Calibre
Is the XREF XNAME SOURCE OFF statement order dependent?
2023-05-16T11:39:15.000-0400
IC Verification & Signoff
Summary
XREF XNAME SOURCE OFF statement is order dependent and it should appear before outputting the statements that it affects.
Details
As the QS scripts are Tcl based, they are executed sequentially and not in series.
Consider the following 2 cases:
In the query.tcl script the order of the statements is following:
# write the source placement hierarchy files (sph) SOURCE HIERARCHY WRITE ./bad.sph # Suppress X on the instance for gate flow XREF XNAME SOURCE OFF
As the bad.sph file was written before the execution of XREF XNAME SOURCE OFF, accordingly, the file didn’t have the expected changes.
If we switch the statements’ location, so that writing the source file comes after the command “XREF XNAME SOURCE OFF”, then the file “bad.sph” would have all the expected results.
In the query.tcl script the order of the statements is following:
# suppress X on the instance for gate flow XREF XNAME SOURCE OFF # write the source placement hierarchy files (sph) SOURCE HIERARCHY WRITE ./good.sph
This is the correct order, therefore we will see the output as expected.
So, for the right output of this command, it’s obligatory to add the statement “XREF XNAME SOURCE OFF” prior to outputting the statements that it affects, such as:
INSTANCE XREF WRITE LAYOUT HIERARCHY WRITE LAYOUT NET XREF WRITE NET XREF WRITE SOURCE HIERARCHY WRITE