Answers Database

M1.3 MAP: Designs which fit a target XC4000/E/L device in XACT may not fit when mapped with the M1 Mapper due to register ordering


Record #2274

Product Family:  Software

Product Line:  Merged Core

Problem Title:
M1.3 MAP: Designs which fit a target XC4000/E/L device in XACT may not
fit when mapped with the M1 Mapper due to register ordering



Problem Description:
Keywords: fit overmap register ordering 4000 -r utilization

Urgency: standard

General Description:

Reference Number: 16695
Some designs which fit a specific XC4000/E/L device in XACT
may not fit the same device when mapped with the M1 Mapper.
One possible reason for this may be the fact that the
M1 Mapper turns on register ordering by default.  In designs
containing registers, this may over-constrain the Mapper in
such a way that it no longer has sufficient flexibility to
achieve the optimal packing density for the design



Solution 1:

If the reason for the higher resource utilization is due
to register ordering, you can easily get around this by
reprocessing your design through Map with register
ordering disabled by specifying the -r option:

   map -r design.ngd




End of Record #2274