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.\" Tool    : Man pages
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.\" Modified by Czo <Olivier.Sirol@lip6.fr> 1996,97
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.pl -.4
.TH LOON 1 "Sept 01 2000"  "ASIM/LIP6" "CAO\-VLSI Reference Manual"
.SH NAME
.TP
LooN \- Local optimizations of Nets.


.so jessie/alliance/alc_origin.1.en.gz

.SH SYNOPSIS
.TP
\f4loon\fP  [-hmxlo] \fIinput_file\fP \fIoutput_file\fP  [\fIlax_file\fP]
.br

.SH DESCRIPTION
.br
\f4loon\fP 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.
\f4loon\fP runs in batch mode and a parameter file can be used
(see man \f4lax\fP) to parametrize optimization by adding informations
on outputs (fanin), inputs (fanout, delay) and by setting general
parameters such as optimization level.
\f4loon\fP permits to compute delays of gates in the netlist and gives
the critical path in the netlist.
The global optimization of \f4loon\fP performs gate repowering to
decrease the critical path delay and global capacitance.
Buffers are only inserted in critical path.
.br


.br
\f4  lax Parameter file description\fP
.br
The lax file is common with other logic synthesis tools and is used
for driving the synthesis process. 
See \f4lax\fP(5) manual for more detail.

.br
\f4lax\fP uses a lot of parameters to guide every step of the synthesis process.
Some parameters are globally used (for example, \fIoptimization level\fP whereas others are specifically used (\f4load capacitance\fP 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):
.br

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


.SH OPTION
.TP 10
\f4\-h\fP
Help mode. Displays possible uses of \f4loon\fP.
.TP 10
\f4\-o input_file\fP
Overwrites the source file if no \fIoutput_file\fP is given. This can be usefull if you don't want several netlist files.
.TP 10
\f4\-m optim_mode\fP
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 \fI0\fP and \fI4\fP. It indicates the way of optimization the user wants. If \fI0\fP is chosen, the circuit area will be improved. On the other hand, \fI4\fP will improve circuit delays. \fI2\fP is a medium value for optimization.
.TP 10
\f4\-x xsch_mode\fP
Generate a '.xsc' file. It is a color map for each signals contained in \fIoutput_file\fP network. This file is used by \f4xsch\fP 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.
.TP 10
\f4\-l lax_file\fP
Just another way to show explicitely the \f4LAX\fP parameter file name.
.br

.SH ENVIRONMENT VARIABLES
.br
The following environment variables have to be set before using \f4loon\fP :
.HP
.ti 7
\fIMBK_CATA_LIB\fP gives the auxiliary paths of the directories of input files (behavioural description). 
.HP
.ti 7
\fIMBK_TARGET_LIB\fP gives the path (single) of the directory of the selected standard cell library. 
.HP
.ti 7
\fIMBK_IN_LO\fP gives the input format of the structural description.
.HP
.ti 7
\fIMBK_OUT_LO\fP gives the output format of the structural description.


.SH EXAMPLE
.br
You can call \f4loon\fP as follows :
.br
.br
	loon alu alu_loon



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


.so jessie/alliance/alc_bug_report.1.en.gz