if statement error in adexl

OK, so it appears you are trying to use a SKILL expression for the condition. This only works if the expression can be fully evaluated inside ADE XL (or the newer supported Explorer/Assembler; ADE XL is obsolete), and if some of the variable references are not understood by ADE (e.g. they are being set in an external spectre include file or varied in Monte Carlo), ADE attempts to evaluate the expression and if it fails, passes it through to the netlist. Since it's not a valid Spectre expression (it's not in Spectre's language), it will fail, unsurprisingly.

You'd need to use the Spectre ternary expression as I showed in one of your previous posts. 

Andrew

OK, so it appears you are trying to use a SKILL expression for the condition. This only works if the expression can be fully evaluated inside ADE XL (or the newer supported Explorer/Assembler; ADE XL is obsolete), and if some of the variable references are not understood by ADE (e.g. they are being set in an external spectre include file or varied in Monte Carlo), ADE attempts to evaluate the expression and if it fails, passes it through to the netlist. Since it's not a valid Spectre expression (it's not in Spectre's language), it will fail, unsurprisingly.

You'd need to use the Spectre ternary expression as I showed in one of your previous posts. 

Andrew

Hi Andrew,

actually with ternary expression(following code) I already get the right result, before this I tried to use "if statement" but I failed, I just want to know why.

I_cout = (IFL !=11) ? 0 : (IFL==11) &&(cin_1==0 && a_1==vdd && b_1==vdd) || (cin_1==vdd && a_1==0 && b_1==vdd)  ||  (cin_1==vdd && a_1==vdd && b_1==0)  ||  (cin_1==vdd && a_1==vdd && b_1==vdd) ? current : -current

In user guide of spectre I found how to write if statement, so in adexl I wrote my code like:

I_cout =  if(IFL==11) {if((cin_1==0 && a_1==vdd && b_1==vdd) || (cin_1==vdd && a_1==0 && b_1==vdd) || (cin_1==vdd && a_1==vdd && b_1==0) || (cin_1==vdd && a_1==vdd && b_1==vdd)) {current} else {-current}} else {0}

And in "Run summary" I got 4 points sweep, which is not supported in monte carlo simulation. I didn't know where these points come from. So I tired to change the code like what I have posted, it's SKILL and but no point sweeps. It's weird

Huh? Where in the Spectre User Guide does it say that an if statement like that is supported? Spectre has a "structural if" which is used for conditionally instantiating instances - it is not for use in expressions (as far as I can see there's nothing that says that - in Spectre 20.1 docs it's on page 190).

I was able to enter (in IC6.1.8 ISR21, in ADE XL) the I_cout ternary expression - although it doesn't like it if you try to add the variable and add it on the "Create Global Variable" form. Best to add a simple value, and then in the box in the Global Variables section in the Data View assistant, click, erase the simple value, and then paste in your long expression.

I suspect that's why it's getting confused as a sweep - the colons might be confusing matters.

Which IC sub-version are you using? It may be that it's something old (which might also explain why you're using the obsolete ADE XL) and there's an issue there?

It might just be simplest to put the expression into an include file (using ternary) rather than trying to enter it into the ADE XL global variables. The challenge here is that you're mixing some things in a spectre file and some in the UI and things are getting a bit mixed up.

Andrew

Thanks andrew. Yes you are right, I confused the "structure if" and "if statement" in expression. Ternary expression solved my problem