Assembler mov issue

Question

I have the next code:

mov  ax,@data
mov  ds,ax

Why I can not write just like this?

mov ds,@data

All source:

Answer 1

General purpose register as the 'ax' is designed to hold the 16 bit number pointing to the data (in your case the string inside the DATA)

So if you try to directly pass the data to the special register (ds or data segment here) it will not work correctly as it does not know to accept data that way. So we first get that 'number' or the point in memory location where data starts & pass that point to ds register.