A debug technique for software on high performance processors an initial feasibility study

In many of the popular, high performance processors, the ability to debug embedded software is complicated by the advanced architecture of the processors. When attempting to debug the embedded software, the most difficult debug problems leave few clues with which to identify offending actions. Modern software debugging systems often require software and/or hardware intrusion into the process under test. This "intrusion" often modifies the behavior of the system under test and therefore hampers the correction of errors. Methods which employ only minimum intrusion often require extensive measurements, which are rapidly becoming either very difficult or impossible to achieve. This paper provides initial study results of a method for the debug of embedded computer systems differing from the typical intrusive and non-intrusive methods. The primary difference is that the current initial study employs a 'priori knowledge of both the software text segment and the processor architecture to supplant intrusive acquisition of measurement information. The method further combines the a 'priori information with exclusively non-intrusive measurements to assist in the isolation of system errors. The current paper supplies case studies based upon the Motorola's 68020 processor. The 68020 was selected since it contains many of the advanced architecture features which tend to create the complications. Therefore the 68020 serves as a representative model and also provides concrete illustrations. The current method provides for no special measurement ports requiring non-standard configurations. Measurements include only readily available information provided by implemented configurations (e.g., ports, busses).