Experimental Software Systems: Hardware-Software Co-Design of an Experimental Real-Time Operating System and a Microcontroller Architecture

9806645 Stewart, David B. Jacob, Bruce L.马里兰大学，College Park实验软件系统：实验实时操作系统和微控制器架构的软硬件协同设计一种软硬件协同设计策略被用于为实时嵌入式系统创建一个环境，该环境包括用于微控制器的实时操作系统（RTOS）和一组增强微架构实时能力的硬件机制。该项目通过在模拟处理器上进行广泛的测试来验证该实验系统，并在广泛的设计选择中测量硬件架构扩展的成本效益。硬件方面的主要贡献是在主处理器核心上增加了多个“纳米处理器”和软件管理的缓存；它们都是软件可配置的有限状态机（FSM），处理能力有限，但都可以访问大多数处理器状态。这些硬件机制与底层微架构是正交的，即使在低成本的微控制器中也可以低成本地实现。RTOS将其所有高开销操作系统功能作为fsm实现，并将其映射到可配置硬件上。每个纳米处理器都成为操作系统的个人助手，执行诸如中断优先级排序、过滤输入/输出或充当高分辨率计时器等日常任务。这就为应用程序在主处理器核心上留下了100%的CPU处理时间。

9806645 Stewart, David B. Jacob, Bruce L. University of Maryland, College Park Experimental Software Systems: Hardware-Software Co-Design of an Experimental Real-Time Operating System and Microcontroller Architecture A hardware-software co-design strategy is being used to create an environment for real-time embedded systems, comprising a real-time operating system (RTOS) for microcontrollers, and a set of hardware mechanisms that enhance a microarchitecture's real-time capabilities. The project validates this experimental system through extensive testing on a simulated processor, and measures the cost-effectiveness of the hardware architecture extensions over a wide range of design choices. The central contribution on the hardware side is the addition of multiple "nanoprocessors" and software-managed caches to the main processor core; each of these is a software-configurable finite state machine (FSM) with limited processing capabilities, but each has access to most of the processor state. These hardware mechanisms are orthogonal to the underlying microarchitecture and can be implemented inexpensively even in a low-cost microcontroller. The RTOS implements all of its high-overhead operating system functions as FSMs that are mapped onto the configurable hardware. Each of the nanoprocessors becomes a personal assistant to the operating system, performing mundane tasks such as prioritizing interrupts, filtering input/output, or acting as high-resolution timers. This leaves the full 100% of CPU processing time on the main processor core for applications.