Manipulating Packed Arrays (structures) using DPI

I'm sharing this code which is a demo of how to manipulate a SystemVerilog Packed Array (SV data structure) using DPI. Unpacked refers to anything on the left side of an array. logic [7:0] my_array [1023:0] |-- packed |-- unpacked This code will work with IUS5.83. ----file: top.v------------ module top (); // import functions do a call from SV to C import "DPI-C" context addone_c= function int addone_sv(input int x); import "DPI-C" context function void show_vec_inC(input bit [31:0] some_vec); import "DPI-C" context function void show_logic_inC(input logic [31:0] some_vec); typedef struct packed { int a; bit [9:0] b; bit [5:0] c; } mydata_struct_s; import "DPI-C" context function void pass_struct(inout mydata_struct_s t ); bit [31:0] some_vec = 32'h12345678; logic [31:0] some_logic = 32'h8765X32Z; mydata_struct_s mydata_struct_i; initial begin $display("Gimme_Int %d",addone_sv(5)); show_vec_inC(some_vec); // pass reference per SV spec show_logic_inC(some_logic); // pass reference per SV spec // stuff the structure with data mydata_struct_i.a = 9; mydata_struct_i.b = 10'b10_1011_0110; mydata_struct_i.c = 6'b11_0101; pass_struct(mydata_struct_i); // pass reference to packed struct $display("Verilog a %d", mydata_struct_i.a); $display("Verilog b %h", mydata_struct_i.b); $display("Verilog c %h", mydata_struct_i.c); end endmodule --------file: mydpi.c---------------- #include #include // Copyright Cadence Design Systems, Todd Mackett 2007 // This is an example of manipulating packed data structure in SystemVerilog // Use /tools/inca/include/svdpi.h as a reference int addone_c(int x) { return x +1; } void show_vec_inC(svBitVecVal* x) { io_printf("show_vec_inC\n"); io_printf("a= %x\n", *x); } // svLogicVecVal can have 0,1,X,Z void show_logic_inC(svLogicVecVal* x) { io_printf("show_Logic_inC\n"); io_printf("a= %x\n", *x); io_printf("aval %x\n", x->a); // identical to aval bval as in PLI io_printf("bval %x\n", x->b); } // use VPI io_printf() instead of printf() to go to ncsim.log file void pass_struct( svBitVecVal* x) { // NOT const so that this can be modified // can use x[0] to reference raw array // io_printf("Struct = %x, %x\n", x[0], x[1] ); svBitVecVal aa; // define a local svBitVecVal // extract field a of SV "struct packed {...} mydata_struct_s svGetPartselBit(&aa , x, 16, 32); // corresponds to mydata_struct.a io_printf("mydata_struct_s.a: %x \n", aa); svGetPartselBit(&aa , x, 6, 10); // corresponds to mydata_struct.b io_printf("mydata_struct_s.b: %x \n", aa); svGetPartselBit(&aa , x, 0, 6); // corresponds to mydata_struct.c io_printf("mydata_struct_s.c: %x \n", aa); io_printf("AA %x \n", aa); // do some manipulation on the local svBitVecVal aa = ~aa; // invert the bits (some generic bit manipulation routine) // can do something like this too: just set the value of Verilog Structure // aa = 13; io_printf("AA %x \n", aa); svPutPartselBit(x, aa, 0, 6); // this will modify the Verilog structure } -----file: RUN_NC (script)----- rm -r INCA_libs rm *.so rm *.log rm *.h # Create .h file for Exported tasks/functions only # (imported function do NOT need .h file): ncverilog +sv top.v +ncdpiheader+dpi.h +elaborate +ncelabargs+-messages # ncvlog -sv top.v -mess # ncelab top -sv -dpiheader dpi.h -mess gcc -fPIC -shared -o mydpi.so mydpi.c -I/`ncroot`/tools/inca/include ncverilog +sv top.v +sv_lib=mydpi.so +ncsimargs+"-sv_root ./" ------file: ncverilog.log---------- ncsim> run Gimme_Int 6 show_vec_inC a= 12345678 show_Logic_inC a= 8765f320 aval 8765f320 bval f00f mydata_struct_s.a: 9 mydata_struct_s.b: 2b6 mydata_struct_s.c: 35 AA 35 AA ffffffca Verilog a 9 Verilog b 2b6 Verilog c 0a ncsim: *W,RNQUIE: Simulation is complete. ncsim> exit TOOL: ncverilog 05.83-p003: