shiftregister.txt

来自「esta es muy buena ahora un shift registe」· 文本 代码 · 共 35 行

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;

entity test_shift is
  generic ( width : integer := 17 );
  port ( clk   : in  std_ulogic;
         reset : in  std_ulogic;
         load  : in  std_ulogic;
         en    : in  std_ulogic;
         inp   : in  std_logic_vector ( width downto 0 );
         outp  : out std_ulogic );
end test_shift;

architecture rtl of test_shift is
  signal shift_reg : unsigned ( width downto 0 );
begin

  outp <= shift_reg (shift_reg'high);

  shifter : process ( clk, reset )
  begin
    if ( reset = '0' ) then
      shift_reg <= (others => '0');
    elsif rising_edge ( clk ) then
      if (load = '1' ) then
        shift_reg <= unsigned (inp);
      elsif ( en = '1' ) then
        shift_reg <= rotate_left ( shift_reg, 1 );
      end if;
    end if;
  end process shifter;

end rtl;