what is the meaning of ARR DB 5 DUP(2)?

Question

ARRAY DB 5 DUP (2)

what is the meaning of this expression? what are values inside of ARR?

Answer 1

For operators/directives used by MASM (such as DUP) you can usually find some form of documentation on MSDN. In this case, the relevant page is here.

As the documentation says:

count DUP (initialvalue [[, initialvalue]]...)

Specifies count number of declarations of initialvalue.

So DB 5 DUP (2) outputs 5 bytes that all have the value 2. ARRAY is just a label so that you have an easy way of referring to those bytes elsewhere in your code.