Absolute loader

IMPLEMENTATION OF ABSOLUTE LOADER

AIM

To implement absolute loader using C.

ALGORITHM

1.Read loader record and filter the starting location and other details.

2.Read the first text record.

3.If the object code is in character form convert it into internal hexadecimal representation.

4.Move object code to specified location in memory.

5.Write starting location couter value of block of object code and corresponding internal hexadecimal representation to the output file.

6.Read next record from the input file.

7.Close all opened files and exit.

PROGRAM:

#include<stdio.h>

#include<conio.h>

#include<string.h>

char input[10],label[10],ch1,ch2;

int addr,w=0,start,ptaddr,l,length=0,end,count=0,k,taddr,address,i=0;

FILE *fp1,*fp2;

void check();

void main()

 {

   clrscr();

   fp1=fopen("INPUT.dat","r");

   fp2=fopen("OUTPUT.dat","w");

   fscanf(fp1,"%s",input);

   printf("\n\n\t\t\tAbsolute loader\n");

   fprintf(fp2,"\n---------------------------\n");

   fprintf(fp2,"MEMORY ADDRESS\t\t\tCONTENTS");

   fprintf(fp2,"\n---------------------------\n");

   while(strcmp(input,"E")!=0)

    {

     if(strcmp(input,"H")==0)

      {

       fscanf(fp1,"%s %x %x %s",label,&start,&end,input);

       address=start;

      }

     else if(strcmp(input,"T")==0)

      {

                l=length;

                ptaddr=addr;

                fscanf(fp1,"%x %x %s",&taddr,&length,input);

                addr=taddr;

                if(w==0)

                 {

                   ptaddr=address;

                   w=1;

                 }

                for(k=0;k<(taddr-(ptaddr+l));k++)

                 {

                   address=address+1;

                   fprintf(fp2,"xx");

                   count++;

                   if(count==4)

                    {

                                fprintf(fp2," ");

                                i++;

                                if(i==4)

                                 {

                                   fprintf(fp2,"\n\n%x\t\t",address);

                                   i=0;

                                 }

                                count=0;

                    }

                 }

                if(taddr==start)

                fprintf(fp2,"\n\n%x\t\t",taddr);

                fprintf(fp2,"%c%c",input[0],input[1]);

                check();

                fprintf(fp2,"%c%c",input[2],input[3]);

                check();

                fprintf(fp2,"%c%c",input[4],input[5]);

                check();

                fscanf(fp1,"%s",input);

      }

     else

      {

                fprintf(fp2,"%c%c",input[0],input[1]);

                check();

                fprintf(fp2,"%c%c",input[2],input[3]);

                check();

                fprintf(fp2,"%c%c",input[4],input[5]);

                check();

                fscanf(fp1,"%s",input);

      }

   }

  fprintf(fp2,"\n-----------------------------\n");

  fcloseall();

  printf("\n\n The contents of output file:\n\n");

  fp2=fopen("OUTPUT3.DAT","r");

  ch2=fgetc(fp2);

  while(ch2!=EOF)

   {

     printf("%c",ch2);

     ch2=fgetc(fp2);

   }

  fcloseall();

  getch();

 }

void check()

{

count++;

address++;

taddr=taddr+1;

if(count==4)

{

fprintf(fp2," ");

i++;

if(i==4)

{

fprintf(fp2,"\n\n%x\t\t",taddr);

i=0;

}

count=0;

}

}

INPUT FILES:

INPUT.DAT

H COPY 001000 00107A

T 001000 1E 141033 482039 001036 281030 301015 482061 3C1003 00102A 0C1039 00102D

T 00101E 15 0C1036 482061 081033 4C0000 454F46 000003 000000

T 001047 1E 041030 001030 E0205D 30203F D8205D 281030 302057 549039 2C205E 38203F

T 001077 1C 101036 4C0000 000000 001000 041030 E02079 302064 509039 DC2079 2C1036

E 001000

OUTPUT:

RESULT

Thus absolute loader is successfully implemented using C.