//
// Title       : 8-bit shifter test fixture
// Design      : Homework 4
// Author      : Carl Ebeling
// Company     : CSE 370
//
//-------------------------------------------------------------------------------------------------
//
// File        : shift8_tf.v
//
// Description : This test fixture tests the 8-bit shifter
//				 Execute for 21000 ns.
//-------------------------------------------------------------------------------------------------
`timescale 1ns / 1ns


module shift8_tf (D, S, Q);

output [7:0] D;		// Data input to shifter	  
output[2:0] S;		// Shift amount
input [7:0] Q;		// Data output of shifter

reg [7:0] D;		// Data input to shifter	  
reg [2:0] S;		// Shift amount
reg [7:0] result;  	
reg [7:0] test;

integer	errors;
integer count;

initial	begin  
	errors = 0;
	// Perform exhaustive test: D and S have 11 bits total
	for (count = 0; count < 1<<11; count = count + 1) begin
		{ D, S } = count; 		// Test vector
		result = {{7{D[7]}}, D} >> S;
		#10
		if (Q !== result) begin
			$display("***Error*** D:%b, S:%d, Q:%b", D, S, Q);
			errors = errors + 1;	
		end
	end
	if (errors == 0) $display("Test passed - No errors!!");
		else $display("**** %d Errors****", errors);
end
	
endmodule