yima.vhd

本程序利用VHDL语言实现拔河游戏机的功能

library ieee;
use ieee.std_logic_1164.all;

entity yima is
 port(a,b,c,d:in std_logic;
            y: inout std_logic_vector(14 downto 0));
end yima;

architecture one of yima is
signal indata:std_logic_vector (3 downto 0);
begin
 indata<=d&c&b&a;
 process(indata)
  begin
    case indata is
      when "0000"=>y<="000000010000000";
      when "0001"=>y<="000000100000000";
      when "0010"=>y<="000001000000000";
      when "0011"=>y<="000010000000000";
      when "0100"=>y<="000100000000000";
      when "0101"=>y<="001000000000000";
      when "0110"=>y<="010000000000000";
      when "0111"=>y<="100000000000000";
      when "1001"=>y<="000000000000001";
      when "1010"=>y<="000000000000010";
      when "1011"=>y<="000000000000100";
      when "1100"=>y<="000000000001000";
      when "1101"=>y<="000000000010000";
      when "1110"=>y<="000000000100000";
      when "1111"=>y<="000000001000000";
      when others=>y<="000000000000000";
  end case;
 end process;
end one;