Re: I hate VHDL!!!

Discussion in 'VHDL' started by Tom Verbeure, Jul 28, 2004.

  1. Tom  Verbeure

    Tom Verbeure Guest


    > Now take the example and imagine the same case but with a typo error

    on
    > clk name, which is an other existing signal of the design.
    > If the sensitivity list is (*), I have no way to flag the typo error.


    > And possibly no tests fail, except perhaps in very hard to find

    corner
    > case (if both signal have similar behavior, except under very

    specific
    > cases).


    Basically you're saying that you want to (ab?)use the sensititivity
    list as a redundancy mechanism against ordinary typos.

    At what point do you have to stop holding the hand of a designer and
    trust that he will fix typos, run simulations to verify a design and
    read the error reports of his synthesis and/or linting tool?

    Say a designer writes:
    a <= b;
    instead of:
    a <= c;
    How can we protect a designer against such a potentially disastrous
    typo?

    Tom
     
    Tom Verbeure, Jul 28, 2004
    #1
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  2. Use of (*) as sensitivity list definition

    Hi,

    I have change the subject line, because I think it is no more link with
    initial message.

    Tom Verbeure wrote:

    >>Now take the example and imagine the same case but with a typo error
    >>
    >>

    >on
    >
    >
    >>clk name, which is an other existing signal of the design.
    >>If the sensitivity list is (*), I have no way to flag the typo error.
    >>
    >>

    >
    >
    >
    >>And possibly no tests fail, except perhaps in very hard to find
    >>
    >>

    >corner
    >
    >
    >>case (if both signal have similar behavior, except under very
    >>
    >>

    >specific
    >
    >
    >>cases).
    >>
    >>

    >
    >Basically you're saying that you want to (ab?)use the sensititivity
    >list as a redundancy mechanism against ordinary typos.
    >
    >

    Not exactly, the aspect that you put into the sensitivity list are the
    control part of a process.
    You can have some mechanism that use content of sensitivity list to make
    some check, or some assertion.

    When you introduce a new element, you need extend the feature of the
    language. In that case I think that is a reduction, because you can't no
    more use the sensitivity list.
    To me, have no sensitivity list or have (*) in sensitivity list are
    equivalent.

    >At what point do you have to stop holding the hand of a designer and
    >trust that he will fix typos, run simulations to verify a design and
    >read the error reports of his synthesis and/or linting tool?
    >
    >Say a designer writes:
    >a <= b;
    >instead of:
    >a <= c;
    >How can we protect a designer against such a potentially disastrous
    >typo?
    >
    >

    In that case, that is not a real typo problem, but more a logic problem.
    In my example, the typo error is in the sensitivity list content.

    To check your case, formal verification, simulation...

    >Tom
    >
    >
    >

    JaI
     
    Just an Illusion, Jul 29, 2004
    #2
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  3. Jim,
    I fully agree with Tom's ideas:
    1. Never put into consideration any typos for new keywords, new ideas,
    new proposals.
    2. If you can recognize 3 different types of process(), software can
    recognize it much faster and better than you do.

    Weng
     
    Weng Tianxiang, Jul 29, 2004
    #3
  4. Tom  Verbeure

    Wallclimber Guest

    Re: Use of (*) as sensitivity list definition

    > Not exactly, the aspect that you put into the sensitivity list are the
    > control part of a process.
    > You can have some mechanism that use content of sensitivity list to make
    > some check, or some assertion.
    >
    > When you introduce a new element, you need extend the feature of the
    > language. In that case I think that is a reduction, because you can't no
    > more use the sensitivity list.
    > To me, have no sensitivity list or have (*) in sensitivity list are
    > equivalent.


    ???

    Where did I claim that I wanted to get rid of sensitivity lists? The
    (*) notation would be an addition for those cases where it is useful
    (like combinational processes...). This is no different than for
    Verilog.

    Tom
     
    Wallclimber, Jul 29, 2004
    #4
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