A Strategy for Generating Time-Predictable Code

Prohibiting external control is one of the key principles engineers apply when building time-predictable computer systems (e.g., time-triggered computer systems do not react to any external interrupts from sensors or devices, but all actions of these computer systems are triggered solely by the progression of the local clock). In this paper we apply this principle of prohibiting external control to code generation: The single-path code generator is a compiler that produces real-time code that does not contain any input-dependent control flow. All inputdependent control-flow dependencies are eliminated by if-conversion or by the generation of loops whose iteration counts are fixed. We explain the principle of operation of single-path code generation and illustrate how single-path code generation contributes to the time-predictable behavior of real-time computer systems.