What does the @data directive mean in MASM?

I have c开发者_JAVA技巧ome across the following directive in some assembly code:

mov    ax, @data

I've gone through my assembler book and tried some Googl-ing, but can't find a definition.

Thanks,

Scott

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@data is a macro for the default data group, which is only relevant if you're not using the FLAT model.

The code you provided is typically followed by mov ds, ax, which sets up the data segment register for the current executable.

(MSDN reference at @data.)