cpu/src/r_w_ram_b.vhd

   1 library ieee;
   2
   3 use IEEE.std_logic_1164.all;
   4 use IEEE.numeric_std.all;
   5
   6 use work.mem_pkg.all;
   7
   8 architecture behaviour of r_w_ram is
   9
  10         subtype RAM_ENTRY_TYPE is std_logic_vector(DATA_WIDTH -1 downto 0);
  11         type RAM_TYPE is array (0 to (2**ADDR_WIDTH)-1) of RAM_ENTRY_TYPE;
  12
  13                                                                         -- r0 = 0, r1 = 1, r2 = 3, r3 = A
  14
  15         signal ram : RAM_TYPE := (  0 => "11100000000100001000000000000000", --add r2, r1, r0    => r2 = 1
  16                                     1 => "11100000000110001000000000000000", --add r3, r1, r0    => r3 = 1
  17                                     2 => "11100000001000011001000000000000", --add r4, r3, r2    => r4 = 2
  18                                     3 => "11100000000100001000000000000000", --add r2, r1, r0    => r2 = 1
  19                                     4 => "11100000000110001000000000000000", --add r3, r1, r0    => r3 = 1
  20                                     5 => "11100000001000011001000000000000", --add r4, r3, r2    => r4 = 2
  21                                     6 => "11101100000000001000000000000000", --cmp r0 , r1       => 0-1 => 0100
  22                                     7 => "00000000001010101010000000000001", --addnqd r5, r5, r4 => r5 = 2
  23                                     8 => "00000000001010101010000000000000", --addnq r5, r5, r4  => r5 = 4
  24                                     9 => "11101100001000100000000000000000", --cmp r4 , r4       => 2-2 => 1001
  25                                    10 => "00000001001100001000000001010000", --addinq r6, r1, 0xA => nix
  26                                    11 => "00010001001100001000000001010000", --addieq r6, r1, 0xA => r6 = 0xB
  27                                    12 => "00010001101100110000000001010000", --subieq r6, r5, 0xA => r6 = 1
  28                                    13 => "11100000000100001000000000000000", --add r2, r1, r0     => r2 = 1
  29                                    14 => "11100010000100001000000000000000", --and r2, r1, r0     => r2 = 0
  30                                    15 => "11101100000000001000000000000000", --cmp r0 , r1        => 0-1 => 0100
  31                                    16 => "10000000001010101010000000000001", --addabd r5, r5, r4  => r5 = 6
  32                                    17 => "10110011101110001000010000110001", --orxltd r7, 1086    => r7 = 1086
  33                                    18 => "10110101001110001000010000000001", --shiftltd r7, r1, 1 => r7 = 2
  34                                    19 => "01010101001110001000100000000001", --shiftltd r7, r1, 2 => r7 = 4
  35                                   others => x"F0000000");
  36
  37
  38 begin
  39         process(clk)
  40         begin
  41                 if rising_edge(clk) then
  42                         data_out <= ram(to_integer(UNSIGNED(rd_addr)));
  43
  44                         if wr_en = '1' then
  45                                 ram(to_integer(UNSIGNED(wr_addr))) <= data_in;
  46                         end if;
  47                 end if;
  48         end process;
  49 end architecture behaviour;