On Tue, Sep 22, 2009 at 04:47:56PM -0700, John M McIntosh wrote:
> 
> On 2009-09-22, at 4:16 PM, Ken Treis wrote:
> 
> > Eliot, Johan, Fernando, et. al.:
> >
> > On Sep 16, 2009, at 3:09 PM, Eliot Miranda wrote:
> >
> >> Hi Ken,
> >>
> >> On Wed, Sep 16, 2009 at 12:17 PM, Ken Treis <[email protected]>  
> >> wrote:
> >> Perhaps there would need to be new primitives for the basic size of  
> >> each relevant C type? I'm anxious to hear what Eliot might have to  
> >> say about this since he's got about 2000x more experience with this  
> >> than I do.
>
> I'll note the most modern squeak VM's return wordSize, this might be  
> helpful somewhere.
> 
> wordSize
>       "Answer the size (in bytes) of an object pointer."
>       "Smalltalk wordSize"
> 
>       ^[SmalltalkImage current vmParameterAt: 40] on: Error do: [4]

Actually, this is just the size of an object "pointer" in the object
memory (i.e. BytesPerWord in ObjectMemory), which is independent of the
size of a C pointer. So you would need new primitives to get at the
underlying machine data types. The implementations are trivial if you
are writing a plugin anyway, for example see #primitiveSizeOfPointer
and #primitiveSizeOfInt in OSProcessPlugin.

The "pointer" terminology referring to words the object memory is needlessly
confusing, I guess we should clean that up one of these days.

Dave 


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