Xi Ruoyao <[email protected]> writes:
> On Mon, 2026-03-09 at 14:41 +0000, Richard Sandiford wrote:
>> As Andrew said in one of the PRs, although the older MIPS ISA specs
>> required inputs to 32-bit instructions to be sign-extended, no MIPS
>> hardware that I know of actually trapped on invalid register inputs. 
>> And almost all MIPS hardware does the obvious thing.  (IIRC, SB-1
>> didn't sign-extend the result if the inputs weren't sign-extended, but
>> I don't remember any others caring either way.)
>
> For 32-bit division with non-sign-extended register input, Loongson
> 3A4000 really produces trashes (for some cases happen to be the non-
> extended result, but completely nonsense for other cases).

Ah, interesting, thanks.  I suppose it makes sense that, if one
operation was going to be affected, it would be division.  Some gates
could be saved by assuming that the inputs are correct...

Richard

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