cpu/src/ram_xilinx_b.vhd

   1 library ieee;
   2
   3 use IEEE.std_logic_1164.all;
   4 use IEEE.numeric_std.all;
   5
   6 use work.common_pkg.all;
   7 use work.mem_pkg.all;
   8
   9 architecture behaviour of ram_xilinx is
  10         type word_t is array (0 to 3) of std_logic_vector(7 downto 0);
  11         subtype stfu_t is std_logic_vector(BYTE_WIDTH-1 downto 0);
  12         type ram_t is array (0 to (2**ADDR_WIDTH)-1) of stfu_t;
  13         signal ram0 : ram_t := (others => x"00");
  14         signal ram1 : ram_t := (others => x"00");
  15         signal ram2 : ram_t := (others => x"00");
  16         signal ram3 : ram_t := (others => x"00");
  17         signal q_local : word_t;
  18
  19 begin -- Re-organize the read data from the RAM to match the output
  20         unpack: for i in 0 to 3 generate
  21                 q(8*(i+1) - 1 downto 8*i) <= q_local(i);
  22         end generate unpack;
  23
  24         process(clk)
  25         begin
  26                 if(rising_edge(clk)) then
  27                         if(we = '1') then
  28                                 if(be(0) = '1') then
  29                                         ram0(to_integer(UNSIGNED(waddr))) <= wdata(7 downto 0);
  30                                 end if;
  31                                 if be(1) = '1' then
  32                                         ram1(to_integer(UNSIGNED(waddr))) <= wdata(15 downto 8);
  33                                 end if;
  34                                 if be(2) = '1' then
  35                                         ram2(to_integer(UNSIGNED(waddr))) <= wdata(23 downto 16);
  36                                 end if;
  37                                 if be(3) = '1' then
  38                                         ram3(to_integer(UNSIGNED(waddr))) <= wdata(31 downto 24);
  39                                 end if;
  40                         end if;
  41                         q_local(0) <= ram0(to_integer(UNSIGNED(raddr)));
  42                         q_local(1) <= ram1(to_integer(UNSIGNED(raddr)));
  43                         q_local(2) <= ram2(to_integer(UNSIGNED(raddr)));
  44                         q_local(3) <= ram3(to_integer(UNSIGNED(raddr)));
  45                 end if;
  46         end process;
  47
  48 end architecture behaviour;