Path: utzoo!censor!geac!torsqnt!tmsoft!masnet!canremote!stephen.dawson
From: stephen.dawson@canremote.uucp (STEPHEN DAWSON)
Newsgroups: comp.lang.pascal
Subject: SWAP A RUNNING PROGRAM
Message-ID: <421fb810bf262744bb24@canremote.uucp>
Date: 17 Nov 90 01:23:00 GMT
Organization: Canada Remote Systems Limited, Mississauga, ON, Canada
Lines: 28


  in a message from Zhou@brazil.psych.purdue. to All
  in the U-PASCAL conference was written...

z.>I am planning to write a TSR program in the following way. I wonder
z.>if anybody will comment on its feasibility:
z.>        (1) Interrupt a running program;
z.>        (2) Save all RAM content into hard disk;
z.>        (3) Run the TSR program;
z.>        (4) Upon finishing, load the original RAM content into the
z.>memory.
z.>        (5) Return the control to the running program.

Two points. 1) You must also save, and restore, all the register
values in the CPU; and 2) the difficult part, make sure you do not
interrupt while a DOS call is being processed, otherwise you will
destroy DOS's stacks and corrupt the system.

I don't have the specifications, but DOS sets some flags when you
cannot interrupt; that's how PRINT works.

STEPHEN

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  stephen.dawson@canremote.uucp, Canada Remote Systems, Toronto.
  entered 11-16-90 at 8:23pm in Downsview, Ontario
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