Re: Address spaces

Ulrich Weigand
2008-07-24T09:26:48Z

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 ...

Bye,
Ulrich

--
Dr. Ulrich Weigand
GNU Toolchain for Linux on System z and Cell BE
Ulrich.Weigand@de.ibm.com