head	1.2;
access;
symbols;
locks; strict;
comment	@# @;


1.2
date	2006.10.05.16.17.15;	author petebleackley;	state Exp;
branches;
next	1.1;
commitid	e2245252fbe4567;

1.1
date	2006.06.13.12.45.00;	author petebleackley;	state Exp;
branches;
next	;
commitid	44b6448eb3494567;


desc
@@


1.2
log
@Restored after CVS server crashed. Changed bitwidths and exp-golomb format to current specification. Placed copy of specification in docs directory
@
text
@-- ***** BEGIN LICENSE BLOCK *****
-- 
-- 
--  Version: MPL 1.1/GPL 2.0/LGPL 2.1
-- 
--  The contents of this file are subject to the Mozilla Public License
--  Version 1.1 (the "License"); you may not use this file except in compliance
--  with the License. You may obtain a copy of the License at
--  http://www.mozilla.org/MPL/
-- 
--  Software distributed under the License is distributed on an "AS IS" basis,
--  WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for
--  the specific language governing rights and limitations under the License.
-- 
--  The Original Code is BBC Research and Development code.
-- 
--  The Initial Developer of the Original Code is the British Broadcasting
--  Corporation.
--  Portions created by the Initial Developer are Copyright (C) 2006.
--  All Rights Reserved.
-- 
--  Contributor(s): Peter Bleackley (Original author)
-- 
--  Alternatively, the contents of this file may be used under the terms of
--  the GNU General Public License Version 2 (the "GPL"), or the GNU Lesser
--  Public License Version 2.1 (the "LGPL"), in which case the provisions of
--  the GPL or the LGPL are applicable instead of those above. If you wish to
--  allow use of your version of this file only under the terms of the either
--  the GPL or LGPL and not to allow others to use your version of this file
--  under the MPL, indicate your decision by deleting the provisions above
--  and replace them with the notice and other provisions required by the GPL
--  or LGPL. If you do not delete the provisions above, a recipient may use
--  your version of this file under the terms of any one of the MPL, the GPL
--  or the LGPL.
-- * ***** END LICENSE BLOCK ***** */

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;

---- Uncomment the following library declaration if instantiating
---- any Xilinx primitives in this code.
--library UNISIM;
--use UNISIM.VComponents.all;

entity EXP_GOLOMB_COUNTER is
    Port ( DATA_IN : in std_logic_vector(31 downto 0);
           TEST : in std_logic;
           RESET : in std_logic;
           CLOCK : in std_logic;
           COUNTING : out std_logic;
           DATA_OUT : out std_logic);
end EXP_GOLOMB_COUNTER;

architecture RTL of EXP_GOLOMB_COUNTER is
signal DATA2 : std_logic_vector (32 downto 0);
signal LOG : std_logic_vector (4 downto 0);
signal OUT_ADDRESS : std_logic_vector( 4 downto 0); 
signal MODE : std_logic;
signal OUTPUT_ACTIVE : std_logic;
begin

DATA2 <= ('0' & DATA_IN) + "000000000000000000000000000000001";

LOGARITHM : process (CLOCK)
begin
	if CLOCK'event and CLOCK = '1' then
		if DATA2(32) = '1' then
			LOG <= "11111";
		elsif DATA2(31) = '1' then
			LOG <= "11110";
		elsif DATA2(30) = '1' then
			LOG <= "11101";
		elsif DATA2(29) = '1' then
			LOG <= "11100";
		elsif DATA2(28) = '1' then
			LOG <= "11011";
		elsif DATA2(27) = '1' then
			LOG <= "11010";
		elsif DATA2(26) = '1' then
			LOG <= "11001";
		elsif DATA2(25) = '1' then
			LOG <= "11000";
		elsif DATA2(24) = '1' then
			LOG <= "10111";
		elsif DATA2(23) = '1' then
			LOG <= "10110";
		elsif DATA2(22) = '1' then
			LOG <= "10101";
		elsif DATA2(21) = '1' then
			LOG <= "10100";
		elsif DATA2(20) = '1' then
			LOG <= "10011";
		elsif DATA2(19) = '1' then
			LOG <= "10010";
		elsif DATA2(18) = '1' then
			LOG <= "10001";
		elsif DATA2(17) = '1' then
			LOG <= "10000";
		elsif DATA2(16) = '1' then
			LOG <= "01111";
		elsif DATA2(15) = '1' then
			LOG <= "01110";
		elsif DATA2(14) = '1' then
			LOG <= "01101";
		elsif DATA2(13) = '1' then
			LOG <= "01100";
		elsif DATA2(12) = '1' then
			LOG <= "01011";
		elsif DATA2(11) = '1' then
			LOG <= "01010";
		elsif DATA2(10) = '1' then
			LOG <= "01001";
		elsif DATA2(9) = '1' then
			LOG <= "01000";
		elsif DATA2(8) = '1' then
			LOG <= "00111";
		elsif DATA2(7) = '1' then
			LOG <= "00110";
		elsif DATA2(6) = '1' then
			LOG <= "00101";
		elsif DATA2(5) = '1' then
			LOG <= "00100";
		elsif DATA2(4) = '1' then
			LOG <= "00011";
		elsif DATA2(3) = '1' then
			LOG <= "00010";
		elsif DATA2(2) = '1' then
			LOG <= "00001";
		else
			LOG <= "00000";
		end if;
	end if;
end process LOGARITHM;


