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[/] [mod_sim_exp/] [tags/] [Release_1.1/] [rtl/] [vhdl/] [core/] [mont_ctrl.vhd] - Rev 49
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---------------------------------------------------------------------- ---- mont_ctrl ---- ---- ---- ---- This file is part of the ---- ---- Modular Simultaneous Exponentiation Core project ---- ---- http://www.opencores.org/cores/mod_sim_exp/ ---- ---- ---- ---- Description ---- ---- control unit for a pipelined montgomery multiplier, with ---- ---- split pipeline operation and "auto-run" support ---- ---- ---- ---- Dependencies: ---- ---- - autorun_cntrl ---- ---- ---- ---- 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; -- This module controls the montgommery mutliplier and controls traffic between -- RAM and multiplier. Also contains the autorun logic for exponentiations. entity mont_ctrl is port ( clk : in std_logic; reset : in std_logic; -- bus side start : in std_logic; x_sel_single : in std_logic_vector(1 downto 0); y_sel_single : in std_logic_vector(1 downto 0); run_auto : in std_logic; op_buffer_empty : in std_logic; op_sel_buffer : in std_logic_vector(31 downto 0); read_buffer : out std_logic; done : out std_logic; calc_time : out std_logic; -- multiplier side op_sel : out std_logic_vector(1 downto 0); load_x : out std_logic; load_result : out std_logic; start_multiplier : out std_logic; multiplier_ready : in std_logic ); end mont_ctrl; architecture Behavioral of mont_ctrl is signal start_d : std_logic; -- delayed version of start input signal start_pulse : std_logic; signal auto_start_pulse : std_logic; signal start_multiplier_i : std_logic; signal start_up_counter : std_logic_vector(2 downto 0) := "100"; -- used in op_sel at multiplier start signal calc_time_i : std_logic; -- high ('1') during multiplication signal x_sel : std_logic_vector(1 downto 0); -- the operand used as x input signal y_sel : std_logic_vector(1 downto 0); -- the operand used as y input signal x_sel_buffer : std_logic_vector(1 downto 0); -- x operand as specified by fifo buffer (autorun) signal auto_done : std_logic; signal start_auto : std_logic; signal auto_multiplier_done_i : std_logic; begin ----------------------------------------------------------------------------------- -- Processes related to starting and stopping the multiplier ----------------------------------------------------------------------------------- -- generate a start pulse (duration 1 clock cycle) based on ext. start sig START_PULSE_PROC: process(clk) begin if rising_edge(clk) then start_d <= start; end if; end process START_PULSE_PROC; start_pulse <= start and (not start_d); start_auto <= start_pulse and run_auto; -- to start the multiplier we first need to select the x_operand and -- clock it in the x shift register -- the we select the y_operand and start the multiplier -- start_up_counter -- default state : "100" -- at start pulse counter resets to 0 and counts up to "100" START_MULT_PROC: process(clk, reset) begin if reset = '1' then start_up_counter <= "100"; elsif rising_edge(clk) then if start_pulse = '1' or auto_start_pulse = '1' then start_up_counter <= "000"; elsif start_up_counter(2) /= '1' then start_up_counter <= start_up_counter + '1'; else start_up_counter <= "100"; end if; end if; end process; -- select operands (autorun/single run) x_sel <= x_sel_buffer when (run_auto = '1') else x_sel_single; y_sel <= "11" when (run_auto = '1') else y_sel_single; -- y is operand3 in auto mode -- clock operands to operand_mem output (first x, then y) with start_up_counter(2 downto 1) select op_sel <= x_sel when "00", -- start_up_counter="00x" (first 2 cycles) y_sel when others; -- load_x <= start_up_counter(0) and (not start_up_counter(1)); -- latch x operand if start_up_counter="x01" -- start multiplier when start_up_counter="x11" start_multiplier_i <= start_up_counter(1) and start_up_counter(0); start_multiplier <= start_multiplier_i; -- signal calc time is high during multiplication CALC_TIME_PROC: process(clk, reset) begin if reset = '1' then calc_time_i <= '0'; elsif rising_edge(clk) then if start_multiplier_i = '1' then calc_time_i <= '1'; elsif multiplier_ready = '1' then calc_time_i <= '0'; else calc_time_i <= calc_time_i; end if; end if; end process CALC_TIME_PROC; calc_time <= calc_time_i; -- what happens when a multiplication has finished load_result <= multiplier_ready; -- ignore multiplier_ready when in automode, the logic will assert auto_done when finished done <= ((not run_auto) and multiplier_ready) or auto_done; ----------------------------------------------------------------------------------- -- Processes related to op_buffer cntrl and auto_run mode -- start_auto -> start autorun mode operation -- auto_start_pulse <- autorun logic starts the multiplier -- auto_done <- autorun logic signals when autorun operation has finished -- x_sel_buffer <- autorun logic determines which operand is used as x -- check buffer empty signal ----------------------------------------------------------------------------------- -- multiplier_ready is only passed to autorun control when in autorun mode auto_multiplier_done_i <= (multiplier_ready and run_auto); autorun_control_logic : autorun_cntrl port map( clk => clk, reset => reset, start => start_auto, done => auto_done, op_sel => x_sel_buffer, start_multiplier => auto_start_pulse, multiplier_done => auto_multiplier_done_i, read_buffer => read_buffer, buffer_din => op_sel_buffer, buffer_empty => op_buffer_empty ); end Behavioral;
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