In LoongArch ABI spec, we can see that in the LP64D ABI, unsigned 32-bit
types, such as unsigned int, are stored in general-purpose registers as
proper sign extensions of their 32-bit values.
Reference:
https://loongson.github.io/LoongArch-Documentation/LoongArch-ELF-ABI-EN.html#_abi_lp64d
The comment should be tweaked accordingly too.