Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cwjcc!tut.cis.ohio-state.edu!bloom-beacon!apple!keith
From: keith@Apple.COM (Keith Rollin)
Newsgroups: comp.sys.apple
Subject: Re: GS Loader bug?; ProDOS sparse files & PaintWorks
Message-ID: <24973@apple.Apple.COM>
Date: 29 Jan 89 21:39:05 GMT
References: <8901281420.aa10989@SMOKE.BRL.MIL>
Organization: Apple Computer Inc, Cupertino, CA
Lines: 42

In article <8901281420.aa10989@SMOKE.BRL.MIL> AWCTTYPA@UIAMVS.BITNET ("David A. Lyons") writes:
>>Date:         Sun, 22 Jan 89 12:59:40 CST
>>From:         Brian Greenstone <orcus@PRO-LEP.CTS.COM>
>>Subject:      RE: Pascal bug in GS/OS and GS/OS bugs.
>
>>In response to the letter about using TML pascal with GS/OS and a
>>crash occuring, you might want to know that there is a apparently a
>>bug in GS/OS's loader that occasionally writes "mystery" bytes into
>>programs.  I found the bug in an assembly program that Im writing and
>>after many days of testing found that for some reason, GS/OS writes a
>>few random bytes into the same place in memory.
>
>Please be specific so I can try to verify the bug and report it
>through official channels.  How many bytes get trashed, where are
>they, does it _always_ happen or just for your particular program,
>etc.  Are you _sure_ the trashing is happening when your program is
>loaded and _not_ while your program is already running?  (Messing up
>the B register in your program would be a very effective way of
>trashing your code instead of loading/storing global variables, for
>example.  Really...I've done it!)
>

Brian and Dave,

This might be one that we know about. I remember that the Loader itself had
the problem with not setting the B register, and was trashing two
bytes in memory. I thought that it was fixed in System Disk 4.0, but I could
be wrong.

I can't remember many of the characteristics, except that it really only shows
up with large, multi-segmented programs. We found this out after driving the
author of Medley insane by trying to track down this bug. Also, the term
"Bank $06" comes to mind when I think of this bug.

In any case, Dave is right -- please let us know more about the problem. That
way we can track it down and nuke it.

Keith Rollin  ---  Apple Computer, Inc.  ---  Developer Technical Support
INTERNET: keith@apple.com
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      "You can do what you want to me, but leave my computer alone!"