Typically there are tens of thousands of connections at the top level. It is almost impossible to get
this correct when done manually. Companies typically develop internal tools that help to create this
top level SOC. (including the instantiations and connections). The input to these tools could be some
tabular inputs that can be reviewed easily.
In addition to instantiations and connections there will be a minimal amount of glue logic. For example
there could be clock gating logic at the top level.
There are also formal apps that can be used to verify this connectivity.
Logie Ramachandran
Verikwest Systems Inc