Path: utzoo!utgpu!watmath!clyde!att!rutgers!apple!parent
From: parent@Apple.COM (Sean Parent)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Stack manipulation problems
Summary: QD stack space
Message-ID: <23589@apple.Apple.COM>
Date: 9 Jan 89 17:52:29 GMT
References: <ebmyn#1CMsZI=bob@xanadu.COM> <275@berlin.acss.umn.edu> <18694@santra.UUCP>
Organization: Apple Computer Inc., Cupertino, CA
Lines: 14

In article <18694@santra.UUCP>, jmunkki@kampi.hut.fi (Juri Munkki) writes:
> In article <275@berlin.acss.umn.edu> grg@berlin.acss.umn.edu (George Gonzalez) writes:
> >What's happening is that many of the ROM traps assume that they can
> >use the space above the op of the appl heap up to the bottom of the stack
> >for temporary storage.  I think UnionRgn is one of the worst offenders,
> Makes me wonder what happens if an exception happens when quickdraw is
> using the space below the stack. If this exception uses a lot of stack

I believe that QD just moves A7 to gobble up a good sized piece of the stack.
The worst problem is that it uses a couple different methods to determine where
the bottom of the stack is (I believe they are all based on low memory globals).
Using multible stacks with QD is very tricky and certinly not recomended.

Sean