Generating normally distributed random numbers

you can use an LFSR. its easy to code looking at a diagram (try Wikipedia).

If you are interested in LFSR automatic generated code, you could try this link to have a look :

Tricky: good point, i was thinking of pseudo-white noise as having a normal distribution, though i haven't checked.

absolutely, thanks for pointing out my oversight.

a nice looking VHDL package that can create a signal with a normal distribution:

Thats good to see. Im sure Ive seen someone from whoever the VHDL controlling body is coming up with something similar, that I think might make it into the next revision of VHDL (of course not synthesisable - only there for testbenching and verification.)

I normally code as below

signal shift : std_logic_vector(15 downto 1);
process(reset,clk)
if reset = '1' then
    shift <= "010"&x"123";   -- seed
elsif rising_edge(clk) then
   if en = '1' then
     shift(1) <= shift(14) xor shift(15);  -- taps
     shift(2 to 15) <= shift(1 to 14);   -- shift
 
   end if;
end if;
end process;