[Solved] Enabling A20 on a 64-bit machine

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madanra
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[Solved] Enabling A20 on a 64-bit machine

Post by madanra »

http://wiki.osdev.org/A20 describes 3 ways to enable A20 - keyboard controller, fast A20 gate and BIOS.
Presubably using fast A20 gate is the fastest (!), but on most info about enbaling A20 (which seems to generally be aimed at 32-bit development) advises against using only that as it's not always supported. My question is: is it a safe assumption that any 64-bit machine will support using the fast A20 gate?
Last edited by madanra on Mon Mar 29, 2010 1:14 pm, edited 1 time in total.
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Brendan
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Re: Enabling A20 on a 64-bit machine

Post by Brendan »

Hi,
madanra wrote:My question is: is it a safe assumption that any 64-bit machine will support using the fast A20 gate?
It's a safe assumption that the BIOS function will use the best method, and will be supported on modern computers.

Even if fast A20 does work it can cause problems later (e.g. for hibernate).


Cheers,

Brendan
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madanra
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Re: Enabling A20 on a 64-bit machine

Post by madanra »

Thanks, I'll go with that then :)
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Love4Boobies
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Re: Enabling A20 on a 64-bit machine

Post by Love4Boobies »

Brendan wrote:Even if fast A20 does work it can cause problems later (e.g. for hibernate).
Could you describe what kind of problems and why they might occur?
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StephanvanSchaik
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Re: Enabling A20 on a 64-bit machine

Post by StephanvanSchaik »

Love4Boobies wrote:
Brendan wrote:Even if fast A20 does work it can cause problems later (e.g. for hibernate).
Could you describe what kind of problems and why they might occur?
I would like to know this as well.


Regards,
Stephan J.R. van Schaik.
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