Re: [Qemu-devel] [PATCH 1/3] cpu-common: Modify cpu_physical_memory_read and cpu_physical_memory_write

[Stefan Weil]

Am 10.04.2011 00:37, schrieb Aurelien Jarno:
> On Sat, Mar 26, 2011 at 09:06:55PM +0100, Stefan Weil wrote:
> > A lot of calls don't operate on bytes but on words or on structured data.
> > So instead of a pointer to uint8_t, a void pointer is the better choice.
> >
> > This allows removing many type casts.
> >
> > (Some very early implementations of memcpy used char pointers
> > which were replaced by void pointers for the same reason).
> >
> > Cc: Blue Swirl <address@hidden>
> > Signed-off-by: Stefan Weil <address@hidden>
> > ---
> > cpu-common.h | 4 ++--
> > 1 files changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/cpu-common.h b/cpu-common.h
> > index ef4e8da..f44a2b0 100644
> > --- a/cpu-common.h
> > +++ b/cpu-common.h
> > @@ -68,12 +68,12 @@ void cpu_unregister_io_memory(int table_address);
> > void cpu_physical_memory_rw(target_phys_addr_t addr, uint8_t *buf,
> > int len, int is_write);
> > static inline void cpu_physical_memory_read(target_phys_addr_t addr,
> > - uint8_t *buf, int len)
> > + void *buf, int len)
> > {
> > cpu_physical_memory_rw(addr, buf, len, 0);
> > }
> > static inline void cpu_physical_memory_write(target_phys_addr_t addr,
> > - const uint8_t *buf, int len)
> > + const void *buf, int len)
> > {
> > cpu_physical_memory_rw(addr, (uint8_t *)buf, len, 1);
>
> We might want to also do the change here, that is replacing (uint8_t *)
> to (void *). Also instead of doing half the job, it would be nice to do
> the same changes on cpu_physical_memory_rw().

Hello Aurelien,

this type cast removes the const attribute from buf, so it is needed.

And I did not change cpu_physical_memory_rw (and some more
functions) because the gain is small: there are only 10 type casts
used with cpu_physical_memory_rw, and at least some of them
are needed because of const attributes.

I don't like type casts which remove the const attribute, so there
should be additional changes. But I don't think that it would be a
good idea to mix them with this patch.