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--

-- T80 Registers for Xilinx Select RAM

--

-- Version : 0244

--

-- Copyright (c) 2002 Daniel Wallner (jesus@opencores.org)

--

-- All rights reserved

--

-- Redistribution and use in source and synthezised forms, with or without

-- modification, are permitted provided that the following conditions are met:

--

-- Redistributions of source code must retain the above copyright notice,

-- this list of conditions and the following disclaimer.

--

-- Redistributions in synthesized form must reproduce the above copyright

-- notice, this list of conditions and the following disclaimer in the

-- documentation and/or other materials provided with the distribution.

--

-- Neither the name of the author nor the names of other contributors may

-- be used to endorse or promote products derived from this software without

-- specific prior written permission.

--

-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

-- AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,

-- THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

-- PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE

-- LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

-- CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

-- SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

-- INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

-- CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

-- ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

-- POSSIBILITY OF SUCH DAMAGE.

--

-- Please report bugs to the author, but before you do so, please

-- make sure that this is not a derivative work and that

-- you have the latest version of this file.

--

-- The latest version of this file can be found at:

--      http://www.opencores.org/cvsweb.shtml/t51/

--

-- Limitations :

--

-- File history :

--

--      0242 : Initial release

--

--      0244 : Removed UNISIM library and added componet declaration

--

library IEEE;

use IEEE.std_logic_1164.all;

use IEEE.numeric_std.all;

entity T80_Reg is

        port(

                Clk                     : in std_logic;

                CEN                     : in std_logic;

                WEH                     : in std_logic;

                WEL                     : in std_logic;

                AddrA           : in std_logic_vector(2 downto 0);

                AddrB           : in std_logic_vector(2 downto 0);

                AddrC           : in std_logic_vector(2 downto 0);

                DIH                     : in std_logic_vector(7 downto 0);

                DIL                     : in std_logic_vector(7 downto 0);

                DOAH            : out std_logic_vector(7 downto 0);

                DOAL            : out std_logic_vector(7 downto 0);

                DOBH            : out std_logic_vector(7 downto 0);

                DOBL            : out std_logic_vector(7 downto 0);

                DOCH            : out std_logic_vector(7 downto 0);

                DOCL            : out std_logic_vector(7 downto 0)

        );

end T80_Reg;

architecture rtl of T80_Reg is

        component RAM16X1D

                port(

                        DPO             : out std_ulogic;

                        SPO             : out std_ulogic;

                        A0              : in std_ulogic;

                        A1              : in std_ulogic;

                        A2              : in std_ulogic;

                        A3              : in std_ulogic;

                        D               : in std_ulogic;

                        DPRA0   : in std_ulogic;

                        DPRA1   : in std_ulogic;

                        DPRA2   : in std_ulogic;

                        DPRA3   : in std_ulogic;

                        WCLK    : in std_ulogic;

                        WE              : in std_ulogic);

        end component;

        signal  ENH             : std_logic;

        signal  ENL             : std_logic;

begin

        ENH <= CEN and WEH;

        ENL <= CEN and WEL;

        bG1: for I in 0 to 7 generate

        begin

                Reg1H : RAM16X1D

                        port map(

                        DPO => DOBH(i),

                        SPO => DOAH(i),

                        A0 => AddrA(0),

                        A1 => AddrA(1),

                        A2 => AddrA(2),

                        A3 => '0',

                        D => DIH(i),

                        DPRA0 => AddrB(0),

                        DPRA1 => AddrB(1),

                        DPRA2 => AddrB(2),

                        DPRA3 => '0',

                        WCLK => Clk,

                        WE => ENH);

                Reg1L : RAM16X1D

                        port map(

                        DPO => DOBL(i),

                        SPO => DOAL(i),

                        A0 => AddrA(0),

                        A1 => AddrA(1),

                        A2 => AddrA(2),

                        A3 => '0',

                        D => DIL(i),

                        DPRA0 => AddrB(0),

                        DPRA1 => AddrB(1),

                        DPRA2 => AddrB(2),

                        DPRA3 => '0',

                        WCLK => Clk,

                        WE => ENL);

                Reg2H : RAM16X1D

                        port map(

                        DPO => DOCH(i),

                        SPO => open,

                        A0 => AddrA(0),

                        A1 => AddrA(1),

                        A2 => AddrA(2),

                        A3 => '0',

                        D => DIH(i),

                        DPRA0 => AddrC(0),

                        DPRA1 => AddrC(1),

                        DPRA2 => AddrC(2),

                        DPRA3 => '0',

                        WCLK => Clk,

                        WE => ENH);

                Reg2L : RAM16X1D

                        port map(

                        DPO => DOCL(i),

                        SPO => open,

                        A0 => AddrA(0),

                        A1 => AddrA(1),

                        A2 => AddrA(2),

                        A3 => '0',

                        D => DIL(i),

                        DPRA0 => AddrC(0),

                        DPRA1 => AddrC(1),

                        DPRA2 => AddrC(2),

                        DPRA3 => '0',

                        WCLK => Clk,

                        WE => ENL);

        end generate;

end;