From mboxrd@z Thu Jan  1 00:00:00 1970
To: 9fans@cse.psu.edu
Subject: Re: [9fans] calculating the gdt pointer in 32 bit (protected) mode
From: "Russ Cox" <rsc@plan9.bell-labs.com>
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Date: Wed, 23 Jan 2002 18:51:09 -0500
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It's pretty much what it says.
$tgdtptr(SB) is a constant evaluated
for us by the loader as though it were
a function.

The byte sequence here:

	 BYTE	$0x0f
	 BYTE	$0x01
	 BYTE	$0x16
	 WORD	$tgdtptr(SB)

assembles to "LGDT $tgdtptr".
It's a word-sized instruction, though.
If you're already in 32-bit mode, you
need to use

	 BYTE	$0x0f
	 BYTE	$0x01
	 BYTE	$0x16
	 LONG	$tgdtptr(SB)

so that the immediate data is the right size.

Russ