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[/] [mod_sim_exp/] [tags/] [Release_1.4/] [rtl/] [vhdl/] [core/] [fifo_generic.vhd] - Rev 54
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---------------------------------------------------------------------- ---- fifo_generic ---- ---- ---- ---- This file is part of the ---- ---- Modular Simultaneous Exponentiation Core project ---- ---- http://www.opencores.org/cores/mod_sim_exp/ ---- ---- ---- ---- Description ---- ---- behavorial description of a FIFO, ---- -- Synthesizing Unit <fifo_generic>. -- Related source file is "/dropbox/svn/mod_sim_exp/rtl/vhdl/core/fifo_generic.vhd". -- aw = 8 -- depth = 128 --WARNING:Xst:3035 - Index value(s) does not match array range for signal <RAM>, simulation mismatch. -- Found 129x32-bit dual-port RAM <Mram_RAM> for signal <RAM>. -- Found 8-bit register for signal <rd_addr>. -- Found 1-bit register for signal <push_i_d>. -- Found 1-bit register for signal <nopop>. -- Found 1-bit register for signal <nopush>. -- Found 8-bit register for signal <wr_addr>. -- Found 8-bit adder for signal <wr_addr[7]_GND_107_o_add_0_OUT> created at line 89. -- Found 8-bit adder for signal <rd_addr[7]_GND_107_o_add_10_OUT> created at line 114. -- Found 8-bit comparator equal for signal <wr_addr[7]_rd_addr[7]_equal_2_o> created at line 89 -- Found 8-bit comparator equal for signal <empty_i> created at line 93 -- Summary: -- inferred 1 RAM(s). -- inferred 2 Adder/Subtractor(s). -- inferred 19 D-type flip-flop(s). -- inferred 2 Comparator(s). --Unit <fifo_generic> synthesized. ---- ---- ---- Authors: ---- ---- - Geoffrey Ottoy, DraMCo research group ---- ---- - Jonas De Craene, JonasDC@opencores.org ---- ---- ---- ---------------------------------------------------------------------- ---- ---- ---- Copyright (C) 2011 DraMCo research group and OPENCORES.ORG ---- ---- ---- ---- This source file may be used and distributed without ---- ---- restriction provided that this copyright statement is not ---- ---- removed from the file and that any derivative work contains ---- ---- the original copyright notice and the associated disclaimer. ---- ---- ---- ---- This source file is free software; you can redistribute it ---- ---- and/or modify it under the terms of the GNU Lesser General ---- ---- Public License as published by the Free Software Foundation; ---- ---- either version 2.1 of the License, or (at your option) any ---- ---- later version. ---- ---- ---- ---- This source is distributed in the hope that it will be ---- ---- useful, but WITHOUT ANY WARRANTY; without even the implied ---- ---- warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR ---- ---- PURPOSE. See the GNU Lesser General Public License for more ---- ---- details. ---- ---- ---- ---- You should have received a copy of the GNU Lesser General ---- ---- Public License along with this source; if not, download it ---- ---- from http://www.opencores.org/lgpl.shtml ---- ---- ---- ---------------------------------------------------------------------- library ieee; use ieee.std_logic_1164.all; use ieee.std_logic_unsigned.all; use ieee.std_logic_arith.all; library mod_sim_exp; use mod_sim_exp.all; entity fifo_generic is generic ( aw : integer := 6; depth : integer := 32 ); port ( clk : in std_logic; -- clock input din : in std_logic_vector (31 downto 0); -- 32 bit input data for push dout : out std_logic_vector (31 downto 0); -- 32 bit output data for pop empty : out std_logic; -- empty flag, 1 when FIFO is empty full : out std_logic; -- full flag, 1 when FIFO is full push : in std_logic; pop : in std_logic; reset : in std_logic; nopop : out std_logic; nopush : out std_logic ); end fifo_generic; architecture arch of fifo_generic is -- read and write pointer signal rd_addr : std_logic_vector(aw-1 downto 0); signal wr_addr : std_logic_vector(aw-1 downto 0); -- control signals signal empty_i : std_logic; signal full_i : std_logic; signal push_i : std_logic; signal push_i_d : std_logic; signal pop_i : std_logic; -- the memory type ram_type is array (depth downto 0) of std_logic_vector (31 downto 0); signal RAM : ram_type; begin empty <= empty_i; full <= full_i; -- full flag is 1 when read address is one below write address full_i <= '1' when (wr_addr+'1'=rd_addr) or (wr_addr=conv_std_logic_vector(depth, aw) and (rd_addr=conv_std_logic_vector(0, aw))) else '0'; -- empty flag is 1 when read and write address are the same empty_i <= '1' when (wr_addr=rd_addr) else '0'; fifo_addr_proc : process (clk) begin if rising_edge(clk) then if reset='1' then -- if reset, both read and write address point to the maximum address (depth) wr_addr <= conv_std_logic_vector(depth, aw); rd_addr <= conv_std_logic_vector(depth, aw); else if push_i='1' then -- push if (wr_addr=conv_std_logic_vector(depth, aw)) then wr_addr <= (others=>'0'); -- if overflow, set to zero else wr_addr <= wr_addr+'1'; -- else, increase address end if; end if; if pop_i='1' then -- pop if (rd_addr=conv_std_logic_vector(depth, aw)) then rd_addr <= (others=>'0'); -- if overflow, set to zero else rd_addr <= rd_addr+'1'; -- else, increase address end if; end if; end if; push_i_d <= push_i; -- delayed version of push signal nopop <= (pop and empty_i) or (pop and reset); nopush <= (push and full_i) or (push and reset); end if; end process; push_i <= push and not full_i; pop_i <= pop and not empty_i; -- Block RAM process (clk) begin if (clk'event and clk = '1') then if (push_i_d = '1') then RAM(conv_integer(wr_addr)) <= din; end if; dout <= RAM(conv_integer(rd_addr)); end if; end process; end arch;
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