Help multiplier vhdl

--- Quote Start ---

take this example:

A = 1111101

B = 1111111

y = 0

count = 0 , A(0) = '1' hence result of A(0) *B = B (1111111), I called it temp

update sum: y = y+temp;

count <= count + 1;

count = 1 , A(1) = '0' hence result of A(1) *B = 0, I called it temp

update sum: y = y+temp&'0'; --shift temp by one bit

count <= count + 1;

count = 2 , A(2) = '1' hence result of A(2) *B = B, I called it temp

update sum: y = y+temp&'00'; --shift temp by two bits

count <= count + 1;

...

--- Quote End ---

I've been working in this project and I've get this:

library IEEE;

use IEEE.STD_LOGIC_1164.ALL;

use IEEE.std_logic_unsigned.all;

use IEEE.numeric_std.all;

entity prueba2 is

port (

A : in std_logic_vector (7 downto 0);

B : in std_logic_vector (7 downto 0);

inicio : in std_logic;

clk : in std_logic;

reset: in std_logic;

q : out std_logic_vector (2 downto 0);

resultado : out std_logic_vector (15 downto 0)

);

end prueba2;

architecture behavioral of prueba2 is

begin

multi : process (A, clk, reset)

variable y : std_logic_vector (15 downto 0);

variable cuenta : std_logic_vector (2 downto 0);

variable temp : std_logic_vector (7 downto 0);

begin

if reset = '1' then y:= "0000000000000000";

else

if clk'event and clk = '1' and inicio = '1' then

cuenta := cuenta + 1;

end if;

q <= cuenta;

end if;

case cuenta is

when "000" =>

if A(0) = '1' then

temp := B;

else

temp := "00000000";

end if;

y := y + temp;

when "001" =>

if A(1) = '1' then

temp := B;

else

temp := "00000000";

end if;

y := y + temp&"0";

when "010" =>

if A(2) = '1' then

temp := B;

else

temp := "00000000";

end if;

y := y + temp&"00";

when "011" =>

if A(3) = '1' then

temp := B;

else

temp := "00000000";

end if;

y := y + temp&"000";

when "100" =>

if A(4) = '1' then

temp := B;

else

temp := "00000000";

end if;

y := y + temp&"0000";

when "101" =>

if A(5) = '1' then

temp := B;

else

temp := "00000000";

end if;

y := y + temp&"00000";

when "110" =>

if A(6) = '1' then

temp := B;

else

temp := "00000000";

end if;

y := y + temp&"000000";

when "111" =>

if A(7) = '1' then

temp := B;

else

temp := "00000000";

end if;

y := y + temp&"0000000";

end case;

resultado <= y;

end process;

end behavioral;

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But there is an error when I do y := y + temp&"0"; because expression has 17 elements, but must have 16 elements.

How can I correct this?