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NAME

       LooN - Local optimizations of Nets.

SYNOPSIS

       loon  [-hmxlo] input_file output_file  [lax_file]

DESCRIPTION

       loon is a CAD tool that allows to remove fanout problems within a gate netlist and also to
       optimize the delay.  The netlist can be hierarchical and is flattened if necessary.   loon
       runs  in  batch  mode  and  a  parameter  file  can  be  used (see man lax) to parametrize
       optimization by adding informations on outputs (fanin),  inputs  (fanout,  delay)  and  by
       setting  general parameters such as optimization level.  loon permits to compute delays of
       gates in the netlist and gives the critical path in the netlist.  The global  optimization
       of  loon  performs  gate  repowering  to  decrease  the  critical  path  delay  and global
       capacitance.  Buffers are only inserted in critical path.

         lax Parameter file description
       The lax file is common with other logic synthesis  tools  and  is  used  for  driving  the
       synthesis process.  See lax(5) manual for more detail.

       lax  uses  a  lot  of  parameters  to  guide  every  step  of the synthesis process.  Some
       parameters  are  globally  used  (for  example,  optimization  level  whereas  others  are
       specifically  used  (load  capacitance  for  the  netlist optimization only).  Here is the
       default lax file (see the user's manual for further information about the  syntax  of  the
       '.lax' file):

          Optimization mode = 2 (50% area - 50% delay)
          Input impedance = 0
          Output capacitance = 0
          Delayed input = none
          Auxiliary signal saved = none

OPTION

       -h        Help mode. Displays possible uses of loon.

       -o input_file
                 Overwrites  the  source  file if no output_file is given. This can be usefull if
                 you don't want several netlist files.

       -m optim_mode
                 Optimization mode. Can be defined in lax file, it's only a shortcut to define it
                 on  command  line.  This  mode  number  has an array defined between 0 and 4. It
                 indicates the way of optimization the user wants. If 0 is  chosen,  the  circuit
                 area  will be improved. On the other hand, 4 will improve circuit delays. 2 is a
                 medium value for optimization.

       -x xsch_mode
                 Generate a '.xsc' file. It  is  a  color  map  for  each  signals  contained  in
                 output_file  network. This file is used by xsch to view the netlist. By choosing
                 level 0 or 1 for xsch_mode, you can color respectively the critical path or  all
                 signals with delay graduation.

       -l lax_file
                 Just another way to show explicitely the LAX parameter file name.

ENVIRONMENT VARIABLES

       The following environment variables have to be set before using loon :

       MBK_CATA_LIB  gives  the  auxiliary  paths  of the directories of input files (behavioural
              description).

       MBK_TARGET_LIB gives the path (single) of the directory  of  the  selected  standard  cell
              library.

       MBK_IN_LO gives the input format of the structural description.

       MBK_OUT_LO gives the output format of the structural description.

EXAMPLE

       You can call loon as follows :
            loon alu alu_loon

SEE ALSO

       loon(1),  boog(1), boom(1), lax(5), vbe(5), proof(1), asimut(1), vhdl(5), ocp(1), nero(1),
       sxlib(5).