select48.vhd

来自「出租车的计费系统」· VHDL 代码 · 共 36 行

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all;
use ieee.std_logic_unsigned.all;
entity select48 is
    port(d0,d1,d2,d3,d4,d5,d6,d7:in std_logic_vector(0 to 3);
         sel :in std_logic_vector(0 to 2);
         y:out std_logic_vector(0 to 3));
end select48;
architecture selt of select48 is
begin
    process(sel,d0,d1,d2,d3,d4,d5,d6,d7)
           begin 
                if sel="000"then
                   y<=d0;
                 elsif sel="001" then
                   y<=d1;
                 elsif sel="010" then
                   y<=d2;
                 elsif sel="011" then
                   y<=d3;
                 elsif sel="100" then
                   y<=d4;
                 elsif sel="101"then
                   y<=d5;
                 elsif sel="110" then
                   y<=d6;
                 elsif sel="111" then
                   y<=d7;
                 end if;
      end process;
end selt;