SystemVerilog DPI Tutorial

Examples of Argument Passing

Imported function: passing integer from SystemVerilog to C

On the SystemVerilog side:

   import "DPI" function integer my_C_func (integer my_arg);

   ...
      result = my_c_func (some_arg);

   int my_c_func(int);
   int my_c_func(int i) {
      ...
   }

Imported function: passing an input integer from SystemVerilog to C

On the SystemVerilog side:

   import "DPI" function integer my_C_func (input integer my_arg);

   ...
      result = my_c_func (some_arg);

   int my_c_func(const int); // const => input
   int my_c_func(const int i) {
      ...
   }

Imported function: passing an output bit vector from SystemVerilog to C

On the SystemVerilog side:

   import "DPI" function integer my_C_func (input integer my_inp_arg, 
                                            output bit [63:0] my_outp_arg);

   ...
      result = my_c_func (some_arg);

   int my_c_func(const int, svBitPackedArrRef); 
   // const => input and bit vector passed as handle
   int my_c_func(const int i, svBitPackedArrRef j) {
      ...
   }

Exported function: passing an array of int as output from C to SystemVerilog

On the SystemVerilog side:

   export "DPI" function int my_SV_func;

   function int my_SV_func(input int i, output j [7:0]);
   begin 
      ...
   end 
   endfunction

   extern int my_SV_func (int, int*);
   ...
   // use it later on
   int k, l, m;
   ...
   k = my_SV_func (l, &m);