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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).