design accumulator in VHDL

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VHDL

I write accumulator in VHDL , but when I build it's wave form it is a little wrong!

my code contain 4 file:
1) 1 bit full adder
2) 8 bit adder
3) 1 bit D_FF
4) accumulator

there are codes:


1) 1 bit full adder

Library ieee;
Use ieee.std_logic_1164.all;

---------------------------------------------------------------------------

Entity fullAdder is
port(
CLK : in std_logic;
Cin : in std_logic;
x : in std_logic;
y : in std_logic;
s : out std_logic;
Cout : out std_logic
);
end fullAdder;

Architecture fullAdder_logic of fullAdder is
begin

process(CLK)
begin
if rising_edge(CLK) then
s <= x xor y xor Cin;
Cout <= (x and y) or (x and Cin) or (y and Cin);
end if;
end process;

end Architecture;

2) 8 bit adder

Library ieee;
Use ieee.std_logic_1164.all;
Use work.all;

---------------------------------------------------------------------------

Entity eightBitAdder is
port(
CLK : in std_logic;
Cin : in std_logic;
x : in std_logic_vector(7 downto 0);
y : in std_logic_vector(7 downto 0);
s : out std_logic_vector(7 downto 0);
Cout: out std_logic
);
end eightBitAdder;

Architecture eightBitAdder_logic of eightBitAdder is

component fullAdder
port(
CLK :in std_logic;
Cin,x,y : in std_logic;
s,Cout : out std_logic
);
end component;

signal carry : std_logic_vector(8 downto 0);

begin

carry(0) <= Cin;

gen_add: for i in 0 to 7 generate
lebel_fulladd: fullAdder port map (CLK, carry(i), x(i), y(i), s(i), carry(i + 1)); 
end generate gen_add;

Cout <= carry(8);

end Architecture;

3 ) 1 bit flip flop

library ieee;
use ieee.std_logic_1164.all;

entity D_ff is
port (
D: in std_logic;
CLK: in std_logic;
RST: in std_logic;
Q: out std_logic
);
end D_ff;

architecture D_ff_logic of D_ff is

signal ff_state: std_logic; -- This will hold flip flop state

begin

process(CLK)
begin
if rising_edge(CLK) then
if RST='1' then
ff_state <= '0'; -- Reset, change state to 0.
else
ff_state <= D; -- 'clock' in input.
end if;
end if;
end process;

-- Output current flip flop state

Q <= ff_state;

end architecture;

4 ) accumulator

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;

entity accumulator is
port (
Input: in std_logic_vector(7 downto 0);
CLK:	in std_logic;
Output: out std_logic_vector(7 downto 0)
);
end entity accumulator;

architecture accumulator_logic of accumulator is

component D_ff is
port (
D: in std_logic;
CLK: in std_logic;
RST: in std_logic;
Q: out std_logic
);
end component; 

component eightBitAdder is
port(
CLK : in std_logic;
Cin : in std_logic;
x : in std_logic_vector(7 downto 0);
y : in std_logic_vector(7 downto 0);
s : out std_logic_vector(7 downto 0);
Cout: out std_logic
);
end component;

signal DFF_AC: std_logic_vector(7 downto 0);
signal ALU_out: std_logic_vector(7 downto 0);
signal overFlow: std_logic;
signal cout: std_logic;

begin

--DFF_Ac0: D_ff port map ( '0', CLK, '1', DFF_AC(0));
--DFF_Ac1: D_ff port map ( '0', CLK, '1', DFF_AC(1));
--DFF_Ac2: D_ff port map ( '0', CLK, '1', DFF_AC(2));
--DFF_Ac3: D_ff port map ( '0', CLK, '1', DFF_AC(3));
--DFF_Ac4: D_ff port map ( '0', CLK, '1', DFF_AC(4));
--DFF_Ac5: D_ff port map ( '0', CLK, '1', DFF_AC(5));
--DFF_Ac6: D_ff port map ( '0', CLK, '1', DFF_AC(6));
--DFF_Ac7: D_ff port map ( '0', CLK, '1', DFF_AC(7));

adder: eightBitAdder port map(CLK, '0', std_logic_vector(Input), std_logic_vector(DFF_AC), ALU_out,cout);

DFF0: D_ff port map ( ALU_out(0), CLK, '0', DFF_AC(0));
DFF1: D_ff port map ( ALU_out(1), CLK, '0', DFF_AC(1));
DFF2: D_ff port map ( ALU_out(2), CLK, '0', DFF_AC(2));
DFF3: D_ff port map ( ALU_out(3), CLK, '0', DFF_AC(3));
DFF4: D_ff port map ( ALU_out(4), CLK, '0', DFF_AC(4));
DFF5: D_ff port map ( ALU_out(5), CLK, '0', DFF_AC(5));
DFF6: D_ff port map ( ALU_out(6), CLK, '0', DFF_AC(6));
DFF7: D_ff port map ( ALU_out(7), CLK, '0', DFF_AC(7));



process(CLK)
begin
if rising_edge(CLK) then
Output <= DFF_AC;
else
overFlow <= cout xor DFF_AC(7);
end if;
end process;


end architecture;

if give input(00000001) to accumulator and draw wave form it work's but a little wrong!