Here is a code for assembler; in which every-thing is gonna run except Origin directive..
#include<stdio.h>
#include<string.h>
#include<conio.h>
struct mottab //declaring mot table structure
{
char mn[6];
int Class;
char opcode[3];
};
struct symtab //declaring structure for symbol table
{
char symbol[8];
int address;
int size;
}st[20];
struct littab //declaring structure for literal table
{
int literal;
int address;
}lt[10];
int pt[20]; //array for pool table
struct intcode //structure for intermediate code
{
int lc;
int code1,type1;
int code2,type2;
int code3,type3;
}ic[30];
//mot table filled with necessory keywords and directives
static struct mottab mot[29]={{"STOP",1,"00"},{"ADD",1,"01"},{"SUB",1,"02"},
{"MULT",1,"03"},{"MOVER",1,"04"},{"MOVEM",1,"05"},
{"COMP",1,"06"},{"BC",1,"07"},{"DIV",1,"08"},
{"READ",1,"09"},{"PRINT",1,"10"},{"START",3,"01"},
{"END",3,"02"},{"END",3,"02"},{"ORIGIN",3,"03"},
{"EQU",3,"04"},{"LTORG",3,"05"},{"DS",2,"01"},
{"DC",2,"02"},{"AREG",4,"01"},{"BREG",4,"02"},
{"CREG",4,"03"},{"EQ",5,"01"},{"LT",5,"02"},
{"GT",5,"03"},{"LE",5,"04"},{"GE",5,"05"},{"NE",5,"06"},
{"ANY",5,"07"}};
int nmot=28;//number of entries in mot
int lc=0; //location counter
int ipt; // index of next entry in pool tabel
int ilt=0;//index of next entry in literal table
int ist=0; //index of next entry in symbol table
int iic=0; //index of next entry in intermidiate code tabel
int searchst(char symbol[]) //search symbol in symtab
{
int i;
for(i=0;i<ist;i++)
if(strcmp(st[i].symbol,symbol)==0)
return(i);
return(-1);
}
int searchmot(char symbol[]) //search mneumonic
{
int i;
for(i=0;i<nmot;i++)
if(strcmp(mot[i].mn,symbol)==0)
return(i);
return(-1);
}
//insert symbol in symbol table
int insertst(char symbol[],int address,int size)
{
strcpy(st[ist].symbol,symbol);
st[ist].address=address;
st[ist].size=size;
ist++;
return(ist-1);
}
void imperative(); //handle an executable statement
void declaration(); //handle declaration statement
void directive(); //handle an assembler directive
void print_symbol(); // display symbol table
void print_pool();//display pool table
void print_literal();//display literal table
void print_opcode();//display opcode table
void intermediate(); //display intermidiate code
void mcode(); //generate machine code
char s1[8],s2[8],s3[8],label[8];
void ltorg(); //for ltorg directive
void DC(); //handle declaration statement dc
void DS(); // handle declaration statement ds
void START(); // handle start directive
int tokencount; //total number of words in a statement
void main()
{
char file1[40],nextline[80];
int len,i,j,temp,errortype;
FILE *ptr1;
clrscr();
printf("\nEnter source file name:");
gets(file1);
ptr1=fopen(file1,"r");
while(!feof(ptr1))
{
i=0;
nextline[i]=fgetc(ptr1);
while(nextline[i]!='\n'&&nextline[i]!=EOF)
{
if(!isalnum(nextline[i]))
nextline[i]=' ';
else
nextline[i]=toupper(nextline[i]);
i++;
nextline[i]=fgetc(ptr1);
}
nextline[i]='\0';
//if next line is an END statement
sscanf(nextline,"%s",s1); //read from the nextline in s1
if(strcmp(s1,"END")==0)
break;
//if the nextline contains a label
if(searchmot(s1)==-1)
{
if(searchst(s1)==-1)
insertst(s1,lc,0);
//separate opcode and operands
tokencount=sscanf(nextline,"%s%s%s%s",label,s1,s2,s3);
tokencount--;
}
else
// separate opcode and operands
tokencount=sscanf(nextline,"%s%s%s%",s1,s2,s3);
if(tokencount==0)//blank line
continue;//goto the beginning of the loop
i=searchmot(s1);
if(i==-1)
{
printf("\nWrong opcode..%s",s1);
break;
}
switch(mot[i].Class)
{
case 1:imperative();
break;
case 2:declaration();
break;
case 3:directive();
break;
default: printf("\nWrong opcode..%s",s1);
break;
}
}
ltorg();
printf("\n\n");
print_symbol();
getch();
printf("\n\n");
print_pool();
getch();
printf("\n\n");
print_literal();
getch();
printf("\n\n");
print_opcode();
getch();
printf("\n\n");
intermediate();
getch();
printf("\n\n");
// mcode();
getch();
}
void imperative()
{
int index;
index=searchmot(s1);
ic[iic].type1=ic[iic].type2=ic[iic].type3=0;//initialize
