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library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all;
library work;
use work.genram_pkg.all;
entity generic_spram is
generic (
-- standard parameters
g_data_width : natural := 32;
g_size : natural := 1024;
-- if true, the user can write individual bytes by using bwe_i
g_with_byte_enable : boolean := false;
-- RAM read-on-write conflict resolution. Can be "read_first" (read-then-write)
-- or "write_first" (write-then-read)
g_addr_conflict_resolution : string := "write_first";
g_init_file : string := ""
);
port (
rst_n_i : in std_logic; -- synchronous reset, active LO
clk_i : in std_logic; -- clock input
-- byte write enable, actiwe when g_
bwe_i : in std_logic_vector((g_data_width+7)/8-1 downto 0);
-- global write enable (masked by bwe_i if g_with_byte_enable = true)
we_i : in std_logic;
-- address input
a_i : in std_logic_vector(f_log2_size(g_size)-1 downto 0);
-- data input
d_i : in std_logic_vector(g_data_width-1 downto 0);
-- data output
q_o : out std_logic_vector(g_data_width-1 downto 0)
);
end generic_spram;
architecture syn of generic_spram is
constant c_num_bytes : integer := (g_data_width+7)/8;
type t_ram_type is array(0 to g_size-1) of std_logic_vector(g_data_width-1 downto 0);
type t_string_file_type is file of string;
signal ram : t_ram_type;
signal s_we : std_logic_vector(c_num_bytes-1 downto 0);
signal s_ram_in : std_logic_vector(g_data_width-1 downto 0);
signal s_ram_out : std_logic_vector(g_data_width-1 downto 0);
begin
assert (g_init_file = "" or g_init_file = "none")
report "generic_spram: Memory initialization files not supported yet. Sorry :("
severity failure;
gen_with_byte_enable_writefirst : if(g_with_byte_enable = true and g_addr_conflict_resolution = "write_first") generate
s_we <= bwe_i when we_i = '1' else (others => '0');
process(s_we, d_i)
begin
for i in 0 to c_num_bytes-1 loop
if s_we(i) = '1' then
s_ram_in(8*i+7 downto 8*i) <= d_i(8*i+7 downto 8*i);
s_ram_out(8*i+7 downto 8*i) <= d_i(8*i+7 downto 8*i);
else
s_ram_in(8*i+7 downto 8*i) <= ram(conv_integer(unsigned(a_i)))(8*i+7 downto 8*i);
s_ram_out(8*i+7 downto 8*i) <= ram(conv_integer(unsigned(a_i)))(8*i+7 downto 8*i);
end if;
end loop; -- i
end process;
process(clk_i)
begin
if rising_edge(clk_i) then
ram(conv_integer(unsigned(a_i))) <= s_ram_in;
q_o <= s_ram_out;
end if;
end process;
end generate gen_with_byte_enable_writefirst;
gen_with_byte_enable_readfirst : if(g_with_byte_enable = true and (g_addr_conflict_resolution = "read_first" or
g_addr_conflict_resolution = "dont_care")) generate
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s_we <= bwe_i when we_i = '1' else (others => '0');
process(s_we, d_i)
begin
for i in 0 to c_num_bytes-1 loop
if (s_we(i) = '1') then
s_ram_in(8*i+7 downto 8*i) <= d_i(8*i+7 downto 8*i);
else
s_ram_in(8*i+7 downto 8*i) <= ram(conv_integer(unsigned(a_i)))(8*i+7 downto 8*i);
end if;
end loop;
end process;
process(clk_i)
begin
if rising_edge(clk_i) then
ram(conv_integer(unsigned(a_i))) <= s_ram_in;
q_o <= ram(conv_integer(unsigned(a_i)));
end if;
end process;
end generate gen_with_byte_enable_readfirst;
gen_without_byte_enable_writefirst : if(g_with_byte_enable = false and g_addr_conflict_resolution = "write_first") generate
process(clk_i)
begin
if rising_edge(clk_i) then
if(we_i = '1') then
ram(conv_integer(unsigned(a_i))) <= d_i;
q_o <= d_i;
else
q_o <= ram(conv_integer(unsigned(a_i)));
end if;
end if;
end process;
end generate gen_without_byte_enable_writefirst;
gen_without_byte_enable_readfirst : if(g_with_byte_enable = false and (g_addr_conflict_resolution = "read_first" or
g_addr_conflict_resolution = "dont_care")) generate
process(clk_i)
begin
if rising_edge(clk_i) then
if(we_i = '1') then
ram(conv_integer(unsigned(a_i))) <= d_i;
end if;
q_o <= ram(conv_integer(unsigned(a_i)));
end if;
end process;
end generate gen_without_byte_enable_readfirst;
end syn;