CLARINET: A quire-enabled RISC-V-based framework for posit arithmetic empiricism

• Published in: Journal of systems architecture Vol. 135; p. 102801
• Main Authors: Sharma, Niraj N., Jain, Riya, Pokkuluri, Mohana Madhumita, Patkar, Sachin B., Leupers, Rainer, Nikhil, Rishiyur S., Merchant, Farhad
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2023
• Subjects: Custom-instructions; Open-source hardware; Posit-arithmetic; RISC-V; RISC-V; Custom-instructions; Posit-arithmetic; Open-source hardware
• ISSN: 1383-7621; 1873-6165
• DOI: 10.1016/j.sysarc.2022.102801

Many applications require high-precision arithmetic. IEEE 754-2019 compliant (floating-point) arithmetic is the de facto standard for performing these computations. Recently, posit-arithmetic has been proposed as a drop-in replacement for floating-point arithmetic. The posit data representation and arithmetic claim several advantages over the floating-point format and arithmetic, including higher dynamic range, better accuracy, and superior performance-area trade-offs. However, very few accessible and holistic frameworks facilitate the validation of these claims of posit-arithmetic, especially with long accumulations (quire). We present a consolidated general-purpose processor-based framework to support posit-arithmetic empiricism. Users can seamlessly experiment using posit and floating-point arithmetic in their applications since the framework is designed for the two number systems to coexist. Melodica is a posit-arithmetic core that implements parametric fused operations on the quire data type. Clarinet is a Melodica-enabled processor based on the RISC-V ISA. To the best of our knowledge, this is the first-ever integration of the quire in a RISC-V core. We report results from application studies on Clarinet and benchmark common linear algebra and computer vision kernels. We synthesize Clarinet on a Xilinx FPGA and present utilization and timing data. Clarinet and Melodica remain actively under development and are available as open-source.