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-----------------------------------------------------------------------------
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-----------------------------------------------------------------------------
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-- NoCem -- Network on Chip Emulation Tool for System on Chip Research
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-- NoCem -- Network on Chip Emulation Tool for System on Chip Research
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-- and Implementations
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-- and Implementations
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--
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--
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-- Copyright (C) 2006 Graham Schelle, Dirk Grunwald
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-- Copyright (C) 2006 Graham Schelle, Dirk Grunwald
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--
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--
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-- This program is free software; you can redistribute it and/or
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-- This program is free software; you can redistribute it and/or
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-- modify it under the terms of the GNU General Public License
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-- modify it under the terms of the GNU General Public License
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-- as published by the Free Software Foundation; either version 2
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-- as published by the Free Software Foundation; either version 2
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-- of the License, or (at your option) any later version.
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-- of the License, or (at your option) any later version.
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--
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--
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-- This program is distributed in the hope that it will be useful,
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-- This program is distributed in the hope that it will be useful,
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-- but WITHOUT ANY WARRANTY; without even the implied warranty of
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-- but WITHOUT ANY WARRANTY; without even the implied warranty of
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-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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-- GNU General Public License for more details.
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-- GNU General Public License for more details.
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--
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--
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-- You should have received a copy of the GNU General Public License
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-- You should have received a copy of the GNU General Public License
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-- along with this program; if not, write to the Free Software
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-- along with this program; if not, write to the Free Software
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-- Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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-- Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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-- 02110-1301, USA.
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-- 02110-1301, USA.
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--
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--
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-- The authors can be contacted by email: <schelleg,grunwald>@cs.colorado.edu
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-- The authors can be contacted by email: <schelleg,grunwald>@cs.colorado.edu
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--
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--
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-- or by mail: Campus Box 430, Department of Computer Science,
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-- or by mail: Campus Box 430, Department of Computer Science,
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-- University of Colorado at Boulder, Boulder, Colorado 80309
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-- University of Colorado at Boulder, Boulder, Colorado 80309
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--------------------------------------------------------------------------------
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--------------------------------------------------------------------------------
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--
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--
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-- Filename: fifo_reg.vhd
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-- Filename: fifo_reg.vhd
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--
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--
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-- Description: a single register FIFO
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-- Description: a single register FIFO
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--
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--
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library IEEE;
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library IEEE;
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use IEEE.STD_LOGIC_1164.ALL;
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use IEEE.STD_LOGIC_1164.ALL;
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use IEEE.STD_LOGIC_ARITH.ALL;
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use IEEE.STD_LOGIC_ARITH.ALL;
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use IEEE.STD_LOGIC_UNSIGNED.ALL;
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use IEEE.STD_LOGIC_UNSIGNED.ALL;
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use work.pkg_nocem.all;
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use work.pkg_nocem.all;
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entity fifo_reg is
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entity fifo_reg is
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generic (
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generic (
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WIDTH : integer := 16
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WIDTH : integer := 16
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);
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);
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port (
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port (
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clk: IN std_logic;
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clk: IN std_logic;
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din: IN std_logic_VECTOR(WIDTH-1 downto 0);
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din: IN std_logic_VECTOR(WIDTH-1 downto 0);
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rd_en: IN std_logic;
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rd_en: IN std_logic;
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rst: IN std_logic;
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rst: IN std_logic;
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wr_en: IN std_logic;
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wr_en: IN std_logic;
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dout: OUT std_logic_VECTOR(WIDTH-1 downto 0);
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dout: OUT std_logic_VECTOR(WIDTH-1 downto 0);
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empty: OUT std_logic;
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empty: OUT std_logic;
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full: OUT std_logic);
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full: OUT std_logic);
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end fifo_reg;
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end fifo_reg;
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architecture Behavioral of fifo_reg is
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architecture Behavioral of fifo_reg is
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signal empty_i : std_logic;
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signal empty_i : std_logic;
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begin
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begin
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full <= not empty_i;
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full <= not empty_i;
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empty <= empty_i;
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empty <= empty_i;
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delay_gen : process (clk,rst)
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delay_gen : process (clk,rst)
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begin
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begin
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if rst='1' then
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if rst='1' then
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dout <= (others => '0');
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dout <= (others => '0');
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empty_i <= '1';
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empty_i <= '1';
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elsif clk'event and clk='1' then
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elsif clk'event and clk='1' then
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-- manage empty signal
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-- manage empty signal
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if empty_i = '0' and rd_en ='1' and wr_en = '0' then
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if empty_i = '0' and rd_en ='1' and wr_en = '0' then
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empty_i <= '1';
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empty_i <= '1';
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elsif empty_i = '1' and rd_en='0' and wr_en='1' then
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elsif empty_i = '1' and rd_en='0' and wr_en='1' then
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empty_i <= '0';
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empty_i <= '0';
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end if;
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end if;
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--manage dout
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--manage dout
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if rd_en='1' and wr_en='0' then
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if rd_en='1' and wr_en='0' then
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dout <= (others => '0');
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dout <= (others => '0');
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elsif wr_en='1' then
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elsif wr_en='1' then
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dout <= din;
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dout <= din;
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end if;
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end if;
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end if;
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end if;
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end process;
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end process;
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end Behavioral;
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end Behavioral;
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