A multiplier, as a key component in many different applications, is a time-consuming, energy-intensive computation block. Approximate computing is a practical design paradigm that attempts to improve hardware efficacy while keeping computation quality satisfactory. A novel multicolumn 3,3:2 inexact compressor is presented in this paper. It takes three partial products from two adjacent columns each for rapid partial product reduction. The proposed inexact compressor and its derivates enable us to design a high-speed approximate multiplier. Then, another ultra-fast, high-efficient approximate multiplier is achieved utilizing a systematic truncation strategy. The proposed multipliers accumulate partial products in only two stages, one fewer stage than other approximate multipliers in the literature. Implementation results by Synopsys Design Compiler and 45 nm technology node demonstrates nearly 11.11% higher speed for the second proposed design over the fastest existing approximate multiplier. Furthermore, the new approximate multipliers are applied to the image processing application of image sharpening, and their performance in this application is highly satisfactory. It is shown in this paper that the error pattern of an approximate multiplier, in addition to the mean error distance and error rate, has a direct effect on the outcomes of the image processing application.

翻译：乘法器作为众多不同应用中的关键组件，是一种耗时且高能耗的计算模块。近似计算是一种实用的设计范式，旨在提升硬件效能的同时保持计算质量令人满意。本文提出了一种新型多列3,3:2非精确压缩器。该压缩器从相邻两列中各取三个部分积，以实现快速的部分积缩减。所提出的非精确压缩器及其衍生结构使我们能够设计出高速近似乘法器。随后，利用系统性截断策略实现了另一种超快高效的近似乘法器。所提出的乘法器仅在两个阶段内完成部分积累加，比现有文献中的其他近似乘法器少一个阶段。采用Synopsys Design Compiler和45纳米工艺节点的实现结果表明，第二种设计方案相比现有最快的近似乘法器速度提高了近11.11%。此外，将新型近似乘法器应用于图像锐化这一图像处理任务中，其性能表现高度令人满意。本文表明，近似乘法器的误差模式除了平均误差距离和错误率之外，对图像处理应用的结果也有直接影响。