Date: Mon, 7 Aug 1995 20:36:15 -0400 (EDT)
From: Cuthalion / Sliced Bread <enrico AT max DOT tiac DOT net>
To: Kevin Baca <kbaca AT skygames DOT com>
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Re: CLI asm instruction

On Mon, 7 Aug 1995, Kevin Baca wrote:

> This works great under plain DOS, but under Windows it's about 20%
> slower.  If I remove the CLI, the performance goes back up, but then 
> my buffer gets trashed.  Anyone have any idea why the CLI slows 
> performance under Windows?

	This is one of the few things I remember from reading "The Tao Of 
Interrupts". (or something)  Under DPMI (Windows), CLI can take a _LONG_ 
time.  It suggests you do a check to make sure your interrupt flag is not 
already cleared before you CLI, just because the CLI instruction can take 
so long.  It's something to do with the virtualized nature of interrupts 
on the various virtual machines that Windows does to you, I think.  (IT 
MIGHT not be DPMI, but specific to Windows instead.)


/***************************************************************
*** Jesse Morris *** enrico AT max DOT tiac DOT net *** jmorris AT ace DOT com ***
***************** Cuthalion / Sliced Bread  *******************/