VPR and T-VPack 5.0.2 Known Bugs


Current Version: 5.0.2 -- April 24, 2009.

Routing sometimes fails for heterogeneous blocks with height >= 3

Problem:
The bounding box used by the router is calculated according to the bottom tile of the heterogeneous block, this means that it is too small for blocks with height greater than 1. So it may not route for blocks with height >= 3 using default settings.

Solution:
set bb_factor to max height + 2 for example, if your heterogeneous block has height 4, -bb_factor 6 This will have a small runtime impact.

Incorrect Routing Area For Single-Driver Routing in version 5.0, fixed in version 5.0.2

Problem:
The multiplexer area for single-driver routing is not being counted.

Solution:
In the file rr_graph_area.c on line 421, replace the code:

trans_per_mux(rr_node[from_node].num_wire_drivers + rr_node[from_node].num_opin_drivers,
with
trans_per_mux(rr_node[from_node].fan_in,


Note: The results in the VPR 5.0 paper submitted to FPGA 2009 counts area correctly and does not have this bug. The current version has this bug fixed


If you have questions, comments, or bug reports regarding VPR or the CAD tool flow please e-mail vpr@eecg.utoronto.ca