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Hello,

On Nov 28, 2007, at 11:28, Valeriy E. Ushakov wrote:

> On Wed, Nov 28, 2007 at 09:33:38 -0500, Michael Lorenz wrote:
>
>> On Nov 28, 2007, at 01:36, der Mouse wrote:
>>
>>>> is there a good reason why OF handles, node numbers etc. are
>>>> represented as int in our code?  As far as I can tell using a  
>>>> signed
>>>> type here only causes trouble since at least node numbers may well
>>>> have the upper bit set.
>>>
>>> Perhaps I'm missing something, but, what difference does it make if
>>> some of the values happen to be negative?  They're just opaque
>>> handles,
>>> right?
>>
>> People (including myself at times ) keep running into the trap of
>> checking node numbers for >0, which apparently works on some machines
>> ( not macs though ). Since there is no reason for node numbers and
>> handles to be signed as far as I can see I want to make them  
>> unsigned.
>
> OFW standard says that some client interface functions,
> e.g. finddevice or instance-to-package return (cell_t)-1 on error so
> an invalid handle is going to pass your > 0 test for an unsigned type.

As I said, testing for >0 is wrong and usually happens with just  
that, -1 as error, in mind.

> So you are just trading one set of signedness related problems for  
> another.

I want to keep people from thinking of handles as signed at all.  
Don't call it -1, call it 0xffffffff.

> The issue here is not signedness per se (unsigned type is more natural
> (whatever that means) for handles, I guess), it's how you use it.

Exactly.

have fun
Michael
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