Area and Delay Estimation in Hardware/Software Cosynthesis for Digital Signal Processor Cores

Nozomu TOGAWA  Yoshiharu KATAOKA  Yuichiro MIYAOKA  Masao YANAGISAWA  Tatsuo OHTSUKI  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E84-A   No.11   pp.2639-2647
Publication Date: 2001/11/01
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on VLSI Design and CAD Algorithms)
Category: Hardware/Software Codesign
area estimation,  delay estimation,  hardware/software cosynthesis,  digital signal processor (DSP),  microprocessor,  

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Hardware/software partitioning is one of the key processes in a hardware/software cosynthesis system for digital signal processor cores. In hardware/software partitioning, area and delay estimation of a processor core plays an important role since the hardware/software partitioning process must determine which part of a processor core should be realized by hardware units and which part should be realized by a sequence of instructions based on execution time of an input application program and area of a synthesized processor core. This paper proposes area and delay estimation equations for digital signal processor cores. For area estimation, we show that total area for a processor core can be derived from the sum of area for a processor kernel and area for additional hardware units. Area for a processor kernel can be mainly obtained by minimum area for a processor kernel and overheads for adding hardware units and registers. Area for a hardware unit can be mainly obtained by its type and operation bit width. For delay estimation, we show that critical path delay for a processor core can be derived from the delay of a hardware unit which is on the critical path in the processor core. Experimental results demonstrate that errors of area estimation are less than 2% and errors of delay estimation are less than 2 ns when comparing estimated area and delay with logic-synthesized area and delay.