ex_p13_is_xz.vhd

来自「This is the course for VHDL programming」· VHDL 代码 · 共 25 行

library IEEE;
use IEEE.std_logic_1164.all;
entity IS_XZ_TEST is end IS_XZ_TEST;
architecture A of IS_XZ_TEST is
   function IS_XZ(a:STD_LOGIC_VECTOR) 
      return boolean is
	begin
		for i in a'range loop
		if (a(i)='X') or (a(i)='Z')then
		 return true;end if;
		end loop;
		return false;
   end IS_XZ;
begin
    process
        variable x:boolean;
    begin
        x := IS_XZ("11110000");
        report boolean'image(x);
        x := IS_XZ("111ZX000");
        report boolean'image(x);
        wait;
    end process;
end A;