I am running Virtuoso version IC126.96.36.1990.10 and I have been having some problems streaming out a P-Cell to GDS. I have a custom SKILL P-Cell code that loads properly in Cadence and does not have any P-Cell evaluation errors. I have four tiles that uses this P-Cell that are placed in a holding cell and I get the following error when I stream out:
*WARNING* ("dbCreateParamInst" 0 t nil ("*Error* dbCreateParamInst: The stack used by pcell evaluation internal overflows.\n"))ERROR (211): Pcell evaluation has failed. This is because of either a syntax error or the usage of an unsupported XStream function in Pcell SKILL code. For more information refer to the standard output or CDS.log. To continue, either specify the ignorePcellEvalFail option in Stream In/Out options or correct the Pcell SKILL code. XStream failed
The strange thing is that each of the four tiles individually streamed out successfully to GDS. Can somebody help give a better description of the error: "The stack used by pcell evaluation internal overflows"? Does anybody have any idea of how this can be prevented?
Thanks in advance, Paul
Not sure if this will fix your problem, but look through your pcell code for any functions that are not contained in the Skill Language Reference. I was using int() in a pcell and it caused problems when translating until I changed it to floor(). Here are the functions supported in pcells:
absacosadd1addDefstructClassaliasalphalesspalphaNumCmpandappendappend1applyargcargvarrayparrayrefasinassoc, assq, assvatanatofatoiatombandbcdpbeginbitfield1bitfieldblankstrpbnandbnorbnotbooleanpborboundpbuildStringbxnorbxorcaar, caaar, caadr, cadr, caddr, cdar, cddr, ...carcase, caseqcdrcdsGetInstPathceilingchangeWorkingDircharToIntclearExitProcsclosecompareTimecompressconcatcondconsconstarcopycopy_<name>copyDefstructDeepcoscputimecreateDircshdeclaredeclareLambdadeclareNLambdadeclareSQNLambdadefinedefmacrodefMathConstantsdefpropdefstructdefstructpdefundefUserInitProcdefvardeleteDirdeleteFiledifferencedisplaydodraindtprededieditedlenvobjeqequaleqverrerrorerrseterrsetstringevalevalstringevenpexistsexitexpexpandMacroexptfboundpfileLengthfileSeekfileTellfileTimeModifiedfixfixpfloatfloatpfloorforforallforeachfprintffscanf, scanf, sscanffuncallfunobjgcgensymgeqpgetget_filenameget_pnameget_stringgetcgetchargetCurrentTimegetdgetDirFilesgetFnWriteProtectgetFunTypegetInstallPathgetLogingetPromptsgetqgetqqgetTempDirgetsgetShellEnvVargetSkillPathgetSkillVersiongetVarWriteProtectgetVersiongetWarngetWorkingDirgogreaterphelpifimportSkillVarindexinfileinportpinSchemeinSkillinstringintegerpintToCharisCallableisDirisExecutableisFileisFileEncryptedisFileNameisInfinityisLargeFileisLinkisMacroisNaNisReadableisWritablelambdalastlconcleftshiftlengthleqplesspletletrecletseqlinereadlinereadstringlistlistplistToVectorloadloadiloadstringloglog10lowerCasemake_<name>makeTablemakeTempFileNamemakeVectormapmapcmapcanmapcarmaplistmaxmeasureTimemember, memq, memvminminusminuspmodmodulomprocedurenconcnconsneedNCellsnegativepneqnequalnewlinenindexnlambdanotnprocedurenthnthcdrnthelemnullnumberpnumOpenFilesoddponepopenportporotherpoutfileoutportppairpparseStringplistpluspluspportppostdecrementpostincrementpprintpredecrementpreincrementprependInstallPathprintprintfprintlevprintlnprocedureprocedurepprogprog1prog2prognputdputpropputpropqputpropqqquotequotientrandomrangereadreadstringreadTablerealpregExitAfterregExitBeforeremainderremdremdqremExitProcremoverempropremqrenameFilereturnreverserexCompilerexExecuterexMagicrexMatchAssocListrexMatchListrexMatchprexReplacerexSubstituterightshiftrindexroundrplacarplacdschemeTopLevelEnvsetsetarraysetcarsetcdrsetFnWriteProtectsetofsetplistsetPromptssetqsetqbitfield1setqbitfieldsetShellEnvVarsetSkillPathsetVarWriteProtectsh, shellsimplifyFilenamesinsortsortcarsprintfsqrtsrandomsstatusstatusstrcatstrcmpstringpstringToFunctionstringToSymbolstringToTimestrlenstrncatstrncmpsub1substsubstringsxtdsymbolpsymbolToStringsymevalsymstrpsystemtableptableToListtailptantconctheEnvironmenttimestimeToStringtimeToTmtmToTimetruncatetype, typepunaliasunlessupperCasevectorvectorpvectorToListvi, vii, vilwarnwhenwhichwhilewritewriteTablexconsxCoordxdifferencexplusxquotientxtimesyCoordzeropzxtd
In reply to ahamlett:
I assume you meant the other way around? floor is supported, but int is not (it's not core SKILL, but a function provided by the analog tools). Essentially you can use core SKILL, db, dd, cdf, rod, tech and a few pc functions. You only listed core SKILL functions...
Anyway, I don't think this is the problem here. I can find no reports of this error occurring before.
I did a bit of digging, and I think it might be possible if you have a recursive pcell - or a pcell that ends up instanting itself.
I think you're going to have to report it to Cadence via customer support, including a testcase to reproduce it. I'm certainly interested, so if you want to send me a message with the SR number I can take a look.
In reply to Andrew Beckett:
Note, the latter part of my post was addressed to Paul, rather than Alan...
Oops, I meant that I changed int() to floor() and I forgot the functions starting with db, dd, cdf, rod, or tech.
I'd be interested to see where this goes too so please keep us updated.
Andrew and ahamlett,
Thank you for your help and replies. We began troubleshooting the code, and found that cellviews were opened using "dbOpenCellViewByType" and were not closed after opening it. We cleaned up those calls as much as possible by using dbClose, but we still saw the same problems. We could not find any calls to functions that are not allowed in P-Cells.
Since we could successfully stream out the tiles individually, we streamed out the tiles, then streamed them back into Virtuoso. This way, we retained the hierarchy and layout and removed the dependence of the P-Cell code.