[Vm-dev] Integer overflow with BitBlt rule 20 and depth 32

[Juan Vuletich]

Eliot Miranda wrote:
>
> On Mon, Oct 26, 2009 at 6:01 AM, Juan Vuletich <juan at jvuletich.org 
> <mailto:juan at jvuletich.org>> wrote:
>
>
>     Hi Folks,
>
>     I've just opened http://bugs.squeak.org/view.php?id=7407 , with a
>     description of the problem, several tests (based on Henrik's
>     scripts) and the fix I propose.
>
>     David T. Lewis wrote:
>
>          On Sat, Oct 24, 2009 at 10:40:17AM -0300, Juan Vuletich wrote:
>          
>
>             What worries me a bit is the other changes I needed to do
>             to be able to run the Smalltalk BitBlt simulation and to
>             do the translation. These are:
>             BitBltSimulator >> #oopForPointer:   "May be harmless"
>             CArrayAccessor >> #long32At:         "Why is this needed?"
>             CArrayAccessor >> #long32At:put:      "Why is this needed?"
>                
>
>
>         I am just guessing here, but I think that BitBltSimulator
>         expects to
>         be used with an interpreter simulator, so perhaps if you
>         initialize it
>         with a simulator there will be no need to add these methods.
>
>          sim := BitBltSimulator new setInterpreter:
>         InterpreterSimulator new
>
>         Dave
>          
>
>
>     Given that BitBltSimulation calls #isIntegerObject: it looks like
>     the ivar interpreterProxy should hold an InterpreterProxy (as it
>     already does) and not an InterpreterSimulator. I did not add my
>     patch to make simulation work to Mantis, as I'm not sure about them.
>
>
> When simulating the interpreterProxy inst var should hold the 
> InterpreterSimulator, not the proxy.
>  

Maybe it should be an InterpreterSimulator when simulating the whole 
interpreter. When calling #copyBitsSimulated, it is set to an 
InterpreterProxy in #copyBitsFrom: .

Anyway, I'm asking for help on making #copyBitsSimulated work again, 
like it should do when called from BitBltTest. If nobody can help with 
that, I guess I'll open a Mantis issue for this problem, in the hope 
that some day it gets fixed.

>     Andreas, perhaps you (or anyone knowledgeable enough) can try
>     making the bitblt simulator tests included in the Mantis issues
>     work. BTW, I moved these tests to VMMaker, as the current version
>     in trunk does test nothing if VMMaker is not loaded. That's why
>     these old tests didn't catch the problem of BitBltSimulator not
>     working anymore.
>
>     Cheers,
>     Juan Vuletich
>
>

Cheers,
Juan Vuletich