PASS2 OF DIRECTLINKING LOADER

PROGRAM:

#include<stdio.h>

#include<conio.h>

#include<string.h>

#include<stdlib.h>

struct exttable

{

  char csect[20],sname[20];

  int padd,plen;

}estab[20];

struct objectcode

{

  unsigned char code[15];

  int add;

}obcode[500];

void main()

{

  FILE *fp1,*fp2,*fp3;

  int i,j,x,y,pstart,exeloc,start,textloc,loc,textlen,length,location,st,s;

  int n=0,num=0,inc=0,count=0,record=0,mloc[30],mlen[30];

  signed long int newadd;

  char operation,lbl[10],input[10],label[50][10],opr[30],ch,*add1,address[10];

  clrscr();

  fp1=fopen("LINK1IN.dat","r");

  fp2=fopen("LINK1OUT.dat","r");

  fp3=fopen("L2OUT.dat","w");

  while(!feof(fp2))

   {

     fscanf(fp2,"%s %s %x %x",estab[num].csect,estab[num].sname,&estab[num].padd,&estab[num].plen);

     num++;

   }

  exeloc=estab[0].padd;

  loc=exeloc;

  start=loc;

  st=start;

  while(!feof(fp1))

   {

     fscanf(fp1,"%s",input);

     if(strcmp(input,"H")==0)

      {

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

                for(i=0;i<num;i++)

                if(strcmp(input,estab[i].csect)==0)

                 {

                                pstart=estab[i].padd;

                                break;

                 }

                while(strcmp(input,"T")!=0)

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

      }

     do

      {

                if(strcmp(input,"T")==0)

                 {

                   fscanf(fp1,"%x",&textloc);

                   textloc=textloc+pstart;

                   for(i=0;i<(textloc-loc);i++)

                    {

                                strcpy(obcode[inc].code,"..");

                                obcode[inc++].add=start++;

                    }

                   fscanf(fp1,"%x",&textlen);

                   loc=textloc+textlen;

                }

       else if(strcmp(input,"M")==0)

                {

                  fscanf(fp1,"%x",&mloc[record]);

                  mloc[record]=mloc[record]+pstart;

                  fscanf(fp1,"%x",&mlen[record]);

                  fscanf(fp1,"%s",label[record++]);

     }

    else

     {

                length=strlen(input);

                x=0;

                for(i=0;i<length;i++)

                 {

                   obcode[inc].code[x++]=input[i];

                   if(x>1)

                    {

                                obcode[inc++].add=start++;

                                x=0;

                    }

                }

      }

     fscanf(fp1,"%s",input);

    }

   while(strcmp(input,"E")!=0);

   if(strcmp(input,"E")==0)

   fscanf(fp1,"%s",input);

  }

 for(n=0;n<record;n++)

  {

    operation=label[n][0];

    length=strlen(label[n]);

    for(i=1;i<length;i++)

     {

                lbl[i-1]=label[n][i];

     }

    lbl[length-1]='\0';

    length=0;

    strcpy(address,'\0');

    location=mloc[n]-exeloc;

    loc=location;

    count=0;

    while(length<mlen[n])

     {

                strcat(address,obcode[location++].code);

                count++;

                length+=2;

     }

    for(i=0;i<num;i++)

     {

                if(strcmp(lbl,estab[i].csect)==0)

                break;

                if(strcmp(lbl,estab[i].sname)==0)

                break;

     }

    switch(operation)

     {

                case '+':

                newadd=strtol(address,&add1,16)+(long int)estab[i].padd;

                break;

                case '-':

                newadd=strtol(address,&add1,16)-(long int)estab[i].padd;

                break;

     }

    ltoa(newadd,address,16);

    x=0;y=0;

    while(count>0)

     {

                obcode[loc].code[x++]=address[y++];

                if(x>1)

                 {

                                x=0;loc++;

                                count--;

                 }

     }

  }

 count=0;

 n=0;

 s=st-16;

 fprintf(fp3,"%x\t",s);

 for(i=1;i<=16;i++)

  {

   fprintf(fp3,"xx");

   if(i==4||i==8||i==12)

    {

      fprintf(fp3,"\t");

    }

  }

 fprintf(fp3,"\n\n%x\t",obcode[0].add);

 for(i=0;i<inc;i++)

  {

    fprintf(fp3,"%s",obcode[i].code);

    n++;

    if(n>3)

     {

                fprintf(fp3,"\t");

                n=0;

                count++;

     }

    if(count>3)

     {

                fprintf(fp3,"\n\n%x\t",obcode[i+1].add);

                count=0;

     }

  }

 fcloseall();

 printf("\n\t*****PASS TWO OF A DIRECT-LINKER LOADER****\n");

 printf("\n The contents of the output file(L2OUT.DAT):");

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

 printf("\nAddress\t\t\t\tContents");

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

 fp3=fopen("L2OUT.dat","r");

 ch=fgetc(fp3);

 while(ch!=EOF)

  {

    printf("%c",ch);

    ch=fgetc(fp3);

  }

 fclose(fp3);

 getch();

}

INPUT FILES:

LINK1IN.DAT

H PROGA 000000 000063

D LISTA 000040 ENDA 000054

R LISTB ENDB LISTC ENDC

T 000020 0A 03201D 77100004 050014

T 000054 0F 100014 000008 004051 000004 100000

M 000024 05 +LISTB

M 000054 06 +LISTC

M 000060 06 +LISTB

M 000060 06 -LISTA

E 000020

H PROGB 000000 00007F

D LISTB 000060 ENDB 000070

R LISTA ENDA LISTC ENDC

T 000036 0B 03100000 772027 05100000

T 000070 0F 100000 000008 004051 000004 100060

M 000037 05 +LISTA

M 00003E 05 +ENDA

M 00003E 05 -LISTA

M 000070 06 +ENDA

M 000070 06 -LISTA

M 000070 06 +LISTC

M 00007C 06 +PROGB

M 00007C 06 -LISTA

E 000000

H PROGC 000000 0000051

D LISTC 000030 ENDC 000042

R LISTA ENDA LISTB ENDB

T 000018 0C 03100000 77100004 05100000

T 000042 0F 100030 000008 004051 000004 100000

M 000019 05 +LISTA

M 00001D 05 +LISTB

M 000021 05 +ENDA

M 000021 05 -LISTA

M 000042 06 +ENDA

M 000042 06 -LISTA

M 000042 06 +PROGC

M 00004E 06 +LISTB

M 00004E 06 -LISTA

E 000000

LINK1OUT.DAT

PROGA ** 4000 63

** LISTA 4040

** ENDA 4054

PROGB ** 4063 7F

** LISTB 40C3

** ENDB 40D3

PROGC ** 40E2 51

** LISTC 4112

** ENDC 4124

OUTPUT: