[PATCH v3] netbsd: Stop depending upon nonstandard __WORDSIZE

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On 2015-12-17 14:50, Andrey Semashev wrote:
> On 2015-12-17 02:44, Kamil Rytarowski wrote:
>>
>> On 16.12.2015 11:02, Pali Rohár wrote:
>>>
>>> Hi! There is probably no portable way for checking CPU type. But
>>> you do not need to know CPU type here. You need to know if CPU has
>>> fast 64bit numeric operations (and use 64bit speed optimization),
>>> right?
>>>
>>> And this could be possible by checking size of int_fast32_t type
>>> (defined in stdint.h). If is same as size of int_fast64_t type then
>>> you could use 64bit optimization otherwise not (= 32bit integers
>>> are faster then 64bit).
>>>
>>> But I will let this suggestion for reviewing of other people.
>>
>> This sounds like a good way to go.
>
> I don't think it does. int_fast32_t does not have to be 64-bit if 32-bit
> integers are fast. It _may_ be larger than 32-bit if 32-bit integers are
> slow (most likely - do not have the target hardware support). I don't
> think this is the case for x32 or x86_64.
>
> If integer performance is what this preprocessor check influences, I'd
> suggest checking the size of size_t. Or testing for particular
> architectures explicitly, with 64-bit being the default and 32-bit only
> for the tested architectures (this would probably make the code more
> easily maintainable in the future).

I've sent this privately in error.

Also, it seems size_t is 32-bit on x32, so disregard that suggestion.




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