[squeak-dev] [Vm-dev] Bug in PolygonMorph>>#filledForm

Eliot Miranda eliot.miranda at gmail.com
Sun Feb 23 17:07:52 UTC 2020



> On Feb 22, 2020, at 4:48 PM, tim Rowledge <tim at rowledge.org> wrote:
> 
> 
> Well, that's interesting. The bug is different on a Raspberry Pi (I was hoping non-existent) because the bitblt code is quite different as a result of the Pi Foundation paying to get much faster ARM assembler blt code written.
> <Screen Shot 2020-02-22 at 4.46.32 PM.png>
> Same sort of pattern but not identical. Sigh. This will be 'fun' to investigate.

It would be great if the ARM fast bit of work could be refactored to affect inner loops and hence avoid duplicating the set up code.

I *think* the bug Nicolas fixed is a regression caused by me fixing a different bug, the code reading an extra word off the end of the bitmap in some circumstances (which caused a seg fault if the bitmap was at the end of a memory mapping).  It’s quite likely that that bug is in the ARM fast blt code if it does its own set up.

> 
> 
> tim
> --
> tim Rowledge; tim at rowledge.org; http://www.rowledge.org/tim
> Strange OpCodes: NBR: Unconditional No BRanch
> 
> 
> 
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