Creating A New Vector Table - Motorola MVME162LX 300 Series Installation And Use Manual

The 162Bug initializes the target vector table with the debugger vectors
listed in Table 4-2 and fills the other vector locations with the address of a
generalized exception handler (refer to the 162Bug Generalized Exception
Handler section in this chapter). The target program may take over as
many vectors as desired by simply writing its own exception vectors into
the table. If the vector locations listed in Table 4-2 are overwritten then the
accompanying debugger functions are lost.
The 162Bug maintains a separate vector table for its own use. In general,
you do not have to be aware of the existence of the debugger vector table.
It is completely transparent and you should never make any modifications
to the vectors contained in it.

Creating a New Vector Table

Your program may create a separate vector table in memory to contain its
exception vectors. If this is done, the program must change the value of the
VBR to point at the new vector table. In order to use the debugger facilities
you can copy the proper vectors from the 162Bug vector table into the
corresponding vector locations in your program vector table.
The vector for the 162Bug generalized exception handler (described in
detail in the 162Bug Generalized Exception Handler section found in this
chapter) may be copied from offset $08 (bus error vector) in the target
vector table to all locations in your program vector table where a separate
exception handler is not used. This provides diagnostic support in the event
that your program is stopped by an unexpected exception. The generalized
exception handler gives a formatted display of the target registers and
identifies the type of the exception.
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Preserving the Debugger Operating Environment
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