We present a new approach to the problem of register-transfer level design optimization of pipelined data paths.
The output of high level synthesis procedures, such as Sehwa, consists of a schedule of operations into time steps,
and a fixed set of hardware operators. In order to obtain a register-transfer level design, we must assign operations
to specific operators, values to registers, and finish the interconnections. We first perform module assignment
with the goal of minimizing the interconnect requirements between RT-level components as a preprocessing
procedure to the RT-level design. This will result in a smaller netlist which makes the design more compact and
the design process more efficient. In addition to reducing the total number of interconnects, this approach will
also reduce the total number of multiplexors in the design by eliminating unnecessary multiplexing at the inputs
of shared modules. The interconnect sharing task is modeled as a constrained clique partitioning problem. We
developed a fast and efficient polynomial time heuristic procedure to solve this problem. This procedure is 30–50 times faster than other existing heuristics while still producing better results for our purposes. Using this
procedure, we can produce near optimal interconnect sharing schemes in a few seconds for most practical size
pipelined designs. This efficient approach will enable designers to explore a larger portion of the design space
and trade off various design parameters effectively.
Register-Transfer Synthesis of Pipelined Data Paths