--core_design
--instruction memory
--all right reserved
--rom tyoe

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

package rom_pack is
constant rom_high:integer:=320;
subtype rom_range is integer range 0 to rom_high;
subtype rom_word is std_logic_vector(7 downto 0);
type rom_type is array(rom_range) of rom_word;
constant rom:rom_type:=(
    ("00000000"),("00000000"),("00000000"),("10110000"),("00000001"),("00000000"),("00000000"),("10110000"),
    ("00000010"),("00000000"),("00000000"),("10110000"),("00000011"),("00000000"),("00000000"),("10110000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000001"),("00000000"),("11100101"),("10110100"),("00000010"),("00000000"),("10100111"),("10110100"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00001000"),("10100111"),("10000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000110"),("00000000"),("00000001"),("10110000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),("00000000"),
    ("00000000"));
end rom_pack;   		        

library ieee;
use ieee.std_logic_1164.all;
use work.rom_pack.all;

entity ins_rom is
   generic(ins_rom_delay:time:=3 ns);
   port(clk:in std_logic;
        a:in std_logic_vector(31 downto 0);
        readdata:out std_logic_vector(31 downto 0)
       );
end ins_rom;

architecture mem_core of ins_rom is
function logic2int(din:std_logic_vector(7 downto 0)) return rom_range is
    variable result:rom_range:=0;
  begin
    for i in 0 to 7 loop 
      if din(i)='1' then
        result:=result+2**i;
      end if;
    end loop;
    return result;
end logic2int;

begin
 process(clk)
   variable b:rom_range;
   begin
    if clk'event and clk='1' then
     if logic2int(a(7 downto 0))>320 then
       b:=320;
     else 
       b:=logic2int(a(7 downto 0));
     end if;
      readdata(7 downto 0)<=rom(b) after ins_rom_delay;
      readdata(15 downto 8)<=rom(b+1) after ins_rom_delay;
      readdata(23 downto 16)<=rom(b+2) after ins_rom_delay;
      readdata(31 downto 24)<=rom(b+3) after ins_rom_delay;
    end if;
 end process;
end mem_core;