2test16_Fct.vhd

--
-- Created on Wed 29 Mar 2017 16:02:16 PDT
-- 

library IEEE;
use IEEE.STD_LOGIC_1164.all;
use IEEE.STD_LOGIC_ARITH.all;


entity ROM_VHDL is
    port(
         clk      : in  std_logic;
         addr     : in  std_logic_vector (6 downto 0);
         data     : out std_logic_vector (15 downto 0)
         );
end ROM_VHDL;

architecture BHV of ROM_VHDL is

    type ROM_TYPE is array (0 to 127 ) of std_logic_vector (15 downto 0);

    constant rom_content : ROM_TYPE := (
	000 => "0000000000000000", -- NOP # CENG450
	001 => "0000000000000000", -- NOP # The factorial of IN input number
	002 => "0000000000000000", -- NOP # OUT(r1)=IN*(IN-1)*(IN-2)**2
	003 => "0000000000000000", -- NOP # This loop should run (N-1) times
	004 => "0000000000000000", -- NOP # The start of this program must be at address 0, make sure of the correct branching
	005 => "0010010000000001", -- LOADIMM.lower #1 
	006 => "0010011101111000", -- MOV r5, r7	-- r5 is the decrement value
	007 => "0010011001101000", -- MOV r1, r5 	-- r1 is the Factorial variable, so it is initialized to 1
	008 => "0010011110101000", -- MOV r6, r5 	-- r6 is initialized to 1, then its shifted to get 2
	009 => "0000101110000001", -- SHL r6#1 	-- the lowest value to be multiplied by (r6=2)
	010 => "0100001000000000", -- IN r0
	011 => "0000000000000000", -- NOP
	012 => "0000000000000000", -- NOP
	013 => "0000011001001000", -- Mul r1,r1,r0 -- the actual multiplication to find the factorial (IN!)
	014 => "0000010000000101", -- Sub r0,r0,r5 -- to move to the lower number (r0-1)
	015 => "0000010100000110", -- Sub r4,r0,r6 -- to check if r0 reaches 2
	016 => "0000000000000000", -- NOP
	017 => "0000000000000000", -- NOP
	018 => "0000111100000000", -- TEST r4 		-- IF negative 
	019 => "1000001000000011", -- BRR.N +3		-- goto OUT
	020 => "1000011101001011", -- BR r5,11		-- ElSE: r5=1, 11+1 Byte = 12 Word : goto 12
	021 => "0000000000000000", -- NOP
	022 => "0000000000000000", -- NOP
	023 => "0100000001000000", -- OUT r1 		-- Printout the Factorial
	024 => "0000000000000000", -- NOP
	025 => "1000000111101011", -- BRR -21		-- goto to the beginning 
	026 => "0000000000000000", -- NOP
	027 => "0000000000000000", -- NOP
	others => x"0000" ); -- NOP
begin

p1:    process (clk)
	 variable add_in : integer := 0;
    begin
        if rising_edge(clk) then
					 add_in := conv_integer(unsigned(addr));
                data <= rom_content(add_in);
        end if;
    end process;
end BHV;