[sv-bc] Errata: mixed 2/4-state packed structs unclear

Section 3.11 says:

"If any data type within a packed structure is 4-state, the whole structure
is treated as 4-state. Any 2-state members are converted as if cast."

This second sentence is completely unclear. Are they converted in the
declaration, i.e. a member declared as bit is treated as if it had been
declared as logic? Or does this involve data conversions when performing
reads and/or writes to those bits using the 2-state member? If the latter,
does this happen on reads or writes or both? And cast from what to what?

The later text on packed unions with 2-state and 4-state members is much
clearer, giving specific implicit conversions to be used on reads and
writes (and it helps that they make logical sense). I can infer that
packed structs are supposed to do the same kind of conversions, but the
LRM certainly does not say so.

Steven Sharp
sharp@cadence.com
Received on Tue Aug 31 17:03:39 2004