From: Florian Pigorsch (pigorsch_at_informatik.uni-freiburg.de)
Date: Wed Jul 12 2006 - 05:14:30 MDT
Hello list,
I need to convert BLIF-MV files to plain BLIF files. For this purpose I
normally use "read_blif_mv", a series of "collapse_child" to flatten the
hierarchy, and finally "write_blif". This works fine unless there are
latches with non-constant reset tables: vis simply uses a 2 (undefinied)
initial value for the corresponding BLIF latch, ignoring the
relationship to the BLIF-MV reset table.
On possible solution to this problem would be to transform the BLIF-MV
file such that all latches have constant resets by using a multiplexer
to select the reset-value in the first step instead of the latches value:
# the latch has a non-constant reset value
.reset r ff
.default 0
1 1
.latch in ff
->
# the output of firststep is 1 in the first step and 0 in the following
steps
.table zero
0
.reset firststep
1
.latch zero firststep
# the latch now has a constant reset value
.reset ff_out
0
.latch in ff_out
# select reset value in the first step
.table firststep ff_out ff_reset ff
0 - - =ff_out
1 - - =ff_reset
The resulting BLIF-MV file can then be converted to BLIF using the above
procedure.
Do you have any idea how to automate this transformation, or is there a
better solution?
Regards,
Florian Pigorsch
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