Further details see in Salonen 1970: 150.
Var. addu
the meaning is highly uncertain
for other Semitic cognates to this Old Assyrian verb v. Kogan 2006c: 187
Also adu, gadu, ḳаdu, ḫadu, ad. The background of variants with initial ḳ and g is difficult to establish.
It is hard to avoid thinking that adīni ‘until now; not yet’, has something to do with PWS *ˁād- '(he is) still' also in terms of etymology (Kogan 2015: 76).
specifically Assyrian word (Kogan 2006c: 180)
The word occurs in Neo-Babylonian, Late Babylonian, and Standard Babylonian only.