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 Shutting Down 
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Joined: Wed Oct 14, 2009 9:39 am
Posts: 198
Location: United States
Post Shutting Down
I was wondering if anyone knew how to shutdown the computer after the operating system was finished. Do you send a HLT and then set some bit, or does just the HLT do the trick?

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Charles Timko
push %esp ;Musings of a computer addict


Sun Oct 25, 2009 7:10 pm
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Joined: Sat Jul 25, 2009 11:26 am
Posts: 81
Post Re: Shutting Down
All HLT does is halt the execution stream until an interrupt. Most often, HLT is used in endless loops (which are close to your aim) as such:

Code:
hang:
hlt
jmp hang


CLI won't do the trick here because all types of hardware interrupts can stop the halt (IRQs, IPIs, SMIs, NMIs). Another problem is that HLT only affects the CPU, which is not responsible for anything else. Hence, you cannot stop other components this way. The right way to do it is to use ACPI and if that's not available, fall back to APM (i.e., if you're running code on an x86 PC with BIOS).

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Bogdan


Mon Oct 26, 2009 12:00 am
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Joined: Sat Jul 25, 2009 7:44 am
Posts: 274
Location: United Kingdom
Post Re: Shutting Down
Yes, APM is the correct way to do it, however there is also a way of doing a shutdown using the keyboard controller, I cannot remember the exact way, but im sure it wont be to hard to locate.

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Kieran C G Foot


Mon Oct 26, 2009 4:03 am
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Posts: 81
Post Re: Shutting Down
I was suggesting ACPI over APM. And no, the 8042 controller can send a RESET# signal, you won't be able to shut down using that.

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Bogdan


Mon Oct 26, 2009 4:29 am
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Location: United Kingdom
Post Re: Shutting Down
lol Well I couldnt remember exactly what, but yes it is only a restart sorry.

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Kieran C G Foot


Mon Oct 26, 2009 5:40 am
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Joined: Sun Aug 16, 2009 7:28 am
Posts: 60
Location: The Netherlands
Post Re: Shutting Down
The keyboard controller can be used for reboots, not for shutdowns.

The ACPI or APM can be used. I prefer ACPI too. The ACPI is available on all new PCs, since it is used for controller power and thermal too.

I have read a topic of the forums of osdev.org about shutting down using the ACPI.

// Jarvix/PHPnerd

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Jinix {Operating System}


Tue Oct 27, 2009 9:43 am
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Joined: Sat Jul 25, 2009 11:26 am
Posts: 81
Post Re: Shutting Down
The 25th guy who repeats what I've said wins a prize! 8-)

Cheers,
Bogdan


Tue Oct 27, 2009 11:41 am
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Joined: Sat Jul 25, 2009 7:44 am
Posts: 274
Location: United Kingdom
Post Re: Shutting Down
Can i post again to get the prize??? lol

On a serious note, ACPI is a plus for any OS, Im working on implementing it in my own os atm.

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Kieran C G Foot


Tue Oct 27, 2009 11:44 am
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Joined: Sat Jul 25, 2009 11:26 am
Posts: 81
Post Re: Shutting Down
ACPI is a big universe. I've been playing around with it for years. Just like many other standards, it's a piece of crap but it's the best we've got. The fact that it's so big and complex also makes it difficult to implement, especially for hobbyists. I thus recommend ACPICA, Intel's reference implementation. Port that and you're set. Another advantage to using ACPICA is that even if ACPI were to change in some drastic way, ACPICA would be updated by Intel. If anyone cares (I know I don't), it's what Linux uses.

Cheers,
Bogdan


Tue Oct 27, 2009 11:53 am
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Joined: Wed Oct 14, 2009 9:39 am
Posts: 198
Location: United States
Post Re: Shutting Down
Thanks for the responses. Who ever first mentioned ACPI you get +rep from me...when it gets implemented. I had been looking in the wrong place for the answer, and I didn't think about that for some reason (even though I had been staring at it in BIOS for a while now...).

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Charles Timko
push %esp ;Musings of a computer addict


Tue Oct 27, 2009 2:11 pm
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