Subversion Repositories mod_sim_exp

----------------------------------------------------------------------  

----  mod_sim_exp_core                                            ---- 

----                                                              ---- 

----  This file is part of the                                    ----

----    Modular Simultaneous Exponentiation Core project          ---- 

----    http://www.opencores.org/cores/mod_sim_exp/               ---- 

----                                                              ---- 

----  Description                                                 ---- 

----    toplevel of a modular simultaneous exponentiation core    ----

----    using a pipelined montgommery multiplier with split       ----

----    pipeline and auto-run support                             ----

----                                                              ----

----  Dependencies:                                               ----

----    - mont_mult_sys_pipeline                                  ----

----    - operand_mem                                             ----

----    - fifo_primitive                                          ----

----    - mont_ctrl                                               ----

----                                                              ----

----  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_arith.all;

use ieee.std_logic_unsigned.all;

library mod_sim_exp;

use mod_sim_exp.mod_sim_exp_pkg.all;

use mod_sim_exp.std_functions.all;

-- toplevel of the modular simultaneous exponentiation core

-- contains an operand and modulus ram, multiplier, an exponent fifo

-- and control logic

entity mod_sim_exp_core is

  generic(

    C_NR_BITS_TOTAL   : integer := 1536;

    C_NR_STAGES_TOTAL : integer := 96;

    C_NR_STAGES_LOW   : integer := 32;

    C_SPLIT_PIPELINE  : boolean := true;

    C_FIFO_AW         : integer := 7;      -- Address width for FIFO pointers

    C_MEM_STYLE       : string  := "asym"; -- xil_prim, generic, asym are valid options

    C_FPGA_MAN        : string  := "xilinx"   -- xilinx, altera are valid options

  );

  port(

    core_clk : in  std_logic;

    reset    : in  std_logic;

      -- operand memory interface (plb shared memory)

    bus_clk      : in  std_logic;

    write_enable : in  std_logic; -- write data to operand ram

    data_in      : in  std_logic_vector (31 downto 0);  -- operand ram data in

    rw_address   : in  std_logic_vector (8 downto 0); -- operand ram address bus

    data_out     : out std_logic_vector (31 downto 0);  -- operand ram data out

    collision    : out std_logic; -- write collision

      -- op_sel fifo interface

    fifo_din    : in  std_logic_vector (31 downto 0); -- exponent fifo data in

    fifo_push   : in  std_logic;  -- push data in exponent fifo

    fifo_full   : out std_logic;  -- high if fifo is full

    fifo_nopush : out std_logic;  -- high if error during push

      -- control signals

    start          : in  std_logic; -- start multiplication/exponentiation

    exp_m          : in  std_logic; -- single multiplication if low, exponentiation if high

    ready          : out std_logic; -- calculations done

    x_sel_single   : in  std_logic_vector (1 downto 0); -- single multiplication x operand selection

    y_sel_single   : in  std_logic_vector (1 downto 0); -- single multiplication y operand selection

    dest_op_single : in  std_logic_vector (1 downto 0); -- result destination operand selection

    p_sel          : in  std_logic_vector (1 downto 0); -- pipeline part selection

    calc_time      : out std_logic;

    modulus_sel    : in  std_logic   -- selects which modulus to use for multiplications

  );

end mod_sim_exp_core;

architecture Structural of mod_sim_exp_core is

  -- constants

  constant nr_op : integer := 4;

  constant nr_m  : integer := 2;

  -- data busses

  signal xy : std_logic_vector(C_NR_BITS_TOTAL-1 downto 0);  -- x and y operand data bus RAM -> multiplier

  signal m  : std_logic_vector(C_NR_BITS_TOTAL-1 downto 0);  -- modulus data bus RAM -> multiplier

  signal r  : std_logic_vector(C_NR_BITS_TOTAL-1 downto 0);  -- result data bus RAM <- multiplier

  -- control signals

  signal op_sel         : std_logic_vector(1 downto 0); -- operand selection

  signal result_dest_op : std_logic_vector(1 downto 0); -- result destination operand

  signal mult_ready     : std_logic;

  signal start_mult     : std_logic;

  signal load_x         : std_logic;

  signal load_result    : std_logic;

  signal modulus_sel_i  : std_logic_vector(0 downto 0);

  signal core_ready     : std_logic;

  signal core_calc_time : std_logic;

  signal core_collision : std_logic;

  signal core_start     : std_logic;

