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Constraint issue

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Hi,
 
I’m trying to constraint two fields through a keep statement, but I’m receiving an error. This is the code:
 
struct packet{
...
    clkm: uint;
    keep soft clkm == 100;
 
    pkt_delay: uint;
    keep soft pkt_delay * 2 * clkm
...
};
  
The error message:
  
      Previous constraints reduced its range of possible values,
        then the following constraint contradicted these values:
          keep pkt_delay * 2 * clkm
        Reduced: packet_s-@20.(pkt_delay*2*clkm) from [0..9999] into []
          Using: packet_s-@20.pkt_delay == [2116432017]
          Using: packet_s-@20.clkm == [100]
 
It seems that the last keep is ignored when attributing value to fields clkm and pkt_delay; I tried without the “soft” in the keep statements but received the same error.
 
Thanks in advice
 
Montu


Originally posted in cdnusers.org by vbdc_montu

  • My previous post is incorrect: when I use the code above I didn’t receive any errors, but the constraints seems to be ignored and a get values like 1270727026 for the pkt_delay field. I get the error above when I remove the soft constraints

    Thanks for any suggestion


    Originally posted in cdnusers.org by vbdc_montu

  • if you're using PGEN (rather than IntelliGen) please try this:

    keep soft pkt_delay == calc_pkt_delay();

    calc_pkt_delay(): uint is {
    gen result keeping {
    it < 10000 / (2 * clkm);
    };
    };


    Yaron


    Originally posted in cdnusers.org by thinkverification

  • Hi Yaron, I’m using IntelliGen. But I tried:



    keep pkt_delay < 10000 / 10000 / (2 * clkm);



    , as you suggested inside your method and it worked (and I get surprised because I think I have tried this before and still get the error...).



    Anyway, it worked!



    Thank you!


    Originally posted in cdnusers.org by vbdc_montu

  • Great! Glad I could help.


    Originally posted in cdnusers.org by thinkverification

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