How is the number of value bits in the result determined in the following operations:
5 = -3 & 5 # (1)11 & (0)101 -> (0)101
-3 = -3 | 5 # (1)11 & (0)101 -> (1)11
-8 = -3 ^ 5 # (1)11 ^ (0)101 -> (1)1000
?
So it seems that bitwise AND results in the biggest number of value bits between two operands and bitwise OR results in the smallest number of value bits between two operands. The bitwise XOR, however, totally doesn’t make sense. How did the 2nd lowest bit got set to 0? Why is the number of value bits bigger than the number of value bits in either operand?
>Solution :
negative number are stored in a form called two’s complement
in 4 bit system for 3 .. the representation will be 1101 and 5 is 0101
now your calculations should make sense
or
1101
0101
----
1101 -> -3
and
1101
0101
----
0101 -> 5
xor
1101
0101
-----
1000 -> -8 ( in 2s complement form .. it is negative 8 not positive 8)