Re: [PATCH 1/2] cpu: use ROUND_UP() to define xxx_PAGE_ALIGN

[Wei Yang]

On Sun, Oct 13, 2019 at 07:38:04PM -0700, Richard Henderson wrote:
>On 10/13/19 6:01 PM, Wei Yang wrote:
>>> No, please.
>>>
>>> (1) The compiler does not know that qemu_*host_page_size is a power of 2, 
>>> and
>>> will generate a real division at runtime.  The same is true for
>>> TARGET_PAGE_SIZE when TARGET_PAGE_BITS_VARY.
>>>
>> 
>> Confused
>> 
>> The definition of ROUND_UP is:
>> 
>> #define ROUND_UP(n, d) (((n) + (d) - 1) & -(0 ? (n) : (d)))
>
>Ah, my bad, I did confuse this with QEMU_ALIGN_UP.
>
>Hmm.
>
>       lea     -1(n, size), t
>       neg     size
>       and     size, t
>
>vs
>
>       mov     mask, t
>       not     t
>       add     n, t
>       and     mask, t
>
>which is what I proposed here
>
>>> https://lists.gnu.org/archive/html/qemu-devel/2019-09/msg04526.html
>
>I'm ok with your version.
>
>Reviewed-by: Richard Henderson <address@hidden>
>

Thanks for your clarification.

Have a nice day

>
>r~
>

-- 
Wei Yang
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