Question

The foreign language layer of the interface (which is transparent to SystemVerilog) shall specify how actual arguments are passed, how they can be accessed from the foreign code, how SystemVerilog-specific data types (such as logic and packed) are represented, and how to translate them to and from some predefined C-like types.

The data types allowed for formal arguments and results of imported functions or exported functions are generally SystemVerilog types (with some restrictions and with notational extensions for open arrays). The user is responsible for specifying in their foreign code the native types equivalent to the SystemVerilog types used in imported declarations or export declarations. Software tools, like a SystemVerilog compiler, can facilitate the mapping of SystemVerilog types onto foreign native types by generating the appropriate function headers.

The SystemVerilog compiler or simulator shall generate and/or use the function call protocol and argument passing mechanisms required for the intended foreign language layer. The same SystemVerilog code (compiled accordingly) shall be usable with different foreign language layers, regardless of the data access method assumed in a specific layer. Annex F defines DPI foreign language layer for the C programming language.