add comments to clarify how to select CB ports when connecting to SBs at the top level
@@ -570,6 +570,10 @@ void add_top_module_nets_connect_sb_and_cb(ModuleManager& module_manager,
} else {
VTR_ASSERT(IN_PORT == module_sb.get_chan_node_direction(side_manager.get_side(), itrack));
}
+
+ /* Upper CB port is required if the routing tracks are on the top or right sides of
+ * the switch block, which indicated bottom and left sides of the connection blocks
+ */
bool use_cb_upper_port = (TOP == side_manager.get_side()) || (RIGHT == side_manager.get_side());
std::string cb_port_name = generate_cb_module_track_port_name(cb_type,
cb_port_direction,
