Re: [PATCH v4 6/6] qht: Fix threshold rate calculation

[Peter Maydell]

On Wed, 17 Jun 2020 at 21:59, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> On 6/17/20 1:13 PM, Richard Henderson wrote:
> > -        *threshold = rate * UINT64_MAX;
> > +        *threshold = (rate * 0xffff000000000000ull)
> > +                   + (rate * 0x0000ffffffffffffull);
>
> Well, while this does silence the warning, it produces the exact same results
> as before, since the intermediate double result still only has 53 bits of
> precision.
>
> We're probably be better off with the nextafter(0x1p64, 0.0) form that we've
> used elsewhere.

Yeah, the code does look a bit odd. I'm going to apply this one to master
as well just to suppress all the patchew nagmails, but we should
figure out the correct thing to do here.

thanks
-- PMM