Instruction Encoding for Reducing Power Consumption of I-ROMs Based on Execution Locality

Koji INOUE  Vasily G. MOSHNYAGA  Kazuaki MURAKAMI  

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E86-A   No.4   pp.799-805
Publication Date: 2003/04/01
Online ISSN: 
DOI: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section of Selected Papers from the 15th Workshop on Circuits and Systems in Karuizawa)
Category: 
Keyword: 
low power,  instruction ROM,  embedded systems,  encoding,  

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Summary: 
In this paper, we propose an instruction encoding scheme to reduce power consumption of instruction ROMs. The power consumption of the instruction ROM strongly depends on the switching activity of bit-lines due to their large load capacitance. In our approach, the binary-patterns to be assigned as op-codes are determined based on the frequency of instructions in order to reduce the number of bit-line dis-charging. Simulation results show that our approach can reduce 40% of bit-line switchings from a conventional organization.