Efficient Implementations of Multi-pumped Multi-port Register Files in FPGAs

Abstract

Existing implementation methods of multi-port register files (MPo-RF) in FPGAs are not scalable enough to deal with the increased number of ports due to higher logic area and power. While the usage of dedicated block RAMs (BRAMs) limits the designer to use only single read and single write port, slice based approach causes large resource occupation and degrades design performance significantly. Similarly, the conventional multi-pumping (MPu) approaches are not efficient enough due to increased combinational delay and area of huge multiplexers. In this paper, we propose a new design which exploits the banking and replication of BRAMs with efficient shift register based multi-pumping (SR-MPu) approach. While increased port number causes internal frequency drops in conventional multiplexer based MPu approaches, it does not affect internal operating frequency of our SR-MPu methodology. Test results on Xilinx Virtex-5 XC5VLX110T FPGA show that our 32-bit 12-read & 6-write (12R&6W) RF can operate internally up to 429 Mhz while 64-bit version up to 408 Mhz. The speed of our RF is independent from MPu factor and occupies lower logic resources up to 47% when compared with other design methods. In terms of energy consumption, our RF design saves energy up to 26% according to the Xilinx Power Analyzer (XPA) results.