Xref: utzoo comp.sys.ibm.pc:19278 comp.lang.c:12682
Path: utzoo!attcan!uunet!husc6!psuvax1!rutgers!ucsd!ucbvax!techunix.BITNET!baruchc
From: baruchc@techunix.BITNET (Baruch Cochavy)
Newsgroups: comp.sys.ibm.pc,comp.lang.c
Subject: need help on Multi-Tasking with TC1.5
Message-ID: <5496@techunix.BITNET>
Date: 17 Sep 88 09:36:26 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Reply-To: baruchc%techunix.bitnet@jade.berkeley.edu (Baruch Cochavy)
Organization: Technion, Israel Inst. Tech., Haifa Israel
Lines: 20

Hello,

        I have run into some strange problem while trying to implement
multi-tasking with TC 1.5.
        What I'm trying to do is do a full context switch, that changes
to whole machine state, with the help of SETJMP-LONGJMP. I have stored
a pointer to the old context at INT F0 location, so that I can return to
my program's context. Then, changing the registers value in the longjmp
structure, I have created the new context. The problem is that when I
try to return to my program's context (I manage to get into the task's
context), the whole system just stays in limbo, and does not respond to
anything.
        I have tried a different approach, that is to change only the DS
register. This, again, led to the same results. I finally set on PUSH DS,
and then POP DS, with no intervening code, but this has also led to the
same result.
        Any clue ? Any help will be most appreciated.

                                        Baruch Cochavy
                                        baruchc@techunix.BITNET