1 files changed, 100 insertions, 0 deletions
diff --git a/shifter_tb.v b/shifter_tb.v
new file mode 100644
index 0000000..7d28915
--- /dev/null
+++ b/shifter_tb.v
@@ -0,0 +1,100 @@
+`timescale 1 ns / 100 ps
+
+module shifter_tb ();
+	reg [15:0] v;
+	reg [15:0] by;
+	reg dir;
+	reg [1:0] extend;
+	wire [15:0] result;
+	reg [15:0] expected_result;
+	
+	// xxxxxxxxxxxxxxxx1111101000001010xxxxxxxxxxxxxxxx
+
+	initial begin
+		v = 16'hFA0A;
+		by = 16'h0;
+		dir = 1'b0;
+		extend = 2'h0;
+		expected_result = 16'hFA0A;
+
+		#2
+		by = 16'h1;
+		expected_result = 16'hF414; // 1111 0100 0001 0100
+
+		#2
+		by = 16'h2;
+		expected_result = 16'hE828; // 1110 1000 0010 1000
+
+		#2
+		dir = 1'b1;
+		expected_result = 16'h3E82; // 0011 1110 1000 0010
+
+		#2
+		by = 16'h4;
+		expected_result = 16'h0FA0; // 0000 1111 1010 0000
+
+		#2
+		dir = 1'b0;
+		expected_result = 16'hA0A0; // 1010 0000 1010 0000
+
+		#2
+		extend = 2'h1;
+		expected_result = 16'hA0AF; // 1010 0000 1010 1111
+
+		#2
+		dir = 1'b1;
+		expected_result = 16'hFFA0; // 1111 1111 1010 0000
+
+		#2
+		extend = 2'h2;
+		dir = 1'b0;
+		expected_result = 16'hA0A0; // 1010 0000 1010 0000
+
+		#2
+		dir = 1'b1;
+		expected_result = 16'hFFA0; // 1111 1111 1010 0000
+
+		#2
+		extend = 2'h3;
+		expected_result = 16'hAFA0; // 1010 1111 1010 0000
+
+		#2
+		dir = 1'b0;
+		expected_result = 16'hA0AF; // 1010 0000 1010 1111
+
+		#2
+		v = 16'h0001;
+		extend = 2'h2;
+		dir = 1'b0;
+		by = 16'hE;
+		expected_result = 16'h7FFF;
+		
+		#2
+		by = 16'h10;
+		expected_result = 16'hFFFF;
+		
+		#2
+		dir = 1'b1;
+		expected_result = 16'h0000;
+		
+		#2
+		dir = 1'b0;
+		by = 16'h1000;
+		expected_result = 16'hFFFF;
+
+		#2
+		dir = 1'b1;
+		expected_result = 16'h0000;
+		
+		#5
+		$stop;
+	end
+	
+	shifter shifter_inst (
+		.v(v),
+		.by(by),
+		.dir(dir),
+		.extend(extend),
+		.result(result)
+	);
+endmodule