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Index > OS Construction > MBR: relocation minimization

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Tomasz Grysztar



Joined: 16 Jun 2003
Posts: 8356
Location: Kraków, Poland
Tomasz Grysztar 06 Mar 2009, 09:49
Yes, that's a risky thing to do.
BTW, what do we know about IF on entry from BIOS? Because the only safe way to move stack when IF=1 is to use LSS.
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 20361
Location: In your JS exploiting you and your system
revolution 06 Mar 2009, 09:58
You can also use the two instruction sequence -
Code:
mov ss,something
mov sp,anotherThing    
CPU ignores interrupts for one instruction cycle after the mov ss
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Tomasz Grysztar



Joined: 16 Jun 2003
Posts: 8356
Location: Kraków, Poland
Tomasz Grysztar 06 Mar 2009, 10:35
Oh, right, that was working already on 8086. Only on 8088 it was bugged. Smile
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bitRAKE



Joined: 21 Jul 2003
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Location: vpcmpistri
bitRAKE 06 Mar 2009, 17:01
I wonder how many computers boot daily with various MBRs?
Post 06 Mar 2009, 17:01
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 20361
Location: In your JS exploiting you and your system
revolution 06 Mar 2009, 17:10
I wonder how many computers stay on 24/7 and boot rarely?
Post 06 Mar 2009, 17:10
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bitRAKE



Joined: 21 Jul 2003
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Location: vpcmpistri
bitRAKE 06 Mar 2009, 17:40
Having tried to educate problem about the various power/time saving techniques, I can tell you that it is not as successful as I'd like it to be. I cringe watching someone at the coffee shop spend 5 minutes to close all their work and shutdown Windows.

<ah, another topic branch - I've got that MBR here somewhere under this stack of windows...>
Post 06 Mar 2009, 17:40
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