sfixed to ufixed conversition

This is the architecture code:

...

architecture mul_four of mul_four is

signal n1: sfixed (4 downto -4);

signal n2: sfixed (n1'high + 1 downto n1'low);

signal n3: ufixed (5 downto -4);

signal u: ufixed (5 downto -4);

begin

n1 <= to_sfixed(-0.129,n1);

n2 <= abs(n1);

n3 <= ufixed(n2);

process(clk)

begin

if (clk'event and clk='1') then

for i in 0 to 3 loop

out_A(i) <= (to_ufixed (A(i),u)) * n3;

end loop;

end if;

end process;

end mul_four;

I have simulate in ModelSim and the output seem like correct. I just want to confirm,do I convert the sfixed to ufixed in the right way?..thanks for helps