[libre-riscv-dev] [isa-dev] Re: FP transcendentals (trigonometry, root/exp/log) proposal

[Luke Kenneth Casson Leighton]

On Thursday, January 16, 2020, <whygee at f-cpu.org> wrote:

> On 2020-01-16 04:04, lkcl . wrote:



> the time (let alone rounding).  how do you *know* when the rounding (or the
>> last bit of the mantissa) is wrong?
>>
>
> That was my reaction :
> if you *know* your LSB is wrong then you can correct it...


... or can you? this is what i'm fascinated to hear about, mitch.

is there some mathematical way in which the accuracy can be computed yet
the effort not known?

or... oh hold on, are you saying that the exception would be raised (every
time?) then the partially-accurate result would be dropped into Newton
Raphson for (probably only one iteration) to get full accuracy?

l.



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