labb8.vhd.bak

this is vhdl program for two address method

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;

entity greatest is
   port(pb1,pb2,st,clk:in std_logic;
        input:in std_logic_vector(7 downto 0);
        --sum:out std_logic_vector(15 downto 0);
       number:out std_logic_vector(15 downto 0);
       done: out std_logic);-- can be sum or largest
end greatest;

Architecture greatest_arch of greatest is
signal state,next_state:integer range 0 to 3;
signal v,adder,load_reg1,count_out,comparator_out,load_max_reg:std_logic:='0';
signal reg1,max_reg:std_logic_vector(6 downto 0):=(others=>'0');
signal sum_out:std_logic_vector(15 downto 0):=(others=>'0');
signal count:std_logic_vector(2 downto 0):=(others=>'0');

begin

process(state,v,count_out,comparator_out,st,input)
  begin
    load_reg1<='0';adder<='0';load_max_reg<='0';done<='0';
    case state is
    when 0 => if(st='1') then
               next_state<=1;
             else
                next_state<=0;
              end if;
  when 1 => if(v='1') then
             load_reg1<='1';
             adder<='1';
             next_state<=2;
           else
             load_reg1<='0';
             adder<='0';
             next_state<=1;
           end if;
when 2=> if(count_out='1')then
         next_state<=3;
       else
           if(comparator_out='1')then
            load_max_reg<='1';
            
          else
            load_max_reg<='0';
        end if;
        next_state<=1;
      end if;
when 3=>if(st='1')then
        next_state<=3;
      else
           next_state<=0;
           done<='1';
         end if;
end case;
end process;


process(clk)
begin
if(clk'event and clk='1')then
    state<=next_state;
    if(load_reg1='1')then
      reg1<=input(6 downto 0);
      count<=count+1;end if;
  if(load_max_reg ='1')then
    max_reg<=reg1;end if;
    
    
            
            
   end if;
   
 end process;
 count_out<='1' when count="111" else '0';
 v<='1' when input(7)='1'else '0';
 comparator_out<='1' when (reg1>max_reg)else '0';
 sum_out<=sum_out+reg1 when (adder='1') else sum_out;
 number<=sum_out when(pb1='1') else 
          "000000000"& max_reg when (pb2='1') else (others=>'0');
          
  end greatest_arch;