--This module implements an algorithm for countring the number of 1's in a word
--stored in MEM[256] and places the solution into MEM[257]

--This program taken from a lab done in CS61
--by Ron Feliciano

library IEEE;
use IEEE.std_logic_1164.all;
use IEEE.std_logic_unsigned.all;
use IEEE.std_logic_arith.all;

entity ram_module is
   port(clk      : in std_logic;
      enable     : in std_logic;
      R_W        : in std_logic;
      addr       : in std_logic_vector (15 downto 0);  
      data_in    : in std_logic_vector (15 downto 0);	
      data_out   : out std_logic_vector (15 downto 0));

end ram_module;	

-- Read is 1
-- Write is 0

architecture BHV of ram_module is	   

type memory is array (0 to 333) of std_logic_vector(15 downto 0);


signal reg : memory := (


   "1010001000001111",		--LDI R1 x000F
   "0101011011100000",		--AND R3 R3 x0000
   "0101111111100000",		--AND R7 R7 x0000
   "0010010000001110",		--LD R2 x000E
   "0010100000010000",		--LD R4	x0010
   "0101011010000001",		--AND R3 R2 R1
   "0000010000001000",		--BRz x0008
   "0001111111100001",		--ADD R7 R7 x0001
   "0001010010000010",		--ADD R2 R2 R2
   "0001100100111111",		--ADD R4 R4 xFFFF
   "0000001000000101",		--BRp x0005
   "0010000000010001",		--LD R0 x0011
   "0111111000000000",		--STR R7 x0000
   "1111000000100101",		--HALT
   "0000000000000001",
   "0000000100000000",
   "0000000000010000",
   "0000000100000001",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",		--30
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",		--45
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",		--60
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",		--75
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",		--90
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000001",
   "0000000000000001",
   "0000000000000001",
   "0000000000000001",
   "0000000000000001",
   "0000000000000001",		--105
   "0000000000000001",
   "0000000000000001",
   "0000000000000001",
   "0000000000000001",
   "0000000000000001",
   "0000000000000001",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",		--120
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",						 	
   "0000000000000000",		
   "0000000000000000",		
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",		
   "0000000000000000",		
   "0000000000000000",		
   "0000000000000000",		
   "0000000000000000",					
   "0000000000000000",		
   "0000000000000000",		
   "0000000000000000",	  
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",		
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",		
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",		
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",		
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",		
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",		
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000001",
   "0000000000000001",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",						 	
   "0000000000000000",		
   "0000000000000000",		
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",		
   "0000000000000000",		
   "0000000000000000",		
   "0000000000000000",		
   "0000000000000000",					
   "0000000000000000",		
   "0000000000000000",		
   "0000000000000000",	  
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",		
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000001",		--interger
   "0000000000100001",		--interger
   "0000000000000001",		--interger
   "0000000000000001",		--interger
   "0000000000000001",		--interger
   "0000000000000001",		--interger
   "0000000000000001",		--interger
   "0000000000000001",		--interger
   "0000000000000001",		--interger
   "0000000000000001",		--interger
   "0000000000000001",		--interger
   "0000000000000001",		--interger
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",		
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",		
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",		
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",		
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000000",
   "0000000000000001",
   "0000000000000001"
   );	 

begin
process(clk, enable, R_W, addr)
   begin
	
   if (enable = '1') then
      if (clk = '1' and clk' event) then 	
         if (R_W = '1') then
            data_out <= reg(conv_integer(addr));
         else
            reg(conv_integer(addr)) <=  data_in;
         end if;	
      else 
      end if;	
   end if;
			
end process;
end BHV;