88. ADDRESS TRANSLATION OF 80386 IN PROTECTED MODE IN JAVA

import java.util.*;

class addrxlation

{

                public static void main(String args[])

                {

                                Scanner read = new Scanner(System.in);

                String GDT[][]={{"0000000000000000","00000000000000000000000000001111"},{"0000000000000001","00000000000000000000000011111111"},

{"0000000000000010","00000000000000000000111111111111"}};

                String PD[][]={{"00000000000000000000000000000000","00000000000000000001000000000000"},{"00000000000000000000000000000001","00000000000000000010000000000000"},

{"00000000000000000000000000000001","00000000000000000011000000000000"}};

                String PT[][]={{"00000000000000000001000000000000","00000000000000000100000000000000"},{"00000000000000000010000000000000","00000000000000001000000000000000"},

{"00000000000000000011000000000000","00000000000000001100000000000000"}};

                String Page[][]={{"00000000000000000100000000010000","00000101000000010000001111100000"},{"00000000000000001000000000000000","00000101000000100000000000000000"},

{"00000000000000001100000000000000","00000000000000110000000000000000"}};

                System.out.println("enter the virtual addreaa:");

                String virtual=read.next();

                System.out.println("is paging enabled?(true/false):");

                boolean paging =Boolean.parseBoolean(read.next());

                String CR3=new String();

                if(paging)

                {

                                System.out.println("Enter the content of cr3(base addr):");

                                CR3=read.next();

                }

                String base= new String();

                String linear= new String();

                String temp= new String();

                boolean found=false;

int i;

String segment=virtual.substring(0,16);

System.out.println("Segment \t::"+segment);

String offset=virtual.substring(16,48);

System.out.println("Offset \t:"+offset);

for(i=0;i<GDT.length;i++)

{

                if(GDT[i][0].equals(segment))

                {

                                found=true;

                                base=GDT[i][1];

                                System.out.println("base address \t:"+base);

                                linear=add(offset,base);

                                System.out.println("linear addreass \t:"+linear);

                }

}

if(!found)

{              System.out.println("Segment does not exist");

                return;

}

if(paging)

{

                String directory=linear.substring(0,10);

                System.out.println("Directory \t:"+directory);

                String table = linear.substring(10,20);

                System.out.println("Table \t\t:"+table);

                String page=linear.substring(20,32);

                System.out.println("Page \t\t:"+page);

                found=false;

                directory=add(CR3,directory);

                for(i=0;i<PD.length;i++)

                {

                                if(PD[i][0].equals(directory))

                                {

                                                found=true;

                                                temp=PD[i][1];

                }              }

if(!found)

{

                System.out.println("Page Directory Entry does not exist");

return;

}

found=false;

table=add(table,temp);

for(i=0;i<PT.length;i++)

{

if(PT[i][0].equals(table))

{

found =true;

temp=PT[i][1];

}}

if(!found)

{

System.out.println("Page tqable entry does not exit.");

return;

}

found=false;

page=add(page,temp);

for(i=0;i< Page.length;i++)

{

if(Page[i][0].equals(page))

{

found=true;

temp=Page[i][1];

}}

if(!found)

{

                System.out.println("page does not exist.");

                return;

}

System.out.println("Physical Address:"+temp);

}}

static String add(String a,String b)

{

                String result= new String();

                String result1= new String();

                int carry=0;

int c,d;

for(int i=(a.length());i<=31;i++)

                a="0"+a;

for(int i=(b.length());i<=31;i++)

                b="0"+b;

for(int i=31;i>=0;i--)

{

                c=a.charAt(i);

                d=b.charAt(i);

                if(c=='o' && d=='0')

                {

                                if(carry==1)

                                {

                                                result=result+"1";

                                                carry=0;

                                }

                                else

                                {

                                                result=result+"0";

                                                carry=0;

                                }

                }

                else if((c=='1' && d=='0') || (c=='0' && d=='1'))

                {

                                if(carry==1)

                                {

                                                result=result+"1";

                                                carry=1;

                                }

                                else

                                {

                                                result=result+"1";

                                                carry=0;

                                }

                }

                else if((c=='1' && d=='1') || (c=='1' && d=='1'))

                {

                                if(carry==1)

                                {

                                                result=result+"1";

                                                carry=1;

                                }

                                else

                                {

                                                result=result+"0";

                                                carry=1;

                                }

                }

}

int j;

for(j=31;j>=0;j--)

result1=result1+result.charAt(j);

return result1;

}

}

/*output:-

C:\Java\jdk1.6.0_17\bin>javac addrxlation.java

C:\Java\jdk1.6.0_17\bin>java addrxlation

enter the virtual addreaa:

000000000000000000000000000000000000000000000000000000001

is paging enabled?(true/false):

true

Enter the content of cr3(base addr):

000000000000000000000000000000000001

Segment         ::0000000000000000

Offset  :00000000000000000000000000000000

base address    :00000000000000000000000000001111

linear address:

directory:0000000000

table:000000000

page:000000010000

physical address:00000101000000010000001111100000

/*output 2:-

C:\Java\jdk1.6.0_17\bin>javac addrxlation.java

C:\Java\jdk1.6.0_17\bin>java addrxlation

enter the virtual addreaa:

000000000000000000000000000000000000000000000000000000001

is paging enabled?(true/false):

true

Enter the content of cr3(base addr):

000000000000000000000000000000000001

Segment         ::0000000000000000

Offset  :00000000000000000000000000000000

base address    :00000000000000000000000000001111

/*output3:-

C:\Java\jdk1.6.0_17\bin>javac addrxlation.java

C:\Java\jdk1.6.0_17\bin>java addrxlation

enter the virtual addreaa:

000000000000000000000000000000000000000000000000000000001

is paging enabled?(true/false):

true

Enter the content of cr3(base addr):

000000000000000000000000000000000001

Segment         ::0000000000000000

Offset  :00000000000000000000000000000000

base address    :00000000000000000000000000001111