Serg,

> In my attempts at porting Squeak to BeOS I've run into a problem/issue 
> that you may be able to shed some light on.  During the course of my 
> initial attempts to read in the Squeak image into the interpreter, I got a 
> PPC exception.  Looking into it I've discovered that the initial malloc 
> was succeeding but the conversion of the unsigned char* to int was failing due 
> to BeOS's using 32bit addresses, with application memory starting 
> at 0x80000000...the type conversion was failing with a negative value, 
> which messed up all the succeeding memory calculations.

Actually, this should not be a problem. Even if the memory address is
negative, the computations should be done correctly (since number1 +
number2 will be greater than number1 even if it is negative). I'd think
that there should be some way to turn the sign check off, so that all is
running correctly.

> 1) Shouldn't the typecast be uint?  Memory addresses should never be negative.

You're right. Unfortunately, this would force a number of warnings at
other locations (which don't matter as long as you can turn the sign
check off).

> 2) Under BeOS I'll probably have to use:
> uint32 memStart = (uint32) memory;
> What else will this affect off the top of your head(s) so I don't have 
> to debug line by line ;-)

Provided that your C compiler _does_ sign checking you'll run into a
number of problems. All of the memory stuff is done in relation to
memStart so the best way is probably to assure your C compiler to forget
about sign checking. 

> 3) I'm assuming the Smalltalk->c conversion code needs to take into account 
> 32 bit addresses.  Any hints on what I need to change?  And if I change 
> this, this will break the portability issues dealing with the inner interpreter; 
> how best should I handle this?  Is this something you should be worried about 
> in your versions?

As long as everything is done with the right data types (see those checks
in the main() function of sqMacWindow.c, sqXWindow.c, and sqWin32Window.c)
everything should work as expected. These basic assumptions are:
* sizeof(int) = 4 
* sizeof(double) = 8
* sizeof(time_t) = 4

Hope this helps,
  Andreas

-- 
Linear algebra is your friend - Trigonometry is your enemy.
+===== Andreas Raab ============= (raab at isg.cs.uni-magdeburg.de) =====+
I Department of Simulation and Graphics      Phone: +49 391 671 8065  I
I University of Magdeburg, Germany           Fax:   +49 391 671 1164  I
+=============< http://isgwww.cs.uni-magdeburg.de/~raab >=============+