According to this Wikipedia article, when arithmetic left shift operation is applied to a signed number, the number is multiplied by 2. But there are certain situations where a negative number becomes a positive number when an arithmetic left shift is applied.
Eg.: Take a 2's complement signed integer -5 and 5 bits are used to represent it.
11011 ==> -5 10110 ==> -10 (-5x2) 01100 ==> +12 (?)
So after two arithmetic left shifts -5 became 24. I expected -20. Why is this the case?