IMPLEMENTATION OF PASS OF A DIRECT LINKING LOADER

IMPLEMENTATION OF PASS OF A DIRECT LINKING LOADER

#include<stdio.h>

#include<conio.h>

#include<stdlib.h>

#define MAX 10

struct estab

{

   char csect[10],sym_name[10];

   long int add;

   int length;

}table[MAX];

void main()

{

   FILE *fp1,*fp2;

   char in[10];

   long int i,count=0,start,len,loc;

   clrscr();

   printf("\nImplementation Of Pass1 Of A Direct Linking Loader:");

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

   fp1=fopen("link1in.txt","r");

   fp2=fopen("link1out.txt","w");

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

   scanf("%lx",&start);

   fprintf(fp2,"CSECT\tSYM_NAME\tADDRESS\tLENGTH\n");

   rewind(fp1);

   while(!feof(fp1))

   {

     fscanf(fp1,"%s",in);

     if(strcmp(in,"H")==0)

     {

       fscanf(fp1,"%s",in);

       strcpy(table[count].csect,in);

       strcpy(table[count].sym_name,"\0");

       fscanf(fp1,"%s",in);

       table[count].add=atoi(in)+start;

       fscanf(fp1,"%s",in);

       len=atoi(in);

       table[count++].length=atoi(in);

       fscanf(fp1,"%s",in);

     }

     if(strcmp(in,"D")==0)

     {

       fscanf(fp1,"%s%lx",in,&loc);

       while(strcmp(in,"R")!=0)

       {

             strcpy(table[count].csect,"\0");

             strcpy(table[count].sym_name,in);

             table[count].add=loc+start;

             table[count++].length=0;

             fscanf(fp1,"%s%lx",in,&loc);

       }

       while(strcmp(in,"T")!=0)

             fscanf(fp1,"%s",in);

     }

     if(strcmp(in,"T")==0)

     while(strcmp(in,"E")!=0)

     fscanf(fp1,"%s",in);

     fscanf(fp1,"%s",in);

     start=start+len;

   }

   for(i=0;i<count;i++)

   fprintf(fp2,"%s\t%s\t%lx\t%d\n",table[i].csect,table[i].sym_name,table[i].add,table[i].length);

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

   getch();

}

OUTPUT:

Implementation Of Pass1 Of A Direct Linking Loader:

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

Enter the Location where the program has to be loaded: 4000

Program Completed Successfully...

INPUT FILE:

LINK1IN.TXT

H     PROGA    000000   000070

D     LISTA      000040   ENDA     000054

R     LISTB      ENDB    LISTC     ENDC

T     000020   10    03201D    77100004    150014

T     000054   16    100014     15100006    00002F    100014    FFFFC0

M    000024   05    +LISTB

M    000054   06    +LISTC

M    000058   06    +ENDC

M    000064   06    +LISTB

E     000000

H     PROGB     000000    000088

D     LISTB       000060    ENDB     000070

R     LISTA       ENDA     LISTC     ENDC

T     000036   11    03100000    772027       05100000

T     000070   18    100000        05100006   05100020    05100030   100000

M    000037   05    +LISTA

M    000044   05    +ENDA

M    000070   06    +ENDA

M    000074   06    +ENDC

M    000078   06    +ENDC

M    000082   06    +ENDA

E     000000

H    PROGC     000000     000057

D    LISTC       000030     ENDC     000042

R    LISTA       ENDA      LISTB     ENDB

T    000018    12    03100000    77100004    05100000

T    000042    15    100030        100008        100011     100000    100000

M   000019    05    +LISTA

M   000023    05    +LISTB

M   000027    05    +ENDA

M   000048    06    +LISTA

M   000051    06    +ENDA

M   000054    06    +LISTB

E    000000

OUTPUT FILE:

LINK1OUT.TXT

CSECT               SYM_NAME          ADDRESS       LENGTH

PROGA                                                 4000                  70

                                LISTA                    4040                  0

                                ENDA                    4054                  0

PROGB                                                 4046                 88

                                LISTB                    40a6                  0

                                ENDB                    40b6                  0

PROGC                                                 409e                  57

                                LISTC                    40ce                   0

                                ENDC                    40e0                  0