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Error of undeclared identifier while calling c-function in VHDL with ncsim

jayvyas13

I am getting error of undeclared identifier while calling c-function in VHDL with ncsim.

I am trying to call C-functions existing in a .so filed - c_api.so inside a VHDL file, something like:

begin
    wait for 1 ns;
    if ( RESETEN = '1') then
       c_matrix_multi( size, cofficient_m1, cofficient_m2, cofficient_reduced);
    end if;
    wait;
end process initial;  


But i am getting following error of c-function name "c_matrix_multi" not declared.
                                c_matrix_multi( size, cofficient_m1, cofficient_m2, cofficient_reduced);
ncvhdl_p: *E,IDENTU (.../compute_cofficient.vhd,107|46): identifier (c_matrix_multi) is not declared [10.3].

Plz, provide a sample code of c-function being used inside VHDL using three steps (compile, elab and run).

  • There is no way to call foreign language functions directly from VHDL, the simulator assumes all references are native to VHDL unless you explicitly declare them to be "foreign", i.e. in another language domain. For SystemVerilog it's really easy using the DPI, but for VHDL things are slightly more complex. You will need to study the Foreign Model Import library (FMI) documentation to understand how to declare your C code within the VHDL so that you can make the calls the way you want. There is a worked example in the simulator installation directory: `ncroot`/inca/examples/cif/import_function/, and you can get eh right part of the docs by running the Linux command "cdnshelp -search 'Foreign Model Integration' ".

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