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[/] [mod_sim_exp/] [trunk/] [rtl/] [vhdl/] [ram/] [dpram_generic.vhd] - Blame information for rev 94

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1 59 JonasDC
----------------------------------------------------------------------  
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----  dpram_generic                                               ---- 
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----                                                              ---- 
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----  This file is part of the                                    ----
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----    Modular Simultaneous Exponentiation Core project          ---- 
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----    http://www.opencores.org/cores/mod_sim_exp/               ---- 
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----                                                              ---- 
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----  Description                                                 ---- 
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----    behavorial description of a dual port ram with one 32-bit ----
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----    write port and one 32-bit read port                       ----            
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----                                                              ---- 
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----  Dependencies: none                                          ----
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----                                                              ----
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----  Authors:                                                    ----
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----      - Geoffrey Ottoy, DraMCo research group                 ----
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----      - Jonas De Craene, JonasDC@opencores.org                ---- 
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----                                                              ---- 
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---------------------------------------------------------------------- 
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----                                                              ---- 
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---- Copyright (C) 2011 DraMCo research group and OPENCORES.ORG   ---- 
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----                                                              ---- 
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---- This source file may be used and distributed without         ---- 
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---- restriction provided that this copyright statement is not    ---- 
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---- removed from the file and that any derivative work contains  ---- 
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---- the original copyright notice and the associated disclaimer. ---- 
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----                                                              ---- 
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---- This source file is free software; you can redistribute it   ---- 
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---- and/or modify it under the terms of the GNU Lesser General   ---- 
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---- Public License as published by the Free Software Foundation; ---- 
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---- either version 2.1 of the License, or (at your option) any   ---- 
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---- later version.                                               ---- 
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----                                                              ---- 
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---- This source is distributed in the hope that it will be       ---- 
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---- useful, but WITHOUT ANY WARRANTY; without even the implied   ---- 
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---- warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR      ---- 
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---- PURPOSE.  See the GNU Lesser General Public License for more ---- 
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---- details.                                                     ---- 
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----                                                              ---- 
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---- You should have received a copy of the GNU Lesser General    ---- 
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---- Public License along with this source; if not, download it   ---- 
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---- from http://www.opencores.org/lgpl.shtml                     ---- 
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----                                                              ---- 
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----------------------------------------------------------------------
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library ieee;
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use ieee.std_logic_1164.all;
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use ieee.std_logic_unsigned.all;
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library mod_sim_exp;
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use mod_sim_exp.std_functions.all;
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-- altera infers ramblocks from a depth of 9
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-- xilinx infers ramblocks from a depth of 2
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entity dpram_generic is
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  generic (
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    depth : integer := 2
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  );
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  port  (
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    -- write port A
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    clkA   : in std_logic;
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    waddrA : in std_logic_vector(log2(depth)-1 downto 0);
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    weA    : in std_logic;
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    dinA   : in std_logic_vector(31 downto 0);
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    -- read port B
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    clkB   : in std_logic;
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    raddrB : in std_logic_vector(log2(depth)-1 downto 0);
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    doutB  : out std_logic_vector(31 downto 0)
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  );
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end dpram_generic;
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architecture behavorial of dpram_generic is
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  -- the memory
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  type ram_type is array (depth-1 downto 0) of std_logic_vector (31 downto 0);
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  shared variable RAM : ram_type := (others => (others => '0'));
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  -- xilinx constraint to use blockram resources
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  attribute ram_style : string;
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  attribute ram_style of ram:variable is "block";
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  -- altera constraints:
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  -- for smal depths:
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  --  if the synthesis option "allow any size of RAM to be inferred" is on, these lines 
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  --  may be left commented.
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  --  uncomment this attribute if that option is off and you know wich primitives should be used.
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  --attribute ramstyle : string;
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  --attribute ramstyle of RAM : variable is "M9K, no_rw_check";
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begin
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  process (clkA)
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  begin
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    if rising_edge(clkA) then
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      if (weA = '1') then
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        RAM(conv_integer(waddrA)) := dinA;
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      end if;
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    end if;
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  end process;
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  process (clkB)
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  begin
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    if rising_edge(clkB) then
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      doutB <= RAM(conv_integer(raddrB));
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    end if;
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  end process;
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end behavorial;
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