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Explorer
Explorer
8,287 Views
Registered: ‎03-18-2008

Multi Pass Place and Route

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Xilinx Employee
Xilinx Employee
8,245 Views
Registered: ‎11-28-2007

Re: Multi Pass Place and Route

Here is what the link that you sent out says: For Virtex®-5 devices, only the Route Only and Reentrant Route options are available.


For Virtex5, map only works in timing driven mode (i.e. map -timing), which means the placement is done in map and par only routes the design. You wouldn't gain too much by only changing the cost table for par.

 

Cheers,

Jim

Cheers,
Jim
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Xilinx Employee
Xilinx Employee
8,237 Views
Registered: ‎07-01-2008

Re: Multi Pass Place and Route

MPPR varies placement cost tables during PAR. Since placement is always done during MAP for V5 devices, MPPR is not suitable. MPPR is being phased out in ISE 11.1, but SmartXplorer will support a new MPPR mode that will vary the cost tables during the MAP phase. You can have it find the best strategy and then run cost table iterations on that, or you can just go straight into cost table mode if you already have a best strategy identified. Windows machines will now support SmartXplorer also.

 

Until, 11.1 is available it is possible to write command line scripts that will loop through MAP/PAR using multiple cost tables. The following is a simple csh script that I use to run ten cost tables:

 

---cut here--- 

#!/bin/csh -f

 

set i=1

while ($i<11)

 

map -intstyle ise -pr b -timing -ol high -t $i -o mapped_t$i design.ngd

par -w -intstyle ise -ol high -t $i mapped_t$i routed_t$i

 

@ i++

end

---cut here--- 

 

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