SystemVerilog DPI Interface

SystemVerilog DPI is much more easy to interface with external C like languages. We can still use the exisiting TF and ACC routines. Below is same example shown with VPI.

 There are only three files that are different

• counter_dpi.c
• counter.sv
• Makefile

DPI C wrapper

  1 #include

  2 #include

  3 #include "acc_user.h"

  4 #include "vcs_acc_user.h"

  5 #include "svdpi.h"

  6

  7

  8 #include "counter_tb_ports.h"

  9 #include "counter_tb_exports.h"

 10

 11 void sc_counter_init() {

 12   init_sc();  // Initialize SystemC Model

 13 }

 14

 15 int sc_counter_interface(int iclk, int idout) {

 16   static unsigned long SimNow = 0;

 17   int lrst;

 18   // IO ports systemC testbench

 19   static INVECTOR   invector;

 20   static OUTVECTOR  outvector;

 21   invector.clk   = iclk;

 22   invector.d_out = idout;

 23   // Execute the SytemC Shell

 24   exec_sc(&invector, &outvector, (tf_gettime()-SimNow));

 25   SimNow = tf_gettime();

 26   lrst =  outvector.rst;

 27   if (outvector.done) {

 28     tf_dofinish();

 29   }

 30

 31   return(lrst);

 32 }

SystemVerilog Counter

  1 `timescale 1ns / 1ns

  2 //---------------------------------------

  3 // Verilog DUT

  4 //---------------------------------------

  5 module counter(

  6 rst,   // Reset input

  7 clk,   // Clock Input

  8 d_out  // Counter output

  9 );

 10 // Port Declation

 11 input      rst;

 12 input      clk;

 13 output  [31:0]  d_out;

 14 // Internal data type

 15 reg  [31:0]  d_out;

 16 // Code starts here

 17 always @ (posedge clk)

 18   if (rst) d_out = 0;

 19   else d_out = d_out + 1;

 20

 21 endmodule

 22 //---------------------------------------

 23 // Testbench top level

 24 //---------------------------------------

 25 module tb();

 26 reg      rst;

 27 reg      clk;

 28 integer  iclk,irst,idout;

 29 wire  [31:0]  d_out;

 30 // Import the C functions

 31 import "DPI" function void sc_counter_init();

 32 import "DPI" function int sc_counter_interface

 33     (input int iclk, idout);

 34 // Assign Integer to reg

 35 always @ (clk)   iclk  =  clk;

 36 always @ (irst)  rst   =  irst;

 37 always @ (d_out) idout =  d_out;

 38 // Call SystemC interface method, when ever

 39 // Input changes

 40 always @ (idout or iclk)

 41 begin

 42   irst = sc_counter_interface(iclk,idout);

 43 end

 44 // Init the simulation

 45 initial begin

 46  sc_counter_init();

 47  clk = 0;

 48 end

 49 // Clock generator

 50 always #1 clk = ~clk;

 51 // DUT connection

 52 counter dut (

 53     // Inputs

 54     rst,

 55     clk,

 56     // Outputs

 57     d_out

 58 );

 59

 60 endmodule

Makefile DPI

  1 # Point to you systemC Install Dir

  2 SYSTEMC_HOME = /appl/systemc

  3 INC_OPT      = -I. -I$(VCS_HOME)/include \

  4            -I$(SYSTEMC_HOME)/include

  5 COMP_OPT     = -c

  6 LIB_OPT      = $(SYSTEMC_HOME)/lib-linux/libsystemc.a

  7 CPP_FILE     = counter.cpp counter_tb.cpp

  8 DPI_C_FILE   = counter_dpi.c

  9 V_FILE       = counter.sv

 10

 11 DPI_O_FILE   = counter.o counter_dpi.o counter_tb.o

 12 VCS_OPT      = -CFLAGS -lstdc++ $(LIB_OPT)

 13

 14 dpi:c cpp

 15     vcs -sverilog $(DPI_O_FILE) counter.sv $(VCS_OPT) -R

 16

 17 cpp : $(CPP_FILE)

 18     gcc $(INC_OPT) $(COMP_OPT) $(CPP_FILE)

 19

 20 c : $(DPI_C_FILE)

 21     gcc $(INC_OPT) $(COMP_OPT) $(DPI_C_FILE)

 22

 23 clean:

 24     rm -rf *.o simv csrc simv.daidir vcs.key *.vpd *.vcd \

 25     vc_hdrs.h
DPI Simulation Output

  1 Note: VCD trace timescale unit is set by user to 1e-9 sec.

  2 @0 s Started SystemC Schedular

  3 @0 s Asserting Reset

  4 @2 nsCounter Monitor : tb 0 dut 0

  5 @4 nsCounter Monitor : tb 0 dut 0

  6 @6 nsCounter Monitor : tb 0 dut 0

  7 @8 nsCounter Monitor : tb 0 dut 0

  8 @10 nsCounter Monitor : tb 0 dut 0

  9 @12 nsCounter Monitor : tb 0 dut 0

 10 @14 nsCounter Monitor : tb 0 dut 0

 11 @16 nsCounter Monitor : tb 0 dut 0

 12 @18 nsCounter Monitor : tb 0 dut 0

 13 @20 ns De-asserting Reset

 14 @20 nsCounter Monitor : tb 0 dut 0

 15 @22 nsCounter Monitor : tb 1 dut 1

 16 @24 nsCounter Monitor : tb 2 dut 2

 17 @26 nsCounter Monitor : tb 3 dut 3

 18 @28 nsCounter Monitor : tb 4 dut 4

 19 @30 nsCounter Monitor : tb 5 dut 5

 20 @32 nsCounter Monitor : tb 6 dut 6

 21 @34 nsCounter Monitor : tb 7 dut 7

 22 @36 nsCounter Monitor : tb 8 dut 8

 23 @38 nsCounter Monitor : tb 9 dut 9

 24 @40 nsCounter Monitor : tb 10 dut 10

 25 @42 nsCounter Monitor : tb 11 dut 11

 26 @44 nsCounter Monitor : tb 12 dut 12

 27 @46 nsCounter Monitor : tb 13 dut 13

 28 @48 nsCounter Monitor : tb 14 dut 14

 29 @50 nsCounter Monitor : tb 15 dut 15

 30 @52 nsCounter Monitor : tb 16 dut 16

 31 @54 nsCounter Monitor : tb 17 dut 17

 32 @56 nsCounter Monitor : tb 18 dut 18

 33 @58 nsCounter Monitor : tb 19 dut 19

 34 =======================================

 35  SIMULATION PASSED

 36 =======================================

 37 @60 nsCounter Monitor : tb 20 dut 20

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