Lexical Analizer

/* TO IMPLEMENT LEXICAL ANALIZER IN C */

#include <stdio.h>

#include <conio.h>

#include <string.h>

#include <ctype.h>

void main()

{

            int i,j,lc;

            char *a[9][4]={

                                    "PRG","START" ," " ," "," " ,"USING" ,"*" ,"15"," ","L","1","FIVE",

                                    " ","A","1","FOUR"," ","ST","1","TEMP","FOUR ","DC","F","4",

                                    "FIVE","DC","F","5","TEMP","DS","1","F"," " ,"END"," "," ",

                        };

            clrscr();

            printf("\n \t\t LEXICAL ANALIZER \n");

            for(i=0;i< 9;i++)

            {

            for(j=0;j< 4;j++)

                        {

                        if(isalpha(*a[i][j]))

                                                printf("\n STRING : %s",a[i][j]);

                                    if(isdigit(*a[i][j]))

                                                printf("\n DIGIT : %s",a[i][j]);

                        }

                        printf("\n");

            }

            getch();

}


Output:
 

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Two Pass Assembler - 2

#include<stdio.h>

#include<string.h>

#include<conio.h>

void main()

{

char *code[9][4]={

{"PRG1","START","",""},

{"","USING","*","15"},

{"","L","",""},

{"","A","",""},

{"","ST","",""},

{"FOUR","DC","F",""},

{"FIVE","DC","F",""},

{"TEMP","DS","1F",""},

{"","END","",""}

};

char av[2],avail[15]={'N','N','N','N','N','N','N','N','N','N','N','N','N','N','N'};

int i,j,k,count[3],lc[9]={0,0,0,0,0,0,0,0,0},loc=0;

clrscr();

printf("----------------------------------------------------\n");

printf("LABEL\t\tOPCODE\n");

printf("----------------------------------------------------\n\n");

for(i=0;i<=8;i++)

{

for(j=0;j<=3;j++)

{

printf("%s\t\t",code[i][j]);

}

j=0;

printf("\n");

}

getch();

printf("-----------------------------------------------------");

printf("\nVALUES FOR LC : \n\n");

for(j=0;j<=8;j++)

{

if((strcmp(code[j][1],"START")!=0)&&(strcmp(code[j][1],"USING")!=0)&&(strcmp(code[j][1],"L")!=0))

lc[j]=lc[j-1]+4;

printf("%d\t",lc[j]);

}

printf("\n\nSYMBOL TABLE:\n----------------------------------------------------\n");

printf("SYMBOL\t\tVALUE\t\tLENGTH\t\tR/A");

printf("\n----------------------------------------------------\n");

           

for(i=0;i< 9;i++)

{

if(strcmp(code[i][1],"START")==0)

{

printf("%s\t\t%d\t\t%d\t\t%c\n",code[i][0],loc,4,'R');

}

else if(strcmp(code[i][0],"")!=0)

{

printf("%s\t\t%d\t\t%d\t\t%c\n",code[i][0],loc,4,'R');

loc=4+loc;

}

else if(strcmp(code[i][1],"USING")==0) {}

else

{

loc=4+loc;

}

}

printf("----------------------------------------------------");

printf("\n\nBASE TABLE:\n-------------------------------------------------------\n");

printf("REG NO\t\tAVAILIBILITY\tCONTENTS OF BASE TABLE");

printf("\n-------------------------------------------------------\n");

for(j=0;j<=8;j++)

{

if(strcmp(code[j][1],"USING")!=0)

{ }

else

{

strcpy(av,code[j][3]);

}

}

count[0]=(int)av[0]-48;

count[1]=(int)av[1]-48;

count[2]=count[0]*10+count[1];

avail[count[2]-1]='Y';

for(k=0;k< 16;k++)

{

printf(" %d\t\t %c\n",k,avail[k-1]);

}

printf("-------------------------------------------------------\n");

printf("Continue..??");

getchar();

printf("PASS2 TABLE:\n\n");

printf("LABEL\t\tOP1\t\tLC\t\t");

printf("\n----------------------------------------------------\n");

loc=0;

for(i=0;i<=8;i++)

{

for(j=0;j<=3;j++)

{

printf("%s\t\t",code[i][j]);

}

j=0;

printf("\n");

}

printf("-----------------------------------------------------");

getch();

}


Output:
 

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Two Pass Assembler

#include<stdio.h>

#include<conio.h>

#include<string.h>

#define lines_in_program 9

void print(char *p,int loc,int len,char ra)

{

            printf("%s\t%d\t%d\t%c\n",p,loc,len,ra);

}

void main()

{

            char *p[9][4] = {

                                                {"PRG1","START","",""},{"","USING","*","15"},

                                                {"","L","1","FIVE"}, {"","A","1","FOUR"},

                                                {"","ST","1","TEMP"}, {"FOUR","DC","F'4'",""},

                                                {"FIVE","DC","F'5'",""}, {"TEMP","DS","1F",""},

                                                {"","END","",""}

                                     };

            int i,j=0,location_counter=0;

            clrscr();

            for (i=0;i< 9;i++)

            {

                        for(j=0;j< 4;j++)

                        printf("%s\t",p[i][j]);

                        printf("\n");

            }

            printf("\n\n\n\n Symbol ");

            printf("Table:\nSYMBOL\tVALUE\tLENGTH\tRelocatable/Absolute\n");

            printf("---------------------------------------------\n");

           

            for(i=0;i< 9;i++)

            {

                        if(strcmp(p[i][1],"START")==0)

                        print(p[i][0],location_counter,1,'R');

                        else if(strcmp(p[i][0],"")!=0)

                        {

                                    print(p[i][0],location_counter,4,'R');

                                    location_counter=4+location_counter;

                        }

                        else if(strcmp(p[i][1],"USING")==0)

                        { }

                        else{

                                    location_counter=4+location_counter;

                        }

            }

            getch();

}

Output:

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