mov cx, 80
i have used borlandc 3.1 which is a good compiler to learn assembly for beginers. this compiler contains TASM (assemblers), seems that ur using the same.
what i think is, u need Nortan Guid (NG).
any how the code is a working code run it in tasm, but think it must also work with masm.
this will invert dos screen.
i assume that u know how to run the asm code using cammand prompt.
knowledge has no limits so always be a student.