Using DPI inside an SV Interface

A customer wanted me to post my example to this forum: From: ramnararyan [mailto:ramnarayan@xxxxxxxx] Hi, I got information from cdnuser forum that u have example code of the dpi import/export declarations, and the export function inside the interface, and you were able to access the import function from both modules attached to the interface. so i would like to adopt this methodology.I m using NCSIM 6.2. please send me example. ----------------- so here is the example. This example has more than the orginal request, it also shows how to pass a queue of class thru an interface, as well as how to access DPI inside an interface: -----file: class_across_interface.sv--------------- // Todd Mackett Cadence Design Systems // irun class_across_interface.sv dpi.c // tested with IUS5.83s1 and IUS6.2s1 /* top-------------------------- | test --->interface---->dut | |----------------------------- */ package mypack; class some_class; int some_int; real some_real; protected string some_string; // needs to be protected for IUS5.83 function void set_data (int i, real r, string s); some_int =i; some_real = r; some_string = s; endfunction task get_data(output int i, output real r, output string s); i = some_int; r = some_real; s = some_string; endtask function void print_data(); $display("Int: %d, Real: %f, String: %s", some_int, some_real, some_string); endfunction endclass endpackage // ------ // This channel is an interface that is a queue of classes interface myIF; import mypack::*; // -----dpi------ import "DPI-C" context c_func = function int my_c_func (input int a); export "DPI-C" sv_func = function my_sv_func; function int my_sv_func(input int a); return a + 2; endfunction // -----end dpi----- event some_event; some_class some_classQ[$]; function int some_classQ_size(); return some_classQ.size(); endfunction task push_class_in_Q(input some_class Qin); some_classQ.push_front(Qin); endtask task pop_class_out_Q(output some_class Qout); Qout = some_classQ.pop_back(); endtask endinterface // ----------------- module top(); int top_int; reg clk = 'b1; initial forever clk = #10 ~clk; // system clk myIF myIFi(); // instantiate interface test testi(clk, myIFi); dut duti(clk, myIFi); endmodule // -------------- // The test module create a class of information and puts it in the // channel (a queue in the interface) module test (input clk, myIF myIFi); import mypack::*; int i; real r; string s; initial #200 $finish; some_class top_class; always @(posedge clk) begin top_class = new; i = $urandom_range(5,1); randcase 1: r = 3.14; 1: r = 123.456; 1: r = -943.825; endcase randcase 1: s = "IUS SystemVerilog"; 1: s = "Cadence"; 1: s = "Who needs VHDL?"; endcase // dpi call inside interface: $display("DPI Call %d", myIFi.my_c_func(30)); top_class.set_data(i, r, s); // set the values into class myIFi.push_class_in_Q(top_class); // transmit the class -> myIFi.some_event; // cause the event end endmodule // The dut module consumes the class when the event is valid // and displays its contents as it comes across the interface module dut (input clk, myIF myIFi); import mypack::*; some_class dut_class =new; always @(myIFi.some_event) // process event begin $display("\nQueue Size %d",myIFi.some_classQ_size() ); myIFi.pop_class_out_Q(dut_class); dut_class.print_data(); // dpi call inside interface: $display("DPI Call %d", myIFi.my_c_func(997)); end endmodule -------------end file: class_across_interface.sv--------------- ----file: dpi.c-------- #include "dpi.h" //extern int sv_func(int a); int c_func(int a) { return sv_func(a); } -----end file: dpi.c--------- ----partial irun.log file:-------- Queue Size 1 Int: 1, Real: 3.140000, String: Who needs VHDL? DPI Call 999 DPI Call 32 ... ... ...