A symbolic debugger for real‐time embedded Ada software

Abstract

AND SUMMARYRockwell's Ada symbolic debugging system (ASDS) is designed especially for use in debugging and testing embedded system software. ASDS uses a combination of software and special hardware to support unobtrusive monitoring, breakpoint and display facilities that can be applied during the development of an embedded system and during the 'downstream' stages of the embedded system life cycle associated with production and field unit testing. The ASDS software kernel executes on a stand-alone monitor processor with modest computational power (e.g. a personal computer), connected to the embedded target system via a target interface that allows the monitor to observe transactions on the target bus in real-time. The use of a monitor processor with modest power limits the degree of 'high level' monitoring support-though ASDS can detect the execution of a particular line of source code or access to a particular variable it contains no facilities for monitoring interactions between high-level dynamic objects such as tasks. However, the modest power required for the monitor also reduces its costs, with the result that ASDS debugging and test stations have been readily available to engineers working on system development, in production and in the field. Our description of the ASDS design and implementation focuses on its practical solutions to the problems associated with building and maintaining a symbolic debugging system to support embedded system development.

A window based visual debugger for a real time Ada tasking environment

“…We will generally not concern ourselves with additional details of the base system here. For additional details regarding an example of this type of debugging system for embedded systems, see [11].…”

“…Many of these aspects of portability must be addressed in the base debugger; for more details on how they are addressed in ASDS, see [11].…”

“…Given this interface, our debugging facility focuses on the analysis of the tasking event sequence, the dynamic determination of the state of various tasks, and the display of pertinent aspects of the tasking environment. We describe tasking analysis and display facilities in detail in the remainder of the paper; see [10,11,5,7] for more information on the target interface hardware.…”

“…As described in detail below, the design was motivated and strongly influenced by experience with ASDS, an "industrial strength" symbolic debugging system developed by the Collins Government Avionics Division (CGAD) of Rockwell International for use with the first generation of Ada-based embedded systems [10,11]. In large part, the project described here was designed to explore the utility of features that might be added to future versions of ASDS.…”