bladeRF-wiphy/fpga/vhdl/wlan_viterbi_encoder.vhd
2020-12-30 23:19:51 -08:00

84 lines
2.7 KiB
VHDL

-- This file is part of bladeRF-wiphy.
--
-- Copyright (C) 2020 Nuand, LLC.
--
-- This program is free software; you can redistribute it and/or modify
-- it under the terms of the GNU General Public License as published by
-- the Free Software Foundation; either version 2 of the License, or
-- (at your option) any later version.
--
-- This program is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-- GNU General Public License for more details.
--
-- You should have received a copy of the GNU General Public License along
-- with this program; if not, write to the Free Software Foundation, Inc.,
-- 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
library ieee ;
use ieee.std_logic_1164.all ;
use ieee.numeric_std.all ;
library work ;
entity wlan_viterbi_encoder is
generic (
WIDTH : positive := 4
) ;
port (
clock : in std_logic ;
reset : in std_logic ;
init : in std_logic ;
in_data : in std_logic_vector(WIDTH-1 downto 0) ;
in_valid : in std_logic ;
in_done : in std_logic ;
out_a : out std_logic_vector(WIDTH-1 downto 0) ;
out_b : out std_logic_vector(WIDTH-1 downto 0) ;
out_done : out std_logic ;
out_valid : out std_logic
) ;
end entity ;
architecture arch of wlan_viterbi_encoder is
signal state : unsigned(5 downto 0) := (others =>'0') ;
begin
encode : process(clock, reset)
variable tempstate : unsigned(state'range) := (others =>'0') ;
begin
if( reset = '1' ) then
state <= (others =>'0') ;
out_a <= (others =>'0') ;
out_b <= (others =>'0') ;
out_valid <= '0' ;
out_done <= '0' ;
tempstate := (others =>'0') ;
elsif( rising_edge(clock) ) then
out_valid <= '0' ;
out_done <= in_done ;
if( init = '1' ) then
state <= (others =>'0') ;
else
out_valid <= in_valid ;
if( in_valid = '1' ) then
tempstate := state ;
for i in 0 to in_data'high loop
out_a(i) <= tempstate(5) xor tempstate(4) xor tempstate(2) xor tempstate(1) xor in_data(i) ;
out_b(i) <= tempstate(5) xor tempstate(2) xor tempstate(1) xor tempstate(0) xor in_data(i) ;
tempstate := tempstate(4 downto 0) & in_data(i) ;
end loop ;
state <= tempstate ;
end if ;
end if ;
end if ;
end process ;
end architecture ;