| Summary: | 碩士 === 國立交通大學 === 資訊工程系 === 89 === The requirement in reducing the power of a processor has grown dramatically over the past few years. Research show that 50%~80% power are dissipated on the transmission between CPU and Memory. Power consumed on buses are decided by numbers of bit toggles on the buses, and instructions transmitted on buses determine the numbers of bit toggles at instruction buses.
In this thesis, we propose a basic-block instruction dictionary to reduce power consumption on instruction bus. Basic-block is one of the characteristics of program execution behavior that once a processor step into a basic-block, the whole block is executed except interrupt occurs. Our method tries to place the most frequently used basic-blocks into the instruction dictionary, which has smaller power consumption and is closer to CPU. The basic-blocks at original program are replaced by codewords indexing to the basic-blocks in the dictionary. We can reduce the power consumption when repeatedly executing on these basic-blocks because only the codewords are transferred in the instruction bus. A codeword lookaside buffer is also applied to provide more power reduction when accessing codeword repeatedly.
Experimental results show that on average 91.2% power reduction can be achieved with comparing to the base system. By accessing the instruction at internal dictionary, we can also improve the execution time by 16.4%.
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