COMPILING REAL-TIME PROGRAMS WITH TIMING CONSTRAINT REFINEMENT AND STRUCTURAL CODE MOTION

We present a programming language called TCEL (Time-Constrained Event Language), whose semantics are based on time-constrained relationships between observable events, Such a semantics infers only those timing constraints necessary to achieve real-time correctness, without overco nstraining the system, Moreover, an optimizing compiler can exploit th is looser semantics to help tune the code, so that its worst-case exec ution time is consistent with its real-time requirements. In this pape r we describe such a transformation system, which works in two phases. First, the TCEL source code is translated into an intermediate repres entation. Then an instruction-scheduling algorithm rearranges selected unobservable operations and synthesizes tasks guaranteed to respect t he original event-based constraints.