Initial import

git-svn-id: http://moon:8086/svn/vhdl/trunk@5 cc03376c-175c-47c8-b038-4cd826a8556b

lib/FIFO/src/fifo_ctrl_pkg.vhd

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+-----------------------------------------------------------------------
+-- $Header: /tmp/cvsroot/VHDL/lib/FIFO/src/fifo_ctrl_pkg.vhd,v 1.1 2008-08-23 08:20:28 Jens Exp $
+-----------------------------------------------------------------------
+LIBRARY IEEE;
+USE IEEE.STD_LOGIC_1164.ALL;
+USE IEEE.NUMERIC_STD.ALL;
+
+package fifo_ctrl_pkg is
+
+	-- Constants
+	-- Types
+	
+	-- Functions
+	function bin2gray(xb : unsigned) return unsigned;
+	function gray2bin(xg : unsigned) return unsigned;
+
+end fifo_ctrl_pkg;
+
+package body fifo_ctrl_pkg is
+
+	function bin2gray(xb : unsigned) return unsigned is
+	variable xg : unsigned(xb'left downto xb'right);
+	begin
+	
+    	xg(xg'left) := xb(xb'left);
+		for i in 1 to xb'left loop
+			xg(xg'left-i) := xb(xb'left-i+1) xor xb(xb'left-i);
+		end loop;
+	
+		return xg;
+	end bin2gray;
+	
+	function gray2bin(xg : unsigned) return unsigned is
+	variable xb : unsigned(xg'left downto xg'right);
+	begin
+
+     	xb(xb'left) := xg(xg'left);
+		for i in 1 to xg'left loop
+			xb(xb'left-i) := xb(xb'left-i+1) xor xg(xg'left-i);
+		end loop;
+		
+		return xb;
+	end gray2bin;
+
+end fifo_ctrl_pkg;
+