溢出并行检测低功耗饱和乘加单元的研究与实现  

Study and Implementation of a Parallel Overflow Checking and Saturating Low Power MAC Units

作　　者：卢结成[1] 成学斌[1] 丁丁 朱少华 丁晓兵 桂万如[1] 

机构地区：[1]中国科学技术大学电子科学与技术系,安徽合肥230026 [2]上海精致科技有限公司,上海201203

出　　处：《小型微型计算机系统》2005年第10期1869-1872,共4页Journal of Chinese Computer Systems

摘　　要：提出了一种溢出并行检测的低功耗饱和乘加单元的新结构,并采用0．35μm CMOS工艺实现了该结构．采用这种结构 的MAC单元,不再需要额外地执行特殊的溢出检测指令,减少了取指译码的功耗开销．该结构通过专门的溢出检测单元来并 行检测计算溢出的情况,一旦检测到结果溢出,就立即停止最后一级的串行加法运算过程,采取饱和操作,把结果置成正的最大 值,保证以后无用的计算不要继续进行,降低了计算功耗．实验结果表明,同传统的MAC单元相比,计算溢出之后不但不用执 行专门的饱和溢出指令,提高了MAC单元的运算速度,而且可以节省10％-20％的功耗．This paper presents a new structure of parallel overflow checking and saturating low power MAC Unit. Because of the parallel overflow detection and calculation, this new MAC Unit needs not perform extra particular overflow detection instruction, so the power of the instruction fetching and decoding is saved. In the case of overflow, it stops the last stage＇s carry-propagated operation and keeps them in their own states although this addition has not been completely finished. Then, it saturates the results to the most positive number and prevents this stage from acting in order to save power. Finally, this MAC Unit is fabricated using 0. 35μm CMOS process. The experiments have proved that compared with conventional MAC Unit, it not only accelerate calculation, but also can save power from 10 to 20 percents.

关 键 词：溢出检测 饱和操作 Wallance树 乘加单元(MAC) DSP 

分 类 号：TP331[自动化与计算机技术—计算机系统结构]