Date: Tue, 17 Dec 1996 09:12:08 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
To: Shawn Hargreaves <Shawn AT talula DOT demon DOT co DOT uk>
cc: djgpp AT delorie DOT com
Subject: Re: pmode selectors
In-Reply-To: <2V4eiFAhrbtyEwOQ@talula.demon.co.uk>
Message-ID: <Pine.SUN.3.91.961217091010.20273J@is>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII


On Mon, 16 Dec 1996, Shawn Hargreaves wrote:

>    _farpokeb(_dos_ds, __tb & 0xFFFFF, 0);
> 
> I'm not 100% sure why it's neccessary to mask of the high bits of the
> address, but that's what Eli's FAQ says you should do :-)

That's because DPMI host doesn't guarantee that __tb above 20 bits is 
zeroed.  In v1.x, it actually was non-zero.  Some library functions would 
GP Fault if you pass them such addresses.  Better be safe than sorry.