Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!gatech!gitpyr!kpk
From: kpk@gitpyr.gatech.EDU (Kevin P. Kleinfelter)
Newsgroups: comp.sys.ibm.pc
Subject: Secondary command processor w/Turbo
Message-ID: <3509@gitpyr.gatech.EDU>
Date: Tue, 28-Apr-87 21:31:01 EDT
Article-I.D.: gitpyr.3509
Posted: Tue Apr 28 21:31:01 1987
Date-Received: Thu, 30-Apr-87 04:14:23 EDT
Distribution: na
Organization: Georgia Institute of Technology
Lines: 16
Keywords: Tough

The problem with invoking a secondary command processor under Turbo
is that Turbo places code at low memory and data (heap or stack)
in high memory.  Thus you can't really release the memory to
do an EXEC call.  The solution I created was to write a little
"Job Control" program which installed itself into an interrupt vector
and then called a Turbo program.  The Turbo program could post requests
to the Job Control via registers (via inline code) and interrupt
calls.  Capabilities of the Job Control included "terminate me and run
the next program", "add this program to the Job Queue", etc.
To simulate a program call, I wrote a parameter file, terminated
and ran the next program, and when it was complete I reran the
original program (which skipped forward to the point of the call,
based on the parameter file).

This took me about a month, and I'm pretty good at low-level programming.
				Good Luck.