FPGA-Optimised Uniform Random Number Generators Using LUTs and Shift Registers

FPGA-optimised Random Number Generators (RNGs) are more resource efficient than software-optimised RNGs, as they can take advantage of bit-wise operations and FPGA-specific features. However, it is difficult to concisely describe FPGA-optimised RNGs, so they are not commonly used in real-world designs. This paper describes a new type of FPGA RNG called a LUT-SR RNG, which takes advantage of bit-wise XOR operations and the ability to turn LUTs into shift-registers of varying lengths. This provides a good resource-quality balance compared to previous FPGA-optimised generators, between the previous high-resource high-quality LUT-FIFO RNGs and low-resource low-quality LUT-OPT RNGs. The LUT-SR generators can also be expressed using a simple C++ algorithm contained within the paper, allowing 60 fully-specified LUT-SR RNGs with different characteristics to be embedded in the paper, backed up by an online set of VHDL generators and test-benches.