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--! @file
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--! @file
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--! @brief Arithmetic logic unit http://en.wikipedia.org/wiki/Arithmetic_logic_unit
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--! @brief Arithmetic logic unit http://en.wikipedia.org/wiki/Arithmetic_logic_unit
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--! Use standard library
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--! Use standard library and import the packages (std_logic_1164,std_logic_unsigned,std_logic_arith)
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library IEEE;
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library IEEE;
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use IEEE.STD_LOGIC_1164.ALL;
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use ieee.std_logic_1164.all;
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use ieee.std_logic_unsigned.all;
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use ieee.std_logic_arith.all;
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--! Use CPU Definitions package
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--! Use CPU Definitions package
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library pkgOpenCPU32;
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use work.pkgOpenCPU32.all;
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--! ALU is a digital circuit that performs arithmetic and logical operations.
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--! ALU is a digital circuit that performs arithmetic and logical operations.
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--! ALU is a digital circuit that performs arithmetic and logical operations. It's the fundamental part of the CPU
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--! ALU is a digital circuit that performs arithmetic and logical operations. It's the fundamental part of the CPU
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entity Alu is
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entity Alu is
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Port ( A : in STD_LOGIC_VECTOR (7 downto 0); --! Alu Operand 1
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generic (n : integer := nBits - 1);
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B : in STD_LOGIC_VECTOR (7 downto 0); --! Alu Operand 2
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Port ( A : in STD_LOGIC_VECTOR (n downto 0); --! Alu Operand 1
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S : out STD_LOGIC_VECTOR (7 downto 0); --! Alu Output
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B : in STD_LOGIC_VECTOR (n downto 0); --! Alu Operand 2
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sel : in STD_LOGIC_VECTOR (2 downto 0)); --! Select operation
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S : out STD_LOGIC_VECTOR (n downto 0); --! Alu Output
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sel : in aluOps); --! Select operation
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end Alu;
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end Alu;
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--! @brief Architure definition of the ALU
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--! @brief Architure definition of the ALU
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--! @details More details about this mux element.
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--! @details More details about this mux element.
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architecture Behavioral of Alu is
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architecture Behavioral of Alu is
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begin
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begin
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--! Behavior description of combinational circuit (Can not infer any FF(Flip flop))
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process (A,B,sel) is
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begin
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case sel is
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when alu_sum =>
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S <= A + B;
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when alu_sub =>
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S <= A - B;
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when alu_inc =>
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S <= A - B;
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when alu_dec =>
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S <= A - B;
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when alu_and =>
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S <= A and B;
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when alu_or =>
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S <= A or B;
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when alu_xor =>
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S <= A xor B;
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when others =>
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S <= (others => 'Z');
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end case;
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end process;
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end Behavioral;
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end Behavioral;
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