In reply to amandepanda:
I think there has been some incorrect use of the term time-slot. By the LRM definition, a time-slot is the exception of all event regions from Preponed to Postponed where $time is a constant value. A #0 event delay causes an iteration of active and inactive event regions. In other HDLs, this is formally defined as a delta cycle.
Sriram, I can only give you the same answer to the same question. Whether the two loops appear to execute sequentially top to bottom or bottom to top, or in parallel is not defined by the LRM, it is a race condition.