On 15-Jun-06, at 3:37 AM, Wolfgang Helbig wrote:

> Squeakers,
>
> at
> 	http://www.ba-stuttgart.de/~helbig/st80/bsearch.txt
> you'll find an article about two Squeak related bugs, one in Java,  
> one in the
> GNU-C-optimizer.
>
> The last bug provokes three questions. One to Tim Rowledge, one to  
> Jan Piumarta
> and one to Stefane Ducasse. But others may read it as well :-)

So my first question is why you couldn't simply ask the question in  
email.

Second question is why you are spending effort on the 1.18 vm,  
something so old and obsolete it practically smells of mold.

Third, the shift/xor trick for determining a valid smallInt value is  
one I came up with in 1987 and it was put into the Squeak vm  in  
probably 1.2 or thereabouts, when nobody was considering anything  
other than 32 bit cpus and so the comment was perfectly reasonable.  
In what way is the comment 'rather useless'? I think it explains the  
point quite adequately and it's sure as hell better than the complete  
lack of comments in 90% or more of the methods in the system..

Fourth, the code generator changes quite a lot of things in the  
process of transliterating from the VM code to the C code so you  
shouldn't be at all surprised when one formulation is used in the  
image and another in the generated code. It would be nice if things  
could be more directly connected but no-one has had time to tackle  
what is actually a big problem. We tried at Interval and concluded it  
required a lot of work to do well.

Fifth - you're surely not surprised to find bugs in gcc?


tim
--
tim Rowledge; tim at rowledge.org; http://www.rowledge.org/tim
Strange OpCodes: SDJ: Send all Data to Japan