On Mon, May 13, 2013 at 09:20:08PM +0100, Peter Maydell wrote:
> On 13 May 2013 21:01, Michael S. Tsirkin <m...@redhat.com> wrote:
> > Sometimes we need to pass ranges around, add a
> > handy structure for this purpose.
> >
> > Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
> > ---
> > include/qemu/range.h | 22 ++++++++++++++++++++++
> > 1 file changed, 22 insertions(+)
> >
> > diff --git a/include/qemu/range.h b/include/qemu/range.h
> > index 3502372..4bcd346 100644
> > --- a/include/qemu/range.h
> > +++ b/include/qemu/range.h
> > @@ -1,6 +1,28 @@
> > #ifndef QEMU_RANGE_H
> > #define QEMU_RANGE_H
> >
> > +#include <inttypes.h>
> > +
> > +/*
> > + * Operations on 64 address ranges.
>
> missing "bit" ?
>
> > + * Notes:
> > + * - ranges must not wrap around 0, but can include the last byte ~0x0LL.
> > + * - this can not represent a full 0 to ~0x0LL range.
> > + */
> > +
> > +/* A structure representing a range of addresses. */
> > +struct Range {
> > + uint64_t begin; /* First byte of the range, or 0 if empty. */
> > + uint64_t end; /* 1 + the last byte. 0 if range empty or ends at
> > ~0x0LL. */
> > +};
> > +typedef struct Range Range;
> > +
> > +/* verify that range is not empty and does not overlap */
>
> Doesn't overlap what?
I meant wrap around there.
> Why isn't an empty range valid?
> The struct definition above says it's OK.
Yes it's a bad name. Should be range_non_empty or something.
> > +{
> > + return range->begin + 1 <= range->end;
> > +}
>
> I note that memory.c defines its own concept of an AddrRange.
>
> thanks
> -- PMM
Good point, maybe I'll reuse that or just use two 64 bit fields explicitly.
--
MST
