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Using the 187Bug Debugger
Preserving the Debugger Operating Environment
This section explains how to avoid contaminating the operating environment of the debugger. Topics covered include:
❏187Bug Vector Table and workspace
❏Hardware functions
❏Exception vectors used by 187Bug
❏CPU/MPU registers
187Bug uses certain of the MVME187 onboard resources and may also use offboard system memory to contain temporary variables, exception vectors, etc. If you disturb resources upon which 187Bug depends, then the debugger may function unreliably or not at all.
If your application enables translation through the Memory Management Units (MMUs), and utilizes resources of the debugger (e.g., system calls), your application must create the necessary translation tables for the debugger to have access to its various resources. The debugger honors the enabling of the MMUs; it does not disable translation.
187Bug Vector Table and Workspace
The debugger and diagnostic firmware resides in the EPROMs. The first 64KB of RAM are also used by the debugger for storage of the Vector Table, executable code, variables, and stack.
