Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!sun-barr!newstop!sun!imagen!atari!apratt
From: apratt@atari.UUCP (Allan Pratt)
Newsgroups: comp.sys.atari.st
Subject: Re: GEM multi-tasking interface (please!!)
Message-ID: <1684@atari.UUCP>
Date: 7 Sep 89 18:53:27 GMT
References: <CMM.0.88.621125609.larserio@kyrre.uio.no>
Organization: Atari Corp., Sunnyvale CA
Lines: 16

larserio@IFI.UIO.NO (LarsErikOsterud) writes:
>BIOS, XBIOS and GEMDOS can be called from within themselves !!
>I do this in many of my TSR program (even call GEMDOS inside BIOS !!!!)

This statement both incomplete and partly false.  There are
restrictions on re-entering BIOS and XBIOS, and YOU CAN NOT REENTER
GEMDOS.  You can *enter* GEMDOS (from BIOS, for instance) but if GEMDOS
calls BIOS and your handler calls GEMDOS you will be in BIG TROUBLE.

I can go into gruesome detail about why this is true, but face it: it
only takes one non-stack-type access to bestow non-reentrancy, and
there are a LOT of them when you're entering and exiting GEMDOS.

============================================
Opinions expressed above do not necessarily	-- Allan Pratt, Atari Corp.
reflect those of Atari Corp. or anyone else.	  ...ames!atari!apratt