Date   : Mon, 15 Jul 1985 23:16:00 GMT
From   : Bruce Eckel <morgan%fluke.uucp@BRL.ARPA>
Subject: Stuffing commands to the ccp

I have found myself a complexing little puzzle: I want to invoke a new
.COM program from inside MBASIC.  Now, I know MBASIC overwrites the CCP.
So the first thing I will do is find where the CCP starts and use the
/M directive when invoking MBASIC to prevent it from overwriting the
CCP.

I also suspect the CCP may not start at its lowest memory location, so
I will write a little assembly program which pops the CCP return address
off the stack (if you do not disturb the stack, you can just ret from a
program).

Now the problem is, the CCP seems to have its own buffer which it keeps
the command line in.  As the CCP is proprietary, I don't know where that
is (maybe I should know and am just stupid.  Someone enlighten me).  But
the people who write SUBMIT, XSUB and EX know how to do it.  I really
wonder how.  Perhaps they take control of standard input and force it
to the CCP somehow (a warm boot is always executed between programs, so
the CCP gets reloaded, and they can't be diddling with it).  If you
could just feed the thing a line terminated with a CR, you would be home
free.

I am not trying to make any money with this, I just think it would be
a very neat trick.  Any suggestions?

               Bruce Eckel
               uw-beaver!fluke!morgan