positive32BitValueOf: fail with LargePositiveInteger

On Fri, Oct 08, 2010 at 07:12:13PM +0200, Mariano Martinez Peck wrote:
>
> So....I don't understand...how can I have a LargePositiveInteger but that is
> less than 32 bits?  Wouldn't that  be a SmallInteger?

SmallInteger maxVal hex ==> '16r3FFFFFFF'.

The largest positive two-compliment integer that fits into 32 bits is
16rEFFFFFFF, so any Integer in the range 16r4000000 through 16rEFFFFFFF
is a LargePositiveInteger that can fit into a signed 32-bit C int.

Thus the number of LargePositiveInteger values that fit into a 32-bit
twos-compliment representation is (16r4000000 to: 16rEFFFFFFF) size ==> 3959422976

Note that a SmallInteger is represented internally as a 31-bit value,
which accounts for the difference. It's a bit confusing when you are used
to thinking of 32-bit int values.

Dave

On 10.10.2010, at 13:05, stephane ducasse wrote:

> Yes I saw and I appreciated. Now my point is that some assumptions (like that mariano did not read books
> are bad). Now mariano told me that he will check more. And this is bad because mariano is helping a lot
> people so we all lost something.
>
> Stef

I don't see how "we all lost something", we gained something instead. Knowing which question is basic and which is advanced is not easy. How SmallIntegers are represented in the Squeak VM is something very basic, so it was appropriate to mention that.

And as Nicolas pointed out, not a single answer was "RTFM", nobody called anyone an idiot. There were 3 different actual explanations. No reason you get all upset about it. Relax, all is fine :)

That is, unless there is a hidden problem you did not mention. But in that case it would be better to name it.

- Bert -

>>> Why do you all think that mariano is not trying to learn?
>>> He is! He read all the chapters available and books on the topics.
>>> Now may be tell him simply that he is an idiot.
>>> This would be more efficient. But Mariano is a really smart guy so may be
>>> we can also tell him to do ruby or python and we can stay in our nice little
>>> club or we can consider that learning alone is difficult.
>>>
>>> Stef
>>>
>>
>> Apologize to Mariano,
>> Sure we got a little upset by the gap between the level of the
>> question and the hard task of modifying the VM.
>> But stephane is right, we all have the right to be idiot, and most of
>> us are, sometimes (I recently asked a very stupid question about
>> Heap).
>> The spirit behind Smalltalk is not to build walls around complex
>> things, and reserve the knowledge to a happy few cast, and ideally
>> this should apply to the VM too (otherwise, no use to specify it in
>> pseudo Smalltalk code).
>>
>> But Steph, you must see the good side of this community: despite the
>> tone of the answers, Mariano got 3 responses driving him to the
>> answer.
>> In other languages I bet this would have been just RTFM.
>>
>> Nicolas

2010/10/9 stephane ducasse <[hidden email]>:

>
> Why do you all think that mariano is not trying to learn?
> He is! He read all the chapters available and books on the topics.
> Now may be tell him simply that he is an idiot.
> This would be more efficient. But Mariano is a really smart guy so may be
> we can also tell him to do ruby or python and we can stay in our nice little
> club or we can consider that learning alone is difficult.
>
> Stef
>

Apologize to Mariano,
Sure we got a little upset by the gap between the level of the
question and the hard task of modifying the VM.
But stephane is right, we all have the right to be idiot, and most of
us are, sometimes (I recently asked a very stupid question about
Heap).
The spirit behind Smalltalk is not to build walls around complex
things, and reserve the knowledge to a happy few cast, and ideally
this should apply to the VM too (otherwise, no use to specify it in
pseudo Smalltalk code).

But Steph, you must see the good side of this community: despite the
tone of the answers, Mariano got 3 responses driving him to the
answer.
In other languages I bet this would have been just RTFM.

Nicolas