VCS and Verilator support

[LucaRufer]

Minimal changes required to compile sources and simulation targets for VCS (version W-2024.09-1) and Verilator (v5.028-44-g1d79f5c59):

• Verilator requires the std:: prefix when using built-in classes like std::semaphore and std::mailbox.
• Verilator cannot compute static variables at compile time when conditional operator is used.
• Verilator cannot determine the default type for Associative Arrays if a parameter is used.
• VCS requires parameter types to match when calling a function with a class object. If any of the axi_??_beat classes are instantiated directly and not from the typedefs in axi_driver, they cannot be passed to a function of a axi_driver object, as parameter and parameter int are not the same.

[thommythomaso]

Which tool is upset with using the values from the package?

[LucaRufer]

Verilator cannot compile with the following error:

%Error: Internal Error: src/axi_sim_mem.sv:119:34: ../V3Width.cpp:7074: Node has no type:
  119 |   axi_pkg::resp_t rerr[addr_t] = '{default: axi_pkg::RESP_OKAY};
      |                                  ^~
                        ... See the manual at https://verilator.org/verilator_doc.html for more assistance.

I tried different ways of re-writing using casting and other approaches, but it just does not work with Verilator.

[thommythomaso]

Ok, can you then keep the link to the package as a comment and write a note why this was changed? Please open an issue for that on the verilator page to have this eventually fixed in the simulator.

[thommythomaso]

Thanks for the fixes. Can you change the parameters to int unsigned directly?
Also, why don't we reference the package anymore for the AXI response in the simulation memory?

[LucaRufer]

Thanks for the fixes. Can you change the parameters to int unsigned directly? Also, why don't we reference the package anymore for the AXI response in the simulation memory?

I updated the pull request as requested.
Verilator has problems with typed defaults for arrays. Even casting does not work. The only way I found to make it compilable with Verilator is to expand it to zero.