Motorola MVME197LE Calling System Utilities From User Programs, 197Bug Vector Table and Workspace

Using the 197Bug Debugger

Other ways are by reading in the program from disk, using one of the disk commands (BO, BH, IOP), or by reading the program as a file from a remote computer on a network, using one of the network commands, such as NIOP. Once the object code has been loaded into memory, the user can set breakpoints if desired and run the code or trace through it.

Calling System Utilities From User Programs

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A convenient way of doing character input/output and many other useful operations has been provided so that the user does not have to write these routines into the target code. The user has access to various 197Bug routines via one of the MC88110 TRAP instructions, using vector #496. Refer to the MVME197BUG 197Bug Debugging Package User’s Manual for details on the various TRAP #496 utilities available and how to invoke them from within a user program.

Preserving The Debugger Operating Environment

This section explains how to avoid contaminating the operating environment of the debugger. 197Bug uses certain of the MVME197LE onboard resources and also off-board system memory to contain temporary variables, exception vectors, etc. If the user disturbs resources upon which 197Bug depends, then the debugger may function unreliably or not at all.

197Bug Vector Table and Workspace

The debugger and diagnostic firmware resides in the FLASH memory. The first 64KB of RAM is also used by the debugger for storage of the Vector Table, executable code, variables, and stack.

Hardware Functions

The only hardware resources used by the debugger are the EIA-232-D ports, which are initialized to interface to the debug terminal. If these ports are reprogrammed, the terminal characteristics must be modified to suit, or the ports should be restored to the debugger-set characteristics prior to reinvoking the debugger.

Exception Vectors Used by 197Bug

The top 16 MC88110 exception vectors (i.e., #496 to 511 inclusive) are reserved for use by the debugger.

4-6 Installation Guide