Comparison-Free Bit-Stream Generation for Cost-Efficient Unary Computing

Today, unconventional hardware design techniques based on simple data representations are receiving more and more attention. Unary computing is one of these techniques that processes data in the form of uniform bit-streams. The simplicity of implementing complex arithmetic operations and high tolerance to noise are the crucial advantages of unary systems. However, converting data from weighed binary radix to unary representation with existing comparator-based unary number generators is expensive regarding footprint area and power consumption. The problem aggregates when the number of inputs and data precision increase. This work proposes a low-cost, comparison-free, unary number generation mechanism for efficient data conversion from binary radix to unary representation. We introduce a serial and two parallel (an exact and an approximate) unary number generators. Synthesis results show that the proposed method reduces the hardware area, power consumption, and area-delay product for both serial and parallel designs compared to the state-of-the-art converter. We evaluate the efficiency of the proposed converter in four use cases.