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Sparse array error

abhingp01

Hi all,

I am working with cadence IUS8.2 

Following array declaration is  giving  error

----------------------------------error--------------------------------------------

ncvlog_cg: *F,INTERR: INTERNAL ERROR
-----------------------------------------------------------------
The tool has encountered an unexpected condition and must exit.
Contact Cadence Design Systems customer support about this
problem and provide enough information to help us reproduce it,
including the logfile that contains this error message.
  TOOL: ncvlog_cg       08.20-p001
  HOSTNAME: btc6l138
  OPERATING SYSTEM: Linux 2.6.9-67.ELsmp #1 SMP Wed Nov 7 13:56:44 EST 2007 x86_64
MESSAGE: vsto_ots_data - zero offset, class 529, file: /home/xyz/abc/proj/sv/sparse_memory.sv, line: 6

--------------------------Error line 6 -------------------------------------

// Sparse memory array

reg  [31:0] /*sparse*/  sparsemem[0:4_095_999];  <-------------- error on this specific line - 6

 

Regards

Abhishek

  • Hi Abhishek, Please download and install the latest hotfix for IUS82 (currently that is 8.20-s018) and rerun your simulation with that updated version. I can't guarantee that the problem is fixed in that version, but I'm thinking that it is highly likely. I've seen a couple of fixes that were implemented for issues that resulted in that error. Best regards, Mickey

  • Hi Abhishek,

     

     Following is solution for a test-bench. I would recommend that you have an associative array (in case you are not utilizing all the elements). Just a thought why you would need such a huge array. Maybe you can revisit you are design and think of alternate ways instead of declaring a fixed array.  Also would recommend using bit instead of reg (2-state versus 4-state)

  • Hi,

    "Declaring large arrays as sparse tells the simulator that you do not intend to use the entire

    array. This allows the simulator to perform memory optimizations. It does not affect the

    behavior of arrays. The behavior of a sparse array is identical to a “normal” non-sparse array."

     

    This is as per given in NC-Verilog simulator help. 

     I am just curious why its not working.

     

    Regards

     

  • Hi Abishek,
    As Mickey suggested, please use the latest hotfix and let us know what the outcome was.

    Thanks,
    Hilmar

  • Hi Mickey & Hilmar,

     I installed the latest hotfix for IUS8.2, but the problem still persist.

    If I remove /*sparse*/ pragma, the code runs without any error or warning.

     

    Regards

    Abhishek

  • Hi Abhishek, If the problem is being seen in the latest hotfix, then this is a bug. Please open a service request with our customer support by sending an email to support@cadence.com. If possible include an example testcase replicating the crash so that the issue can be investigated and fixed quickly. Best regards, Mickey

  •  Got this concern also..and I got problem in resolving this one..its quite a week since I experience this one..glad that I found some solutions here,..hopefully I'll definitely fix now my problem...

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