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Title Combined Binary and Decimal Floating-Point Unit
Author Monsson, Peter Kjær
Supervisor Nannarelli, Alberto (System-on-Chip Hardware, Department of Informatics and Mathematical Modeling, Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark)
Institution Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark
Thesis level Master's thesis
Year 2008
Abstract There has been renewed interest in a number system for integrated circuits called decimal floating-point. There are inherent problems in todays binary floating-point numbers that require financial computations to be performed in software which is 100-1000 times slower than a hardware based equivalent. For example adding a 5% tax to a $0.70 phone call will round off wrongly in binary floating-point. With the increase in transistor count surpassing the increse in clock speed on modern computer processors, manufacturers are looking into new strategies for speeding up computations including the financial ones and a commercial processor with decimal floating-point already exists. Despite the interest, the problems of decimal arithmetic slower and requiring more area than binary remain. This thesis explores the possibility of combining binary and decimal floating-point units thereby saving area without sacrificing too much speed. In the course of this investigation a novel decimal fused multiply-add (FMA) based floating-point unit is developed and combined with a known binary FMA algorithm. This FMA primarily uses known components, but one major component – the decimal leading one predictor – is new. Synthesis results show that the latencies for the binary and decimal paths are comparable to current solutions, but the area used is much larger than the individual units. In order to make the FMA fulfill the goals of this thesis, further research should look into reducing area in the FMA. Before the area is reduced significantly, it is not recommended to use a combined binary and decimal floating-point unit.
Series IMM-M.Sc.-2008-78
Original PDF ep08_78_web.pdf (0.82 MB)
Admin Creation date: 2008-08-18    Update date: 2008-08-18    Source: dtu    ID: 222488    Original MXD