fclose(fp2); //closing file pointer
}
//pass II
void PASS_TWO()
{
FILE * fp1,*fp2,*fp3;
char line[100], s1[100], s2[100], s3[100], s4[100], startADDRESS[5], length[5], name[100];
//s1 is Location, s2 is Label, s3 is Opcode, s4 is Operand
char * symbolADDRESS;
char OBJECTCODE[100] ;
int t,flag_SYMTAB,main_flag = 0,linecounter = 0;
printf("Enter the intermediate file name :");
scanf("%s",im_file);
fp1 = fopen(im_file, "r"); //opening intermediate file
if(fp1 == NULL)
{
strcat(im_file, ".txt");
fp1 = fopen(im_file, "r");
if(fp1 == NULL)
{
printf("Could not open Intermediate file!!\n");
exit(0);
}
}
loadSYMTAB_from_file(); //loading symbol table
strcpy(obj_file, im_file);
obj_file[strlen(obj_file)-17] = '\0';
strcat(obj_file, "-object.txt");
fp2 = fopen(obj_file, "w");
if(fp2 == NULL)
{
printf("Could not open Object file!!\n");
exit(0);
}
//Read first line
fgets(line, 100 ,fp1);
linecounter++;
t = sscanf(line,"%s %s %s %s",s1,s2,s3,s4);
if(t==3)
{
strcpy(s4, s3);
strcpy(s3, s2);
}
if(strcmp(s3,"START")==0)
{
strcpy(startADDRESS, s1);
strcpy(name, s2);//s2 != s3
fgets(line, 100 ,fp1);//Read next line
linecounter++;
t = sscanf(line,"%s %s %s %s",s1,s2,s3,s4);
if(t==3)
{
strcpy(s4, s3);
strcpy(s3, s2);
}
}
else
{
strcpy(startADDRESS, "0000");
strcpy(name, "UNNAMED");
}
//Getting Program Length
char S[100];
strcpy(S, im_file);
S[strlen(S)-17] = '\0';
strcat(S, "-length.txt");
fp3 = fopen(S, "r");
fscanf(fp3, "%s",length);
fclose(fp3);
//Writing Header Record
char temp1[7], temp2[7];
make_length(startADDRESS, temp1, 6);
make_length(length, temp2, 6);
fprintf(fp2,"H|%s|%s|%s",name,temp1,temp2);
fprintf(fp2,"\n");
//Initialse text record
fprintf(fp2, "T|%s|%s",temp1,length);
while(!feof(fp1) && (strcmp(s3, "END")!=0))
{
flag_SYMTAB = 0;
if(s2[0] != '#')//Not a comment line
{
char * OPCODE = search_OPTAB(s3);
if(OPCODE != NULL)//OPCODE found in OPTAB
{
if(s4!=NULL)//There is a symbol in operand field
{
symbolADDRESS = search_SYMTAB(s4);
if(symbolADDRESS != NULL)
make_length(symbolADDRESS, temp1, 4);
if(symbolADDRESS == NULL)//Operand does not exist in SYMTAB
{
printf("Line %d : Error : Symbol is not defined\n",linecounter);
main_flag = 1;
flag_SYMTAB = 1;
}
}
else//No symbol in operand field
strcpy(symbolADDRESS,"0000");
//Assemble object code instruction
strcpy(OBJECTCODE, OPCODE);
if(symbolADDRESS != NULL)
strcat(OBJECTCODE, temp1);
}
else if(OPCODE==NULL && (strcmp(s3, "BYTE") == 0))
convert_BYTE(s4,OBJECTCODE);
else if(OPCODE==NULL && (strcmp(s3, "WORD") == 0))
convert_WORD(s4,OBJECTCODE);
else//OPCODE is RESW or RESB
strcpy(OBJECTCODE, "");
if(strcmp(OBJECTCODE,"") != 0)
fprintf(fp2, "|%s",OBJECTCODE);//Add object code to text
}
//Read next line
fgets(line, 100, fp1);
linecounter++;
t = sscanf(line,"%s %s %s %s",s1,s2,s3,s4);
if(t==3)
{
strcpy(s4, s3);
strcpy(s3, s2);
}
}
//Write End Record
fprintf(fp2,"\n");
make_length(startADDRESS, temp1, 6);
fprintf(fp2,"E|%s",temp1);
fclose(fp1);
fclose(fp2);
strcpy(obj_file, im_file);
obj_file[strlen(obj_file)-17] = '\0';
strcat(obj_file, "-object.txt");
if(main_flag == 1) //error in file
remove(obj_file); //removing the object file as error has been detected
}
void pass1(void){
char line[100];
char orig_line[100];
//SICXE_OP *instPtr;
/* Read first input line */
fgets(line, 100, source_file);
strcpy(orig_line, line);
get_format(line);
/* if OPCODE = 'START' then */
if(!strcmp(OPCODE, "START")){
/* Save #[OPERAND] as starting address (Relocation -> start at 0)*/
/* Initialize LOCCTR to starting address */
LOCCTR = 0; // Enable to be Relocation
/* Write line to intermedite file */
insert_to_file(orig_line);
line_Counter++;
/* Read next line */
fgets(line, 100, source_file);
strcpy(orig_line, line);
get_format(line);
}
else{
/* Initialize LOCCTR to 0 */
LOCCTR = 0;
}
/* while OPCODE != 'END' do */
while(strcmp(OPCODE, "END")){
print_type = 1; // Normal
PREV_LOCCTR = LOCCTR;
/* if this is not a comment line then */
if(1){
/* if there is a symbol in the LABEL field then */
if(SYMBOL_ox == 1){
insert_SYMTAB(SYMBOL);
}
/* search OPTAB for OPCODE, if found then */
if(search_OPTAB(&instPtr)){
/* add instruction length to LOCCTR */
LOCCTR += (OPCODE_format);
}
/* else if OPCODE = 'WORD' */
else if(!strcmp(OPCODE, "WORD")){
/* add 3 to LOCCTR */
LOCCTR += 3;
}
/* else if OPCODE = 'RESW' */
else if(!strcmp(OPCODE, "RESW")){
/* add 3 * #[OPERAND] to LOCCTR */
LOCCTR += (3 * atoi(OPERAND1));
}
/* else if OPCODE = 'RESB' */
else if(!strcmp(OPCODE, "RESB")){
/* add #[OPERAND] to LOCCTR */
LOCCTR += atoi(OPERAND1);
}
/* else if OPCODE = 'BYTE' */
else if(!strcmp(OPCODE, "BYTE")){
/* find length of constant in bytes */
/* add length to LOCCTR */
LOCCTR += (byte_Length());
}
/* else if OPCODE = 'BASE' */
else if(!strcmp(OPCODE, "BASE")){
/* find length of constant in bytes */
/* add length to LOCCTR */
print_type = 2; // Directive
}
/* else */
else{
/* Set EORROR flag (invalid operation code) */
printf("EORROR! %s is Invalid Operation Code.\n", OPCODE);
exit(0);
}
}
/* Write line to intermediate file */
insert_to_file(orig_line);
/* Read next line */
fgets(line, 100, source_file);
strcpy(orig_line, line);
get_format(line);
line_Counter++;
}
/* Write last line to intermediate file */
print_type = 2; // Directive
insert_to_file(orig_line);
/* Save (LOCCTR - starting address) as program length */
program_Length = (LOCCTR - 0);
return ;
}
