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Difference in ADE variable expression evaluation with and without a parametric sweep

ItsMichael

Hello everyone,

I'm using an "if else" statement inside the (local design) variable value in ADE Assembler. The expression is used to assign a string value to a corresponding integer value.

The variable is defined as: 

CG_MODE = if(CG_MODE_s=="LCG" then LCG else if(CG_MODE_s=="HCG" then HCG else if(CG_MODE_s=="HDR" then HDR else 0)))

And CG_MODE_s can get string values such as "LCG", "HCG", "HDR".
The variables HCG, LCG and HDR are simple integers that are used inside the testbench.

This is basically a wrapper to use strings which are much easier to read and understand when sweeping these values.

The issue I have is if I'm running a single point simulation (i.e. - no parameter sweeps) the generated netlist contains the if statement inside the parameter (which I guess is not a legal netlist statement):

parameters {some parameters omitted} CG_MODE_s="LCG" HCG=1111 HDR=2222 \
LCG=3333  \ CG_MODE=if(CG_MODE_s=="LCG" then LCG else if(CG_MODE_s=="HCG" then HCG \
else if(CG_MODE_s=="HDR" then HDR else 0)))

But if I sweep any parameter in the simulations (not corners though) than the netlist contains the already evaluated value returned from the if statement (which works as expected):

parameters {some parameters omitted} CG_MODE_s="LCG" HCG=1111 HDR=2222 \
LCG=3333  \ CG_MODE=3333

Clearly the variable if statement is evaluated or parsed/translated differently into the netlist if I'm running a parametric sweep or not. Why does that happen ?
Is there any workaround for this ? or a better way to implement this parameter "alias" that I wanted ?

Currently I use a workaround which involves always sweep some variable and canceling those run points in the run preview window, but this is not an ideal solution.

Thanks in advance,
Michael Shekhtman
  • Andrew Beckett

    Michael,

    Which IC sub-version are you using, and are you using LSCS or ICRP in your job policy? I recall some fixes related to this, but I want to narrow down my starting point for checking behaviour to what you're actually using.

    Thanks,

    Andrew

  • ItsMichael
    in reply to Andrew Beckett

    Hi Andrew, thanks for the quick response.
    The version I'm using is IC6.1.8-64b.500.19.EHF10176

    I originally ran this in LSCS mode but the same issue occurs in ICRP mode.
    I noticed the job log in ICRP mode shows the error message:
    \o ERROR (SFE-874):
    \o "input.scs" 16: Cannot run the simulation because syntax
    \o error `Unexpected quoted string ""LCG"' was encountered at
    \o line 16, column 2
    \o 6. Correct the syntax error and rerun the
    \o simulation.
    \o ERROR (SFE-683): "input.scs" 16: Badly formed
    \o parameters statement.
    \o

    Line 16 in the netlist contains the faulty parameter with the if expression instead of the evaluated expression value.

    BR,
    Michael

  • ItsMichael
    in reply to ItsMichael

    Any thoughts ?
    Btw, I just noticed that running the test in a Run Plan creates a correct netlist even without sweeping any variable.

  • Andrew Beckett
    in reply to ItsMichael

    Sorry - got a bit tied up at the time and overlooked this. I'll try to find some time tomorrow to check this.

    Andrew

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