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lvx - Logical Versus eXtracted net-list comparator
lvx format1 format2 filename1 filename2 [ -a ] [ -u ] [ -o ] [ -f ]
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-
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
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 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
-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 .
MBK_OUT_LO contains the expected format of the netlist output.
MBK_CATAL_NAME contains the name of the user cell catalog.
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