problem with real time delay

Dear friends ,
i m using atmel micro controllers, i m facing problem with real time delay . i coding atmel mcs in C but i m not gettinng pricise delay what i want .this is my delay programme


void delay()
{
if((PINB& (1<<PINB3)))
{
for(i=0;i<255;i++)
{
for(j=0;j<255;j++)
{
for(k=0;k<255;k++)
{
for(l=0;l<10;l++)
{
;


}


}

}

}
}




please help me...............