Re: Enhancement: Dynamic Values on attributes.

From: Krishna Garlapati (krishna@synplicity.com)
Date: Thu Oct 30 2003 - 16:36:09 PST

  • Next message: Michael McNamara: "Re: Enhancement: Dynamic Values on attributes."

    I guess my explanation for this request was not very clear. FPGA designers
    use these attributes primarily to pass custom information (like location,
    mapping methods, types etc) to the vendor backend.

    The vendor's backend tool expects a single attribute in a string form and
    ignores everything else. I agree with you that using multiple Vlog-2001
    style attributes can achieve the requested functionality but it does not
    fulfill the
    purpose.

    My request is to simply provide a function that can take in a bunch
    of strings and constant expressions as parameters and return a string,
    which is the concatenated version that contains all the string
    parameters (as is)
    and evaluated constant expressions. I also think implementing this is
    pretty very
    straightforward.

    We have implemented attributes for VLog-2001 and I don't think there is a
    single system function that can realize this. A good percentage of our
    users
    are already using the $strcat and we think it would be a good idea to
    make it
    into the standard for compatibility issues.

    "From your example, it appears that "xc_rloc" takes a string that
    holds a row and column position encoded by strings of digits after
    "R" and "C" (I'll ignore the ".S" part, since I didn't understand what
    it was). You could do the same thing easily in Verilog-2001 by changing
    this to two attributes, "xc_rloc_R" and "xc_rloc_C", which take the
    row and column directly as numerical values instead of converted to
    strings."

    This is not acceptable to the users for the reasons I listed above.

    ""Printing" a numerical value into a string form is a complex operation,"

    I am wondering why?? I dont see a big problem here or may be I am
    missing something. 

    -- 
- Krishna Garlapati, Synplicity Inc. (408)215-6152

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