[U-Boot] Illegal use of FP ops in clock_ti814x.c

Tom Rini
2013-10-29T12:23:07Z

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On 10/29/2013 06:48 AM, Wolfgang Denk wrote:
> Dear M?ns Rullg?rd,
>
> In message <yw1x8uxc28y9.fsf@unicorn.mansr.com> you wrote:
>>
>>>> Something like this should be equivalent. That said, it
>>>> looks suspiciously like it's meant to simply do a division
>>>> and round up. If that is the case, +225 should be +249. It
>>>> probably makes no difference for the values actually
>>>> encountered.
>>>
>>> Umm... this is the part which I do not understand.
>>>
>>> The original code adds 90%; you add 90%, too. However, to
>>> round up, one usually adds only 50% ?
>>
>> Adding 50% would round to nearest. For integer division to round
>> up, you must add one less than the divisor.
>
> Agreed. But do we want to round up? The original code used +90%,
> which is something else, too...

And I imagine it's unlikely the original author of the code is around
anymore, or recalls exactly why. I'm pretty sure Matt just lifted the
code from the vendor tree and since it wasn't throwing warnings didn't
notice the floating point part.

>>> Where are these 90% coming from? Are they in any way
>>> meaningful, or even critical?
>>
>> My guess is that it was someone's approximation of 249 / 250. I
>> don't know the hardware, so it's conceivable that it really
>> should be this way, although it seems unlikely.
>
> Are you able to test such a modificationon actual hardware?

I suspect Matt can, after Linaro Connect. I don't have one of these
platforms handy but I think he still does.

- --
Tom
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