void shift_array_left(unsigned long* arr, int size){
    int prev_carry,curr_carry, i;
    prev_carry = curr_carry = i = 0;

    for(arr;size--;++arr){
        curr_carry = ~(~0UL >> 1) & *arr;
        *arr <<= 1;
        if( prev_carry ) *arr |= 1UL;
        prev_carry = curr_carry;
    }
}