求教，仿真就出错了-空有一腔热血的回答

求教，仿真就出错了

2019-07-15 21:42发布

library ieee;
use ieee.std_logic_1164.all;

entity first is
      port(x:in std_logic_vector(1 downto 0);
                     y:out std_logic_vector(1 downto 0));
      end first;

architecture behave of first is
      begin
            y(1)<=x(1);
            y(0)<=x(0);

      end behave;

QQ图片20170516091749.png