System of debugging software through use of code markers inserted into

Abstract

A system for inserting code markers for observing indications (external to the microprocessor upon which the software operates) of the occurrence of an event in the execution of the software. Additional instructions or markers are added to the software to be debugged to produce simple, encoded, memory references to otherwise unused memory or I/O locations that will always be visible to a logic analyzer as bus cycles. Although the code markers cause a minimal intrusion in the underlying software, they make tracing events by a conventional logic analyzer much simpler and allow for performance evaluations in manners not heretofore possible. In particular, the inserted code markers provide a method of dynamically extracting information from a running software system under test using simple low intrusion print statements, encoded I/O writes on procedure entries and exits and the like. Generally, the code markers are inserted at compile time or interactively during the debug session to make visible critical points in the code execution, such as function calls, task creation, semaphore operations and other resource usage so as to speed isolation of problems at test points during debugging.