VHDL程序里头出现这句错误

我的程序出现了这句错误：Error (10500): VHDL syntax error at counter.vhd(80) near text "PROCESS";  expecting "if"。该如何改？？？急！！！

源程序：

LIBRARY IEEE;

USE IEEE.STD_LOGIC_1164.ALL;

USE IEEE.STD_LOGIC_UNSIGNED.ALL;

ENTITY counter IS

PORT(rst:in std_logic;

ADD: IN STD_LOGIC;

CHOS:IN STD_LOGIC_VECTOR(3 DOWNTO 0);   

A2,A1,A0:OUT STD_LOGIC_VECTOR(3 DOWNTO 0);

B2,B1,B0:OUT STD_LOGIC_VECTOR(3 DOWNTO 0);

C2,C1,C0:OUT STD_LOGIC_VECTOR(3 DOWNTO 0);

D2,D1,D0:OUT STD_LOGIC_VECTOR(3 DOWNTO 0));

END counter;

ARCHITECTURE rtl OF counter IS

BEGIN

PROCESS(rst,ADD,CHOS)   

VARIABLE POINTS_A2:STD_LOGIC_VECTOR(3 DOWNTO 0);   

VARIABLE POINTS_A1:STD_LOGIC_VECTOR(3 DOWNTO 0);   

VARIABLE POINTS_B2:STD_LOGIC_VECTOR(3 DOWNTO 0);   

VARIABLE POINTS_B1:STD_LOGIC_VECTOR(3 DOWNTO 0);   

VARIABLE POINTS_C2:STD_LOGIC_VECTOR(3 DOWNTO 0);   

VARIABLE POINTS_C1:STD_LOGIC_VECTOR(3 DOWNTO 0);   

VARIABLE POINTS_D2:STD_LOGIC_VECTOR(3 DOWNTO 0);  

VARIABLE POINTS_D1:STD_LOGIC_VECTOR(3 DOWNTO 0);  

BEGIN

IF rst='0' then           ---加分信号上升沿有效

points_a2:="0001";points_a1:="0000";

points_b2:="0001";points_b1:="0000";

points_c2:="0001";points_c1:="0000";

points_d2:="0001";points_d1:="0000";

elsif (ADD'EVENT AND ADD='1') THEN      

if chos="0001" then           ---A组答对，加10分

  IF POINTS_A1= "1001" then              --十位为9

  POINTS_A1:="0000";

else POINTS_A2:=POINTS_A2+"0001";                   ----十位清零

IF points_a2="1001" then           ----百位为9

POINTS_A2:="0000";

else POINTS_A1:=(POINTS_A1)+"0001";

end if;                    ----百位清零

END IF;

IF (CHOS="0010") THEN

IF POINTS_B1="1001" THEN

   else POINTS_B1:="0000";

POINTS_B2:=POINTS_B2+"0001";

   IF POINTS_B2="1001" THEN

POINTS_B2:="0000";

       else POINTS_B1:=POINTS_B1+"0001";

END IF;

end if;

IF CHOS="0010" THEN

IF POINTS_C1="1001" THEN

   POINTS_C1:="0000";

else POINTS_C2:=POINTS_C2+"0001";

   IF POINTS_C2="1001" THEN

        POINTS_C2:="0000";

else POINTS_C1:=POINTS_C1+"0001";

END IF;

end if;

IF CHOS="0010" THEN

IF POINTS_D1="1001" THEN

  POINTS_D1:="0000";

else POINTS_D2:=POINTS_D2+"0001";

   IF POINTS_D2="1001" THEN

       POINTS_D2:="0000";

else POINTS_D1:=POINTS_D1+"0001";

END IF;

END IF;

END IF;

   A2<=POINTS_A2;  -------将各组得分赋给输出信号

A1<=POINTS_A1;

A0<="0000";

B2<=POINTS_B2;

B1<=POINTS_B1;

B0<="0000";

   C2<=POINTS_C2;

C1<=POINTS_C1;

C0<="0000";

   D2<=POINTS_D2;

D1<=POINTS_D1;

D0<="0000";

end if;

end process;

END rtl;



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