帮忙看下手动输入值，然后进行倒计时的程序，小弟刚刚开始学，希望大家帮帮忙

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
use ieee.std_logic_arith.all;
entity jian60 is
port(clk:in std_logic;
     start:in std_logic;--倒计时开始
     reset:in std_logic;--复位信号
     daojishi:in std_logic;--倒计时使能
     shishuru,geshuru:in std_logic_vector(3 downto 0);
     coutut std_logic;
     shi,geut std_logic_vector(3 downto 0));  
end;

architecture a of jian60 is
signal i,j:std_logic_vector(3 downto 0);
begin
process(clk,daojishi,start)
  begin
  if (reset='1') then i<="0000";j<="0000";
  elsif (daojishi='1' and start='0') then
    i<=shishuru;
    j<=geshuru;
  elsif rising_edge(clk) then
   if start='1' then
    if j="0000" then j<="1001";
     if i="0000" then cout<='1';i<="0101";
          else i<=i-1;cout<='0';   
     end if;
    else j<=j-1;
end if;   
end if;
end if;
shi<=i;
ge<=j;
end process;
end;
报错：Only one clock enable signal can be defined for a  flipflop

你觉得你这样的代码能综合成怎么样的电路?想不出来就打回去重写代码。
标准写法是这样的
if (！rst)
...
elsif rising_edge(clk) then
  if xxx then
    ...
  else
    ...
  end if;
end if;