Evening all,
I'm experimenting for the first exciting episode of the new assembly
language mailing list. It's the first time I've sat down with QPC since
I started my new job!
I have noticed something a little odd, well, even to be honest.
Strangely enough, the answer is 42 - what is the question? ;-)
Seriously, when I create a job with any given dataspace, when the job is
activated, A5.L is always set to that data space value plus 42 extra bytes.
There's nothing in the QDOS docs (from Jochen) nor in Dickens or
Pennell. The closest I have found is in Pennell on page 20 where he says
that "... TRNSP is expanded by D2+D3+$68, memory permitting" when a job
is created.
D2 is the code size, D3 is the requested dataspace size and the extra
$68 is for the standard job header area.
I'm wondering if the mysterious 42 extra bytes is also accumulated in
the space desired in TRNSP (it has to be D2+D3+$68+42 or stuff would
crash!) but where does it come from?
I cannot see it as being a rounding to the nearest 16 or 8 or whatever,
because it's always 42. When I say always, I have tried the same job
with the following dataspace sizes, and every one set A5 to be 42 extra:
126, 256, 500, 512, 1000, 1024, 2000, 2048, 3000, 3172, 4000, 4096.
I could, I suppose, look up the source for SMSQ but I don;t, sadly, have
the time at the moment. Not after doing all the above testing! I'm
afraid I shall be lazy and rely on the good will and knowledge of the
list for answers.
Thanks in advance.
Cheers,
Norm.
--
Norman Dunbar
Dunbar IT Consultants Ltd
Registered address:
27a Lidget Hill
Pudsey
West Yorkshire
United Kingdom
LS28 7LG
Company Number: 05132767
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