LIBRARY IEEE;
  USE IEEE.STD_LOGIC_1164.ALL;
  USE IEEE.STD_LOGIC_UNSIGNED.ALL;
ENTITY coma IS 
  PORT( clk,aj,af,bj,bf,rd: IN STD_LOGIC;
        sh: out STD_LOGIC_VECTOR (7 DOWNTO 0);
        al,ah,bl,bh: out STD_LOGIC_VECTOR (3 DOWNTO 0));
END coma;

ARCHITECTURE behav2 OF coma IS
signal amark,bmark:integer;
BEGIN
k2:PROCESS (rd,clk,amark,bmark)
     VARIABLE la,lb,ha,hb:STD_LOGIC_VECTOR (3 DOWNTO 0);
     VARIABLE at,bt:integer;
   BEGIN
     if rd='0' or amark=21 or bmark=21 then
        la:="0000";ha:="0000";at:=0;
        lb:="0000";hb:="0000";bt:=0;
     elsif clk'event and clk='1' then 
        if amark>at then
           if la="1001" then 
               la:="0000";at:=at+1;ha:=ha+1;
           else la:=la+1;at:=at+1;
           end if;
        elsif bmark>bt then
           if lb="1001" then 
               lb:="0000";bt:=bt+1;hb:=hb+1;
           else lb:=lb+1;bt:=bt+1;
           end if;
        end if;
      end if;
    al<=la;ah<=ha; bl<=lb;bh<=hb;
  end PROCESS k2;

k1:PROCESS (rd,clk,amark,bmark)
     VARIABLE sht:STD_LOGIC_VECTOR (7 DOWNTO 0);
     VARIABLE a,b:STD_LOGIC;
   BEGIN
     if rd='0' or amark=21 or bmark=21 then
        a:='0'; b:='0';sht:=(OTHERS=>'0');amark<=0;bmark<=0;
     elsif clk'event and clk='1' then 
        if a='0' and b='0' and af='0' then
           a:='1';sht:="10000000";
        elsif a='0' and b='0' and bf='0' then
           b:='1';sht:="00000001";
        elsif a='0' and b='1' then
           if sht<16 and sht/=0 then
               if aj='0' then 
                  bmark<=bmark+1;b:='0';sht:=(OTHERS=>'0');
               else sht:=sht(6 DOWNTO 0)&'0';
               end if;
           elsif sht=0 then
              bmark<=bmark+1;b:='0';
           else 
               if aj='0' then 
                  a:='1';b:='0';
               else 
                  sht:=sht(6 DOWNTO 0)&'0';  
                end if;
               end if;
        elsif a='1' and b='0' then
           if sht>8 then
               if bj='0' then 
                  amark<=amark+1;a:='0';sht:=(OTHERS=>'0');
               else sht:='0'&sht(7 DOWNTO 1);
               end if;
           elsif sht=0 then
              amark<=amark+1;a:='0';
           else 
                if bj='0' then 
                  a:='0';b:='1';
               else sht:='0'&sht(7 DOWNTO 1); 
               end if;
            end if;
        end if;
      end if;
     sh<=sht;
    end PROCESS k1;
end behav2;