[OpenBIOS] [RFC 2/5] Fix for pointer2cell() and cell2pointer()

[Andreas Färber]

Am 27.10.2010 um 21:48 schrieb Blue Swirl:

> On Tue, Oct 26, 2010 at 11:08 PM, Andreas Färber <andreas.faerber at web.de 
> > wrote:
>> ---
>>  include/kernel/stack.h |    4 ++--
>>  1 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/include/kernel/stack.h b/include/kernel/stack.h
>> index 809ffe9..44fef0f 100644
>> --- a/include/kernel/stack.h
>> +++ b/include/kernel/stack.h
>> @@ -31,8 +31,8 @@ typedef ucell phandle_t;
>>
>>
>>  #ifdef NATIVE_BITWIDTH_EQUALS_HOST_BITWIDTH
>> -#define pointer2cell(x) ((ucell)(x))
>> -#define cell2pointer(x) ((u8 *)(x))
>> +#define pointer2cell(x) ((ucell)(uintptr_t)(x))
>> +#define cell2pointer(x) ((u8 *)(uintptr_t)(x))
>
> Perhaps this should be changed to inline function which returns void
> *, then we may avoid a few casts.

I wouldn't mind inline functions either.

I doubt this quickfix is right at all though. It makes things compile  
with minimal impact, but these decisions seem seriously flawed. switch- 
arch and these macros all assume that just pointer size matters. IMO  
we would need CELL_BITWIDTH_EQUALS_POINTER_BITWIDTH instead and should  
be using CELL_BITWIDTH_SMALLER_THAN_POINTER_BITWIDTH (two #ifdefs  
below) for ppc64 instead of making the equality code path (hardcoded  
in Makefile.target) handle the smaller-than case as well now.
If we want to go ahead with my above patch I should at least add a  
TODO that this is wrong, no?

Andreas