Re: [Help-smalltalk] CStruct ABI and packed structs

[Paolo Bonzini]

On 10/15/2010 06:17 PM, Holger Hans Peter Freyther wrote:
> On 10/15/2010 06:14 PM, Paolo Bonzini wrote:
> > On 10/15/2010 05:55 PM, Holger Hans Peter Freyther wrote:
> > > is there a place for CPackedStruct in the GST Kernel? Somewhere else?
> >
> > There is; however, it's a bit more tricky than this, because access to
> > unaligned members will trap on some architectures.
>
> Sure, would you want to patch it in the 'value' implementations? or somewhere
> in the C code? Would you want to introduce 'parallel' types that can handle
> unaligned access? CArray ->  CArrayUnaligned?

Not really CArrayUnaligned, because those are compound types.  But yes, 
CIntUnaligned and friends would be needed so that the right alignment is 
also propagated to the fields (you want "packedStruct field alignof == 
1" always).

Paolo