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AR# 4735

A1.5/F1.5 PAR - MPPR gives reasonable results at first cost table run, but unreasonable results on subsequent cost tables.

Description

When running MPPR (with 4085xl targeted) starting at cost table 2, reasonable timing scores are given. When MPPR moves to cost table 3 and so forth very unreasonable timing scores are given. Also takes forever to run through PAR sequence. This happens in both Unix and NT.

This is a problem with the High Density Placer (XC4085XL and above).

Solution

1

Work around.
Run PAR using only one cost table at a time. A shell script can be
created to run multiple cost tables using the "-t" switch to specify
the cost table for each pass.

This issue is still under investigation so a release date for a fix has
not been scheduled.

2

A fix for this problem is included in the 1.5i Service Pack 1. For details
on this Service Pack see http://www.xilinx.com/techdocs/5514.htm
AR# 4735
Date Created 08/31/2007
Last Updated 10/05/2008
Status Archive
Type General Article