PATCH: optimized libm single precision routines: erfcf, erff, expf for x86_64.

[Ulrich Drepper]

This time with attachment.

On Wed, Feb 22, 2012 at 10:14, Ulrich Drepper <drepper@gmail.com> wrote:
> On Tue, Feb 21, 2012 at 15:32, Dmitrieva Liubov
> <liubov.dmitrieva@gmail.com> wrote:
>> The updated attached version is significantly hand-tuned assembler code.
>> We are looking forward to accepting and releasing this change.
>
> At least the changes made to the attached version should be made.
> They are small but save another cycle or two.
>
> I don't see why the computation of j has to be that complicated.  6
> bits are taken from the mantissa.  These are then interpreted as a
> signed value.  Why?  I know it works but is there really a reason?
>
> If the bits are considered are unsigned that computation for the
> access of the array DP_T as well as the computation of  n*k are
> simpler (only AND, no shifting and subtracting).  The algo has to be
> adapted but this should be possible.  I think nobody really paid
> attention to that since the DP_T table was too large (it had 65
> entries!).
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