In Diu Indo-Portuguese, unmarked verb forms always have a Perfective reading. These forms code a Past/non-Past distinction, either relying on suppletion or, often, on the use of suffixes.
On the other hand, the expression of Imperfectivity involves pre-verbal markers (be they invariant particles or auxiliary verbal forms), which may themselves be inflected to indicate Tense categories. Pre-verbal markers immediately precede the main verb.
Source: Cardoso 2009: 181
Source: Cardoso 2009: 226
Source: Cardoso 2009: 166
Source: Cardoso 2009: 169
Source: Cardoso 2004-2008