In article <[log in to unmask]
.com>, "Stigers, Gregory - ANDOVER" <[log in to unmask]> writes
>Time for some fun. We got:
>
>> :RUN E017910.EXEC01
>> NEW SYSTEM DATE IS: 06/06/97
>> **** INTERNAL TRAP
>> Instruction Memory Protection Trap
>> [VSM] Undecoded status.info = -37
>> ABORT: E017910.EXEC01.N01
>
I got something similar when I moved all 'X' in a subprogram, to an area
defined in Linkage as X(2048).

However, the calling program thought it was giving access to an X(256)
area (what is passed is really just the start address); 2048 ran off the
end of the data stack, and it barfed instantly, with a Protection error.

However, if 2048 hadn't run off the end, it would have barfed later, in
a much more subtle way.

Point is, there was nothing to see, in the code of either program taken
separately. You needed a model of the stack in your head to detect it by
inspection.

Have you got this sort of problem?

--
Roy Brown               Phone : (01684) 291710     Fax : (01684) 291712
Affirm Ltd              Email : [log in to unmask]
The Great Barn, Mill St 'Have nothing on your systems that you do not
TEWKESBURY GL20 5SB (UK) know to be useful, or believe to be beautiful.'