The Art of Assembly Language, 2nd Edition

5.5 Other Local and Global Symbol Types

As the previous section notes, HLA procedures let you declare constants, values, types, and almost everything else legal in the main program's declaration section. The same rules for scope apply to these identifiers. Therefore, you can reuse constant names, procedure names, type names, and the like in local declarations.

Referencing global constants, values, and types does not present the same software engineering problems that occur when you reference global variables. The problem with referencing global variables is that a procedure can change the value of a global variable in a nonobvious way. This makes programs more difficult to read, understand, and maintain because you can't often tell that a procedure ...