lvx - Logical Versus eXtracted net-list comparator
lvx compares two gate-level or block level net-list. The
goal is to compare a specification net-list (logical net-list), the input to
a place and route tool, with the physical net-list (extracted net-list)
obtained by the cougar(1) extractor.
The net-list 1 is considered as the logical net-list and net-list 2 as the
extracted net-list.
lvx is an one-level hierarchical tool:
- The two net-list are flattened, if the -f option is present, to the
cells contained in the catalog file. The path to the catalog file is
indicated in the MBK_CATA_LIB(1) variable for the cell library, and
in the MBK_WORK_LIB(1) variable with the name
MBK_CATAL_NAME(1) for user blocks ( catal(5) ) that are not
to be flattened.
- For both net-list, the instances are considered as black-boxes.
- The two net-list must have the same external connectors names.
- The two net-list must have the same instances names.
- The two net-list must have the same signals names for unconnected
signals.
- The two net-list cannot directly contain transistors.
Comparison is performed in three steps:
- Compare terminals.
- Compare instances.
- Compare connections.
- Compare unconnected signals.
If an error occurs during first or second step, a message is
immediately displayed and the third step will not start: lvx cannot
compare connections (signals) if terminals or instances are not equivalent.
The -o option allows to order connectors if the steps described before
have been reached successfully. Extracted_netlist is then saved on
disk. The file get the name filename2 suffixed by the value of
MBK_OUT_LO(1) variable.
Routers add automatically empty feed-through cells. These cells must not be
taken into account in the comparison. A cell that have the F
attribute in the catalog file ( catal (5) ) is considered as
feed-through cell, and are deleted, in memory, from the net-list where it
appears.
- -a
- Some routers generate layout with several physical connectors for power
and ground ( VDD or VSS ). If those connectors are not
internally connected, they will have different indexed names ( VDD1
, VDD2 etc...) in the extracted net-list. It is possible to perform
reduction on those power and ground connectors before comparison, using
the -a option. After reduction, each instance contains only one VDD
connector and one VSS connector, as the main figure.
- -o
- In this case, lvx produces a modified net-list (saved with the name
filename2 ), which is a copy of net-list 2 with ordered connectors.
Terminals and instance connectors are relisted in the order of the models
in net-list 1. The saved net-list is done with the MBK_OUT_LO(1)
format, so user has to set this variable before running lvx . If he
does not, default value is used, and net-list 1 could be lost if filename
are identical and input format same as output format.
If -a option is used, then the saved net-list is the reduced net-list with
only one VDD and one VSS .
- -u
- This option force lvx to check the consistency of unassigned
signals between the two netlists.
- -f
- The two net-lists are flattened to the leaf cells contained in the catalog
file. Usually the extracted net-list is a flatten net-list, while the
logical one can be a hierarchical net-list.
With logical_netlist named amd2901.vst and the
corresponding extracted_netlist as amd2901.al containing multiple
power connectors, the command line is :
- lvx vst al amd2901 amd2901 -a
- filename2.xx
- Netlist view saved when the -o option is present. The suffixe
depend on the MBK_OUT_LO(1) environment variable.
- MBK_CATA_LIB
- contains the directories where the cell librtaries are.
MBK_WORK_LIB contains the directory path of the working
directory, usually set to . (dot).
- MBK_OUT_LO
- contains the expected format of the netlist output.
- MBK_CATAL_NAME
- contains the name of the user cell catalog.
The string "_logic" is appended to the net-list 1 and
the string "_extract", is appended to the net-list 2.
Two kinds of error message can occur:
- A fatal error causes the program to exit. It happens when one of the
net-lists is not correct, lvx cannot construct internal structure
for compare.
- A compare error occurs when the figures are not identical. It happens when
basic objects (instances, connectors) do not exist in both net-list, or
when connections (signals) do not connect same terminals or instances in
the two net-lists.
Exit code 0 is returned for identical net-lists.
See the file buster/alliance/alc_bug_report.1.en.gz.