vhdl - 異なるプロセス間で値を共有するための vhdl の変数またはシグナル

Question

2 つのプロセス間で値 (a real) を共有する必要がありますが、コードを実行しようとするとquartusエラーが発生します。

library IEEE;
USE ieee.std_logic_1164.all; 
USE ieee.std_logic_arith.all; 
USE ieee.std_logic_unsigned.all; 
use IEEE.MATH_REAL.ALL;

entity de0nano is
port (
 CLOCK_50      : in  std_logic;
KEY           : in  std_logic_vector(1 downto 0);
 SW            : in  std_logic_vector(3 downto 0);
 LED           : out std_logic_vector(7 downto 0);
 GPIO           : inout std_logic_vector(35 downto 0)


  );
end de0nano;

architecture struct of de0nano is
--declarations
signal   PN                 :  real :=0.0 ;
signal   PR                 :  real :=0.0 ;
signal   RC             :  integer :=1;
signal   NC             :  integer :=1;
signal   BET                :  integer :=1;


begin
count : process (CLOCK_50, GPIO)
begin 
 --A <= KEY(0);
 GPIO(24) <= '1';
--functional coding
LED <= "00011000";
 if (pn > pr) then
GPIO(26) <= '1';
LED <= "00000001";
else
GPIO(26) <= '0';                    
    end if;
 if (pn = pr) then
GPIO(26) <= '1';
LED <= "00000010";
else
GPIO(26) <= '0';                    
end if;
 if (pn < pr) then
GPIO(26) <= '1';
LED <= "00000011";
else
GPIO(26) <= '0';                    
end if;

end process;

probabilityController : process (CLOCK_50, KEY)
begin
--stato iniziale
if((RC + NC + BET)=1) then
pr <= 0.5;
pn <= 0.5;
end if;
--sequenza rossi consecutivi
if(RC>0) then
pr <= (5)**RC;
pn <= 1- (5)**RC;
end if;
--sequenza neri consecutivi
if(NC>0) then
pr <= (5)**NC;
pn <= 1- (5)**NC;
end if;

end process;

betController : process (CLOCK_50)
begin

end process;

colorController : process (CLOCK_50, KEY)
begin
if(KEY(0)='1') then
NC<=0;
RC <= RC+1;
end if;

if(KEY(1)='1') then
RC<=0;
NC <= NC+1;
end if;


end process;

end str

2 つの異なるプロセスから同じシグナル/変数を操作するにはどうすればよいですか?