Provided by: alliance_5.0-20110203-4_i386
LooN - Local optimizations of Nets.
loon [-hmxlo] input_file output_file [lax_file]
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'
Optimization mode = 2 (50% area - 50% delay)
Input impedance = 0
Output capacitance = 0
Delayed input = none
Auxiliary signal saved = none
-h Help mode. Displays possible uses of loon.
Overwrites the source file if no output_file is given. This
can be usefull if you don't want several netlist files.
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.
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.
Just another way to show explicitely the LAX parameter file
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.
You can call loon as follows :
loon alu alu_loon
loon(1), boog(1), boom(1), lax(5), vbe(5), proof(1), asimut(1),
vhdl(5), ocp(1), nero(1), sxlib(5).