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library mod_sim_exp;
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library mod_sim_exp;
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use mod_sim_exp.mod_sim_exp_pkg.all;
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use mod_sim_exp.mod_sim_exp_pkg.all;
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-- This module controls the montgommery mutliplier and controls traffic between
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-- RAM and multiplier. Also contains the autorun logic for exponentiations.
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entity mont_ctrl is
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entity mont_ctrl is
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port (
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port (
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clk : in std_logic;
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clk : in std_logic;
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reset : in std_logic;
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reset : in std_logic;
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-- bus side
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-- bus side
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);
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);
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end mont_ctrl;
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end mont_ctrl;
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architecture Behavioral of mont_ctrl is
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architecture Behavioral of mont_ctrl is
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signal start_delayed_i : std_logic; -- delayed version of start input
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signal start_d : std_logic; -- delayed version of start input
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signal start_pulse_i : std_logic;
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signal start_pulse : std_logic;
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signal auto_start_pulse_i : std_logic;
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signal auto_start_pulse : std_logic;
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signal start_multiplier_i : std_logic;
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signal start_multiplier_i : std_logic;
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signal start_up_counter_i : std_logic_vector(2 downto 0) := "100"; -- used in op_sel at multiplier start
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signal start_up_counter : std_logic_vector(2 downto 0) := "100"; -- used in op_sel at multiplier start
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signal auto_start_i : std_logic := '0';
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signal store_autorun_i : std_logic;
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signal run_auto_i : std_logic;
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signal run_auto_stored_i : std_logic := '0';
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signal single_start_pulse_i : std_logic;
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signal calc_time_i : std_logic; -- high ('1') during multiplication
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signal calc_time_i : std_logic; -- high ('1') during multiplication
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signal x_sel_i : std_logic_vector(1 downto 0); -- the operand used as x input
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signal x_sel : std_logic_vector(1 downto 0); -- the operand used as x input
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signal y_sel_i : std_logic_vector(1 downto 0); -- the operand used as y input
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signal y_sel : std_logic_vector(1 downto 0); -- the operand used as y input
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signal x_sel_buffer_i : std_logic_vector(1 downto 0); -- x operand as specified by fifo buffer (autorun)
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signal x_sel_buffer : std_logic_vector(1 downto 0); -- x operand as specified by fifo buffer (autorun)
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signal auto_done_i : std_logic;
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signal auto_done : std_logic;
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signal start_auto_i : std_logic;
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signal start_auto : std_logic;
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signal new_buf_part_i : std_logic;
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signal new_buf_word_i : std_logic;
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signal buf_part_i : std_logic_vector(3 downto 0);
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signal pop_i : std_logic;
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signal start_autorun_cycle_i : std_logic;
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signal start_autorun_cycle_1_i : std_logic;
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signal autorun_counter_i : std_logic_vector(1 downto 0);
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signal part_counter_i : std_logic_vector(2 downto 0);
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signal auto_multiplier_done_i : std_logic;
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signal auto_multiplier_done_i : std_logic;
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begin
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begin
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-----------------------------------------------------------------------------------
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-----------------------------------------------------------------------------------
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-----------------------------------------------------------------------------------
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-----------------------------------------------------------------------------------
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-- generate a start pulse (duration 1 clock cycle) based on ext. start sig
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-- generate a start pulse (duration 1 clock cycle) based on ext. start sig
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START_PULSE_PROC: process(clk)
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START_PULSE_PROC: process(clk)
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begin
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begin
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if rising_edge(clk) then
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if rising_edge(clk) then
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start_delayed_i <= start;
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start_d <= start;
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end if;
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end if;
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end process START_PULSE_PROC;
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end process START_PULSE_PROC;
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start_pulse_i <= start and (not start_delayed_i);
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start_pulse <= start and (not start_d);
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single_start_pulse_i <= start_pulse_i and (not run_auto_i);
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start_auto <= start_pulse and run_auto;
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start_auto_i <= start_pulse_i and run_auto_i;
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-- to start the multiplier we first need to select the x_operand and
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-- to start the multiplier we first need to select the y_operand and
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-- clock it in the x shift register
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-- clock it in the y_register
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-- the we select the y_operand and start the multiplier
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-- the we select the x_operand and start the multiplier
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-- start_up_counter
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-- default state : "100"
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-- at start pulse counter resets to 0 and counts up to "100"
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START_MULT_PROC: process(clk, reset)
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START_MULT_PROC: process(clk, reset)
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begin
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begin
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if reset = '1' then
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if reset = '1' then
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start_up_counter_i <= "100";
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start_up_counter <= "100";
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elsif rising_edge(clk) then
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elsif rising_edge(clk) then
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if start_pulse_i = '1' or auto_start_pulse_i = '1' then
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if start_pulse = '1' or auto_start_pulse = '1' then
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start_up_counter_i <= "000";
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start_up_counter <= "000";
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elsif start_up_counter_i(2) /= '1' then
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elsif start_up_counter(2) /= '1' then
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start_up_counter_i <= start_up_counter_i + '1';
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start_up_counter <= start_up_counter + '1';