ic[iic].lc=lc;
ic[iic].code1=index;
ic[iic].type1=mot[index].Class;
lc=lc+1;
if(tokencount>1)
{
index=searchmot(s2);
if(index!=-1)
{
ic[iic].code2=index;
ic[iic].type2=mot[index].Class;
}
else
{
//It is a variable
index=searchst(s2);
if(index==-1)
index=insertst(s2,0,0);
ic[iic].code2=index;
ic[iic].type2=7; //value 7 is for variables
}
}
if(tokencount>2)
{
if(isdigit(*s3))
{
lt[ilt].literal=atoi(s3);
ic[iic].code3=ilt;
ic[iic].type3=8; //value 8 is for literal type
ilt++;
}
else
{
index=searchst(s3);
if(index==-1)
index=insertst(s3,0,0);
ic[iic].code3=index;
ic[iic].type3=7; // value 7 is for variables
}
}
iic++;
}
void declaration() // intermidiate code for declarative statements
{
if(strcmp(s1,"DC")==0)
{
DC();
return;
}
if(strcmp(s1,"DS")==0)
DS();
}
void directive() //intermidiate code for directive
{
if(strcmp(s1,"START")==0)
{
START();
return;
}
if(strcmp(s1,"LTORG")==0)
ltorg();
}
void ltorg() //intermidiate code for literals
{
int i,index;
for(i=pt[ipt];i<ilt;i++)
{
lt[i].address=lc;
index=searchmot("DC");
ic[iic].type1=ic[iic].type2=ic[iic].type3=0;//initialize
ic[iic].lc=lc;
ic[iic].code1=index;
ic[iic].type1=mot[index].Class;
ic[iic].type2=6; //6 is type for constants
ic[iic].code2=lt[i].literal;
lc=lc+1;
iic++;
}
ipt++;
pt[ipt]=ilt;
}
void DC()
{
int index;
index=searchmot(s1);
ic[iic].type1=ic[iic].type2=ic[iic].type3=0;//initialize
ic[iic].lc=lc;
ic[iic].code1=index;
ic[iic].type1=mot[index].Class;
ic[iic].type2=6; //6 is type for constants
ic[iic].code2=atoi(s2);
index=searchst(label);
if(index==-1)
index=insertst(label,0,0);
st[index].address=lc;
st[index].size=1;
lc=lc+1; //incrementing lc count
iic++;
}
void DS() //process declarative statement
{
int index;
index=searchmot(s1);
ic[iic].type1=ic[iic].type2=ic[iic].type3=0;//initialize
ic[iic].lc=lc;
ic[iic].code1=index;
ic[iic].type1=mot[index].Class;
ic[iic].type2=6; //6 is type for constants
ic[iic].code2=atoi(s2);
index=searchst(label);
if(index==-1)
index=insertst(label,0,0);
st[index].address=lc;
st[index].size=atoi(s2);
lc=lc+atoi(s2);
iic++;
}
void START() //process start
{
int index;
index=searchmot(s1);
ic[iic].type1=ic[iic].type2=ic[iic].type3=0;//initialize
ic[iic].lc=lc;
ic[iic].code1=index;
ic[iic].type1=mot[index].Class;
ic[iic].type2=6; //6 is type for constants
ic[iic].code2=atoi(s2);
lc=atoi(s2); //convert to integer
iic++;
}
void intermediate() //forming of intermidiate code
{
int i;
char decode[9][3]={" ","IS","DL","AD","RG","CC","C","S","L"};
printf("\n inter code::");
for(i=0;i<iic;i++)
{
printf("\n%3d(%s,%2s)",ic[i].lc,decode[ic[i].type1],mot[ic[i].code1].opcode);
if(ic[i].type2!=0)
{
if(ic[i].type2<6)
printf("(%s,%2s)",decode[ic[i].type2],mot[ic[i].code2].opcode);
else
printf("(%s,%2d)",decode[ic[i].type3],ic[i].code3);
}
if(ic[i].type3!=0)
printf("(%s,%2d)",decode[ic[i].type3],ic[i].code3);
}
}
void print_symbol()
{
int i;
printf("\nSymbol table::");
for(i=0;i<ist;i++)
printf("\n%10s %3d %3d",st[i].symbol,st[i].address,st[i].size);
}
void print_pool()
{
int i;
printf("\nPool Tabel::");
for(i=0;i<ipt;i++)
printf("\n%d",pt[i]);
}
void print_literal()
{
int i;
printf("\nLT Tabel::");
for(i=0;i<ilt;i++)
printf("\n%5d\t%5d",lt[i].literal,lt[i].address);
}
void print_opcode()
{
int i;
printf("\n Opcode Tabel::");
for(i=0;i<nmot;i++)
if(mot[i].Class==1)
printf("\n%6s\t%2s",mot[i].mn,mot[i].opcode);
}
void mcode()
{
int i;
printf("\nMachine Code::");
for(i=0;i<iic;i++)
{
if(ic[i].type1==1)
{
printf("\n%3d %s",ic[i].lc,mot[ic[i].code1].opcode);
if(ic[i].type2==0)
printf("00 000");
else
if(ic[i].type2>6)
printf("00%3d",st[ic[i].code2].address);
else
{
printf("%2s",mot[ic[i].code2].opcode);
if(ic[i].type3==7)
printf("%3d",st[ic[i].code3].address);
else
printf("%3d",lt[ic[i].code3].address);
}
}
else
if(ic[i].type1==2 && strcmp(mot[ic[i].code1].mn,"DC")==0)
{
printf("\n%3d",ic[i].lc);
printf("00 00 %3d",ic[i].code2);
}
}
}If someone have solution then plz tell me where i am going wrong.....
