I have the following example from an answer on a previous post on Stackexchange Electrical Engineering:

show_out   <= show  when player = '0' else '0';
set_out    <= set   when player = '0' else '0';
input_out  <= input when player = '0' else "00000000";
-- etc.

show_out2  <= show  when player = '1' else '0';
set_out2   <= set   when player = '1' else '0';
input_out2 <= input when player = '1' else "00000000";
-- etc.

I want to insert it in a process like the one below:

architecture Behavioral of twoplayermux1 is
    process (show,set,input,try,player)


    end process twoplayermux1;
end Behavioral;

How does the syntax looks like for that?

  • \$\begingroup\$ Just replace it with set of if ...else.. endif. (Why do you insists on using a process?) \$\endgroup\$ – Oldfart Nov 23 '19 at 20:39
  • \$\begingroup\$ I saw your previous post. I think what you are having a problem with is that you are assigning different outputs in each case. So you need to assign both show_out and show_out2 in all your separate cases. The way you have written it, the synthesizer will set show_out = show and show_out2 = show permanently. \$\endgroup\$ – user110971 Nov 23 '19 at 21:06
  • \$\begingroup\$ @user110971 What about two different if statements in-between "begin" and "end process twoplayermux1"? \$\endgroup\$ – user164324 Nov 23 '19 at 21:53

The syntax is the same whether inside or outside a process using VHDL-2008. The example slide below shows the syntax. Source for image is: enter link description here. As mentioned in the comment on your question, there's no real need for the process.

enter image description here

  • \$\begingroup\$ There's also the case-statement \$\endgroup\$ – JHBonarius Nov 26 '19 at 21:25
  • 1
    \$\begingroup\$ Note that some synthesis tools (including Vivado) don't support when statements in processes. \$\endgroup\$ – Caleb Reister Nov 27 '19 at 3:37
  • \$\begingroup\$ @CalebReister have you tried specifying VHDL 2008 type in Vivado? I have certainly synthesized this syntax in Vivado. Perhaps it also depends on your Vivado version. It works in Vivado 2018.3. \$\endgroup\$ – user_007 Nov 27 '19 at 18:35
  • \$\begingroup\$ @user_007 Yes I did, but I would have been using Vivado 2017.4 when I last tried it. \$\endgroup\$ – Caleb Reister Nov 27 '19 at 19:13
  • \$\begingroup\$ +1 for end of vhdl verbosity link. \$\endgroup\$ – Sourabh Tapas Jan 5 '20 at 6:00

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