Development of compiler for real-time LOTOS programs with real-time multi-redezvous

本文定义了E-LOTOS的一个子类(RealTime LOTOS)，并针对其规范开发了一个编译器。编译器首先将一个给定的规范分解成多个基本模块，使每个模块只包括具有差异和迭代的事件序列，然后将每个模块映射到我们的实时线程库上的一个实时线程。在这里，线程之间的交互是通过共享变量来实现的。为了使每个线程能够及时执行其定时事件，我们还设计和实现了一种高效调度线程间定时多路会合的机制。为了将我们的编译器应用到多媒体系统开发中，我们实现了音视频处理的原语，并对编译器进行了修改，使其支持实时LOTOS规范。通过开发几个视频回放应用程序的实验，我们已经证实，从面向约束的实时LOTOS规范(这使得描述简单，但在实现中引入了同步开销)，编译器可以生成与实际应用一样高效的目标代码。

In this research, we define a subclass of E-LOTOS (called realtime LOTOS ) and develop a compiler for its specifications.The compiler first decomposes a given specification into multiple basic modules so that each module includes only event sequences with divergencesand iterations, then it maps each module to a realtime thread on our realtime thread library.Here, interactions between the threads are implemented with shared variables.To make the best effort for each thread to execute its timed events in time, all the running threads set their wake-up time and deadlines so that they are scheduled by EDF( Earliest Deadline First ) policy.We have also designed and implemented a mechanism to efficiently schedule timed multi-rendezvous between threads.To apply our compiler to multimedia system development, we have implemented primitives for audio/video processing and modified our compiler to support them in realtime LOTOS specifications.Through our experiment to develop several video playback applications, we have confirmed that from realtime LOTOS specifications in constraint oriented style (which makes the descriptions simple but introduces synchronization overhead in implementation), the compiler can generate as efficient object codes as to be used practically.