What are the limitations in macros?
What are all the things it can do at compile time? Only what the assembler is able to do at compile time?
Does God exist?
(or, in other words: Could you ask a little bit more specific questions?)
Nevermind. I'll just go on MSDN.
You won't find much there. But google for Microsoft MASM 6.1 Reference Guide (http://www.google.com/search?q=Microsoft+MASM+6.1+Reference+Guide) - fascinating lecture.
I found a heck of a lot of things just now that I never knew existed in MASM.
http://msdn.microsoft.com/en-us/library/afzk3475.aspx
Just take a look through the sections. The directives reference and symbols reference.
Sure. But the 6.1 Ref Guide is a lot better if you want to learn macro programming.
The MASM Programmer's Guide (http://www.masm32.com/board/index.php?topic=5433.0) has a chapter (9) on macros.