VHDL未知标识符在numeric_std中"已签名"

Question

这些是我的声明.为什么它不识别签名类型？我导入了numeric_std库,在文档中我看到它支持signed和unsigned.这有什么不对？

library IEEE;
use IEEE.STD_LOGIC_1164.all;

use work.my_package.all;

entity landmark_1 is
  generic
        (data_length :integer := 8;
        address_length:integer:=3 );
        port ( clk:in std_logic;
        vin:in std_logic;
        rst:in std_logic;
        flag: in std_logic;
        din: in signed(data_length -1 downto 0)

        done: out std_logic
        );
end landmark_1;

Answer 1

尽力包括 use ieee.numeric_std.all;