LIBRARY ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;

entity RAM is
port (
    r_reset             :in std_logic;
    r_ready             :in std_logic;
    clk             : in std_logic;
    r_CPU_cs            : in std_logic;
    r_CPU_data_in           : in std_logic_vector (0 to 63);
    r_CPU_address           : in std_logic_vector (0 to 15);
    r_DMA_cs            : in std_logic;
    r_DMA_data_in           : in std_logic_vector (0 to 63);
    r_DMA_command           : in std_logic_vector (0 to 1);
    r_DMA_address           : in std_logic_vector (0 to 15);
    r_DMA_data_out          : out std_logic_vector (0 to 63));
end RAM;

architecture behave of RAM is
type ram_64k_x64 is array (0 to 65536) of std_logic_vector(0 to 63);
signal r_memory_Ram : ram_64k_x64 := (
15  => x"000000000000001A",
16  => x"C000000000000014",
17  => x"000000000000001A",
18  => x"A000000C0000000A",
19  => x"0000000000001213",
20  => x"C000000000000000",
21  => x"0AAAAAAAAAAA0001",
300     => x"D000000000003456",
301 => x"000000000000001A",
302 => x"C0000000000000A0",
303 => x"0000000000000001",
304 => x"C0000000000000DD",
others  => x"0000000000000000"
);
-- pragma sythesis_off
-- pragma sythesis_on
begin

process(clk) -- cs - выборка кристала, если cs = 1 - zzzz
begin
    If r_reset = '1' then
        r_DMA_data_out <= x"0000000000000000";
    elsif (rising_edge(clk)) then
        IF (r_CPU_cs = '0') then
            r_memory_Ram(to_integer (unsigned(r_CPU_address))) <= r_CPU_data_in;
                r_DMA_data_out <= x"0000000000000000";
        elsif (r_DMA_cs = '1' ) then -- спящий режим
            r_DMA_data_out <= x"0000000000000000";
        elsif (r_ready ='0') then
            if (r_DMA_command = "01") then -- команда чтения
                r_DMA_data_out <= r_memory_Ram(to_integer (unsigned(r_DMA_address)));
            elsif (r_DMA_command = "10") then -- команда записи
                r_memory_Ram(to_integer (unsigned(r_DMA_address))) <= r_DMA_data_in;
                r_DMA_data_out <= x"0000000000000000";
            end if;
        end if;
    end if;
end process;
end behave;