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JSLY's avatar
JSLY
Icon for New Contributor rankNew Contributor
4 years ago

How to turn off or reduce optimization in questa sim

I downloaded and installed questasim started edition 2021.2 for quartus prime lite 21.1 and the tool opens up and compiles and starts a simulation, but nothing shows up in the "OBJECS" window, almost acting like it is optimizing everything out? where is the menu to change optimization to a lower level? I know this is not related to the source files, because I can run the same simulation in Modelsim and everything works just fine.

12 Replies

  • GLT1's avatar
    GLT1
    Icon for Occasional Contributor rankOccasional Contributor
    3 years ago

    It's part of the vsim command line used to open up questa.

    vsim -voptargs=+acc <your simulation test bench name>

    • JSLY's avatar
      JSLY
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      3 years ago

      Yes that helps Thank You. However I hate typing, is there a way to modify the TCL script or the modelsim.ini to turn off optimization so I can just do on the top menu Simulate-> Start Simulation-><test bench> . right now using that command line vsim -voptargs=+acc <your simulation test bench name> works just fine until you shut down the questa, if you restart questa a later time, then you have to type in the vsim arguments all over again.

    • JSLY's avatar
      JSLY
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      4 years ago

      Thank you for trying but closing the window and reopening the window gives the same results. the compiler is optimizing out all the net so there is nothing to view? In the terminal window it says loading the optimized design, I do not know if this is related to the starter edition license, or if it is a configurable setting some where I can turn off or modify?

  • GLT1's avatar
    GLT1
    Icon for Occasional Contributor rankOccasional Contributor
    4 years ago

    Adding -voptargs=+acc to the questa command line will turn off all optimizations and allow all signals to be visible.

    • Maulik0405's avatar
      Maulik0405
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      10 months ago

      This works when also removed the following flag from the vsim - command.

      -novopt

      Overall the command should be looking like this.

      vsim -voptargs=+acc -c -t 1ps -L cyclonev_ver -L altera_ver -L altera_mf_ver -L 220model_ver -L sgate_ver -L altera_lnsim_ver work.firstBlockTest_vlg_vec_tst

  • SyafieqS's avatar
    SyafieqS
    Icon for Super Contributor rankSuper Contributor
    3 years ago

    Hi Jeff,


    Have you tried adding -voptargs=+acc to the questa as suggested below?


  • JSLY's avatar
    JSLY
    Icon for New Contributor rankNew Contributor
    3 years ago

    # reading modelsim.ini
    Questa>-voptargs=+acc
    # invalid command name "-voptargs=+acc"

  • GLT1's avatar
    GLT1
    Icon for Occasional Contributor rankOccasional Contributor
    3 years ago

    I'm not sure. You'd have to check the Questa documentation.

    I just put the command to launch the simulation in a script or makefile and call that to launch the simulation.

    That way I only have to type it once.

  • SyafieqS's avatar
    SyafieqS
    Icon for Super Contributor rankSuper Contributor
    3 years ago

    Jeff,


    What I could this of is to save the command in a script, invoke and read it whenever you want launch simulation

    Thus prevent you from typing.



  • SyafieqS's avatar
    SyafieqS
    Icon for Super Contributor rankSuper Contributor
    3 years ago

    Jeff,


    Let me know if there is any update or concern at your end




  • SyafieqS's avatar
    SyafieqS
    Icon for Super Contributor rankSuper Contributor
    3 years ago

    We do not receive any response from you to the previous reply that I have provided, thus I will put this case to close pending. Please post a response in the next 15 days to allow me to continue to support you. After 15 days, this thread will be transitioned to community support. The community users will be able to help you with your follow-up questions.