library IEEE;
use IEEE.std_logic_1164.all;
use IEEE.numeric_std.all;

package MY_PACKAGE is
    procedure wave_gen (signal clk: out std_logic);
    procedure exec_inst(signal idle : in std_logic; signal clk : out std_logic);

end MY_PACKAGE;

package body MY_PACKAGE is
    procedure wave_gen (signal clk: out std_logic) is
    begin
        clk    <= '0';
            wait for 10 ns;
        clk    <= '1';
        wait for 10 ns;
    end wave_gen;

    procedure exec_inst(signal idle : in std_logic; signal clk : out std_logic) is
    begin
        wave_gen(clk);
        while idle = '0' loop
            wave_gen(clk);
        end loop;
    end exec_inst;

end MY_PACKAGE;