Path: utzoo!attcan!uunet!dino!ux1.cso.uiuc.edu!uxa.cso.uiuc.edu!jb10320
From: jb10320@uxa.cso.uiuc.edu (Jawaid Bazyar)
Newsgroups: comp.sys.apple
Subject: Heartbeat Blues
Message-ID: <1989Nov29.075626.21500@ux1.cso.uiuc.edu>
Date: 29 Nov 89 07:56:26 GMT
References: <1101@mountn.dec.com> <1152@umigw.MIAMI.EDU> <3879@puff.cs.wisc.edu> <1161@umigw.MIAMI.EDU> <36850@apple.Apple.COM>
Sender: news@ux1.cso.uiuc.edu (News)
Reply-To: jb10320@uxa.cso.uiuc.edu (Jawaid Bazyar)
Organization: University of Illinois at Urbana-Champaign
Lines: 39


   I hope someone out there can help me as I've been banging my head for
about a week with this one.
   I wrote a routine to pause X number of tenths of seconds, it's called 
Pause() and it's included in a user tool set.  Pause() calls some Heartbeat
Interrupt handlers I wrote and here is where the trouble starts.
   Pause first calls AddTimer, which creates a new "timer" by giving it
the amount of time to pause.  A routine "DoTimer" is inserted in the Heartbeat
Queue, and is activated every 6 ticks (1/10th second).  DoTimer runs through
the list of timers and decrements each active count.  For example, if I called
Pause(30), AddTimer would create a new timer with a count of 30. After the 30
ticks are up, the timer remains at zero.
   Pause sits in a loop calling CheckTimer, which returns the current
count for a timer. Pause loops until its timer is 0, after which it simply
returns.
   When I call Pause from my program it hangs.  It's not the tool interface-
it's been thoroughly tested from both assembly and a small C program. In these
cases my routine works.  It is only in my large project program that Pause
does not work.  And even stranger, Pause WORKS in my project program if I'm
tracing the code with the Cortland Debugger.
   The system seems to die terribly when Pause is called- using Guy Rice's
Interrupt Detector CDA I've determined that all interrupts cease when Pause
is called (again, it works from debug/trace).
   If it's important the tool code is physically linked to the program. I've
not had a problem with the other several tools I've written and hooked in this
way.
   Is there something strange about the Heartbeat Queue that I'm overlooking?
   Why does my code work when being traced, but not when executed directly?
 
  Thanx for any help anyone can give me. Source available upon request.

--
===============================================================================
jawaid bazyar    jb10320@uxa.cso.uiuc.edu  Junior/Computer Engineering UIUC

         Beneath the noble birth, between the proudest words, 
                behind the beauty, Cracks appear
         Once, with hands held high, they sang out to the sky
		Why do their shadows bow in fear?