基于ARM Cortex-M4的mbedOS调度机制剖析

Analysis of mbedOS Scheduling Mechanism Based on ARM Cortex-M4

为了能清晰理解mbedOS调度基本原理与机制,通过阐述ARM(Advanced RISC Machines)Cortex-M4内核对实时操作系统的支持特性,分析了实时操作系统常用的调度策略,采用流程图分析、上下文核心代码解析等方法重点剖析了SVC(Supervisor Call)中断、PendSV中断和SysTick中断3种mbedOS调度策略实现方法,最后以意法半导体的STM32L431芯片为例给出了mbedOS的线程调度剖析实践。通过对mbedOS的线程调度剖析,有助于深入理解mbedOS的调度机理,为设计多任务系统提供帮助,也为分析其他实时操作系统提供参考借鉴。

In order to clearly understand the basic principle and mechanism of mbedos scheduling,the support characteristics of arm cortex-m4 kernel for real-time operating system is studied.The common scheduling strategies of real-time operating system is analyzed.Using the methods of flow chart analysis and context core code analysis,this paper focuses on the implementation of three mbedos scheduling strategies,SVC(Supervisor Call)interrupt,pendsv interrupt and systick interrupt.Finally,taking stm32 l431 chip of STMicroelectronics as an example,the thread scheduling analysis practice of mbedOS is given.By analyzing the thread scheduling of mbedOS,it is helpful for readers to deeply understand the scheduling mechanism of mbedOS,provide help for the design of multitasking system,and also provide reference for the analysis of other real-time operating systems.