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Development System Reference Guide www.xilinx.com 163
Guided PAR
R
Example 4:
The following command runs PAR (using the Turns Engine) on all nodes listed in the
allnodes file. It runs 10 place and route passes at placer effort level med and router effort
level std on the mydesign.ncd file.
par
–m allnodes –pl med –rl std –n 10 mydesign.ncd output.dir
Note:
This command is not supported on Windows operating systems.
Guided PAR
When PAR runs using a guide design as input, PAR first places and routes any
components and signals that fulfill the matching criteria from the guide file.
Optionally, PAR reads a previously placed and routed NCD file as a guide file to help in
placing and routing the input design. This is useful if minor incremental changes have
been made to create a new design. To increase productivity, you can use your last design
iteration as a guide design for the next design iteration, as shown in the following figure:
Two command line options control guided PAR. The –gf option specifies the NCD guide
file, and the –gm option determines whether exact or leverage or incremental mode is used
to guide PAR.
The guide design is used as follows:
• If a component in the new design is constrained to the same location as a component
placed in the guide file, then this component is defined as matching.
• If a component in the new design has the same name as a component in the guide
design, that component matches the guide component.
• If a signal in the new design has the same name as a signal in the guide design, the
signal matches the guide signal.
Figure 9-2: Guided PAR for Design
NCD
Guide File
X7202
PAR
NCD
Input Design
NCD
Placed and Routed
Design
First PAR Run
NCD
Modified Input Design
PAR
Second PAR Run
NCD
New Placed and Routed
Design