Decoder ROM instructions for the ones counter VHDL microcontroller structural design Xilinx

 library IEEE;  
 use IEEE.STD_LOGIC_1164.ALL;  
 entity decRom2 is  
      Port (  address: in STD_LOGIC_VECTOR(3 downto 0);  
                  condition_select: out STD_LOGIC_VECTOR(1 downto 0);  
                     Functions: out STD_LOGIC_VECTOR(1 downto 0);  
              d_out: out STD_LOGIC_VECTOR(19 downto 0);  
                     done : out STD_LOGIC;  
                     Branch_ADDRESS_M : out STD_LOGIC_VECTOR(3 downto 0));  
 end decRom2;  
 -- Internal Architecture  
 architecture Behavioral of decRom2 is  
      signal delayVal: STD_LOGIC_VECTOR(19 downto 0);  
 --------ALU operation------------------------------  
 --     000          Complement A  
 --     001          And   
 --     010          XOR  
 --     011          or  
 --     100          Increment A  
 --     101          Add A+B  
 --     110          Decrement A  
 --     111          Subtract A-B  
 --------Shifter operation------------------------------  
 --     000          pass  
 --     001          rotate left  
 --     010          shift left input 0  
 --     011       shift left input 1  
 --     100          pass   
 --     101          rotate right  
 --     110          shift right input 0  
 --     111          shift right input 1  
      begin  
           with address select --Input enable 1bit,address where to write 3bits,write address enable 1bit, read address A 3bits,enableaddress A 1bit,read address B 3bits,enable address B 1bit, ALU operation 3bits, shift rotate 3 bits,output enable 1 bit  
                 delayVal <=  "0---0---0---0------0" when "0000",   
                                          "10001---0---0------0" when "0001",  
                                          "00101000100010100000" when "0010",  
                                   "00011010100001000000" when "0011",--0001  
                                   "00111000100110010000" when "0100",--0010  
                                   "00101010101111010000" when "0101",--0100  
                                   "00001000100010011100" when "0110",--0100  
                                   "00000010101010010001" when "0111",--1000  
                                   "00000000000000000000" when others;  
           d_out <= delayVal after 14 ns;  
           --FUNCTION---VALUE-----COUNTER------------------------------------------   
           --------------------  
           ----CA---- ---00---- LC=> 0     EN=>1                         Count alwas go to next state     n+1       
           ----CC---- ---01---- LC=> 0                EN=>condition           Next state if condition is true  
           ----BC---- ---10---- LC=> 1                EN=>contition           jump to random condition m if condition is true otherwise remain there in n  
           ----CBC--- ---11---- LC=> condition EN=>1                     Jum to another state if true otherwise continue n+1 state  
           -- DECIDE WHICH BRANCH FUNCTION TO USE  
           with address select       
           Functions <= "01" when "0000",   
                               "00" when "0001",  
                               "00" when "0010",  
                               "00" when "0011",  
                               "00" when "0100",  
                               "00" when "0101",  
                               "11" when "0110",  
                               "10" when "0111",  
                               "00" when others;  
 --CONDITION---VALUE--  
           --------------------  
           ----'1'----   ---00----      Condition alwas true continue       
           ----Start----  ---01----  Start  
           ----Datanot zero ---10----  If calculation are not finish loop to other states  
           ----not used--- ---11----    
           --DECIDE WHICH STATE TO GO IN WITH                      
           with address select  
           condition_select <= "01" when "0000",   
                               "--" when "0001",  
                               "--" when "0010",  
                               "--" when "0011",  
                               "--" when "0100",  
                               "--" when "0101",  
                               "10" when "0110",  
                               "00" when "0111",  
                               "00" when others;  
           -- IS PROGRAM DONE?  
           with address select  
           done <= '0' when "0000",   
                               '0' when "0001",  
                               '0' when "0010",  
                               '0' when "0011",  
                               '0' when "0100",  
                               '0' when "0101",  
                               '0' when "0110",  
                               '1' when "0111",  
                               '0' when others;  
           -- SELECT NEXT ADDRESS IF BRANCHING        
           with address select  
           Branch_ADDRESS_M <= "----" when "0000",   
                               "----" when "0001",  
                               "----" when "0010",  
                               "----" when "0011",  
                               "----" when "0100",  
                               "----" when "0101",  
                               "0100" when "0110",  
                               "0000" when "0111",  
                               "0000" when others;  
 end Behavioral;