8bitworkshop/test/cli/verilog/t_func_regfirst.v

// DESCRIPTION: Verilator: Verilog Test module
//
// This file ONLY is placed under the Creative Commons Public Domain, for
// any use, without warranty, 2005 by Wilson Snyder.
// SPDX-License-Identifier: CC0-1.0

module t (clk);
   input clk;

   reg [2:0] a;
   reg [2:0] b;
   reg       q;

   f6 f6 (/*AUTOINST*/
	  // Outputs
	  .q				(q),
	  // Inputs
	  .a				(a[2:0]),
	  .b				(b[2:0]),
	  .clk				(clk));

   integer cyc; initial cyc=1;
   always @ (posedge clk) begin
      if (cyc!=0) begin
	 cyc <= cyc + 1;
	 if (cyc==1) begin
	    a <= 3'b000;
	    b <= 3'b100;
	 end
	 if (cyc==2) begin
	    a <= 3'b011;
	    b <= 3'b001;
	    if (q != 1'b0) $stop;
	 end
	 if (cyc==3) begin
	    a <= 3'b011;
	    b <= 3'b011;
	    if (q != 1'b0) $stop;
	 end
	 if (cyc==9) begin
	    if (q != 1'b1) $stop;
	    $write("*-* All Finished *-*\n");
	    $finish;
	 end
      end
   end

endmodule

module f6 (a, b, clk, q);
   input  [2:0] a;
   input [2:0] 	b;
   input 	clk;
   output 	q;
   reg 		out;

   function func6;
      reg 	result;
      input [5:0] src;
      begin
	 if (src[5:0] == 6'b011011) begin
	    result = 1'b1;
	 end
	 else begin
	    result = 1'b0;
	 end
	 func6 = result;
      end
   endfunction

   wire [5:0] w6 = {a, b};
   always @(posedge clk) begin
      out <= func6(w6);
   end

   assign q = out;

endmodule