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From: graeme@zen.UUCP (Graeme Cawsey)
Newsgroups: comp.sys.hp
Subject: Re: System Programming on the HP28C (A Question)
Message-ID: <703@zen.UUCP>
Date: Tue, 27-Oct-87 12:37:53 EST
Article-I.D.: zen.703
Posted: Tue Oct 27 12:37:53 1987
Date-Received: Sat, 31-Oct-87 02:49:11 EST
References: <3970@watdcsu.waterloo.edu>
Reply-To: graeme@zen.UUCP (Graeme Cawsey)
Distribution: comp
Organization: Zengrange Limited, Leeds, England
Lines: 32

In article <3970@watdcsu.waterloo.edu> bmaraldo@watdcsu.UUCP writes:
>
>  Can it be done as on the 41 series?  There is an object evaluation
>  command defined in the reference manual called SYSEVAL (pg. 43) which
>  looks like it might be useful for some system work.  It might be
>  interesting to dabble with the insides of the 28C.  Any comments?
>

What exactly do you mean by "System Programming"? Synthetic
Programming or Machine Code perhaps?

SYSEVAL evalutes an object at an address passed on the stack,
i.e. it starts the threaded interpreter running at that address.
There are a few useful addresses that are commonly known -
accessing the timer, type checking stack arguments etc.

Its far more fun to write in machine code - if you sign up to HPCC
(UK users group for HP calcs and hand-helds) quick enough you should
get my latest 28C assembler.  Now, if you want a copy of the 28C
operating system totally disassembled (I've only managed to
comment little bits of it so far - well it is pretty big), and
you want to pay the phone bill to transfer it (over 2Mbytes) then
let me know!  Of course I could post it on net when I've finshed
commenting it.  (Come on Corvallis, its got to be worth a tenner
not to!).


Graeme Cawsey		(graeme@zen.UUCP or uunet!mcvax!zen.co.uk!graeme)
Zengrange Ltd.		(Tel: +44 532 489048)

Any opinions I have are fictional, and any similarity between my
opinions and those held by anyone else are purely coincidental.