Re: Address spaces

Michael Snyder
2008-07-25T03:29:57Z

On Thu, 2008-07-24 at 11:26 +0200, Ulrich Weigand wrote:
> Stan Shebs wrote:
> > Doug Evans wrote:
> > > It would be useful to have proper address spaces for non-multi-process
> > > situations too. At the moment all one can do is hack in bits to
> > > unused parts of the address (assuming such bits are available ...).
> > > [I'm sure this isn't news. Just saying there are multiple reasons for
> > > addresses being more than just the CORE_ADDR of today, and if we solve
> > > one, let's at least consider the others too.]
> > >
> > Do you have some specific ideas in mind? Because I was assuming (and
> > this is good to be aware of) that there would not be more than one
> > address space associated with a process. (Instantly split I/D targets a
> > la D10V come to mind, although that was handled by distinguishing
> > pointers from addresses.)
>
> Cell/B.E. applications have multiple address spaces per process -- the
> main PowerPC address space (that is also accessible from the SPEs via
> DMA operations) plus a separate local store address space for each SPE
> context that is active in the process.
>
> I'm currently using bit hacks to map all these address spaces into a
> single CORE_ADDR space -- this is working OK for now, but it would
> seem nicer to integrate this into a general notion of address spaces ...

Oh yeah, and how about multi-core arches, like with a DSP copro or
something?