LOON(1) 						     CAO-VLSI Reference Manual							   LOON(1)

NAME

       LooN - Local optimizations of Nets.

ORIGIN

       This  software  belongs	to  the  ALLIANCE CAD SYSTEM developed by the ASIM team at LIP6 laboratory of Universite Pierre et Marie CURIE, in
       Paris, France.

       Web : http://asim.lip6.fr/recherche/alliance/
       E-mail : alliance-users@asim.lip6.fr

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  hierar-
       chical  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  per-
       mits  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 grad-
		 uation.

       -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).

BUG REPORT

       This tool is under development at the ASIM department of the LIP6 laboratory.
       We need your feedback to improve documentation and tools.

ASIM
/LIP6							   Sept 01 2000 							   LOON(1)