library ieee;
|
|
use ieee.std_logic_1164.all;
|
|
use ieee.numeric_std.all;
|
|
|
|
|
|
|
|
entity alu is
|
|
port (
|
|
Reset_n_i : in std_logic;
|
|
Clk_i : in std_logic;
|
|
Opc_i : in std_logic_vector(1 downto 0);
|
|
DinA_i : in std_logic_vector(31 downto 0);
|
|
DinB_i : in std_logic_vector(31 downto 0);
|
|
Dout_o : out std_logic_vector(31 downto 0);
|
|
OverFlow_o : out std_logic
|
|
);
|
|
end entity alu;
|
|
|
|
|
|
|
|
architecture rtl of alu is
|
|
|
|
|
|
constant c_add : std_logic_vector(1 downto 0) := "00";
|
|
constant c_sub : std_logic_vector(1 downto 0) := "01";
|
|
constant c_and : std_logic_vector(1 downto 0) := "10";
|
|
constant c_or : std_logic_vector(1 downto 0) := "11";
|
|
|
|
|
|
begin
|
|
|
|
|
|
process (Reset_n_i, Clk_i) is
|
|
begin
|
|
if (Reset_n_i = '0') then
|
|
Dout_o <= (others => '0');
|
|
elsif (rising_edge(Clk_i)) then
|
|
case Opc_i is
|
|
when c_add => (OverFlow_o, Dout_o) <=
|
|
std_logic_vector(resize(unsigned(DinA_i), Dout_o'length+1) +
|
|
resize(unsigned(DinB_i), Dout_o'length+1));
|
|
when c_sub => (OverFlow_o, Dout_o) <=
|
|
std_logic_vector(resize(unsigned(DinA_i), Dout_o'length+1) -
|
|
resize(unsigned(DinB_i), Dout_o'length+1));
|
|
when c_and => Dout_o <= DinA_i and DinB_i;
|
|
when c_or => Dout_o <= DinA_i or DinB_i;
|
|
when others => null;
|
|
end case;
|
|
end if;
|
|
end process;
|
|
|
|
|
|
end architecture rtl;
|
|
|