Publication
Several techniques have been proposed for automatically searching for FPGA switch-blocks which typically show some tangible advantage over the well-known academic architectures. However, the resulting switch-blocks usually exhibit high levels of irregularity, in contrast with what can be observed in a typical commercial architecture. One wonders whether the architectures produced by such search methods can actually be laid out in an efficient manner while retaining the perceived gains. In this work, we propose a new switch-block exploration method that enhances a recently published search algorithm by combining it with ILP, in order to guarantee that the obtained solution satisfies arbitrary regularity constraints. We measure the impact of regularity constraints commonly seen in industrial architectures (such as limiting the number of different multiplexer sizes or forced sharing of inputs between pairs of multiplexers) and observe benefits to the routability of complex circuits with only a limited reduction in performance.