Extending Harmless architecture description language for embedded real-time systems validation

Harmless is a hardware architecture description language targeted to the simulation of embedded and realtime software. It allows to describe the instruction set and the micro-architecture of a processor. From this description, the Harmless compiler generates an Instruction Set Simulator and a Cycle Accurate Simulator. Both simulators are useful to test and validate embedded software and the latter is essential for Real-Time software. Their use is cheaper and more comfortable than the execution on the actual hardware. Moreover, with simulation, it is easy and unobtrusive to trace the execution and to report useful informations. However, tracing mechanisms may be difficult or even impossible to integrate without ad-hoc support in the simulator and, in our case, in the description of the processor. This paper presents how Harmless is modified and used to add tracing support to simulators. This mechanism called action is used to extract high level information such has the task scheduling observation and stack safety analysis from the low level simulation. It also highlights how the Harmless description of a processor should be updated to support these features and applies it on three processors models.