Does VHDL have a ternary operator?

vhdl ternary-operator
user1058795 picture user1058795 · Apr 19, 2013 · Viewed 9.8k times · Source

I love the neatness of the ternary operator vs if clauses.

Does this operator exist in vhdl? My search was to the contrary. I also checked the when statement out, but it's not an operator, and I want to be able to use it in processes, too...

Answer

EML picture EML · Apr 19, 2013

No. It was discussed for VHDL-2008, but didn't get in. You've got a couple of options. If your tools support VHDL-2008, conditional assignments are now supported as sequential statements (they were previously just concurrent), so you can write something like:

process(clock)
begin
  if rising_edge(clock) then
    q <= '0' when reset else d; -- ie. much like q <= reset? '0':d;
  end if;
end process;

If you haven't got 2008, just write a function (q <= sel(reset, '0', d)). You have to write it for every type you're interested in, though.

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