A single-source debugger for multiple target processors

Arizona State University has used microprocessors in the Motorola M6800 family in support of classes in Computer Science-and Engineering since 1973. These microprocessors run a common operating system and debugger known as MUDBUG (for Monitor-Utility-DeBUG). We originally developed the first version of MUDBUG back in 1975, and we have made extensive upgrades over the years since then. MUDBUG employs conditional assembly to support a number of target systems with various processors in the M6800 family. Now we are developing a new 6809-based microprocessor training system, and the M6809 microprocessor is not instruction-set compatible with the M6800 family. This paper presents a plan for extending MUDBUG with conditional assembly, macros, and other techniques to make it support the M6809 target system from the same source program that supports the M6800 family.