  -- fifo signals

  signal fifo_empty : std_logic;

  signal fifo_pop   : std_logic;

  signal fifo_nopop : std_logic;

  signal fifo_dout  : std_logic_vector(31 downto 0);

begin

  -- check the parameters

  assert (C_MEM_STYLE="xil_prim" or C_MEM_STYLE="generic" or C_MEM_STYLE="asym")

    report "C_MEM_STYLE incorrect!, it must be one of these: xil_prim, generic or asym" severity failure;

  assert (C_FPGA_MAN="xilinx" or C_FPGA_MAN="altera")

    report "C_FPGA_MAN incorrect!, it must be one of these: xilinx or altera" severity failure;

  -- Block ram memory for storing the operands and the modulus

  the_memory : operand_mem

  generic map(

    width     => C_NR_BITS_TOTAL,

    nr_op     => nr_op,

    nr_m      => nr_m,

    mem_style => C_MEM_STYLE,

    device    => C_FPGA_MAN

  )

  port map(

    bus_clk        => bus_clk,

    data_in        => data_in,

    data_out       => data_out,

    rw_address     => rw_address,

    write_enable   => write_enable,

    op_sel         => op_sel,

    xy_out         => xy,

    m              => m,

    core_clk       => core_clk,

    result_in      => r,

    load_result    => load_result,

    result_dest_op => result_dest_op,

    collision      => core_collision,

    modulus_sel    => modulus_sel_i

  );

  modulus_sel_i(0) <= modulus_sel;

        result_dest_op <= dest_op_single when exp_m = '0' else "11"; -- in autorun mode we always store the result in operand3

  -- A fifo for exponentiation mode

  xil_prim_fifo : if C_MEM_STYLE="xil_prim" generate

    the_exponent_fifo : fifo_primitive

    port map(

      push_clk => bus_clk,

      pop_clk => core_clk,

      din    => fifo_din,

      dout   => fifo_dout,

      empty  => fifo_empty,

      full   => fifo_full,

      push   => fifo_push,

      pop    => fifo_pop,

      reset  => reset,

      nopop  => fifo_nopop,

      nopush => fifo_nopush

    );

  end generate;

  gen_fifo : if (C_MEM_STYLE = "generic") or (C_MEM_STYLE = "asym") generate

    the_exponent_fifo : entity mod_sim_exp.generic_fifo_dc_gray

    generic map(

      dw => 32,

      aw => C_FIFO_AW

    )

    port map(

      wr_clk => bus_clk,

      rd_clk => core_clk,

      din    => fifo_din,

      dout   => fifo_dout,

      empty  => fifo_empty,

      full   => fifo_full,

      we     => fifo_push,

      re     => fifo_pop,

      clr    => reset,

      nopop  => fifo_nopop,

      nopush => fifo_nopush

    );

  end generate;

  -- The actual multiplier

  the_multiplier : mont_multiplier

  generic map(

    n     => C_NR_BITS_TOTAL,

    t     => C_NR_STAGES_TOTAL,

    tl    => C_NR_STAGES_LOW,

    split => C_SPLIT_PIPELINE

  )

  port map(

    core_clk => core_clk,

    xy       => xy,

    m        => m,

    r        => r,

    start    => start_mult,

    reset    => reset,  -- asynchronious reset

    p_sel    => p_sel,

    load_x   => load_x,

    ready    => mult_ready

  );

  -- The control logic for the core

  the_control_unit : mont_ctrl

  port map(

    clk              => core_clk,

    reset            => reset, -- asynchronious reset

    start            => core_start,

    x_sel_single     => x_sel_single,

    y_sel_single     => y_sel_single,

    run_auto         => exp_m,

    op_buffer_empty  => fifo_empty,

    op_sel_buffer    => fifo_dout,

    read_buffer      => fifo_pop,

    done             => core_ready,

    calc_time        => core_calc_time,

    op_sel           => op_sel,

    load_x           => load_x,

    load_result      => load_result,

    start_multiplier => start_mult,

    multiplier_ready => mult_ready

  );

  -- go from bus clock domain to core clock domain

  start_pulse : pulse_cdc

  port map(

    reset  => reset,

    clkA   => bus_clk,

    pulseA => start,

    clkB   => core_clk,

    pulseB => core_start

  );

  -- go from core clock domain to bus clock domain

  ready_pulse : pulse_cdc

  port map(

    reset  => reset,

    clkA   => core_clk,

    pulseA => core_ready,

    clkB   => bus_clk,

    pulseB => ready

  );

  sync_to_bus_clk : clk_sync

  port map(

    sigA => core_calc_time,

    clkB => bus_clk,

    sigB => calc_time

  );

  collision_pulse : pulse_cdc

  port map(

    reset  => reset,

    clkA   => core_clk,

    pulseA => core_collision,

    clkB   => bus_clk,

    pulseB => collision

  );

end Structural;