int namematch(char* ,char*);

void printString(char*);

void readString(char*);

void readSector(char* , int );

int div(int ,int );

int mod(int ,int );

handleInterrupt21(int,int,int,int);

void readfile(char*,char*);

void executeProgram(char* , int );

void terminate();

void writeSector(char*, int);

void deleteFile(char*);

void writeFile(char*, char* , int );

void main(){

// char line[80];

// printString("Enter a line: \0");

// readString(line);

// printString(line);

// char buffer[512];

// readSector(buffer, 30);

// printString(buffer);

// makeInterrupt21();

// interrupt(0x21,0,0,0,0);

// char line[80];

makeInterrupt21();

interrupt(0x21,4,"shell\0",0x2000,0);

// interrupt(0x21,7,"messag\0",0,0);

// interrupt(0x21,1,line,0,0);

// interrupt(0x21,0,line,0,0);

// char buffer[13312] ;/*this is the maximum size of a file*/

// makeInterrupt21();

// char buffer [512];

// interrupt(0x21, 6, "messag\0", 15, 0);

// interrupt(0x21, 2, buffer, 15, 0);

// interrupt(0x21,0,buffer,0,0);

/*read the file into buffer*/

// interrupt(0x21, 0, buffer, 0, 0); /*print out the file*/

// while(1); /*hang up*/

// int i=0;

// char buffer1[13312];

// char buffer2[13312];

// buffer2[0]='h'; buffer2[1]='e'; buffer2[2]='l';

// buffer2[4]='o';

// buffer2[3]='l';

// for(i=5; i<13312; i++) buffer2[i]=0x0;

// makeInterrupt21();

// interrupt(0x21,8, "testW\0", buffer2, 1); //write file testW

// interrupt(0x21,3, "testw\0", buffer1, 0); //read file testW

// interrupt(0x21,0, buffer1, 0, 0); // print out contents of testW

while(1);

}

void readfile(char* s,char* result){

char directory[512] ;

int j = 0;

int k = 0;

int p=0;

readSector(directory,2);

while(j<16){

p = 0;

k=j*32;

while(p<6){

if(s[p]!=directory[k+p])

break ;

p++;

}

j++;

while(p>=6){

if(directory[k+p]==0)

return;

readSector(result,directory[k+p]);

result+=512;

if(p==31)

return;

p++;

}

}

}

void printString(char* s){

for(;*(s)!='\0';s++){

interrupt(0x10, 0xE*256+*(s), 0, 0, 0);

}

}

void readString(char* s){

do{

char typed = interrupt(0x16,0,0,0,0);

if(typed==0xd)

{

*(s)=0xa;

s++;

*(s)=0x0;

return ;

}

if(typed==0x8){

interrupt(0x10, 0xE*256+0x8, 0, 0, 0);

s--;

interrupt(0x10, 0xE*256+0x0, 0, 0, 0);

interrupt(0x10, 0xE*256+0x8, 0, 0, 0);

}

else{

*(s)=typed;

s++;

interrupt(0x10, 0xE*256+typed, 0, 0, 0);

}

}while(1);

}

int div(int n ,int d) {

int result = 0 ;

while (n>d){

n = n- d;

result++;

}

return result ;

}

int mod(int n ,int d) {

int i = n-(div(n,d)*d);

return i;

}

void readSector(char* buffer, int sector){

int ah = 2;

int al = 1;

int cl = mod(sector,18)+ 1;

char* bx = buffer;

int dh = mod(div(sector , 18),2);

int ch = div(sector,36);

int dl = 0;

int cx=ch*256+cl ;

int dx=dh*256+dl ;

int ax=ah*256 + al;

buffer = interrupt(0x13,ax,bx,cx,dx);

}

void writeSector(char* buffer, long sector){

int ah = 3;

int al = 1;

int cl = mod(sector,18)+ 1;

char* bx = buffer;

int dh = mod(div(sector , 18),2);

int ch = div(sector,36);

int dl = 0;

int cx=ch*256+cl ;

int dx=dh*256+dl ;

int ax=ah*256 + al;

interrupt(0x13,ax,bx,cx,dx);

}

void executeProgram(char* name, int segment){

int counter= 0;

int index = 0x0000;

char buffer [13312];

readfile(name, buffer);

while(counter < 13312){

putInMemory(segment, index++, buffer[counter]);

counter++;

}

launchProgram(segment);

}

void terminate(){

char shell[6];

shell[0]='s';

shell[1]='h';

shell[2]='e';

shell[3]='l';

shell[4]='l';

shell[5]='\0';

interrupt(0x21,4,shell,0x2000,0);

while(1);

}

void deleteFile(char* name){

int i = 0;

int j = 0;//number of records in directory

int k = 0; // index in directory

int p = 0;// parse each record

int mapindex=0;

char directory[512];

char map[512];

readSector(directory,2);

readSector(map,1);

while(j<16){

p = 0;

k=j*32;

while(p<6){

if(name[p]!=directory[k+p])

break ;

p++;

}

if(p==6)

directory[k]=0x00;

while(p>=6){

mapindex=directory[k+p]-1;

map[mapindex]=0x00;

if(p==31)

break;

p++;

}

if(p==31)

break;

j++;

}

writeSector(map,1);

writeSector(directory,2);

}

void writeFile(char* name, char* buffer, int secNum){

char directory[512];

char map [512];

int i = 0;

int n= 0;//name

int secto = 0;//sector

int pointer = 6;

int temp;

char tempbuffer [512];

int tempcounter = 0;

readSector(map,1);

readSector(directory,2);

for(;i<16;i++){

n=0;

secto=0;

if(directory[(i*32)]==0x00){

while(name[n]!='\0'&&n<6){

temp=(i*32)+n;

directory[temp]=name[n];

n++;

}

if(n<6)

directory[temp+1]='\0';

temp = (i*32)+6;

while(secto<256)

{

if(secNum==0){

return;

}

n=6;

if(map[secto-1]==0x00)

{

tempcounter = 0;

while(tempcounter<512){

tempbuffer[tempcounter] = *(buffer);

tempcounter++;

buffer++;

if(*(buffer)==0)

break;

}

writeSector(tempbuffer,secto);

map[secto-1]=0xFF;

directory[temp]=secto;

temp++;

n++;

secNum--;

}

if(secNum==0)

break;

secto++;

}

if(secNum!=0){

printString("error no free space");

return;

}

temp = (i*32)+n;

while(n<32){

directory[temp++]=0x00;

if(n==31){

writeSector(map,1);

writeSector(directory,2);

return ;

}

n++;

}

}

}

printString("Error no free space");

return;

}

printInt(char* number1,int numb){

int mod1 ;

int num ;

mod1= mod(numb,10);

num = div(numb,10);

number1[1] = mod1+'0';

number1[0]= num+'0';

}

handleInterrupt21(int ax, int bx, int cx, int dx){

if(ax==0)

printString(bx);

if(ax==1)

readString(bx);

if(ax==2)

readSector(bx,cx);

if(ax==3)

readfile(bx,cx);

if(ax==4)

executeProgram(bx,cx);

if(ax==5)

terminate();

if(ax==6)

writeSector(bx,cx);

if(ax==7)

deleteFile(bx);

if(ax==8)

writeFile(bx,cx,dx);

if(ax>=9)

printString("Error");

}