//--------------------------------------------------------------------------------------------------
//
// Title       : adder4_tf
// Design      : HW3
// Author      : Lucas Kreger-Stickles
// Company     : uw
//
//-------------------------------------------------------------------------------------------------
//
// File        : adder4_tf.v
//
//-------------------------------------------------------------------------------------------------
//
// Description : Run this test fixture for 20us to test your 4 bit ripple carry adder.
//
//-------------------------------------------------------------------------------------------------
`timescale 1ns / 1ns

module adder4_tf ( A ,Cin ,B ,Cout ,Sum );

input Cout ;
input [3:0] Sum ;

output [3:0] A ;
output [3:0] B ;
output Cin ;
reg [3:0] A ;
reg [3:0] B ;	 
reg Cin ;

integer i;

initial begin 
  for (i=0; i<1000 ; i=i+1) begin
    A = $random;
    B = ($random & 1'b1) ? ~A : $random;
	Cin = $random;
    #20;	  			  
	if ({Cout,Sum} != A+B+Cin) begin
		$display("Error: on A: %d, B: %d, Cin: %d... should be: %d",A,B,Cin,(A+B+Cin));
		$stop;
	end		  
  else begin   
	  	 //$display("Correct: on  A:%d, B:%d, Cin:%d == %d ",A,B,Cin,(A+B+Cin));
	  end//else
  end // for (i=0; i<8; i=i+1)  
  $display("Test Passed: No errors found");

end // initial begin

endmodule