* IA32 | [OFFTOPIC]: Segementation Question
@ 2005-06-02 19:06 Matthias-Christian Ott
2005-06-02 19:17 ` Grzegorz Kulewski
0 siblings, 1 reply; 3+ messages in thread
From: Matthias-Christian Ott @ 2005-06-02 19:06 UTC (permalink / raw)
To: linux-kernel
Hi.
I'm currently doing some research on the IA32 Segementation Concept. But there's one thing I don't understand:
If I perform a far jump it looks like this:
jmp 16bit:32bit
The 16bit are representing the segement number and the 32bit the offset. But to what refers the 16bit? To the GDT or the current LDT?
--
Thanks
Matthias-Christian Ott
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: IA32 | [OFFTOPIC]: Segementation Question
2005-06-02 19:06 IA32 | [OFFTOPIC]: Segementation Question Matthias-Christian Ott
@ 2005-06-02 19:17 ` Grzegorz Kulewski
2005-06-02 19:43 ` Matthias-Christian Ott
0 siblings, 1 reply; 3+ messages in thread
From: Grzegorz Kulewski @ 2005-06-02 19:17 UTC (permalink / raw)
To: Matthias-Christian Ott; +Cc: linux-kernel
On Thu, 2 Jun 2005, Matthias-Christian Ott wrote:
> Hi.
> I'm currently doing some research on the IA32 Segementation Concept. But
> there's one thing I don't understand:
> If I perform a far jump it looks like this:
> jmp 16bit:32bit
>
> The 16bit are representing the segement number and the 32bit the offset. But
> to what refers the 16bit? To the GDT or the current LDT?
IIRC, there is one bit flag in selector that decides if it is from GDT or
LDT. But maybe I am wrong...
Grzegorz Kulewski
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: IA32 | [OFFTOPIC]: Segementation Question
2005-06-02 19:17 ` Grzegorz Kulewski
@ 2005-06-02 19:43 ` Matthias-Christian Ott
0 siblings, 0 replies; 3+ messages in thread
From: Matthias-Christian Ott @ 2005-06-02 19:43 UTC (permalink / raw)
To: Grzegorz Kulewski; +Cc: linux-kernel
Grzegorz Kulewski wrote:
> On Thu, 2 Jun 2005, Matthias-Christian Ott wrote:
>
>> Hi.
>> I'm currently doing some research on the IA32 Segementation Concept.
>> But there's one thing I don't understand:
>> If I perform a far jump it looks like this:
>> jmp 16bit:32bit
>>
>> The 16bit are representing the segement number and the 32bit the
>> offset. But to what refers the 16bit? To the GDT or the current LDT?
>
>
> IIRC, there is one bit flag in selector that decides if it is from GDT
> or LDT. But maybe I am wrong...
>
>
> Grzegorz Kulewski
>
Ok, you're right, I read over this (see IA-32 Manual Part 3, Page 81).
--
Matthias-Christian Ott
^ permalink raw reply [flat|nested] 3+ messages in thread
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2005-06-02 19:06 IA32 | [OFFTOPIC]: Segementation Question Matthias-Christian Ott
2005-06-02 19:17 ` Grzegorz Kulewski
2005-06-02 19:43 ` Matthias-Christian Ott
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