or( <var>, <num1>, <num2> )
This will perform a logical OR as follows:
Take num1 and OR it with num2, write the result to var.
A = B OR 32
or(A, B, 32)
A quick way to set upper case characters to lower case is to OR them with 32.
65 (capital A) OR 32 is 97 (lower case A).
On the face of it, an OR is an addition; however it actually sets bits instead of adding in a value. 97 OR 32 is still 97, because the bit is already set so there is no change.