The XOR operator:

Compares two bits and returns a "1" if the operands are different.

Here is the truth table for this:

Bit 1	Bit 2	Result
0	0	0
0	1	1
1	0	1
1	1	0

For example one:

1001 1011       #155
0110 1001       #105
1111 0010       #242
[download]

For example two:

1000 0000       #128
1000 0000       #128
0000 0000       #0
[download]

Hope this helps!
~Hammy