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

[Luke Kenneth Casson Leighton]

On Thu, Jan 16, 2020 at 5:59 PM Mitchalsup <mitchalsup at aol.com> wrote:


> ah HA!  ok now it makes sense.  the error analysis is also a mathematical
> function, which can be implemented *in hardware* and the error-quantity
> computed along-side the actual output.
>
> You could do this, but it is easier to simply recognize that with a given
> number of bits of
> "Known accuracy" (which HAS to be at least 3-bits larger than the
> fraction) you need
> to look for 3-patterns that have the potential of spanning a rounding-
> decision-break-point.
>

because only those patterns will round up or down, all others will not, no
matter what happens.
niice.

l.

>