//input.txt START 200
MOVER AREG , ='5' MOVEM AREG , A LOOP MOVER AREG , A MOVER CREG , B ADD CREG , ='1' LTORG
='5' ='1'
NEXT1 SUB AREG , ='1' ORIGIN LOOP+6
MUL CREG , B A DS 2
B DC 3
NEXT2 EQU LOOP END ='1' //Pass 1 Assembler #include<stdio.h> #include<conio.h> #include<string.h> #include <stdlib.h> #include<ctype.h> //---// char label[4][10]; //To store all words in a line
int location_counter=0; int literal_no1=1; int literal_no2=1;
int L=0; //To keep track of Literals int C=0; //To keep track of Constants int cnt=0;
int s=0; //For symbols FILE *fp2,*fp3;
//---// //Structure for Mnemonic Table
typedef struct mnemonic_table mnemonic_table; struct mnemonic_table
{
int mno;
char mcode[10]; //Assembly mnemonic int ocode; //Instruction Opcode int length; //Default 1
char type[5]; //AD,DL,IS };
mnemonic_table mtable[15];
//---// //Structure for Symbol Table
typedef struct symbol symbol; struct symbol
{
int sno; //Symbol No char sname[10]; //Symbol
int saddr; //Symbol Addresss int slength; }; symbol sym_table[10]; //---// void initialize_mtable(); int find(char []); void label_initialize(); void pass1(); void labels(); //---// main(void) { FILE *fp1,*fp2; char temp[30]; fp1=fopen("C:\input.txt","r"); if(!fp1)
printf("\t\t FILE NOT OPENED !!!\n");
printf("\n---INPUT---\n "); while(!feof(fp1)) { fgets(temp,30,fp1); printf("%s",temp); } printf("---\n" ); fp2=fopen("C:\icode.txt","w"); fputs("LC\tIC\tOP\tOPE1\tIC->OPE2\n\n",fp2); fp3=fopen("C:\literal.txt","w"); fputs("No\tLiteral\tAddress\n\n",fp3); fcloseall(); labels(); printf("\nInput Code--->input.txt\n"); printf("\nIntermediate Code--->icode.txt\n"); printf("\nSymbol Table--->symbol.txt\n"); printf("\nLiteral Table--->literal.txt\n");
getch(); } //---// void initialize_mtable() { int i; int j=1; //---// //Assembler Directives strcpy(mtable[0].mcode,"START"); strcpy(mtable[1].mcode,"END"); strcpy(mtable[2].mcode,"ORIGIN"); strcpy(mtable[3].mcode,"LTORG"); strcpy(mtable[4].mcode,"EQU"); for(i=0;i<=4;i++) { mtable[i].mno=i; mtable[i].ocode=i+1; mtable[i].length=0; strcpy(mtable[i].type,"AD"); } //---// //Declarative Statements
strcpy(mtable[5].mcode,"DC"); //Declare Constant strcpy(mtable[6].mcode,"DS"); //Declare Storage while(i<=6) { mtable[i].mno=i+1; mtable[i].ocode=i+1; strcpy(mtable[i].type,"DL"); i++; } //---// //Imperative Statements strcpy(mtable[7].mcode,"MOVER"); strcpy(mtable[8].mcode,"MOVEM"); strcpy(mtable[9].mcode,"ADD"); strcpy(mtable[10].mcode,"MUL"); strcpy(mtable[11].mcode,"SUB"); strcpy(mtable[12].mcode,"DIV"); strcpy(mtable[13].mcode,"BC"); strcpy(mtable[14].mcode,"COMP"); while(i<=14) { mtable[i].mno=i;
mtable[i].ocode=j; mtable[i].length=1; strcpy(mtable[i].type,"IS"); i++; j++; } } //---// void label_initialize() { int i; for(i=0;i<4;i++) { strcpy(label[i]," "); } } //---// int find(char check[])
{ int i; for(i=0;i<15;i++) { if(strcmp(check,mtable[i].mcode)==0) return i; } if(strcmp(check,"AREG")==0) return 51; if(strcmp(check,"BREG")==0) return 52; if(strcmp(check,"CREG")==0) return 53; if(strcmp(check,"DREG")==0) return 54; return -1; } //---// void labels() { FILE *fp1,*fp4; char temp[30],tmp[10]; int i=0,j=0; int flag=0; initialize_mtable(); fp1=fopen("C:\input.txt","r"); fp2=fopen("C:\icode.txt","a+"); fp3=fopen("C:\literal.txt","a+");
while(!feof(fp1)) //while(2) { i=0; cnt=0; L=0;C=0; fgets(temp,30,fp1); label_initialize(); while(temp[i]!='\n') //while(1) { j=0; while(isalnum(temp[i])) { flag=1; tmp[j]=temp[i];
