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Xilinx / RapidWright

Build Customized FPGA Implementations for Vivado
http://www.rapidwright.io
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How to use blockplacer to place a design without specifying the location #45

Closed hpan5 closed 4 years ago

hpan5 commented 5 years ago

I'm trying to use plockplace to create a LUT without specifying the location

EDIFCell or2Cell = netlist.getHDIPrimitive(Unisim.OR2); EDIFCellInst or2Inst = top.createCellInst("or2Inst", or2Cell); Cell or2 = design.createCell("or2", or2Inst);

and use blockplacer to place and route the design Design d = new BlockPlacer2().placeDesign(design, false); d.routeSites(); new Router(d).routeDesign(); However, I got the following errors when I was trying to run the program:

WARNING: An illegal reflective access operation has occurred WARNING: Illegal reflective access by com.esotericsoftware.kryo.util.UnsafeUtil (file:/mnt/c/Users/27688/Documents/Git/rapidwright-2019.1.1-standalone-lin64.jar) to constructor java.nio.DirectByteBuffer(long,int,java.lang.Object) WARNING: Please consider reporting this to the maintainers of com.esotericsoftware.kryo.util.UnsafeUtil WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations WARNING: All illegal access operations will be denied in a future release Exception in thread "main" java.lang.NullPointerException at com.xilinx.rapidwright.design.Net.connect(Unknown Source) at autoplaced_or_lut.main(autoplaced_or_lut.java:64) What's the right way to use blockplace to place the design? Any hints and suggestions?

My edition of Lesson1.java can be found here: autoplaced_or_lut.zip

clavin-xlnx commented 5 years ago

The Block Placer (BlockPlacer2) is specifically built to place ModuleInst ojbects (instances of Module objects). These are generally smaller designs that have been placed and routed out of context of a full design. The fine grained placement and routing problem has already been decided and thus are reused by the Block Placer when moving all the cells as a contiguous unit.

It sounds like what you want is a general placement tool which RapidWright currently doesn't have yet. In order to place the LUT by BlockPlacer2 automatically, you would need to instantiated it in a separate design, place it, encapsulate it inside a Module and then create an instance of it (a ModuleInstance) in the design. This may not be the answer you are looking for, but I will attach a code example soon that illustrates how this could be done, although it may not be the best way to proceed.

clavin-xlnx commented 5 years ago

I have made a few minor changes to RapidWright and pushed them today. If you pull the latest changes and run the attached code (autoplaced_or_lut.zip), you should be able to achieve what you were expecting. It is a bit more tedious because the block placer only operates on module instances and so you have to package up the LUT (OR2) into a module and then create the ModuleInst of it in the design.

Typically, a Module and ModuleInst are defined by designs that come directly from Vivado, but you can generate them from scratch--you just have to be consistent in both the logical and physical creation of the netlist.