--
-- EnvelopeMemory.vhd
--
-- Copyright (c) 2006 Mitsutaka Okazaki (brezza@pokipoki.org)
-- All rights reserved.
--
-- Redistribution and use of this source code or any derivative works, are
-- permitted provided that the following conditions are met:
--
-- 1. Redistributions of source code must retain the above copyright notice,
--    this list of conditions and the following disclaimer.
-- 2. Redistributions in binary 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.
-- 3. Redistributions may not be sold, nor may they be used in a commercial
--    product or activity 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 COPYRIGHT OWNER 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.
--
--
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
use WORK.VM2413.ALL;

entity EnvelopeMemory is port (
  clk     : in std_logic;
  reset   : in std_logic;

  waddr   : in SLOT_TYPE;
  wr      : in std_logic;
  wdata   : in EGDATA_TYPE;
  raddr   : in SLOT_TYPE;
  rdata   : out EGDATA_TYPE
  );
end EnvelopeMemory;

architecture RTL of EnvelopeMemory is

  type EGDATA_ARRAY is array (0 to MAXSLOT-1) of EGDATA_VECTOR_TYPE;
  signal egdata_set : EGDATA_ARRAY;

begin

  process (clk, reset)

    variable init_slot : integer range 0 to SLOT_TYPE'high+1;

  begin

   if reset = '1' then

     init_slot := 0;

   elsif clk'event and clk = '1' then

     if init_slot /= SLOT_TYPE'high + 1 then
       egdata_set(init_slot) <= (others=>'1');
       init_slot := init_slot + 1;
     elsif wr = '1' then
       egdata_set(waddr) <= CONV_EGDATA_VECTOR(wdata);
     end if;
     rdata <= CONV_EGDATA(egdata_set(raddr));

   end if;

end process;

end RTL;
