nesting iPar?

Hi all,

I am trying to determine why I am having problems netlisting using
Spectre when iPar is involved in a nested function.

For instance nrs=int(iPar("foo")) does not resovle and so shows up as
nrs=int(iPar("foo")) in the netlist and thus creates an error:
Function 'iPar' is undefined or is used recursively. when the
simulation is started.

Are there any hints for resolving this issue? Anything I should ensure
is set? For instance the netlisting mode is set for analog.

Unfortunately CDSDOC is of little help with regard to this issue or
I am not looking in the right place.

Regards,
sam

 

Make sure you have the "parseAsCEL/parseAsNumber" set properly in the
CDF at each level the parameter is being passed. iPar/pPar are CEL
expressions.

-Brad

 

BTW: int is an undocumented internal cadence function. Use fix instead

 

Thanks Guenther,

The int function is used in the spectre Netlisting, so I believe it is
ok. It is documented under the Spectre Circuit Simulator Reference
section in the CDSDOC.

sam

 

Hi Brad,

THANKS,

That was it! I set parseAsNumber to yes and it worked, parseAsCEL was
already set to yes. I was confused because other parameters with
iPar()s evaluated fine despite parseAsNumber being set to NO. Seems
that if iPar() was nested, as another example 1/iPar("foo"), it did not
evaluate unless parseAsNumber was set to yes. Kind of odd. Any ideas
why this is?

FYI, the iPar()s that evaluated with parseAsNumber set to now are
simple expressions like: iPar("foo1") * iPar("foo2")

Regards,

Sam

 

Hi Sam,

I think the problem is that if you don't have parseAsNumber set to yes - using
the result of this expression in another expression will cause trouble -
because it doesn't see it as being a number.

Regards,

Andrew.

 

Yes - it's important not to confuse AEL (or CEL) expressions with SKILL.
These are the "Analog Expression Language" functions - like iPar() etc, and
are often available natively in the simulator too - like int(), and not SKILL
expressions.

Regards,

Andrew.

 

Andrew,

There is scarce descriptions of the available function in spectre,
although the majority of the functions are recognizable, it would be
great if there was a place to confirm them.

For instance, I am assuming that fmod() is the same as the mod() in
skill. Am I correct?

Best Regards,
Sam

 

spectre -h expressions

is a good place to look. I think this is probably in the spectre documentation
too - since that documentation is built from the "spectre -h" output.

man fmod

will tell you what fmod does. mod() in SKILL is an integer function, whereas
fmod works with floats.

Andrew.

 

Thanks so much Andrew for the fmod help.

Sam