apps/maze: fix possible stack overflow#2
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ringtailsoftware merged 1 commit intoringtailsoftware:mainfrom Dec 14, 2025
Merged
apps/maze: fix possible stack overflow#2ringtailsoftware merged 1 commit intoringtailsoftware:mainfrom
ringtailsoftware merged 1 commit intoringtailsoftware:mainfrom
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The original code this app is inspired from uses rand(), which returns a number >= 0. mulberry32() on the other hand can return a negative number, in which case will overflow the accesses in the dirs array. Fix that by forcing the result to be unsigned.
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Thank you! I got really confused by this and had assumed it was something weird about the optimiser. |
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I used your maze example to test my very own RISC-V emulator, which for some reason kept crashing when being compiled with anything greater than -O0, and I've spent 3 hours trying to figure out where the bug is — and it is in this code snippet! :)
The original code this app is inspired from, mentioned at the top of the file, uses rand(), which returns a number >= 0.
mulberry32() on the other hand can return a negative number, in which case will overflow the accesses in the dirs array. Apparently this wasn't reproducible unless optimizations were turned on.
I know it's such a small part of your project, but perhaps this'll save some headache to anyone using your examples to test their RISC-V emulators!