Specifications

Debugging a Device Driver
11.1 Using the Delta/XDelta Debugger
For more information about using DELTA/XDELTA, see the OpenVMS Delta
/XDelta Debugger Manual.
11.2 Using the OpenVMS AXP System-Code Debugger
The OpenVMS AXP System-Code Debugger (system-code debugger) can be
used to debug nonpageable system code and device drivers running at any
interupt priority level (IPL). You can use the system-code debugger to perform the
following tasks:
• Control the system software’s execution—-stop at points of interest, resume
execution, intercept fatal exceptions, and so on
• Trace the execution path of the system software
• Monitor exception conditions
• Examine and modify the values of variables
• In some cases, test the effect of modifications without having to edit the
source code, recompile, and relink
The system-code debugger is a symbolic debugger. You can specify variable
names, routine names, and so on, precisely as they appear in your source code.
The system-code debugger can also display the source code where the software is
executing, and allow you to step by source line.
You can use the system-code debugger to debug code written in the following
languages:
C
BLISS (Note that a BLISS compiler is not available for OpenVMS AXP.)
Macro
The system-code debugger recognizes the syntax, data typing, operators,
expressions, scoping rules, and other constructs of a given language. If your code
or driver is written in more than one language, you can change the debugging
context from one language to another during a debugging session.
To use the system-code debugger, you must do the following:
• Build a system image or device driver to be debugged.
• Set up the target kernel on a standalone system.
The target kernel is the part of the system-code debugger that resides on
the system that is being debugged. It is integrated with XDELTA and is part
of the SYSTEM_DEBUG execlet.
• Set up the host system, which is integrated with the OpenVMS Debugger.
The following sections cover these tasks in more detail, describe the available
user-interface options, summarize applicable OpenVMS Debugger commands, and
provide a sample system-code debugger session.
11.2.1 User-interface Options
The system-code debugger has the following user-interface options:
• A DECwindows Motif interface for workstations
When using this interface, you interact with the system-code debugger by
using a mouse and pointer to choose items from menus, click on buttons,
select names in windows, and so on.
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