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From: dyer@atari.UUCP (Landon Dyer)
Newsgroups: comp.sys.atari.st
Subject: Re: BIOS re-entrancy
Message-ID: <765@atari.UUCP>
Date: Thu, 25-Jun-87 08:49:45 EDT
Article-I.D.: atari.765
Posted: Thu Jun 25 08:49:45 1987
Date-Received: Sat, 27-Jun-87 04:20:32 EDT
References: <955@eneevax.UUCP>
Distribution: world
Organization: Atari Corp., Sunnyvale CA
Lines: 16

in article <955@eneevax.UUCP>, iarocci@eneevax.UUCP (John Iarocci) says:
> Also, does anyone know if any conflics may arise if a process were preempted
> in the middle of the BIOS, only to have another process make a BIOS call,
> possibly the same one that was interrupted?  The same question goes for the
> XBIOS and GEMDOS.  Thanks in advance for any help you can offer.

The BIOS, XBIOS and GEMDOS are not re-entrant -- TOS is not a
multitasking operating system.  The functions below the trap handlers
(which use temps in memory, twiddle bits in the hardware and so on)
would have serious problems if they were called on multiple threads.

-- 
-Landon Dyer, Atari Corporation	       {sun,amdcad,lll-lcc,imagen}!atari!dyer
The views expressed here do not necessarily reflect those	     BUSINESS
of Atari or the AI software that has taken over my brain.	     IS
Yow! I am waiting for my warranty-expired interrupt!		     HELL