#63 Bug in XNOR simulation

closed-fixed
Stefan Jahn
None
5
2010-03-27
2010-02-05
Anonymous
No

Attempts to run simulation that includes XNOR digital circuit symbol always results in the following errors and warnings:

--8x--cut here--
digi.vhdl: in TestBench(Arch_TestBench):
digi.vhdl:14: no declaration matches use as "xnor"(std_logic, std_logic), candidates are
/usr/share/freehdl/lib/std/standard.vhdl:5: "xnor"(BOOLEAN,BOOLEAN) return BOOLEAN (invalid 0)
/usr/share/freehdl/lib/std/standard.vhdl:6: "xnor"(BIT,BIT) return BIT (invalid 0)
/usr/share/freehdl/lib/std/standard.vhdl:69: "xnor"(BIT_VECTOR,BIT_VECTOR) return BIT_VECTOR (invalid 0)
v2cc: digi.vhdl: 1 errors
--8X--cut here--

I have also attached file xnor.sch which is a basic schematic to test xnor simulation.

Qucs version 0.0.15
Qt version 3.3.8b
Fedora 11

Discussion

  • Basic schematic to test xnor simulation.

     
    Attachments
  • Stefan Jahn
    Stefan Jahn
    2010-03-25

    • assigned_to: nobody --> ela
     
  • Stefan Jahn
    Stefan Jahn
    2010-03-25

    Hello! Thank you very much for the hint! I was checking then the VHDL headers and found this:

    -- Note : The declaration and implementation of the "xnor" function is
    -- specifically commented until at which time the VHDL language has been
    -- officially adopted as containing such a function. At such a point,
    -- the following comments may be removed along with this notice without
    -- further "official" ballotting of this std_logic_1164 package. It is
    -- the intent of this effort to provide such a function once it becomes
    -- available in the VHDL standard.

    Seems like xnor was/is not standard of VHDL?

    Ok, to overcome the problem, I'll rewrite things using "not xor", ok?

    Best regards, Stefan.

     
  • Stefan Jahn
    Stefan Jahn
    2010-03-27

    • status: open --> closed-fixed
     
  • Stefan Jahn
    Stefan Jahn
    2010-03-27

    Fixed the produced XNOR code, since std_logic does not support XNOR by default.