EverNightX: I did not know DOS was written primarily in assembly.
A lot of software was written in raw assembly, especially if you wanted more performance.
Most early console games were also written in assembly. There's a handful of BASIC games for 8bit machines (
Questron comes to mind), but doing assembly was like 400x faster in speed than using the tools available. Course it depended on what you needed.
I did a bunch of assembly language programming when i was a teen (12-13), you tended to put arguments into your registers and use pusha/popa as calls, this was partially space and speed rather than pushing everything onto the stack, among other things. And you didn't have libraries, so exe files weren't a thing (
at that time), instead you used com files which skipped a header and your whole program was under 64k (actually it was probably much smaller than that, unless you somehow needed multiple memory segments, but those were actually fairly rare. You'd be surprised how small you can crunch a program down in raw assembly.