Logo Questions Linux Laravel Mysql Ubuntu Git Menu
 

Does VHDL have a ternary operator?

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...

like image 528
user1058795 Avatar asked Apr 19 '13 19:04

user1058795


2 Answers

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.

like image 91
EML Avatar answered Sep 27 '22 18:09

EML


Not the one like you know from C/C++ but you can use:

destination <= signal1 when condition else signal2;
like image 39
Caladan Avatar answered Sep 27 '22 17:09

Caladan