Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.2 9/18/84; site timeinc.UUCP
Path: utzoo!linus!philabs!cmcl2!seismo!harvard!talcott!panda!genrad!decvax!harpo!whuxlm!whuxl!houxm!vax135!timeinc!greenber
From: greenber@timeinc.UUCP (Ross M. Greenberg)
Newsgroups: net.micro.pc
Subject: Weirdness in PC???
Message-ID: <256@timeinc.UUCP>
Date: Tue, 18-Jun-85 15:07:14 EDT
Article-I.D.: timeinc.256
Posted: Tue Jun 18 15:07:14 1985
Date-Received: Sun, 23-Jun-85 11:48:13 EDT
Reply-To: greenber@timeinc.UUCP (Ross M. Greenberg)
Organization: Time, Inc. - New York
Lines: 63

It seemed simple enough:  I merely wanted to set a flag when there was
a DOS call being processed.  So I took over int21h and had it point to
a routine called 'myint'

myint:
	mov	flag, 1
	int	62h
	mov	flag, 0
	iret

And it didn't work from a terminate and stay resident program, although
it works in the debugger!  As soon as the terminate code is run I
get a whole bunch of "Insufficient disk spaces" error messages forever
and ever.  Time to reset.

So I figured that maybe dos cares about the stack displacement (sounds
reasonable, right?). okay:

myint:
	pop	[pop1]
	pop	[pop2]
	pop	[pop3]
	mov	flag, 1
	int	62h
	mov	flag,0
	push	[pop3]
	push	[pop2]
	push	[pop1]
	iret

No good --- same problem. So therefore it appears that dos is making
recurssive calls to itself and cares about the current "called from"
CS:IP on the stack?

What is going on here?  I know that I can play massive games and save
dos's stack and so forth, but why should it bomb out like it does?

Additionally, I made up a little terminate and stay resident piece
of code for a friend of mine to give him keyclicks. I futzed with
the timer to increase the sound/duration. Works like a charm
on my PC --- but the timer stuff seems to have no effect on his
PC-XT.  What are the weirdnesses betwixt the PC and XT?

And finally, what would cause a terminate and stay resident piece
of code to not give its memory back to dos upon final exit?

Is dos as wierd as it seems? Did Microsoft get paid by some
peculiar "strangness" factor (the stranger the system, the more you
get...).  Or am I missing something?

Mail to me, and I'll post.....

-- 
------------------------------------------------------------------
Ross M. Greenberg  @ Time Inc, New York 
              --------->{ihnp4 | vax135}!timeinc!greenber<---------

I highly doubt that Time Inc. they would make me their spokesperson.
------
"There's something wrong in the world. There's always been. Something no one
has ever named or explained" --- Francisco d'Anconia