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

Juan Vuletich juan at jvuletich.org
Fri Oct 30 13:14:52 UTC 2009

David T. Lewis wrote:
> On Mon, Oct 26, 2009 at 11:57:16AM -0700, Eliot Miranda wrote:
>> On Mon, Oct 26, 2009 at 11:07 AM, Juan Vuletich <juan at jvuletich.org> wrote:
>>> 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.
>> Well with my current VM I see no problems; all 10 tests are green.  What is
>> the bug that you see?  How can I reproduce it?
> Juan provided six new tests (see Mantis 7047) that document the problems.
> I added these six tests to the trunk today, and also updated VMMaker on
> SqueakSource with Juan's fixes for bitblt simulation (mainly some memory
> access methods that had apparently been overlooked during the original
> Squeak 64 bit work).
> Juan's patches (VMMaker-BitBlt-AlphaFixes-jmv-M7407.cs on Mantis 7047)
> do resolve the problems in the VM, and the changes all look correct to me
> (but I have no experience with bitblt, so I'm just commenting on the fixes
> for type declarations and arithmetic overflow). 
> Has anyone else had a chance to review this? If there are no issues or
> concerns, I will add Juan's alpha fixes to VMMaker.
> Dave

Good. Thanks!

Juan Vuletich

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