sc_port 和 sc_export 之间的区别

Question

Can someone clearly and intuitively explain what is the difference between an sc_port and an sc_export in SystemC? When does one use a port, and when an export?

I've been reading portions of the manual but I still fail to grasp the main conceptual difference between the two.

Answer 1

From IEEE Standard for Standard SystemC ® Language Reference Manual

Class sc_export allows a module to provide an interface to its parent module. An export forwards interface method calls to the channel to which the export is bound. An export defines a set of services (as identified by the type of the export) that are provided by the module containing the export.

Providing an interface through an export is an alternative to a module simply implementing the interface. The use of an explicit export allows a single module instance to provide multiple interfaces in a structured manner.

If a module is to call a member function belonging to a channel instance within a child module, that call should be made through an export of the child module.

The upshot of all this being that without sc_export one would need to create an sc_port in the parent module and connect it to the port of the child module in order to expose a child's port as a port of the parent module. Using sc_export allows one to directly expose a child port as port of the parent module. Simply create an instance of sc_export and bind it to a child port.

For a full description and class specification see section 5.13 of IEEE Standard for Standard SystemC ® Language Reference Manual

ps If you do not intend to convert your code to VHDL then there is no need to use sc_export . SystemC is just standard C++ and ports are just normal public members (you could have a private port but there hardly seems much point) so you can just take a reference to it and pretend that it's a member of its parent module or any other module that has access to it for that matter.