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--

--      VHDL implementation of cordic algorithm

--

-- File: p2r_cordic.vhd

-- author: Richard Herveille

-- rev. 1.0 initial release

--

library ieee;

use ieee.std_logic_1164.all;

use ieee.std_logic_arith.all;

entity p2r_cordic is

        generic(

                PIPELINE : integer := 15;

                WIDTH    : integer := 16);

        port(

                clk     : in std_logic;

                ena : in std_logic;

                Xi      : in signed(WIDTH -1 downto 0);

                Yi : in signed(WIDTH -1 downto 0) := (others => '0');

                Zi      : in signed(WIDTH -1 downto 0);

                Xo      : out signed(WIDTH -1 downto 0);

                Yo      : out signed(WIDTH -1 downto 0)

        );

end entity p2r_Cordic;

architecture dataflow of p2r_cordic is

        --

        --      TYPE defenitions

        --

        type XYVector is array(PIPELINE downto 0) of signed(WIDTH -1 downto 0);

        type ZVector is array(PIPELINE downto 0) of signed(19 downto 0);

        --

        --      COMPONENT declarations

        --

        component p2r_CordicPipe

        generic(

                WIDTH   : natural := 16;

                PIPEID  : natural := 1

        );

        port(

                clk             : in std_logic;

                ena             : in std_logic;

                Xi              : in signed(WIDTH -1 downto 0);

                Yi              : in signed(WIDTH -1 downto 0);

                Zi              : in signed(19 downto 0);

                Xo              : out signed(WIDTH -1 downto 0);

                Yo              : out signed(WIDTH -1 downto 0);

                Zo              : out signed(19 downto 0)

        );

        end component p2r_CordicPipe;

        --

        --      SIGNALS

        --

        signal X, Y     : XYVector;

        signal Z        : ZVector;

        --

        --      ACHITECTURE BODY

        --

begin

        -- fill first nodes

        -- fill X

        X(0) <= Xi;

        -- fill Y

        Y(0) <= Yi;

        -- fill Z

        Z(0)(19 downto 4) <= Zi;

        Z(0)(3 downto 0) <= (others => '0');

        --

        -- generate pipeline

        --

        gen_pipe:

        for n in 1 to PIPELINE generate

                Pipe: p2r_CordicPipe

                        generic map(WIDTH => WIDTH, PIPEID => n -1)

                        port map ( clk, ena, X(n-1), Y(n-1), Z(n-1), X(n), Y(n), Z(n) );

        end generate gen_pipe;

        --

        -- assign outputs

        --

        Xo <= X(PIPELINE);

        Yo <= Y(PIPELINE);

end dataflow;