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From: Ralf.Brown@B.GP.CS.CMU.EDU
Newsgroups: comp.os.msdos.programmer
Subject: Re: Is BIOS Reentrant?
Message-ID: <273ff3f7@ralf>
Date: 13 Nov 90 12:24:07 GMT
Sender: ralf@b.gp.cs.cmu.edu
Organization: Carnegie Mellon University School of Computer Science
Lines: 13
In-Reply-To: <4844@trantor.harris-atd.com>

In article <4844@trantor.harris-atd.com>, sonny@charybdis.harris-atd.com (Bob Davis) wrote:
}        May I safely use ALL Interrupts below 20h without checking
}        on ANY such flags or indicators in TSRs?

INT 13h is non-reentrant due to the DMA controller and head-seek setup needed
before a data transfer.  The other BIOS calls are all pretty safe, though you
may want to keep your own "busy" flags for them as well as INT 13h.

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