IMPLEMENTATION OF A RELOCATION LOADER

IMPLEMENTATION OF A RELOCATION LOADER

#include<stdio.h>

#include<conio.h>

#include<string.h>

#include<stdlib.h>

struct object_code

{

   int locctr; char add[10];

}obcode[300];

void main()

{

   char in[100][16],out[100][16],bin[20],addr[20],stloc[10];

   int len,bitmask,loc,tlen=0,tloc,textloc,i=0,location,j,k,count=0,start,n,num=0,inc=0;

   FILE *fp1,*fp2;

   clrscr();

   printf("\nImplementation Of A Relocation Loader:");

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

   fp1=fopen("loadin.txt","r");

   fp2=fopen("loadout1.txt","w");

   printf("Enter the Location where the program has to be loaded : ");

   scanf("%s",stloc);

   start=atoi(stloc);

   location=start;

   tloc=start;

   fscanf(fp1,"%s",in[i]);

   while(strcmp(in[i],"T")!=0)

   {

     strcpy(out[i],in[i]); i++;

     fscanf(fp1,"%s",in[i]);

     strcpy(out[i],in[i]);

   }

   itoa(start,out[2],10);

   while(strcmp(in[i],"E")!=0)

   {

     strcpy(out[i],in[i]);

     if(strcmp(in[i],"T")==0)

     {

       for(j=0;j<3;j++)

       {

             i++;

             fscanf(fp1,"%s",in[i]);

             strcpy(out[i],in[i]);

       }

       bitmask=atoi(out[i]);

       itoa(bitmask,bin,2);

       strcpy(out[i],NULL);

       textloc=atoi(out[i-2]);

       textloc=textloc+start;

       itoa(textloc,out[i-2],10);

       for(n=0;n<(textloc-(tloc+tlen));n++)

       {

             strcpy(obcode[inc].add,"XX");

             obcode[inc++].locctr=location++;

       }

       tlen=atoi(out[i-1]);

       tloc=textloc; k=0;

     }

     else

     {

       if(bin[k]=='1')

       {

             num=0; len=strlen(out[i]);

             strcpy(addr,NULL);

             for(j=2;j<len;j++)

             {

               addr[num]=out[i][j];

               out[i][j]='\0';

               num++;

             }

             loc=atoi(addr); loc=loc+start;

             itoa(loc,addr,10);

             strcat(out[i],addr);

       }

       k++;

       len=strlen(out[i]); num=0;

       for(n=0;n<len;n++)

       {

             obcode[inc].add[num++]=out[i][n];

             if(num>1)

             {

               obcode[inc++].locctr=location++;

               num=0;

             }

       }

     }

     i++;

     fscanf(fp1,"%s",in[i]);

   }

   strcpy(out[i],in[i]); i++;

   fscanf(fp1,"%s",in[i]);

   loc=atoi(in[i]); loc=loc+start;

   strcpy(out[i],itoa(loc,addr,10));

   count=0; i=0; n=0;

   fprintf(fp2,"%d\t",obcode[n].locctr);

   for(n=0;n<inc;n++)

   {

     fprintf(fp2,"%s",obcode[n].add);

     i++;

     if(i>3)

     {

       fprintf(fp2,"\t");

       i=0; count++;

     }

     if(count>3)

     {

       fprintf(fp2,"\n%d\t",obcode[n+1].locctr);

       count=0;

     }

   }

   printf("\nProgram Completed Successfully...\n");

   getch();

}

OUTPUT:

Implementation Of A Relocation Loader:

----------------------------------------------------

Enter the Location where the program has to be loaded : 6000

Program Completed Successfully...

INPUT FILE:

LOADIN.TXT

H    PROG1    000000    000018

T    000000   15    000009    180012    0C0015   000005    000010

T    000023   18    000034    200029    130043    0C0054   000006    00015

E    000000

OUTPUT FILE:

LOADOUT1.TXT

6000    1860120C              00150000      05006010      XXXXXXXX        

6016    XXXXXXXX        20602913      00430C00    54000006    

6032    006015