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else
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else
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start_up_counter_i <= "100";
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start_up_counter <= "100";
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end if;
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end if;
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else
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else
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start_up_counter_i <= start_up_counter_i;
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start_up_counter <= start_up_counter;
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end if;
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end if;
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end process;
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end process;
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-- select operands (autorun/single run)
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-- select operands (autorun/single run)
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x_sel_i <= x_sel_buffer_i when (run_auto_i = '1') else x_sel_single;
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x_sel <= x_sel_buffer when (run_auto = '1') else x_sel_single;
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y_sel_i <= "11" when (run_auto_i = '1') else y_sel_single; -- y is operand3 in auto mode
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y_sel <= "11" when (run_auto = '1') else y_sel_single; -- y is operand3 in auto mode
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-- clock operands to operand_mem output (first y, then x)
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-- clock operands to operand_mem output (first x, then y)
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with start_up_counter_i(2 downto 1) select
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with start_up_counter(2 downto 1) select
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op_sel <= y_sel_i when "00",
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op_sel <= x_sel when "00", -- start_up_counter="00x" (first 2 cycles)
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x_sel_i when others;
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y_sel when others; --
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load_x <= start_up_counter_i(0) and (not start_up_counter_i(1));
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load_x <= start_up_counter(0) and (not start_up_counter(1)); -- latch x operand if start_up_counter="x01"
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-- start multiplier
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start_multiplier_i <= start_up_counter_i(1) and start_up_counter_i(0);
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-- start multiplier when start_up_counter="x11"
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start_multiplier_i <= start_up_counter(1) and start_up_counter(0);
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start_multiplier <= start_multiplier_i;
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start_multiplier <= start_multiplier_i;
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-- signal calc time is high during multiplication
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-- signal calc time is high during multiplication
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CALC_TIME_PROC: process(clk, reset)
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CALC_TIME_PROC: process(clk, reset)
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begin
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begin
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end process CALC_TIME_PROC;
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end process CALC_TIME_PROC;
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calc_time <= calc_time_i;
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calc_time <= calc_time_i;
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-- what happens when a multiplication has finished
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-- what happens when a multiplication has finished
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load_result <= multiplier_ready;
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load_result <= multiplier_ready;
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-- ignore multiplier_ready when in automode, the logic will assert auto_done_i when finished
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-- ignore multiplier_ready when in automode, the logic will assert auto_done when finished
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done <= ((not run_auto_i) and multiplier_ready) or auto_done_i;
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done <= ((not run_auto) and multiplier_ready) or auto_done;
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-----------------------------------------------------------------------------------
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-----------------------------------------------------------------------------------
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-- Processes related to op_buffer cntrl and auto_run mode
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-- Processes related to op_buffer cntrl and auto_run mode
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-- start_auto_i -> start autorun mode operation
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-- start_auto -> start autorun mode operation
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-- auto_start_pulse <- autorun logic starts the multiplier
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-- auto_start_pulse <- autorun logic starts the multiplier
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-- auto_done <- autorun logic signals when autorun operation has finished
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-- auto_done <- autorun logic signals when autorun operation has finished
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-- x_sel_buffer_i <- autorun logic determines which operand is used as x
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-- x_sel_buffer <- autorun logic determines which operand is used as x
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-- check buffer empty signal
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-- check buffer empty signal
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-----------------------------------------------------------------------------------
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-----------------------------------------------------------------------------------
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-- at the beginning of each new multiplication we store the current autorun bit
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-- STORE_AUTORUN_PROC: process(clk)
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-- begin
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-- if rising_edge(clk) then
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-- if store_autorun_i = '1' then
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-- run_auto_stored_i <= run_auto;
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-- else
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-- run_auto_stored_i <= run_auto_stored_i;
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-- end if;
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-- end if;
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-- end process STORE_AUTORUN_PROC;
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run_auto_i <= run_auto;
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-- multiplier_ready is only passed to autorun control when in autorun mode
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-- multiplier_ready is only passed to autorun control when in autorun mode
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auto_multiplier_done_i <= (multiplier_ready and run_auto_i);
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auto_multiplier_done_i <= (multiplier_ready and run_auto);
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autorun_control_logic : autorun_cntrl port map(
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autorun_control_logic : autorun_cntrl port map(
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clk => clk,
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clk => clk,
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reset => reset,
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reset => reset,
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start => start_auto_i,
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start => start_auto,
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done => auto_done_i,
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done => auto_done,
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op_sel => x_sel_buffer_i,
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op_sel => x_sel_buffer,
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start_multiplier => auto_start_pulse_i,
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start_multiplier => auto_start_pulse,
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multiplier_done => auto_multiplier_done_i,
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multiplier_done => auto_multiplier_done_i,
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read_buffer => read_buffer,
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read_buffer => read_buffer,
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buffer_din => op_sel_buffer,
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buffer_din => op_sel_buffer,
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buffer_empty => op_buffer_empty
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buffer_empty => op_buffer_empty
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);
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);
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