update

.gitignore

@@ -4,9 +4,11 @@ simv.daidir
 *.key
 *.log
 *.swp
+.vscode
 
 2_vcs_comp/tb_lib/
 2_vcs_comp/dut_lib/
 2_vcs_comp/partitionlib/
 2_vcs_comp/vc_hdrs.h
 2_vcs_comp/partitionlib_test2/
+3_timing_check/

4_class/Makefile

@@ -0,0 +1,30 @@
+
+LSB_RELEASE = $(shell lsb_release -is)
+LSB_VERSION = $(shell lsb_release -rs)
+ifeq (${LSB_RELEASE}, Ubuntu)
+	ifeq ($(shell echo "${LSB_VERSION}>18.04" | bc), 1)
+    	CC = gcc-4.8
+		CPP = g++-4.8
+	else
+    	CC = gcc
+		CPP = g++
+	endif
+else
+    CC = gcc
+	CPP = g++
+endif
+VCC = vcs -full64 +v2k -sverilog -LDFLAGS -Wl,--no-as-needed -cc $(CC) -cpp $(CPP)\
+		-P ${VERDI_HOME}/share/PLI/VCS/LINUX64/novas.tab ${VERDI_HOME}/share/PLI/VCS/LINUX64/pli.a
+
+.PHONY: clean comp all
+
+clean:
+	- rm -rf csrc simv.daidir ucli.key *.log simv
+
+comp:
+	$(VCC) -debug_access+all -kdb -top tb -l compile.log -timescale=1ns/1ps ./rtl/tb.sv
+
+sim:
+	- ./simv -l sim.log
+
+all: comp sim

4_class/rtl/tb.sv

@@ -0,0 +1,81 @@
+//=========================================================================== 
+// Organization : Individual developer 
+// Filename     : tb.sv
+// Author       : Feng Bohan
+// Create Time  : 11:26:47 2025-03-18
+// Last Modified: 11:27:17 2025-03-18
+// Abstract     :  
+//--------------------------------------------------------------------------
+// Description:
+// 
+//--------------------------------------------------------------------------
+// Modification History:
+//--------------------------------------------------------------------------
+// Rev      Date        Who         Description
+// ---      ----        ---         -----------
+// 0.0.01   2025-03-18  Feng Bohan  initial version
+//===========================================================================
+module tb();
+   class BasePacket;
+      int A; // 1;
+      int B; // 2;
+      int C; // 3;
+
+      function new(int A=1, int B=2, int C=3);
+         this.A=A;
+         this.B=B;
+         this.C=C;
+      endfunction
+
+      virtual function void printA;
+         $display("[%m] A is %0d", A);
+      endfunction
+      virtual function void printB;
+         $display("[%m] B is %0d", B);
+      endfunction : printB
+      function void printC;
+         $display("[%m] C is %0d", C);
+      endfunction : printC
+   endclass : BasePacket
+   class My_Packet extends BasePacket;
+      int   A; // 4
+      int 	B; // 5
+      int   C; // 6
+
+      function new(int A=4, int B=5, int C=6);
+         this.A=A;
+         this.B=B;
+         this.C=C;
+      endfunction
+
+      /* -----\/----- EXCLUDED -----\/-----
+      virtual function void printA;
+         $display("A is %0d", A);
+      endfunction
+       -----/\----- EXCLUDED -----/\----- */
+      virtual function void printB;
+         $display("[%m] B is %0d", B);
+      endfunction : printB
+      function void printC;
+         $display("[%m] C is %0d", C);
+      endfunction : printC
+   endclass : My_Packet
+
+   initial begin
+      BasePacket P1;
+      My_Packet P2  = new;
+
+      P1 = P2;   // P1 has a handle to a My_packet object
+      $display("//******************** P1.print ********************");
+      P1.printA; // A is 1
+      P1.printB; // B is 4
+      P1.printC; // B is 4
+      $display("//**************************************************");
+
+      $display("//******************** P2.print ********************");
+      P2.printA; // A is 1
+      P2.printB; // B is 4
+      P2.printC; // B is 4
+      $display("//**************************************************");
+   end
+endmodule // tb