Re: Mips handling of signed integer overflows

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On Mon, Jul 22, 2024 at 03:59:00PM +0100, Maciej W. Rozycki wrote:
> On Mon, 22 Jul 2024, Lukas Wunner wrote:
> > I assume this means that the compiler uses non-trapping instructions
> > for addition/subtraction on Mips.  Consequently, calling die_if_kernel()
> > from do_ov() in arch/mips/kernel/traps.c should no longer be necessary
> > as it can never happen.
> > 
> > Can you confirm or deny this?
[...]
>  MIPS C compilers have never produced trapping addition/subtraction 
> instructions, which have been reserved for use by other programming 
> languages.  And GCC specifically has never produced these instructions for 
> any of the languages supported, there are no patterns in the MIPS backend 
> defined that would produce these instructions.  The only way to encounter 
> one of them in the execution stream is by means of handcoded assembly.
[...]
>  Did I answer your question?

Yes thank you this helps greatly.

Lukas




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