Module Placement Using Constraint Programming in Run-Time Reconfigurable Systems

Run-time reconfiguration has the potential to allow reuse of resources and the reduce cost of FPGA-based systems. To compute feasible placement locations for PR modules in such systems, multiple constraints have to be evaluated. This includes unused area, placement of heterogeneous resources and communication requirements of the PR module. To improve resource utilization, both polyomino shaped PR modules and PR modules with layout variants have been suggested. In order to compute placement locations for relocatable PR modules, the embedded system has to perform more computation. In this paper, our main target is to demonstrate a constraint solver which computes placement positions at run-time. We have measured the performance of the constraint solver when executed on a MicroBlaze soft CPU. Our experiments show execution times within 30ms when executing the constraint solver on a MicroBlaze soft CPU. The results show that it is indeed feasible to compute placement positions at run time for relocatable PR modules using a constraint solver.