meaning of sizeof(_OS)?

meaning of sizeof(_OS)?

[Micha Feigin]

Was wondering at least theoretically what is supposed to be done
different by the dsdt if the os is M$ NT/XP since I saw there is an
explicit check of _OS against "Microsoft Windows NT".
Also I saw some people talking about a size check of the _OS variable
against 0x14 to see if its the M$ os. In my dsdt the check is for some
reason against 0x27, any idea what os its looking for? (is LEqual less
then or equall or does the L mean something else?)

Thanx


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Re: meaning of sizeof(_OS)?

[Sergey Vlasov]

On Mon, 26 Jan 2004 13:16:48 +0200 Micha Feigin wrote:

> Was wondering at least theoretically what is supposed to be done
> different by the dsdt if the os is M$ NT/XP since I saw there is an
> explicit check of _OS against "Microsoft Windows NT".
> Also I saw some people talking about a size check of the _OS variable
> against 0x14 to see if its the M$ os. In my dsdt the check is for some
> reason against 0x27, any idea what os its looking for? (is LEqual less
> then or equall or does the L mean something else?)

0x27 is probably "Microsoft WindowsME:Millennium Edition".

(I have seen a DSDT which compares strings in one place and checks
length in another place...)



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Re: meaning of sizeof(_OS)?

[greg]

Hi Micha,

   It's tough to know what the DSDT wants to do differently with the _OS 
checks without seeing the actual DSDT, as it varies from system to system.

   I think that 0x27 is checking for "Microsoft WindowsME: Millennium 
Edition" (39 characters).

   The LEqual is a Logical Equal. From the spec:


16.2.3.4.2.21  LEqual (Logical Equal)
LEqualTerm	:= LEqual(
	Source1,	//TermArg=>ComputationalData
	Source2	//TermArg=>ComputationalData
) => Boolean
Source1 and Source2 must be evaluated to the same data type as integers, 
strings, or buffers. If the values are equal, True is returned; otherwise, 
False is returned.


  Hope that helps clarify a bit.
  Greg




---------- Original Message -----------
From: Micha Feigin <michf-+lLcF8/aw9x6auLlOhE+pQ@public.gmane.org>
To: acpi-devel <acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
Sent: Mon, 26 Jan 2004 13:16:48 +0200
Subject: [ACPI] meaning of sizeof(_OS)?

> Was wondering at least theoretically what is supposed to be done
> different by the dsdt if the os is M$ NT/XP since I saw there is an
> explicit check of _OS against "Microsoft Windows NT".
> Also I saw some people talking about a size check of the _OS variable
> against 0x14 to see if its the M$ os. In my dsdt the check is for 
> some reason against 0x27, any idea what os its looking for? (is 
> LEqual less then or equall or does the L mean something else?)
> 
> Thanx
> 
> -------------------------------------------------------
> The SF.Net email is sponsored by EclipseCon 2004
> Premiere Conference on Open Tools Development and Integration
> See the breadth of Eclipse activity. February 3-5 in Anaheim, CA.
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> Acpi-devel mailing list
> Acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
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------- End of Original Message -------



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