Question

Similarly to sized arrays, there are functions for copying data between the simulator representation and the canonical representation and to obtain the actual address of SystemVerilog data object or of an individual element of an unpacked array. This information might be useful for simulator-specific tuning of the application. Depending on the type of an element of an unpacked array, different access methods shall be used when working with elements.

• Packed arrays ( bit or logic) are accessed via copying to or from the canonical representation.
• Scalars (1-bit value of type bit or logic) are accessed (read or written) directly.
• Other types of VALUES (NULL, structures) are accessed via generic pointers; a library function calculates an address and the user needs to provide the appropriate casting.
• Scalars and packed arrays are accessible via pointers only if the implementation supports this functionality (per array), e.g., one array can be represented in a form that allows such access, while another array might use a compacted representation which renders this functionality unfeasible (both occurring within the same simulator).

SystemVerilog allows arbitrary dimensions and, hence, an arbitrary number of indices. To facilitate this, variable argument list functions shall be used. For the sake of performance, specialized versions of all indexing functions are provided for 1, 2, or 3 indices.