From: pavenis AT lanet DOT lv
To: sandmann AT clio DOT rice DOT edu (Charles Sandmann),
        acottrel AT ihug DOT com DOT au (Andrew Cottrell), djgpp-workers AT delorie DOT com,
        eliz AT is DOT elta DOT co DOT il
Date: Tue, 14 Aug 2001 11:15:01 +0300
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Subject: Re: Selector Exhaustion
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References: <5832-Mon13Aug2001212853+0300-eliz AT is DOT elta DOT co DOT il> from "Eli Zaretskii" at Aug 13, 2001 09:28:53 PM
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On 13 Aug 2001, at 14:10, Charles Sandmann wrote:

> 
> We don't need anything on CWSDPMI.
> We only need the CWS patch code on NT/Win2K/XP.
> For other platforms we want to probably check access rights, but I'd
> prefer to avoid making 16,000 DPMI calls to scan all the selectors.
> 

Checking access rights of decriptor does not use any DPMI call (see 
source below) 

Initially I did some timing:
checking all descriptors once took about 1 ms on PIII-700 (Win98SE)

Andris

/* Copyright (C) 1995 DJ Delorie, see COPYING.DJ for details */
	.file "dpmi_lar.s"
#include "dpmidefs.h"

	FUNC(___dpmi_get_descriptor_access_rights)
	ENTER

	movw	ARG1, %ax
	lar	%eax, %eax
	jz	1f
	xorl	%eax, %eax		/* Indicate zero type if not legal */
1:
	shrl	$8, %eax
	andl	$0xf0ff, %eax

	LEAVE