使用有4个16位寄存器的组件和行波加法器组成一个16位加法器的VHDL代码

以下是使用4个16位寄存器和行波加法器组成的16位加法器的VHDL代码。

library IEEE;
use IEEE.STD_LOGIC_1164.all;

entity adder is
    port(
        A : in std_logic_vector(15 downto 0);
        B : in std_logic_vector(15 downto 0);
        Cin : in std_logic;
        Sum : out std_logic_vector(15 downto 0);
        Cout : out std_logic
    );
end entity;

architecture Behavioral of adder is

    -- 4 16-bit registers
    signal r1, r2, r3, r4 : std_logic_vector(15 downto 0);

begin

    -- Connect inputs to registers
    r1 <= A;
    r2 <= B;
    r3 <= (others => '0');
    r4 <= (others => '0');

    -- Row carry lookahead adder
    Sum <= r1 + r2 + r3 + r4 + (Cin => '0');
    Cout <= (r1(15) and r2(15)) or (r2(15) and r3(15)) or (r3(15) and r4(15)) or (r4(15) and r1(15)) or ((r1(15) or r2(15) or r3(15) or r4(15)) and Sum(15));

end architecture;

该代码实现了一个使用4个16位寄存器和行波加法器实现的16位加法器。该加法器可以将输入A和B相加，并在Sum输出端输出结果。Cin输入端用于指定初始进位值。Cout输出端表示加法器是否溢出。