Answer 1

I think the book the art of assembly will help you out. http://flint.cs.yale.edu/cs422/doc/art-of-asm/pdf/

Answer 2

assembly is actually a good language to learn it is good for every type of script developing even you can make you're very own scripting language, and or markup language

Answer 3

only reason I can think is to make new old video games. NES / Sega /etc.. if that is the reason, I hope you figure it out

Answer 4

why would want to learn it? that language is really outdated