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library ieee;
use ieee.std_logic_1164.all,
ieee.numeric_std.all;
entity tdp_ram is
generic (
ADDRWIDTH_A : positive := 10;
WIDTH_A : positive := 32;
ADDRWIDTH_B : positive := 10;
WIDTH_B : positive := 32;
COL_WIDTH : positive := 8
);
port (
clk_a : in std_logic;
read_a : in std_logic;
write_a : in std_logic;
byteen_a : in std_logic_vector(WIDTH_A/COL_WIDTH - 1 downto 0);
addr_a : in std_logic_vector(ADDRWIDTH_A - 1 downto 0);
data_read_a : out std_logic_vector(WIDTH_A - 1 downto 0);
data_write_a : in std_logic_vector(WIDTH_A - 1 downto 0)
);
end tdp_ram;
architecture behavioral of tdp_ram is
function log2(val : INTEGER) return natural is
variable res : natural;
begin
for i in 0 to 31 loop
if (val <= (2 ** i)) then
res := i;
exit;
end if;
end loop;
return res;
end function log2;
function eq_assert(x : integer; y : integer) return integer is
begin
assert x = y;
return x;
end function eq_assert;
constant COLS_A : positive := WIDTH_A / COL_WIDTH;
constant TOTAL_COLS : positive := COLS_A * 2 ** ADDRWIDTH_A;
constant EXTRA_ADDR_BITS_A : positive := log2(COLS_A);
type ram_t is array(0 to TOTAL_COLS - 1) of std_logic_vector(COL_WIDTH - 1 downto 0);
shared variable store : ram_t := (others => (others => '0'));
signal reg_a : std_logic_vector(WIDTH_A - 1 downto 0);
begin
assert WIDTH_A mod COL_WIDTH = 0 and
2 ** (ADDRWIDTH_A + EXTRA_ADDR_BITS_A) = TOTAL_COLS
report "WIDTH_A have to be a power-of-two multiple of COL_WIDTH"
severity failure;
process(clk_a)
begin
if rising_edge(clk_a) then
for i in 0 to COLS_A - 1 loop
if write_a = '1' and byteen_a(i) = '1' then
store(to_integer(unsigned(addr_a) & to_unsigned(i, EXTRA_ADDR_BITS_A))) :=
data_write_a((i+1) * COL_WIDTH - 1 downto i * COL_WIDTH);
end if;
if read_a = '1' then
reg_a((i+1) * COL_WIDTH - 1 downto i * COL_WIDTH) <=
store(to_integer(unsigned(addr_a) & to_unsigned(i, EXTRA_ADDR_BITS_A)));
end if;
end loop;
data_read_a <= reg_a;
end if;
end process;
end behavioral;
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