[Vm-dev] 64bit FFI?

[Philippe Marschall]

2009/2/12 Eliot Miranda <eliot.miranda at gmail.com>:
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> On Thu, Feb 12, 2009 at 10:20 AM, Bert Freudenberg <bert at freudenbergs.de> wrote:
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>> On 12.02.2009, at 19:00, Eliot Miranda wrote:
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>>>>> I see that Bert, but Andreas is asking something different.  He is asking if the existing 32-bit system can be run on a 64-bit platform, not that one can run a 64-bit VM on a 64-bit platform.  In Qwaq we have 32-bit server images and Andreas is interested in using these images largely unchanged to run as 64-bit processes.
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>>>> ... which is what the 64 bit VM does, as Andreas is well-aware. One of the remaining problems is 64 bit FFI, and a few more plugins. Fortunately David has been working on those for quite some time.
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>>> IIUC the 64-bit VM does _not_ run 32-bit images.
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>> It does.
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>>>  So I don't understand how the 64-bit VM is releant.  Can yu lead me by the nose a little further?
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>> Sure. *Please* read the FAQ:
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> Um, I have (studied my Agrippa), and I quote:
> Does my 64-bit VM run both 32-bit and 64-bit images? No. Any VM will run either 32-bit or 64-bit images, but not both. You can select one or the other when you generate sources with VMMaker, and you can install both flavors of VM on your system (one each for 32-bit images and 64-bit images).
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> If you try to run a 64-bit image with a VM built for 32-bit images, you will get an error message such as this:
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> This interpreter (vers. 6502) cannot read image file (vers. 68000).
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> If you try to run a 32-bit image using a VM built for 64-bit images, you will get an error message such as this:
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> This interpreter (vers. 68000) cannot read image file (vers. 6502).
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> So no, one cannot run a 32-bit image in a 64-bit VM (as I had thought) and the FAQ is quite specific about it.

On the contrary:

Can I run a 32-bit image on my 64-bit computer?
Yes. A 32-bit image can be run on either a 32-bit VM or a 64-bit VM.
Some computer platforms (e.g. 64-bit Linux) can run both the 32-bit VM
and 64-bit VM on the same system.

Cheers
PHilippe