FPGA-Specific Custom VLIW Architecture for Arbitrary Precision Floating-Point Arithmetic

Yuanwu LEI  Yong DOU  Jie ZHOU  

Publication
IEICE TRANSACTIONS on Information and Systems   Vol.E94-D   No.11   pp.2173-2183
Publication Date: 2011/11/01
Online ISSN: 1745-1361
DOI: 10.1587/transinf.E94.D.2173
Print ISSN: 0916-8532
Type of Manuscript: PAPER
Category: Computer System
Keyword: 
variable-precision floating-point (VP) arithmetic,  Very Long Instruction Word (VLIW),  elementary function,  Newton's method,  polynomial approximation,  FPGA,  

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Summary: 
Many scientific applications require efficient variable-precision floating-point arithmetic. This paper presents a special-purpose Very Large Instruction Word (VLIW) architecture for variable precision floating-point arithmetic (VV-Processor) on FPGA. The proposed processor uses a unified hardware structure, equipped with multiple custom variable-precision arithmetic units, to implement various variable-precision algebraic and transcendental functions. The performance is improved through the explicitly parallel technology of VLIW instruction and by dynamically varying the precision of intermediate computation. We take division and exponential function as examples to illustrate the design of variable-precision elementary algorithms in VV-Processor. Finally, we create a prototype of VV-Processor unit on a Xilinx XC6VLX760-2FF1760 FPGA chip. The experimental results show that one VV-Processor unit, running at 253 MHz, outperforms the approach of a software-based library running on an Intel Core i3 530 CPU at 2.93 GHz by a factor of 5X-37X for basic variable-precision arithmetic operations and elementary functions.