Date:	Wed, 5 Feb 2003 14:35:31 +0200 (EET)
From:	Esa A E Peuha <peuha AT cc DOT helsinki DOT fi>
Sender:	peuha AT sirppi DOT helsinki DOT fi
To:	djgpp-workers AT delorie DOT com
Subject:	Checking for stack overflow
Message-ID:	<Pine.OSF.4.51.0302051407240.1814@sirppi.helsinki.fi>
MIME-Version:	1.0
Reply-To:	djgpp-workers AT delorie DOT com

Gcc apparently allows to define freely what instructions are used to
allocate space from the stack.  Since we have a fixed stack size, it
would be good to check esp againt the stack limit every time it's
changed.  However, this needs two global symbols in crt0.o; one a
variable to hold the current stack limit (equal to ___djgpp_stack_limit
when esp points to application stack and equal to exception_stack when
that is used), and the other a routine to jump to when the stack is
overflown (which would print "out of stack" and exit since there's
nothing else it can do).  These symbols would need to be implemented
first (preferrably before the 2.04 release), and gcc changed later to
use them.  Does that sound like something worth doing?

-- 
Esa Peuha
student of mathematics at the University of Helsinki
http://www.helsinki.fi/~peuha/

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