add Commen Units

common/TTL/ls85.v

@@ -0,0 +1,37 @@
+`timescale 1ns / 1ps
+//////////////////////////////////////////////////////////////////////////////////
+// Company: 
+// Engineer:	   Paul Wightmore
+// 
+// Create Date:	   22:06:05 05/14/2018 
+// Design Name:	   LS85
+// Module Name:	   system86/ttl/ls85.v
+// Project Name:   Namco System86 simulation
+// Target Devices: 
+// Tool versions: 
+// Description:	   LS85 - 4-Bit Magnitude Comparators
+//
+// Dependencies: 
+//
+// Revision: 
+// Revision 0.01 - File Created
+// Additional Comments: 
+// License:		   https://www.apache.org/licenses/LICENSE-2.0
+//
+//////////////////////////////////////////////////////////////////////////////////
+module LS85(
+        input wire [3:0] A,
+        input wire [3:0] B,
+        output wire AgtBin,
+        output wire AeqBin,
+        output wire AltBin,
+        output wire AgtBout,
+        output wire AeqBout,
+        output wire AltBout
+	);
+
+	assign AgtBout = (A > B) || (!AeqBin && AgtBin && (A == B));
+	assign AeqBout = (A == B) && AeqBin;
+	assign AltBout = (A < B) || (!AeqBin && AltBin && (A == B));
+
+endmodule