if(isdigit(tmp[0]) && temp[i-1]=='\'') //For l iterals
L=1;
else if(isdigit(tmp[0]) && temp[i-1]==' ') // For Constants C=1; i++; j++; } if(flag==1) { flag=0; tmp[j]='\0'; strcpy(label[cnt],tmp); cnt++; j=0; } if(temp[i]=='\n') break; i++; }//end of while(1) pass1(); }//end of while(2) fclose(fp1); fclose(fp2); fclose(fp3); fp4=fopen("C:\symbol.txt","w"); fputs("No\tSymbol\tlength\tAddress\n\n",fp4); for(i=0;i<s;i++) { fprintf(fp4,"%d\t",sym_table[i].sno); fprintf(fp4,"%s\t\t",sym_table[i].sname); fprintf(fp4,"%d\t\t",sym_table[i].slength); fprintf(fp4,"%d\n\n",sym_table[i].saddr); } fclose(fp4); }
//---// //To generate intermediate code
void pass1() { int check,count=0,value=0,length=1,flag=0,i=0; char c; while(count<cnt) { check=find(label[count]);
if(isdigit(label[count][0])) //To convert a string with digits value=atoi(label[count]); //into integer value
if(check==-1 && isalpha(label[count][0]) ) //for symbols { for(i=0;i<s;i++) { if(strcmp(label[count],sym_table[i].sname)==0) { sym_table[i].saddr=location_coun ter; flag=1; break; } } if(flag==0) { sym_table[s].sno=s+1; strcpy(sym_table[s].sname,label[count]); sym_table[s].saddr=location_counter; sym_table[s].slength=length; s++; } if(count!=0) {
//To print symbols c='S'; fprintf(fp2,"\t%c\t",c); if(flag==0) fprintf(fp2,"%d",s); else fprintf(fp2,"%d",sym_table[i].sno); } }
else if(check==0) //for Start(AD) { fprintf(fp2,"\t"); fprintf(fp2,"%s\t",mtable[check].type); fprintf(fp2,"%d",mtable[check].ocode); count++; value=atoi(label[count]);
location_counter=value; c='C'; fprintf(fp2,"\t\t%c\t",c); fprintf(fp2,"%d",value); location_counter--; }
else if(check>=1 && check<=4)//for Assembler Directives { if(check==4)//for equ AD { count++; for(i=0;i<s;i++) { if(strcmp(label[count],sym_table[i].sn ame)==0) break; } sym_table[s-1].saddr=sym_table[i].saddr; } location_counter--; break; }
else if(check>=7 && check<=14)//for Imperative Statements {
fprintf(fp2,"%d",location_counter); //location counte r
fprintf(fp2,"\t");
fprintf(fp2,"%s\t",mtable[check].type); //IS fprintf(fp2,"%d",mtable[check].ocode); //Opcode }
else if(check==5 || check==6)//for Declarative Statements {
fprintf(fp2,"%d",location_counter); //location coun ter
fprintf(fp2,"\t");
fprintf(fp2,"%s\t",mtable[check].type); //DL fprintf(fp2,"%d",mtable[check].ocode); //Opcode }
else if(check>=50 && check<=54) //for registers(A,B,C,D) {
//register number fprintf(fp2,"\t");
fprintf(fp2,"%d",check-50); }
else if(isdigit(label[count][0]) && count==0) //For literal tab le
{
fprintf(fp3,"%d \t",literal_no2); //To put in liter al text file
fprintf(fp3,"%d\t\t",value);
fprintf(fp2,"%d",location_counter);//To put in IC file fprintf(fp2,"\t\t\t");
fprintf(fp2,"\t00%d",value); literal_no2++;
}
else if(isdigit(label[count][0])) //For literals and constants { if(L==1) { c='L'; fprintf(fp2,"\t%c\t",c); //literal L fprintf(fp2,"%d",literal_no1); //literal no literal_no1++; } else { c='C'; fprintf(fp2,"\t\t%c\t",c); //Constant C fprintf(fp2,"%d",value); //Value } } count++; } location_counter++; fputs("\n\n",fp2); } //---// //input //Input Code--->input.txt /* //output Intermediate Code--->icode.txt Symbol Table--->symbol.txt Literal Table--->literal.txt */
//output after pass1
LC IC OP OPE1 IC->OPE2
AD 1 C 200
200 IS 1 1 L 1
201 IS 2 1 S 1
