[Vm-dev] 64bit FFI?

Bert Freudenberg bert at freudenbergs.de
Thu Feb 12 19:30:14 UTC 2009

On 12.02.2009, at 20:18, Eliot Miranda wrote:

> AFAICT you can produce a 64-bit VM that runs a 32-bit image with  
> this technique, but you can't get a VM that runs both.

That's exactly as stated in the FAQ. Any given VM can run *either* 32- 
bit images *or* 64-bit images. It's a compile-time choice.

> On the other hand, start-up code that reads a 32-bit image and  
> swizzles it to a full 64-bit image is perfectly sensible and quite  
> easy in the Squeak context because (IIRC) the 64-bit format doesn't  
> do things like widen the SmallInteger range, implement immediate  
> Floats, etc.  Its simply a matter of reading the data, writing two  
> words for each oop and scaling each non-SmallInteger oop  
> appropriately.  But as I said I don't see this code anywhere.

This is not the job of the VM. You have to manually create a 64 bit  

- Bert -

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