Development of a Energy-Recovering Low-Power Processor Architecture.

(a)开发能量回收处理器结构及其原型芯片实现。本文研究了能量回收处理器体系结构的新概念，并提出了其实现技术。由于绝热电荷回收和指令和数据重用，该架构与传统处理器设计相比，能耗降低了近两个数量级。为了评估该体系结构，设计并制作了一个原型LSI芯片。(b)发展减少加工硬件过渡活动的结构技术。通过数据驱动的操作数编码、自适应位宽压缩、操作数转换、绕过等方法，提出了几种新的方案来最小化功能单元的切换活动和寄存器文件。与传统技术不同，这些方法可以动态禁用其值保持不变的硬件位，从而在不影响处理精度的情况下尽可能减少不必要的信号变化。该方案简单易行。(c)系统存储器可变电压降低的体系结构技术的发展。在指令发布队列、数据和指令缓存中提出了新的自适应降压电路技术。与现有的设计方法相比，该方法根据指令并行性（问题队列）和访问位置（缓存）动态调整供电电压，在不影响性能和非常小的面积开销的情况下，将这些单元的能量耗散减少了两倍。

(a) Development of a Energy-Recovering Processor Architecture and its prototype chip implementation. We investigated a new concept of Energy-Recovering Processor Architecture and presented techniques for its implementation. Due to adiabatic charge-recovering and instruction and, data reuse, the architecture lowers the energy consumption by almost two orders of magnitude in comparison to the traditional processor design. To evaluate the architecture, a prototype LSI chip have been designed and fabricated.(b) Development of Architectural Techniques for Reducing Transition Activity of Processing Hardware.Several new schemes to minimize switching activity of functional units, and register files by datadriven operand encoding, adaptive bit-width compression, operand transformation, bypassing, etc. have been proposed. Unlike conventional techniques, these methods can dynamically disable the hardware bits whose values remain unchanged, thus reducing unnecessary signal variations as much as ha]f without affecting the processing accuracy. The schemes are simple and easy in implementation.(c) Development of Architectural Techniques for Variable Voltage Reduction of System Memory. New circuit techniques for adaptive voltage reduction in instruction issue queue, data and instruction caches have been proposed. In contrast to existing design approaches, the methods dynamically adjust the supply voltage to the level of instruction parallelism (issue queue) as well as the locality of accesses (caches), reducing the energy dissipation in these units by a factor of two without any impact on performance and very small area overhead.