OUTPUT: process (CLOCK)
begin
	if CLOCK'event and CLOCK = '1' then
		if RESET = '1' then
			MODE <= '0';
			OUT_ADDRESS <= "00000";
			DATA_OUT <= '0';
			OUTPUT_ACTIVE <= '0';
		elsif OUTPUT_ACTIVE = '1' then
			if MODE = '1' then 
				DATA_OUT <= DATA2(conv_integer(OUT_ADDRESS));
				MODE <= '0';
			else
				if	OUT_ADDRESS	= "00000" then
					DATA_OUT <= '1';
					OUTPUT_ACTIVE <= '0';
				else
					DATA_OUT <= '0';
					OUT_ADDRESS <= OUT_ADDRESS - "00001";
					MODE <= '1';
				end if;
			end if;
		elsif TEST = '1' then
			OUTPUT_ACTIVE <= '1';
			OUT_ADDRESS <= LOG;
			MODE <= '0';
		end if;
	end if;
end process OUTPUT;

COUNTING <= OUTPUT_ACTIVE;				 
			

end RTL;
@


1.1
log
@Added sources for exp-golomb encoding and decoding
@
text
@d58 3
a60 3
signal LOG : std_logic_vector (5 downto 0);
signal OUT_ADDRESS : std_logic_vector( 5 downto 0); 
signal UPDOWN : std_logic;
d70 1
a70 1
			LOG <= "100000";
d72 1
a72 1
			LOG <= "011111";
d74 1
a74 1
			LOG <= "011110";
d76 1
a76 1
			LOG <= "011101";
d78 1
a78 1
			LOG <= "011100";
d80 1
a80 1
			LOG <= "011011";
d82 1
a82 1
			LOG <= "011010";
d84 1
a84 1
			LOG <= "011001";
d86 1
a86 1
			LOG <= "011000";
d88 1
a88 1
			LOG <= "010111";
d90 1
a90 1
			LOG <= "010110";
d92 1
a92 1
			LOG <= "010101";
d94 1
a94 1
			LOG <= "010100";
d96 1
a96 1
			LOG <= "010011";
d98 1
a98 1
			LOG <= "010010";
d100 1
a100 1
			LOG <= "010001";
d102 1
a102 1
			LOG <= "010000";
d104 1
a104 1
			LOG <= "001111";
d106 1
a106 1
			LOG <= "001110";
d108 1
a108 1
			LOG <= "001101";
d110 1
a110 1
			LOG <= "001100";
d112 1
a112 1
			LOG <= "001011";
d114 1
a114 1
			LOG <= "001010";
d116 1
a116 1
			LOG <= "001001";
d118 1
a118 1
			LOG <= "001000";
d120 1
a120 1
			LOG <= "000111";
d122 1
a122 1
			LOG <= "000110";
d124 1
a124 1
			LOG <= "000101";
d126 1
a126 1
			LOG <= "000100";
d128 1
a128 1
			LOG <= "000011";
d130 1
a130 3
			LOG <= "000010";
		elsif DATA2(1) = '1' then
			LOG <= "000001";
d132 1
a132 1
			LOG <= "000000";
a137 14
MODE : process (CLOCK)
begin
	if CLOCK'event and CLOCK = '1' then
		if RESET = '1' then
			OUTPUT_ACTIVE <= '0';
		elsif TEST = '1' then
			OUTPUT_ACTIVE <= '1';
		elsif OUT_ADDRESS = "000000" then
			OUTPUT_ACTIVE <= '0';
		end if;
	end if;
end process MODE;


d142 2
a143 2
			UPDOWN <= '0';
			OUT_ADDRESS <= "000000";
d145 1
d147 5
a151 2
			if UPDOWN = '0' then
				if OUT_ADDRESS = LOG then
d153 1
a153 1
					UPDOWN <= '1';
d156 2
a157 1
					OUT_ADDRESS <= OUT_ADDRESS + "000001";
a158 3
			else
				OUT_ADDRESS <= OUT_ADDRESS - "000001";
				DATA_OUT	<= DATA2(conv_integer(OUT_ADDRESS));
d160 4
@