203 IS 1 3 S 3 204 IS 3 3 L 2 205 005 206 001 207 IS 5 1 L 3 208 IS 4 3 S 3 209 DL 7 C 2 210 DL 6 C 3 211 001
No Symbol length Address
1 A 1 209 2 LOOP 1 202 3 B 1 210 4 NEXT1 1 207 5 NEXT2 1 202 No Literal Address 1 5 205 2 1 206 3 1 211 //Pass 2
#include<stdio.h> #include<conio.h> #include<string.h> #include<ctype.h> //input //output.txt-->Intetmediate code //literal.txt-->Literal table //symbol.txt--->symbol table //output //ic_t.txt file
//Generating target code
//---// void read_output(); void read_literal(); void read_symbol(); void write_target(); void find_literal(int); void find_symbol(int); FILE *fp1,*fp2;
char label[5][20]; //To store all words in a line int cnt=0; //---// main(void) { read_output(); getch(); } //---// void read_output() { char temp[50],tmp[10]; int i=0,j=0,flag=0; fp1=fopen("C:\output.txt","r"); fp2=fopen("C:\ic_t.txt","w");
printf("\nThe output is in ic_t.txt file\n");
fputs("Mnemonic Register Operand Storage Operand\n\n",fp2); while(!feof(fp1)) //while(2)
{
i=0; cnt=0;
if(isalpha(temp[i])) {
//Ignore the line } else if(isdigit(temp[i])) { while(temp[i]!='\n') //while(1) { j=0; while(isalnum(temp[i])) { flag=1; tmp[j]=temp[i]; i++; j++; } if(flag==1) { flag=0; tmp[j]='\0'; strcpy(label[cnt],tmp); cnt++; j=0; } if(temp[i]=='\n') break; i++; } //end of while(1) write_target(); } //end of else }//end of while(2) fclose(fp1); fclose(fp2); } //---// void write_target() { int i=0,flag=0; char store[10]; while(i<cnt) {
//if(i==0 && isdigit(label[i][0])) //Ignore(location counter)
if(strcmp(label[i],"IS")==0 && i!=0) {
i++;
//Put the mnemonic in target file fprintf(fp2,"%s\t\t",label[i]); i++;
//Put the register operand in target file fprintf(fp2,"\t%s\t",label[i]);
i++;
if(strcmp(label[i],"L")==0)
find_literal(i+1); //Sending the literal no else if(strcmp(label[i],"S")==0)
find_symbol(i+1); //Sending the symbol no i++;
}
if(i==1 && isdigit(label[i][0])) {
//Put the storage operand in target file
fprintf(fp2,"00\t\t\t0\t\t%s\t\n\n",label[i]); } i++; } } //---// void find_literal(int k) { int j=0,i=0,flag=0; char store2[10]; char lit[30]; FILE *fp3; fp3=fopen("C:\literal.txt","r"); while(!feof(fp3)) { if(flag==1) break; fgets(lit,30,fp3); i=0; j=0; if(isalpha(lit[i])) {
//Ignore the line } else { while(lit[i]==' ') i++; while(isdigit(lit[i])) { store2[j]=lit[i]; j++; i++; } store2[j]='\0';
if(strcmp(label[k],store2)==0) { j=0; while(lit[i]!='\n') { j=0; flag=1; while(isdigit(lit[i])) { store2[j]=lit[i]; j++; i++; } store2[j]='\0'; if(lit[i]=='\n') break; i++; } } } // end of else } if(flag==1) {
fprintf(fp2,"\t%s\n\n",store2);//location counter of literal } fclose(fp3); } //---// void find_symbol(int k) { int j=0,i=0,flag=0; char store2[10]; char sym[30]; FILE *fp3; fp3=fopen("C:\symbol.txt","r"); while(!feof(fp3)) { if(flag==1) break; fgets(sym,30,fp3); i=0; j=0; if(isalpha(sym[i])) {
//Ignore the line }
else {
while(sym[i]==' ') i++;
while(isdigit(sym[i])) { store2[j]=sym[i]; j++; i++; } store2[j]='\0'; if(strcmp(label[k],store2)==0) { j=0; while(sym[i]!='\n') { j=0; flag=1; while(isdigit(sym[i])) { store2[j]=sym[i]; j++; i++; } store2[j]='\0'; if(sym[i]=='\n') break; i++; } } } // end of else } if(flag==1) {
fprintf(fp2,"\t%s\n\n",store2);//location counter of symbol }
fclose(fp3); }
//---//
//output of pass2
Mnemonic Register Operand Storage Operand
1 1 205 2 1 209 1 1 209 1 3 210 3 3 206 00 0 005
00 0 001
5 1 211
4 3 210