Re: protected mode problem

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Article #367

#367

From: John S. Fine
Date: Wed, 18 Mar 1998 00:00

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PR Schmitz wrote:

> When I 'switch' to protected mode using MOV CR0,EAX, The system reboots or
> crashes. What am I doing wrong? Can somebody please tell me?
. . .
>         gdtr    LABEL   FWORD
>                 DD      ?
>                 DW      15
. . .-
>         lea     ebx,gdtr
>         mov     DWORD PTR [ebx],eax
>         DB      66h
>         lgdt    gdtr

The gdt psuedo-descriptor should have the length first and the linear
address second.  You have it backwards.

I haven't checked for other errors in your code.

There is a well commented example of switching from real mode to
protected mode, which I wrote:

http://www.erols.com/johnfine/pmcom01.zip

It is in NASM syntax (not TASM), but I think it will help you anyway
to read it.
-- 
http://www.erols.com/johnfine/
http://www.geocities.com/SiliconValley/Peaks/8600/

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From: "John S. Fine" <johnfine@erols.com>
Subject: Re: protected mode problem
Date: 1998/03/18
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